I - * I I -v - L I U L V U - - . - - - - -

Environmental Protection Laboratory September 1978 AeencY Cincinnati OH 45268

Research and Development

Vibratory Spiral Blancher-Cooler

RESEARCH REPORTING SERIES

Research reports of the Off ice of Research and Development, U S Environmental . Protection Agency have been grouped into nine series These nine broad cate- gories were established to facilitate further development and application of en- vironmental technology Elimination of traditional grouping was consciously planned to foster technology transfer and a maximum interface in related fields The nine series are

Environmental Health Effects Research E nv i ron in e i i t a I Pro!e c t i on Te c t i no I og y Ecological Research Environmental Monitoring Soc ioe con0 m i c E nv i ro n menta I Stud i es Scientific and Technical Assessment Reports (STAR) Interagency Energy-Environment Research and Development ' Special Reports Miscellaneous Reports

This report has been assigned to the ENVIRONMENTAL PROTECTION TECH- NOLOGY series This series describes research performed to develop and dem- onstrate instrumentation, eqdipment and methodology to repair or prevent en- vironmental degradation from point and non-point sources of pollution This work provides the new or improved technology required for the control and treatment of pollution sources to meet environmental quality standards

Tt-is dol,iir1ient i s available to tne liLiblic :r-iough the National Technical Informa- tion Service Springfield Virginia 221 61

EPA-60012-78-206 September 1978

VIBRATORY SPIRAL BLANCHER-COOLER

John L. Bomben, J. S . Hudson, W. C. D i e t r i c h , E. L. Durkee, D. F. Farkas

U. S. Department of Agr i cu l tu re , Berkeley, C a l i f o r n i a 94710 Western Regional Research Center , Science and Educat ion Adminis t ra t ion ,

and

Richard Rand, J. W. Farquhar American Frozen Food I n s t i t u t e

McLean, V i r g i n i a 22101

Grant No. S-803312

P r o j e c t O f f i c e r

Harold W. Thompson Food and Wood Products Branch

I n d u s t r i a l Environmental Research Laboratory C o r v a l l i s F i e l d S t a t i o n

C o r v a l l i s , Oregon 97330

INDUSTRIAL ENVIRONMENTAL RESEARCH LABORATORY OFFICE OF RESEARCH AND DEVELOPMENT

U. S. ENVIRONMENTAL PROTECTION AGENCY C I N C I N N A T I , OHIO 45268

DISCLAIMER

This report has been reviewed by the Industrial Environmental Research Laboratory, U. S . Environmental Protection Agency, and approved for publica- tion. Approval does not signify that the contents necessarily reflect the view and policies of the U. S . Environmental Protection Agency, nor does mention of trade names or commercial products constitute endorsement or recommendation for use.

ii

FOREWORD

When energy and material r e sources are e x t r a c t e d , p rocessed , conver ted , and used, t h e r e l a t e d p o l l u t i o n a l impacts on our environment and even on our h e a l t h o f t e n r e q u i r e t h a t new and i n c r e a s i n g l y more e f f i c i e n t p o l l u t i o n c o n t r o l methods be used. The I n d u s t r i a l Environmental Research Laboratory- C inc inna t i (IERL-Ci) assists i n developing and demonstrat ing new and i m - proved methodologies t h a t w i l l m e e t t h e s e needs both e f f i c i e n t l y and econo- mica l ly .

This r e p o r t p r e s e n t s t h e r e s u l t s of a two yea r e v a l u a t i o n of a unique vege tab le b lanching and cool ing system. Study r e s u l t s i n d i c a t e t h a t t h e v l b r a t o r y s p i r a l blancher-cooler w i l l s i g n i f i c a n t l y reduce the was te loads and energy consumption a s s o c i a t e d wi th t h e s e u n i t p rocesses . should b e of in terest t o p rocesso r s of f rozen and canned vege tab le s , food process r e s e a r c h e r s , and manufacturers of equipment f o r t h e u s e r i n d u s t r i e s . Fu r the r in format ion on the p r o j e c t can b e ob ta ined by con tac t ing t h e Food and Wood Products Branch, I n d u s t r i a l P o l l u t i o n Cont ro l D iv i s ion , IERL-Ci .

Study r e s u l t s

David G. Stephan D i r e c t o r

I n d u s t r i a l Environmental Research Laboratory C i n c i n n a t i

iii

ABSTRACT

The o b j e c t i v e of t h i s demonstration p r o j e c t w a s t o test t h e commercial f e a s i b i l i t y of t h e v i b r a t o r y s p i r a l b lancher -cooler , a newly designed steam blancher and a i r c o o l e r that previous small scale tes ts showed could reduce t h e wasteload and energy consumption of p repa r ing v e g e t a b l e s f o r f r eez ing .

A pro to type v i b r a t o r y s p i r a l blancher-cooler w a s designed and con- s t r u c t e d . p rocess ing seasons. c e s s i n g seasons ; a few b r i e f exper imenta l runs wi th b r u s s e l s s p r o u t s , c a u l i f l o w e r and b r o c c o l i were done dur ing one season.

This u n i t was i n s t a l l e d a t a vege tab le f r e e z i n g p l a n t f o r two Snap beans and l i m a beans were t e s t e d f o r both pro-

The r e s u l t s of t h e s e pro to type tests showed t h e fo l lowing:

1. The u n i t reduced t h e h y d r a u l i c wasteload of conven t iona l blanching and cool ing by s e v e r a l o r d e r s of magnitude and t h e o r g a n i c waste- load by as much as 80%.

2. The steam e f f i c i e n c y of t h e b lancher was 85%, which exceeds by 1 7 times t h a t measured f o r a convent iona l steam blancher .

3. The v i b r a t o r y s p i r a l blancher-cooler processed over 2000 kg/hr of snap beans and over 1200 kg /h r of l i m a beans. m o d i f i c a t i o n would be r e q u i r e d t o ach ieve f u l l c a p a c i t y wi th b r o c c o l i , b r u s s e l s s p r o u t s , and c a u l i f l o w e r .

Minor equipment

4. It was e a s y t o c l e a n a f t e r use. m i c r o b i a l counts f a r below t h e accepted p r a c t i c e i n vege tab le f r e e z i n g p l a n t s .

Product l e a v i n g t h e c o o l e r had

5. Sensory tests were done on ly w i t h t h e snap-beans and l i m a beans. Those samples produced by t h e v i b r a t o r y s p i r a l blancher-cooler were judged e i t h e r equal o r s u p e r i o r i n f l a v o r and t e x t u r e t o t h o s e conven t iona l ly blanched and cooled.

6 . Although t h e o p e r a t i n g c o s t s of t h e v i b r a t o r y s p i r a l blancher- c o o l e r were h ighe r t han t h o s e of a conven t iona l water b lancher and a flume c o o l e r , a doubling of t h e combined c o s t s of u t i l i t i e s and waste t rea tment would make t h e o p e r a t i n g c o s t s of t h e two equal .

This r e p o r t was submitted i n f u l f i l l m e n t of Grant No. S-803312 by t h e American Frozen Food I n s t i t u t e under t h e par t ia l sponsor sh ip of t h e U. S. Environmental P r o t e c t i o n Agency. Work was conducted by t h e U. S.

i v

Department of Agr i cu l tu re Western Regional Research Center under c o n t r a c t t o t h e American Frozen Food I n s t i t u t e . This r e p o r t covers t h e per iod J u l y 15, 1974 t o January 1 7 , 1977.

V

CONTENTS

Forword . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iii Abs t r ac t . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . i v F igures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . v i i Tables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . v i i i Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . . . . i x

1 . I n t r o d u c t i o n . . . . . . . . . . . . . . . . . . . . . . . . . 1 2 . Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . 3 3 . Recommendations . . . . . . . . . . . . . . . . . . . . . . . . 4 4 . Experimental Procedures . . . . . . . . . . . . . . . . . . . . 5

Pro to type Design . . . . . . . . . . . . . . . . . . . . . 5

Measurements . . . . . . . . . . . . . . . . . . . . . . 12 P i l o t P l a n t Operating Conditions . . . . . . . . . . . . . 1 4

5 . R e s u l t s and Discuss ion . . . . . . . . . . . . . . . . . . . . 22

P i l o t P l a n t Operating Procedures and Product ion Line

Analys is of Pro to type Design and Opera t ions . . . . . . . 23 Material Balances and Wasteloads . . . . . . . . . . . . . 27 Product Qua l i ty . . . . . . . . . . . . . . . . . . . . . 30 E f f l u e n t Generation and Steam Consumption of Blanchers . . 36 Cost E s t i m a t e s . . . . . . . . . . . . . . . . . . . . . . 38

References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44 Appendix . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46

v i i

FIGURES

Number Page

1 Schematic diagram of v i b r a t o r y s p i r a l blancher-cooler . . . . . . . 6

2 Drawing of v i b r a t o r y s p i r a l blancher-cooler w i th c o o l e r i n up-flow o p e r a t i o n . . . . . . . . . . . . . . . . . . . . . . 7

3 Photograph of v i b r a t o r y s p i r a l blancher-cooler w i th c o o l e r i n up-flow o p e r a t i o n . . . . . . . . . . . . . . . . . . . . . . 8

4. Drawing of v i b r a t o r y s p i r a l blancher-cooler w i t h c o o l e r i n down-flow o p e r a t i o n . . . . . . . . . . . . . . . . . . . . . 9

5 Photograph of v i b r a t o r y s p i r a l blancher-cooler w i t h c o o l e r i n down-flow o p e r a t i o n . . . . . . . . . . . . . . . . . . . . . 10

6 A i r v e l o c i t y d i s t r i b u t i o n over c o o l e r s p i r a l conveyor . . . . . . . 26

v i i i

TABLES

Number Page

1 Operat ing Condit ions f o r Snap Beans . . . . . . . . . . . . . . . . 15

2 Operat ing Condit ions f o r Lima Beans . . . . . . . . . . . . . . . . 18

3 Operat ing Condit ions f o r Brusse l s Sprouts . Caul i f lower and Broccol i . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

4 Yield . So l ids Loss and Liquid Wasteload f o r Snap Beans . . . . . . 28

5

6

7

8

9

10

11

12

13

14

1 5

Yield. So l ids Loss and Liquid Wasteload f o r Lima Beans . . . . . . 29

Yield . S o l i d s Loss and Liquid Wasteload f o r Brusse l s Sprouts . Caul i f lower and Broccol i . . . . . . . . . . . . . . . . . . . . 30

Means of Yie lds . S o l i d s Losses and Liquid Wasteloads wi th 95% Confidence L i m i t s . . . . . . . . . . . . . . . . . . . . . . . . 31

T o t a l Aerobic P l a t e Counts on Vegetables Leaving Cooler . . . . . . 32

Sensory Evalua t ion of Snap Beans and Lima Beans by Duo-Trio T e s t . . 33

Chemical Analyses of Vegetables . . . . . . . . . . . . . . . . . . 35

Wasteloads Produced by D i f f e r e n t Blanching Techniques . . . . . . . 37

Energy Use i n Blanching . . . . . . . . . . . . . . . . . . . . . . 38

C a p i t a l Investment f o r Blanchers and Coolers . . . . . . . . . . . 39

Cost of Blanching and Cooling f o r Freezing . . . . . . . . . . . . 41

Cost of Blanching Without Cooling f o r Vibra tory S p i r a l Blancher and Water Blancher . . . . . . . . . . . . . . . . . . . . . . . 43

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F

ACKNOWLEDGMENTS

The a u t h o r s wish t o express t h e i r a p p r e c i a t i o n t o Harold Thompson, EPA P r o j e c t O f f i c e r , f o r h i s guidance on t h i s p r o j e c t . I n a d d i t i o n , w e would l i k e t o thank personnel of t h e American Frozen Food Ins t i tu te - -Joanne Cox, E l a i n e Carter, Jean Bohannon and Ray McHenry--who provided a d m i n i s t r a t i v e he lp . John Swartz, Chr is Drasbek, Anne Whitney and J o e l Weaver, temporary employees of t h e American Frozen Food I n s t i t u t e , se rved as t e c h n i c i a n s i n s e t t i n g up and t e s t i n g t h e p i l o t p l a n t . n e l of P a t t e r s o n Frozen Foods and Tom Rumsey of t h e Western Regional Research Center who provided p e r i o d i c a s s i s t a n c e f o r t h i s p r o j e c t . cons t ruc t ed by the Vibra t ing Equipment Div i s ion of t h e Rexnord Corporat ion.

We a l s o wish t o thank those person-

The equipment w a s

X

SECTION 1

INTRODUCTION

A major conclus ion of r e p o r t s on t h e wasteload of v e g e t a b l e processing i s t h a t t h e blanching o p e r a t i o n produces a l a r g e percentage of a v e g e t a b l e processing p l a n t ' s wasteload (Weckel, e t a l . , 1968; NCA, 1971; R a l l s and Mercer, 1973; Soderquis t , 1975). The work presented i n t h i s r e p o r t d e s c r i b e s a technique t h a t reduces t h e wasteload from both blanching and t h e subsequent cool ing of vege tab les . sav ings i n t h e use of steam and wi th a des ign r e q u i r i n g less f l o o r space t h a n a convent iona l steam blancher .

It accomplishes t h i s waste r e d u c t i o n wi th a l a r g e

-The pro to type v i b r a t o r y s p i r a l blancher-cooler , whose des ign and perform- ance i s descr ibed h e r e , i s a demonstrat ion of a series of developments of t h e work done a t t h e Western Regional Research Center on steam blanching and cool ing of v e g e t a b l e s before f r e e z i n g (Brown, e t a l . , 1974; Bomben, e t a l . , 1975). Each of t h e s e developments was t e s t e d a t t h e Western Regional Research Center t o t h e s m a l l p i l o t p l a n t s t age . The pro to type v i b r a t o r y s p i r a l blancher-cooler p i l o t p l a n t incorpora ted a l l of t h e s e developments, and i t w a s of adequate c a p a c i t y t o demonstrate t h e s u i t a b i l i t y of t h e s e concepts f o r use i n t h e commercial processing of f r o z e n vegetab les .

The use of v i b r a t o r y conveyors f o r steam blanching w a s developed t o reduce t h e s i z e and improve t h e h e a t e f f i c i e n c y of steam blanchers (Brown, e t a l . , 1974). The s p i r a l v i b r a t o r y conveyor allowed f o r a more compact des ign than d i d t h e convent ional b e l t conveyor i n steam blanchers . I n comparison t o water b lanchers , steam blanchers are l a r g e and have a low thermal e f f i c i e n c y . The lower wasteload of steam blanching as compared t o water blanching ( R a l l s and Mercer, 1973; Lund, 1974) has n o t been s u f f i c i e n t f o r most processors t o j u s t i f y i t s use i n p l a c e of water blanching. thermal e f f i c i e n c y of b lanchers has n o t been a s u b j e c t of much i n t e r e s t u n t i l t h e r e c e n t concern about t h e c o s t and a v a i l a b i l i t y of energy sources .

The

Using steam blancher condensate as a s p r a y dur ing a i r cool ing w a s a n o t h e r development incorpora ted i n t o t h e v i b r a t o r y s p i r a l blancher-cooler.. This technique reduced t h e wasteload of bo th blanching and c o o l i n g (Bomben, e t a l . , 1975). By us ing a i r i n s t e a d of flume c o o l i n g , t h e h y d r a u l i c waste- load of c o o l i n g w a s reduced enormously, and t h e o r g a n i c wasteload produced by t h e leaching of s o l i d s i n t h e flume w a s e l imina ted . By us ing t h e steam blancher condensate a s a s p r a y dur ing a i r c o o l i n g , t h e wasteload of both blanching and cool ing w a s reduced t o t h e unevaporated and unabsorbed l i q u i d l e a v i n g t h e cooler .

The technique of I n d i v i d u a l Quick Blanching (IQB) w a s inc luded i n t h e v i b r a t o r y s p i r a l blancher-cooler s i n c e i t gave an a d d i t i o n a l means of

1

reducing t h e s i z e of t h e blancher (Lazar , e t a l . , 1971). The h e a t i n g and holding technique i n a d d i t i o n provided uniform blanching of vege tab les .

The pro to type v i b r a t o r y s p i r a l blancher-cooler w a s i n s t a l l e d and t e s t e d a t a f r o z e n vegetab le p l a n t ( P a t t e r s o n Frozen Foods, P a t t e r s o n , C a l i f o r n i a ) from August, 1975 t o January, 1977. Snap beans and l i m a beans were t e s t e d dur ing two process ing seasons. A few b r i e f runs were made w i t h b r u s s e l s s p r o u t s , c a u l i f l o w e r and b r o c c o l i during t h e second process ing season. Although t h e tests descr ibed i n t h i s r e p o r t apply t o f r o z e n v e g e t a b l e s , t h e blancher (without t h e c o o l e r ) could be used i n t h e v e g e t a b l e canning i n d u s t r y .

.

2

SECTION 2

CONCLUSIONS

The v i b r a t o r y s p i r a l blancher-cooler w a s a b l e t o b lanch and cool vege-

Snap beans were blanched a t over 2000 kg /h r and l i m a beans were t a b l e s a t a ra te f a r exceeding i t s des ign c a p a c i t y of 900 kg /h r f o r snap beans. blanched a t 1200 kg/hr . ach ieve f u l l c a p a c i t y f o r b r o c c o l i , b r u s s e l s s p r o u t s and cau l i f lower . The v i b r a t o r y c o o l e r w a s opera ted i n two d i f f e r e n t modes; vege tab le s were e i t h e r conveyed up o r down. Higher c a p a c i t i e s were achieved wi th vege tab le flowing down t h e c o o l e r . With product moving down t h e coo l ing v i b r a t o r y s p i r a l , snap beans, l i m a beans, b r u s s e l s s p r o u t s , c a u l i f l o w e r and b r o c c o l i could a l l be processed. With product moving up t h e coo l ing s p i r a l c o n s i s t e n t product flow could be achieved only wi th snap beans.

P lodi f ica t ion of t h e equipment would b e r e q u i r e d t o

The wasteload produced by t h e v i b r a t o r y s p i r a l blancher-cooler ( 1 L/kkg) and 0.9 kg BOD/kkg l i m a beans) was much less than t h a t produced by conven- t i o n a l blanching and cool ing (1000 L/kkg and 4.4 kg BOD/kkg l i m a beans). The steam e f f i c i e n c y of t h e v i b r a t o r y s p i r a l b lancher (85%) was much h ighe r than t h a t measured on a product ion l i n e steam blancher (5%) and those r epor t ed f o r o t h e r b lanchers ( 2 7 - 60%).

Sensory tests of snap beans and l i m a beans produced by t h e v i b r a t o r y s p i r a l blancher-cooler showed them t o be e i t h e r b e t t e r o r t h e same i n f l a v o r and t e x t u r e as those produced i n a convent iona l b lancher on t h e product ion l i n e . v i b r a t o r y s p i r a l coo le r were cons ide rab ly lower than t h e l i m i t s accepted by s a n i t a r y practice i n t h e vege tab le f r e e z i n g i n d u s t r y .

T o t a l a e r o b i c counts made on snap beans and l i m a beans l e a v i n g t h e

The low c a p i t a l investment r equ i r ed by water b lanching makes i t s c o s t s i g n i f i c a n t l y less t h a n o t h e r blanching techniques . A doubling of t h e combined cos t of energy and wastewater t r ea tmen t would make t h e c o s t of blanching and coo l ing wi th t h e v i b r a t o r y s p i r a l blancher-cooler e q u a l t o t h a t of a water b lancher and flume coo le r . When comparing blanching a lone (wi thout c o o l i n g ) , water blanching remained t h e lowes t c o s t method, bu t a g a i n , doubling of t h e combined cos t of energy and wastewater t r ea tmen t would make t h e c o s t of t h e v i b r a t o r y s p i r a l b lancher equa l . The c o s t of blanching wi th t h e v i b r a t o r y s p i r a l blancher was less than t h a t of e i t h e r t h e h y d r o s t a t i c steam blancher o r hot-gas b lancher .

3

S E C T I O N 3

RECOMMENDAT I O N S

Since t h e v i b r a t o r y s p i r a l blancher-cooler t e s t e d i n t h i s p r o j e c t w a s l a r g e enough t o be r e p r e s e n t a t i v e of a t y p i c a l f u l l - s c a l e product ion u n i t , t h e r e i s no need t o test t h e d e s i g n on a l a r g e r scale. Sca le up t o a l a r g e r s i z e can be r e a d i l y accomplished; designs w i t h c a p a c i t i e s 5 and 10 times t h a t of t h e p i l o t p l a n t are a v a i l a b l e from the manufacturer of t h e p i l o t p l a n t . i n s t a l l a t i o n of a f u l l - s i z e v i b r a t o r y s p i r a l blancher-cooler u t i l i z e the p i l o t p l a n t c o n s t r u c t e d under t h i s p r o j e c t t o o b t a i n des ign and product ion d a t a f o r i t s p a r t i c u l a r use.

However, i t i s recommended t h a t any p r i v a t e company cons ider ing t h e

Although t h e r e s u l t s of t h e p r o j e c t i n d i c a t e t h a t b r o c c o l i , b r u s s e l s s p r o u t s and c a u l i f l o w e r can be processed w i t h t h i s equipment, f u l l c a p a c i t y f o r t hese v e g e t a b l e s would r e q u i r e an i n c r e a s e i n t h e s i z e of t h e holder and, i n t h e case of b r o c c o l i , an increase i n t h e s i z e s of t h e i n l e t and d ischarge c ross -sec t ions . Before a f u l l s i z e u n i t f o r t h e s e v e g e t a b l e s can be designed, t h e exact dimensions of t h e s e changes need t o be determined by t e s t i n g t h e v e g e t a b l e s on a modified prototype.

A l l t h e work done i n t h i s p r o j e c t was aimed a t prepar ing v e g e t a b l e s f o r f r e e z i n g , and hence cool ing w a s always used. I n blanching f o r canning, cool ing i s a n unnecessary s t e p , but t h e advantages of compactness and h igh stean e f f i c i e n c y f o r t h e v i b r a t o r y s p i r a l blancher s t i l l have a p p l i c a b i l i t y f o r canning. I n a d d i t i o n , blanching e f f l u e n t could be e n t i r e l y e l i m i n a t e d i f i t were s u i t a b l e f o r use as a b r i n e f o r canning vegetab les . Thus, i t i s recommended that t h e v i b r a t o r y s p i r a l blancher be t e s t e d i n a v e g e t a b l e canning p l a n t and that t h e use o f t h e blancher condensate as a canning b r i n e be eva lua ted .

4

3

SECTION 4

EXPERIMENTAL PROCEDURES

Pro to type Design

The pro to type p i l o t p l a n t , which i s shown schemat i ca l ly i n F igure 1, w a s designed wi th a 0.91 f k g / h r (one ton per hour) c a p a c i t y based on a con- 2 3 veyor l o a ing of 4.9 kg/m (one pound/ft ), and a bulk d e n s i t y of 641 kg/m (40 l b / f t ) f o r t he vege tab le s . The equipment w a s c o n s t r u c t e d using a s t an - dard des ign f o r v i b r a t o r y s p i r a l conveyors. The p i l o t p l a n t occupied a f l o o r area of 3.7 by 3.2 m (12 f t by 10-1/2 f t ) and i t had a sh ipping weight of 8.6 kkg (19000 l b s ) .

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The p i l o t p l a n t w a s opera ted i n two d i f f e r e n t modes. F igures 2 and 3 show t h e p i l o t p l a n t as i t was ope ra t ed dur ing t h e 1975 vege tab le process ing season wi th product moving up t h e coo l ing s p i r a l . p i l o t p l a n t a s i t was ope ra t ed dur ing t h e 1976 season wi th product moving down the coo l ing s p i r a l . The movement of product up t h e coo l ing s p i r a l gave a des ign of less h e i g h t , 4.2 m (13 f t - 11 i n . ) , ve r sus t h a t , 6.1 m (19 f t - 11 i n . ) , f o r product movement down the coo l ing s p i r a l . The down-flow ar range- ment w a s necessa ry s i n c e t h e v i b r a t i o n could n o t move some vege tab le s upward.

F igu res 4 and 5 show t h e

The p i l o t p l a n t c o n s i s t e d of s i x u n i t s : f e e d e r , h e a t e r , h o l d e r , c o o l e r , a i r blower wi th f i l t e r , and condensate sp ray system. These u n i t s are ind ica - t e d i n F igure 1, and they are shown i n more d e t a i l i n F igu res 2, 3 , 4 and 5.

For o p e r a t i o n wi th t h e up-flow c o o l e r , t h e f eede r -e l eva to r c o n s i s t e d of an i n c l i n e d , c l e a t e d f3 .8 cm; 1-1/2 i n . ) rubber b e l t conveyor 30.5 cm wide by 7.6 m long (12 in . by 25 f t ) , a 746 W ( 1 hp.) v a r i a b l e speed d r i v e and a 1 .4 m (50 f t ) f eed bin. For o p e r a t i o n wi th t h e down- low co l e r , t h e above f eede r w a s used as an e l e v a t o r t o the feed b in (0.057 m ; 2 f t ) of a smaller i n c l i n e d , c l e a t e d (3.8 cm; 1-1/2 i n . ) b e l t conveyor 20.3 c m wide by 3.0 m long (8 i n . by 10 f t ) d r iven by a 746 W ( 1 hp) v a r i a b l e speed e l e c t r i c a l d r i v e .

5 s 3 3

The h e a t e r w a s a v i b r a t o r y s p i r a l enc losed i n a double w a l l i n s u l a t e d [2.5 cm (1 in . ) a i r spac ing ] housing having one access door (F igures 3 and 4 ) . A t t h e bottom of t h e housing t h e r e w a s a 5.1 cm ( 2 i n . ) diameter d r a i n f o r condensate from t h e i n s i d e w a l l s . The s p i r a l coriveyor, c o n s i s t i n g of t h r e e 30.3 cm (11-15/16 i n . ) wide f l i g h t s , had a 30.5 cm (12 i n . ) p i t c h . Steam w a s d i s t r i b u t e d through t h e c e n t r a l t u b e , which had twelve 1.9 cm (3/4 i n . ) h o l e s 76.2 cm (30 i n . ) a p a r t and 7.6 cm ( 3 i n . ) above each f l i g h t of t h e s p i r a l conveying s u r f a c e . The s p i r a l and housing were made of s t a i n - less steel (Type 304, No. 2B f i n i s h on s p i r a l and No. 3 f i n i s h on housing).

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A t STEAM

RAW VEGETABL ,E

FEEDER

I

A N D HOLDER

A I R + r’ , COOLER

CONDENSATE SPRAY S Y S T E M

& COOLED VEGETABLES

Figure 1. Schematic diagram of v i b r a t o r y s p i r a l blancher-cooler .

I - 0.991 m I 1.68m I , 0.991 m

. - -

E x a'

-- . I ,

P --

I I I

I

1 J-- I I

F igure 2. Drawing of v i b r a t o r y s p i r a l blancher-cooler w i th coo le r i n up-flow opdra t ion .

7

Figure 3. Photograph of vibratory s p i r a l b lancher -cooler w i t h c o o l e r i n up-flow ope ra t ion .

8

3 . 6 6 m D

-1- F' 0 . 9 9 1 m + 1 . 6 8 m

6.10 m

FEED -

HOLDER

f DISCHARGE

FROM HOLDER

AIR DUCT E-

COOLER 0 D

L'

SCHARGE

- -F igure 4. Drawing of v i b r a t o r y s p i r a l blancher-coo'ler wi th coo le r i n down-flow ope ra t ion .

9

Figure 5. Photograph of v i b r a t o r y s p i r a l blancher-cooler w i th coo le r i n down-flow opera t ion .

10

There were two feed spouts ; one w a s a t t h e beginning of t h e t o p f l i g h t and t h e o t h e r w a s a t t h e beginning of t h e middle f l i g h t . Only t h e t o p feed spout was used i n the experiments desc r ibed i n t h i s r e p o r t . Two 1119 W (1-1/2 hp) e l e c t r i c a l motors (220 V , 900 rpm), which had e c c e n t r i c weights on t h e i r doubly extended s h a f t s and which were mounted a t 45" t o the h o r i z o n t a l , v i b r a t e d t h e s p i r a l a t a frequency of 890 cpm. The d r i v e motor mounting w a s suspended by c a b l e s and s p r i n g s t o i s o l a t e t h e v i b r a t i o n from t h e s t r u c t u r a l framework. The amplitude of v i b r a t i o n could be v a r i e d up t o 9.5 mm (3 /8 in . ) i n t e n s t e p s by s h i f t i n g the p o s i t i o n of t h e e c c e n t r i c weights on the motors. The d i r e c t i o n of v i b r a t i o n moved t h e vege tab le s down t h e h e a t e r s p i r a l , and t h e amplitude of v i b r a t i o n determined t h e i r conveying v e l o c i t y .

The vege tab le s l e a v i n g t h e hea t ing s p i r a l dropped i n t o t h e holder (F igu res 2 and 3 ) , which w a s a h o r i z o n t a l l y v i b r a t i n g conveyor 1.5 m long x 0 . 3 m x 0 . 3 m (5 f t x 1 f t x 1 f t ) enc losed by double w a l l i n s u l a t i o n [2.5 cm (1 i n . ) a i r space] . A t t h e bottom of t h e ho lde r nea r t he feed end t h e r e w a s a 2.5 cm ( 1 in . ) d r a i n f o r t h e condensate produced by t h e vege tab le s i n t h e h e a t e r sp i ra l . A s c r e e n (50% open area, 5 mm diam. h o l e s ) of p e r f o r a t e d s t a i n l e s s s teel w a s i n s t a l l e d over t h e d r a i n t o prevent i t from being plugged by Vegetables. The ho lde r w a s v i b r a t e d a t 890 cpm by a 1119W (1-1/2 hp) e l e c t r i c a l motor (220 V ; 900 rpm) wi th a doubly extended s h a f t on which two series of f o u r e c c e n t r i c weights were mounted. By changing the number of we igh t s , t h e amplitude of v i b r a t i o n could be v a r i e d up t o 6.4 mm (1 /4 i n . ) . In a d d i t i o n , t h e ho lde r motor w a s equipped wi th a t i m e r t h a t c o n t r o l l e d the per iod t h e motor w a s on and o f f t o g e t a d e s i r e d r e s idence t i m e . The v ib ra - t i o n w a s i s o l a t e d from the suppor t ing framework by suspending the holder w i t h c a b l e s and s p r i n g s .

The blanched vege tab le s l eav ing the holder were d ischarged t o the c o o l e r , where t h e v e g e t a b l e s moved up o r down t h e v i b r a t i n g s p i r a l conveyor, depending on t h e mode of ope ra t ion . The c o o l e r s p i r a l conveyor (F igu res 4 and 5 ) had t h e same des ign as t h e one i n t h e h e a t e r except that i t had 6-1/2 f l i g h t s . t h a t i n t h e h e a t e r , and by r o t a t i n g t h e ang le of mounting by 90" t h e product f low could be changed from up-flow t o down-flow. through t h e c e n t r a l t u b e over t h e product th rough twelve 2.5 c m ( 1 i n . ) h o l e s 76.2 cm (30 i n . ) a p a r t and 8.9 cm (3-1/2 i n . ) above each f l i g h t of t h e s p i r a l conveying s u r f a c e . The housing f o r t h e c o o l e r w a s cons t ruc t ed of s t a i n l e s s s teel (Type 304, No. 3 f i n i s h ) . It had two access doors , and i t had a 5.1 cm (2 in . ) d r a i n l ead ing t o an e f f l u e n t c o l l e c t i o n tank.

The d r i v e u n i t f o r t h e c o o l e r was of t h e same des ign as

A i r w a s d i s t r i b u t e d

The blower (Buf fa lo Forge, No. 40 MW) s e d f o r moving a i r over the product i n t h e c o o l e r had a r a t i n g of 150 m /min. (5300 f t /min.) of a i r a t 21°C (70°F) and a p resu re of 15.2 c m (6 i n . ) of water. A f i l t e r (Conti- n e n t a l No. 3P439M Side Access Conopac, 90% e f f i c i e n c y ) was i n s t a l l e d a t t h e i n l e t of t h e blower. A damper on t h e o u t l e t of t h e blower w a s used t o c o n t r o l t he amount of a i r flow.

Y 3

. The condensate sp ray system c o n s i s t e d of a pump (Waukesha S a n i t a r y Pump, No. 10 , c a p a c i t y = 11 L/min.), approximately 4.6 m (15 f t ) of 2.5 c m ( 1 i n . ) diameter s t a i n l e s s s t e e l s a n i t a r y p ipe and f o u r s t a i n l e s s s teel nozz les (Spraying Systems Co., Uni je t Nozzle No. 2503). Condensate w a s sprayed on

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t h e product i n the coo le r a t t h e f i r s t , t h i r d , f i f t h and s i x t h f l i g h t s . The condensate from t h e d r a i n i n t h e ho lde r w a s f i l t e r e d e i t h e r through t h r e e layers of cheesec lo th o r a 100 mesh s t a i n l e s s s teel sc reen t o prevent p a r t i - c l e s from c logging t h e nozz les .

Temperatures a t t he i n l e t and o u t l e t of t h e h e a t e r , ho lde r and coo le r were measured by thermocouples and recorded on a mul t i -poin t temperature r eco rde r . A water manometer measured the p r e s s u r e a t t h e blower, and t h e amount of a i r flow w a s determined from t h e blower performance curve supp l i ed by t h e blower manufac u r e r . A ro tameter [F i sche r -Por t e r , Model No. 10A1152, 100% of scale = 5.6 m /min. (199 scfm) of a i r ] , which had been p rev ious ly c a l i b r a t e d by condensing and weighing t h e steam flowing through i t , w a s used t o measure the flow of steam t o the h e a t e r . Condensate w a s removed from t h e steam supply by pass ing i t through a p u r i f i e r (V. D. Anderson Co., Model LC-150). A p r e s s u r e r e g u l a t o r (Spence Engineering Co., 3 / 4 i n . Type ED) main ta ined a cons t an t p re s su re a t t h e t h r o t t l i n g va lve i n s t a l l e d i n t h e steam l i n e a f t e r t he ro tameter . The r e l a t i v e humidity of t h e a i r a t t h e i n l e t of t h e f i l t e r on t h e blower was measured w i t h an e l e c t r o n i c humidity i n d i c a t o r (Humi-Check, Beckman Ins t ruments ) . A h o t w i r e anemometer (Alnor , Thermo- aneomometer) w a s used t o measure t h e v e l o c i t y p r o f i l e of t h e a i r over t h e product i n the c o o l e r , and a vane anemometer w a s used t o measure the average a i r v e l o c i t y .

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P i l o t P l a n t Opera t ing Procedures and Product ion Line Measurements

Tests on t h e p i l o t p l a n t w i th t h e c o o l e r i n t h e up-flow mode were con- ducted wi th snap bean and l i m a beans dur ing the f a l l of 1975. During t h e summer and f a l l of 1976, snap beans, l i m a beans, b r o c c o l i , b r u s s e l s s p r o u t s and cau l i f lower were t e s t e d wi th t h e coo le r i n the down-flow mode.

R a w vege tab le s f o r t e s t i n g t h e p i l o t p l a n t were c o l l e c t e d i n t o b ins 1.2 m x 1.2 m x 1.2 m ( 4 f t x 4 f t x 4 f t ) from t h e product ion l i n e a t t h e s t a g e where they were ready f o r blanching. a t t h e po in t i n the product ion l i n e a f t e r they had been washed, s o r t e d and c u t . L i m a beans were c o l l e c t e d a f t e r t h e y had been washed and f l o t a t i o n graded i n a 13 - 14% b r i n e s o l u t i o n . Because the f i n a l rod- ree l washers and water-blanchers were s o c l o s e l y connected i n t h e l i m a bean product ion l i n e , i t w a s n o t p o s s i b l e t o c o l l e c t l i m a beans f o r t h e p i l o t p l a n t runs as throughly c leaned and washed a s they were when f e d t o t h e product ion l i n e b lanchers . I n some cases i t w a s necessa ry t o c o l l e c t l i m a beans as t h e y l e f t t h e b r i n e s o r t e r without any subsequent washing; o t h e r t i m e s t h e y could be c o l l e c t e d a f t e r on ly a b r i e f washing fo l lowing the b r i n e s e p a r a t o r . Brusse l s s p r o u t s ( l a r g e s i z e ) , c a u l i f l o w e r ( f l o w e r e t s ) , and b r o c c o l i ( s p e a r s ) were c o l l e c t e d a f t e r trimming and c u t t i n g , but because of t h e p l a n t arrangement, i t w a s not p o s s i b l e t o c o l l e c t them a f t e r washing.

The snap beans were c o l l e c t e d

The t e s t i n g of t h e p i l o t p l a n t c o n s i s t e d of t h r e e k inds of exper imenta l runs : p re l imina ry , ba t ch and continuous. P re l imina ry runs were used t o e s t a b l i s h t h e feed ra te , blanching and cool ing times and t o observe the o p e r a t i n g c h a r a c t e r i s t i c s of t h e p i l o t p l a n t f o r each vege tab le . Batch runs c o n s i s t e d of blanching and cool ing approximately 907 kg (2000 l b s ) of

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r a w v e g e t a b l e s and determining t h e y i e l d of blanched-cooled v e g e t a b l e s , t h e s o l i d s l o s t from t h e raw v e g e t a b l e s and t h e wasteload. In t h e cont inuous r u n s , t h e p i l o t p l a n t w a s opera ted f o r a longer t i m e ( 2 - 5 h r s ) than i n the ba tch runs ; t h e same parameters as i n t h e b a t c h runs were measured, b u t , i n a d d i t i o n , samples were taken f o r m i c r o b i o l o g i c a l a n a l y s i s and sensory evalua- t i o n . A l a b o r s t r i k e a t t h e p l a n t i n t h e l a t e summer and e a r l y f a l l of t h e 1976 season allowed only a s h o r t t i m e t o test b r u s s e l s s p r o u t s , c a u l i f l o w e r and b r o c c o l i ; a s a r e s u l t o n l y pre l iminary runs were p o s s i b l e w i t h t h e s e vege tab les .

The feed ra tes , r e s i d e n c e times i n t h e h e a t e r , h o l d e r and c o o l e r , and the f low rates of steam and a i r were v a r i e d i n t h e pre l iminary runs t o d e t e r - mine s u i t a b l e c o n d i t i o n s f o r processing t h e vege tab les . V e l o c i t i e s on t h e conveyors were measured by bundling approximately 200 g of v e g e t a b l e s i n c h e e s c l o t h and t iming t h e bundle ' s passage on t h e conveyors. With t h e steam t o t h e h e a t e r o f f , p re l iminary runs were a l s o used t o observe t h e product f low on a l l t h e v i b r a t o r y conveyors. With t h e steam t o t h e h e a t e r on , t h e v e g e t a b l e s leav ing t h e c o o l e r were t e s t e d f o r peroxidase ( D i e t r i c h and Neumann, 1968) , and t h e i r temperature was measured. I f t h e peroxidase tes t w a s n e g a t i v e and t h e product temperature was between 27 and 32"C, no f u r t h e r adjustments were made, and a series of b a t c h and cont inuous runs were begun, us ing the c o n d i t i o n s e s t a b l i s h e d i n t h e pre l iminary runs.

For t h e ba tch r u n s , one b i n of r a w v e g e t a b l e s w a s weighed and dumped i n t o t h e feeder -e leva tor . After t h e temperature i n t h e h e a t e r reached approximately 100°C (212"P), t h e v e g e t a b l e s were s t a r t e d through t h e p i l o t p l a n t . Samples (150 g) of raw v e g e t a b l e s and of v e g e t a b l e s l e a v i n g t h e c o o l e r were taken every f i f t e e n minutes. The v e g e t a b l e s l e a v i n g t h e c o o l e r were analyzed f o r peroxidase s e v e r a l times dur ing t h e run. About every f i f t e e n minutes a 500 g sample of product l e a v i n g t h e c o o l e r w a s c o l l e c t e d i n t o a beaker , and t h e bulk temperature w a s measured wi th a d i a l thermometer. A l l t h e v e g e t a b l e s l e a v i n g t h e c o o l e r were c o l l e c t e d from t h e s ta r t of t h e run t o t h e t i m e when v e g e t a b l e s were no longer being d ischarged from t h e holder . The e f f l u e n t was weighed, and t h r e e 500 g samples were taken i n polyethylene b o t t l e s .

For t h e cont inuous r u n s e s s e n t i a l l y t h e same procedure as used i n t h e batch runs w a s r e p e a t e d , except t h a t two t o f o u r b i n s (1.8 - 3.6 kkg) of raw v e g e t a b l e s were processed i n t h e p i l o t p l a n t g i v i n g runs from 2 t o 5.5 hours. Samples (150 g) of raw v e g e t a b l e s and of cooled v e g e t a b l e s , as w e l l as t h e temperature of cooled v e g e t a b l e s , were taken every hour. Every hour , samples (50-100 g f o r t o t a l a e r o b i c count and 1.5 kg f o r sensory e v a l u a t i o n and chemical a n a l y s e s ) were taken of t h e v e g e t a b l e s l e a v i n g t h e cooler . For q u a l i t y comparison, 1.5 kg samples of 'blanched and cooled v e g e t a b l e s from t h e product ion l i n e were a l s o taken every hour dur ing t h e p i l o t p l a n t run. All v e g e t a b l e samples were immediately f r o z e n i n a -23°C s t o r a g e room and t h e n l a t e r t r a n s f e r e d t o a -29°C s t o r a g e room. The f rozen 1.5 kg samples were l a t e r made i n t o s i n g l e composites f o r t h e product ion l i n e and f o r t h e p i l o t p l a n t . The blanched and cooled vegetab les were c o l l e c t e d i n t o b i n s and weighed. The e f f l u e n t was c o l l e c t e d and weighed. I f t h e run produced more t h a n 40L of e f f l u e n t , then t h e e f f l u e n t w a s weighed about every hour , and from t h i s q u a n t i t y a 9 kg composite sample w a s t aken wi th t h e remainder

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being discarded. From t h e e n t i r e c o l l e c t e d e f f l u e n t o r t he composite, t h r e e 500 g samples were taken i n polye thylene b o t t l e s .

A ser ies of a n a l y s e s were done on t h e samples of t h e raw v e g e t a b l e s , blanched and cooled v e g e t a b l e s , and e f f l u e n t . One sample of e f f l u e n t , taken as descr ibed above f o r each r u n , w a s r e f r i g e r a t e d a t 1°C and a suspended s o l i d s (SS) a n a l y s i s (EPA, 1971) was done w i t h i n 24 hours; a n a l y s e s of t o t a l s o l i d s (TS) and t o t a l o rganic carbon (TOC) (EPA, 1971) were done on t h i s r e f r i g e r a t e d sample w i t h i n a week of t h e t i m e of t h e run. Another sample b o t t l e of e f f l u e n t w a s f r o z e n , and a f t e r about one month i t was given t o a water a n a l y s i s l a b o r a t o r y (R. W. Hawksley Co., Richmond, C a l i f o r n i a ) f o r a n a l y s i s of 5 day biochemical oxygen demand (BOD). A s p a r e sample b o t t l e of e f f l u e n t w a s kept f rozen f o r checking any r e s u l t s t h a t were ques t ionable . All v e g e t a b l e samples were taken i n polye thylene bags. The f rozen 150 g samples of r a w and blanched-cooled v e g e t a b l e s were analyzed f o r t o t a l s o l i d s (AOAC, 1965) w i t h i n two months of t h e run. The 50-100 g s a m p l e s taken f o r t o t a l a e r o b i c count were k e p t a t -29°C ( f o r less t h a n one month) u n t i l they were analyzed ( S h a r f , 1966). The v e g e t a b l e composite samples were a l s o s t o r e d a t -29°C; w i t h i n 3 months of t h e sample c o l l e c - t i o g , p a r t (50-100 g ) of t h e composite w a s used f o r a n a l y s i s of peroxidase, a s c o r b i c a c i d and ch lorophyl l conversion ( D i e t r i c h and Neumann, 1968) whi le t h e remainder w a s used f o r sensory e v a l u a t i o n by t h e Duo-Trio tes t (ASTM, 1968).

The o n l y e f f l u e n t and o p e r a t i n g c o n d i t i o n measurements made on t h e product ion l i n e were done on l i m a bean b lanchers and c o o l e r s . i n t he l i m a bean product ion l i n e were water b lanchers of t h e reel conveyor type. flume. Three sets of measurements were made dur ing a seven hour o p e r a t i n g per iod. measured by c o l l e c t i n g and weighing a l l v e g e t a b l e s going i n t o t h e blancher and a l l t h e e f f l u e n t l e a v i n g t h e blancher and c o o l e r f o r s h o r t in te rva ls (0 .25 o r 0.5 min). Samples of raw v e g e t a b l e s (150 g ) , blanched-cooled vege- t a b l e s (150 g ) , and blancher and c o o l e r e f f l u e n t s (500 g) were taken dur ing each measurement. The e f f l u e n t samples were analyzed f o r TS, SS, TOC and BOD, and t h e l i m a beans samples were analyzed f o r TS.

The b lanchers

Cooling was done by e i t h e r a combination of a i r and flume o r o n l y

The feed ra te of v e g e t a b l e s and t h e e f f l u e n t d i s c h a r g e rate were

Steam f low t o a steam blancher on t h e b r o c c o l i p roduct ion l i n e w a s measured dur ing each work s h i f t f o r one week w i t h a n o r f i c e meter and a d i f f e r e n t i a l p ressure r e c o r d e r (Taylor Instrument Co.). The product f low w a s determined from t h e product ion records f o r each s h i f t , and an average steam consumption was c a l c u l a t e d .

P i l o t P l a n t Operat ing Condit ions

T a b l e s 1, 2 and 3 are l i s t s of t h e l e n g t h and type of r u n , f e e d ra te , blanching t i m e ( h e a t i n g and h o l d i n g ) , ho lder tempera tures , steam f low rate and steam consumption, cool ing t i m e , cooled v e g e t a b l e tempera ture , and t h e wet-bulb temperature of t h e cool ing a i r f o r t h e d i f f e r e n t v e g e t a b l e s inves- t i g a t e d . The s e t t i n g of t h e adjustments on t h e v i b r a t o r y conveyors and t h e

14

TABLE 1. OPERATING CONDITIONS FOR SNAP BEANS

Run Veget. Run Feed Heating Holding Holder Steam Cooled Cooling Wet- Steam No.+ Var i e ty Time Rate Time T ime Temp Flow Veget. T i m e bu lb Consumption

(Min) (kg /h r ) (Min) (Min 1 ("C) (kg/hr ) Temp. (Min) Temp (kg/kkg) ("C) ("C)

SB-1P SB-2B SB-3B SB-4P SB -5 P SB-6B SB -7 P SB-8P SB-9P

~n SB-1OP SB-11P SB-12P SB-13P

F

SB-14B

SB-15B

SB-16P

SB-17B SB-18P SB-19B SB-2 OB

G a l ag re en 1 i n c u t 45

50 49 40 52 95 46 33 27 25 26 25 26

Apennine 1 i n c u t 60 Galagreen 1 i n c u t 67 I t a l i a n Ramones 31 1 i n c u t

45 25 44 40

I t

11

I t

11

I 1

I 1

11

I1

11

I 1

I t

I 1

1 1

I1

11

I 1

1000 980 960

1300 1100 1200 1200 1600 2100 2100 2100 2100 2 000

1600

1600

1500

1000 1100 1100 1100

0.75 0.75 0.75 0.75 0.75 0.75 0.75 0.75 0.75 1.3 1.3 1.3 1.3

1.3

1.3

1.2

1 .2 1.2 1.2 1.2

1.1 1.1 1.1 1.1 1.1 1.1 1.1 1.1 1.1 0.9 0.9 0.9 0.9

63-84 85+3 85% 8516 - 88 71-85 88+2 84%4 8213 8611 86Tl 8513 82T3 -

7 7+6 - 0.9

86+2 - 0.9

85+3 - 0.6

0.6 91+3 0.6 91T3 0.6 85T3 0.6 82T3 -

170 129 129 150 177

161-1 81 210

210-269 269

289-309 309 30 9

269-309

2 4 9-309

249

218

170 170 170 170

30 32 31 38 2 9+3 2 912 3 0'- 33+3 35 36 38 36 34

31+1

3 7+1

37

2 8+1 33 26 2 8

-

-

-

-

-- -- -- 3.0 3.0 2.5 2.5 2.5 2.5 2.5 1.9 2.6 2.6

2.6

2.6

2.2

2.2 2.2 2.2 2.2

170 130

19 140 18 110 19 160 18 140-160

190 1 6 130-170 1 3 130 21 140-150 19 150 18 150 2 3 130-150

-- --

--

18 160-190

1 7 150

17 150

1 7 170 18 160 1 7 160 1 6 150

(cont inued)

I

---

TABLE 1 (cont inued)

Run Veget. Run Feed Heating Holding Holder Steam Cooled Cooling Wet- Steam No.+ Var ie ty T ime Rate Time Time Temp Flow Veget. T i m e bu lb Consumption

(Min) (kg/hr ) (Min) (Min) ("C) (kg/hr ) Temp (Min) Temp (kgjkkg) ("C) ( " C >

Galag reen

I t a l i a n

1 i n c u t

Asgrow 274

SB-21B 1 i n c u t 57

SB-22B Ramones 41

41 SB -2 3B

SB-24C 1 i n c u t 190 60 SB-25B

Q\ SB-26P 1 i n c u t 37

I 1

11

Yellow Wax

J u l i a n n

Apennine

Apennine

F

SB-27C 1/2 i n cu t 161

SB-28C 1 / 2 i n c u t 150

SB-29B 1 i n c u t 53 122 SB-30C

SB-31C 1 i n c u t 125

SB-32B 1 i n cu t 57 51 SB-33B

SB-34P 1 i n c u t 23 125 SB-35C

11

Yellow Wax

I 1

Ape nnine

11

8 90

1200

1200

8 90 92 0

8 90

900

980

84 0 860 84 0

870 850

800 84 0

1.2

1.2

1.2

1.1 1.1

1.1

1.1

1.1

1.0 1.0 0.5

0.7 0.7

0.7 0.6

0.9

0.6

0.6

0.9 0.9

0.9

0.9

0.9

1.0 1.1 1.1

0.75 0.75

0.75 0.7

86+3

82+3

88+3

84+3 86'Tl -

85+3

87+3

86+4

91+3 9 1+6 91T3 -

91+3 91T3 -

93 91+3

-

-

-

-

-

-

-

150

170

170

150-1 29 150

150

150

150

150 150 150

150 150

150 150-138

28

31

31

2 9+1 29

26

28

2 8+1

2 7 26 25

26 2 7

29 27

-

-

2.2

2.2

2.2

2.2 2.2

2.2

2.6

2.7

2.5 2.5 2.5

2.5 2.5

2.3 2.4

16

18

19

19 1 7

14

16

1 7

16 14 1 3

1 4 18

18 1 7

170

140

150

170-1 50 160

170

170

150

180 170 180

170 180

1 90 180-1 70

(cont inued)

TABLE 1 (cont inued)

Run Veget. Run Feed Heating Holding Holder Steam Cooled Cooling Wet- Steam No.+ Var ie ty T ime Rate Time Time Temp Flow Veget. T i m e bu lb Consumption

(Min) (kg /h r ) ( M i d (Min 1 ("C) (kg/hr ) Temp (Min) Temp (kg/kkg) ("C) ("C)

Galag reen SB-36C 1 i n c u t 215 880 0.6 0.7 88+3 137 27 2.4 1 7 160

160 SB-3 7C Avg. of a l l runs 160

- 118 860 0.6 0.7 89T3 - 137 28 2.4 1 7 11

+P = pre l imina ry run B = b a t c h run C = cont inuous run

TABLE 2. OPERATING CONDITIONS FOR LIMA BEANS

Run+ Veget. Run Feed Heating Holding Holder Steam Cooled Cooling Wet- Steam No. Var i e ty Time Rate Time T ime Temp Flow Veget. T i m e bu lb Consumption

( M i d (kg/hr ) (Mid (Mid ("C) Ckg/hr) Temp (Min) Temp (kg/kkg) ("C) ("C>

LB-1 P LB-2 P LB-3 P LB-4 P LB-5 P LB-6 P LB-7 P LB-8 B

00 LB-9 B LB-10 C LB-11 C LB-12 C LB-13 C LB-14 C LB-15 C LB-16 B LB-17 C

e

P i l o t P l a n t

Kingston 45 1300 1.1 1.3 86+2 129 32

Bridgeton 35 560 1.1 3.5 98 89 24 11 Run stopped because c o o l e r w a s unable t o move beans

Run stopped because c o o l e r w a s unable t o move beans 11

II II I I I I I I 11 I I

s4 78 540 1.1 Kingston 83 1200 1.1

s4 50 1200 1.1 Br idge ton 57 1100 1.1

Run stopped because Kingston 126 880 1.1

149 840 1.1 Bridgeton 272 840 1.1

331 700 1.1 Kingston 274 740 1.1

42 970 0.8 s 4 130 830 0.8

I t

II

I t

11

1.3 98 1.3

91+6 1.3 1.3

c o o l e r w a s unable 1.3 91+6 2.5 92T3

2.5 93T2 2.5 91T2 - 1.9 98 1.9 93

-- - --

2.5 93T3

2 4+1 - 89 102 23 129 27 149 25

110 29+1 110 2 8Tl 110 2 8 t l 107 2 6T2 109 2 8T2 149 2 6- 127 24

t o move beans

17 100 --

17 160 --

13 160 12 90

-- 14 1 l o 14 130

-- --

-- 1 6 130 16 130 16 130 10 150

1.2 10 150 1.7 14 150 1.7 1 3 150

Avg. of a l l runs 130

-- -- -- --

-

( con t inued)

TABLE 2. ( con t inued) . Run+ Veget. Run Feed Heating Holding Holder Steam Cooled Cooling Wet- Steam No. V a r i e t y Time Rate Time T i m e Temp Flow Veget. T i m e bu lb Consumption

(Min) (kg /h r ) (Min) (Min) ("C) (kg/hr ) Temp. (Min) Temp (kg/kkg) ("C) ("C)

Product ion Line

-- 31 0.9** --

39 0.9**

-- -- -- LB PL-1 Kingston -- 4200 4.5* LB PL-2 Kingston -- 3 000 4.5* LB P L - ~ Kingston -- 5600 4.5*

-- -- -- 43 0.3*** -- -- -- -- -- -- --

+P = pre l imina ry run B = b a t c h run

I- C = continuous run - PL = measurements made on p l a n t product ion l i n e

*blancher temperature = 99°C **0.7 min i n a i r wi th water sprays and 0.2 min i n flume

***0.3 min i n flume

TABLE 3. OPERATING CONDITIONS FOR BRUSSELS SPKOUTS, CAULIFLOWER AND BROCCOLI

Run Veget. Run Feed Heating Holding Holder Steam Cooled Cooling Wet- S t e a m No. +- Variety Time Rate Time Time Temp Flow Veget. T i m e bu lb Consumption

B r u s s e l s Sprouts

BS-1 P s i z e 55 190 1.8 2.4 99 149 35 -- 13 7 80 BS-2 P II 60 200 1.8 2.4 98+1 129 35 3 13 630 BS-3 P 1 1 131 240 1.8 2.4 100- 129-90 40+3 - 3 10 540-3 70

11 32 5 13 430 BS-4 P 93 200 1.8 2.4 100 90 BS-5 P I t 6 80 Run stopped because holder overloaded

l a r g e

Caul i f lower

83 0 1.3 0.6 99 149 21 5 180 - h, o C-1 P f l o w e r e t s 53

B r o c c o l i

900 B-1 P s p e a r s 27 96 1.4 1.3 B-2 P 11 40 240 1.2 0.8 99 90 19 5 9 3 70

-- -- -- 90 --

~~~ ~

+P = pre l iminary run

I

a i r f low r a t e f o r each run are shown i n t h e Appendix (Tables A-1, A-2 and A-3). Table 2 a l s o shows t h e c o n d i t i o n s on t h e lima bean product ion l i n e a t t h e t i m e of measuring the e f f l u e n t .

Blanching t i m e s ( h e a t i n g p lus hold ing) f o r each of t h e v e g e t a b l e s i n t h e i n i t i a l p re l iminary runs were set on t h e b a s i s of t h e t i m e s used on t h e product ion l i n e . The d i v i s i o n of blanching times i n t o h e a t i n g and holding times was u s u a l l y made on t h e b a s i s of ea r l i e r work (Bomben, e t a l . , 1974; Brown, e t a l . , 1974; Lund, 1974). In t h e case of snap beans, a r e d u c t i o n t o t h e minimum blanching t i m e necessary f o r adequate blanching i n t h e pro to type was measured (Runs SB-35 t o 37) . Commercial p r a c t i c e i n blanching l i m a beans i s u s u a l l y t o blanch beyond t h e p o i n t of enzyme i n a c t i v a t i o n t o a t t a i n a s o f t e r t e x t u r e . Commercial blanching times f o r l ima beans may vary between 3.5 t o 6.0 minutes; t h e maximum blanching t i m e p o s s i b l e f o r l i m a beans i n t h e prototype w a s 3.6 minutes. The blanching times achieved wi th b r u s s e l s s p r o u t s , c a u l i f l o w e r , and b r o c c o l i had t o be set l e s s t h a n commer- c i a l p r a c t i c e f o r reasons d iscussed l a t e r i n t h i s r e p o r t .

The h e a t e r was maintained a t t h e atmospheric condensing temperature of s t e a m (100°C) by r e g u l a t i n g t h e f low of steam t o t h e h e a t e r . The holder temperature w a s measured by a thermocouple placed a t 2 / 3 of t h e l e n g t h of t h e holder about 4 cm from t h e bottom. A t a given h e a t i n g and holding t i m e t h e steam flow w a s k e p t a t a minumum whi le main ta in ing a temperature of 85 t o 88°C (185 t o 190°F) i n t h e holder .

The v i b r a t i o n ampli tude of t h e c o o l e r w a s se t a t t h e maximum t h a t would The equipment g i v e a cooled product temperature of 27 t o 32°C (80 t o 90°F).

s e t t i n g t o g i v e t h i s c o n d i t i o n w a s e s t a b l i s h e d during t h e pre l iminary runs. Some d i f f i c u l t y i n c o n t r o l l i n g t h e res idence t i m e w a s experienced wi th t h e up-flow c o o l e r , and t h i s w i l l be d iscussed l a t e r i n t h e r e p o r t .

21

SECTION 5

RESULTS AND DISCUSSION

The wasteload produced by t h e p i l o t p l a n t as compared t o o t h e r blanching and coo l ing techniques w a s t h e focus of t h e p r o j e c t . E f f l u e n t w a s desc r ibed i n terms of h y d r a u l i c wasteload and o rgan ic wasteload. Hydraulic wasteload i s t h e volume o f e f f l u e n t p e r u n i t of raw vege tab le (L/kkg), and t h e o r g a n i c wasteload i s t h e weight of t h e BOD, TOC and SS p e r un i t of vege tab le pro- ces sed -- a l l expressed as kg per 1000 kg of raw v e g e t a b l e s that had been washed, s i z e d , c u t and trimmed. In a d d i t i o n t o these convent iona l parameters f o r d e s c r i b i n g t h e was te load , a material ba l ance on t h e vege tab le s pass ing through t h e process was performed; t h e y i e l d desc r ibed the weight of blanched and cooled v e g e t a b l e obta ined from a g iven weight of raw v e g e t a b l e , and t h e s o l i d s loss desc r ibed the f r a c t i o n of s o l i d s i n the r a w vege tab le l o s t dur ing blanching and cool ing . The Appendix (Table A-4) summarizes t h e c a l c u l a t i o n s used t o o b t a i n the wasteloads and material balances.

Most of t h e exper ience gained i n o p e r a t i n g t h e p i l o t p l a n t w a s ob ta ined w i t h snap beans and l i m a beans. Because of t h e l i m i t e d t i m e a v a i l a b l e f o r running b r u s s e l s s p r o u t s , c a u l i f l o w e r and b r o c c o l i , on ly p re l imina ry runs were p o s s i b l e wi th t h e s e vege tab le s . During the 1975 season , t h e c o o l e r ope ra t ed wi th product f lowing up, and dur ing t h e 1976 season i t opera ted wi th product flowing down.

T i m e l i m i t a t i o n s i n t h i s s t u d y precluded a thorough measurement of t h e e f f l u e n t produced by t h e product ion l i n e . The o n l y e f f l u e n t d a t a measured on t h e product ion l i n e w a s f o r l i m a beans. Although an a t tempt was made t o make measurements on t h e l i m a bean product ion l i n e du r ing normal opera- t i n g c o n d i t i o n s , t h e f a c t that t h e t h r e e measurements l i s t e d w e r e a l l taken dur ing one day of p l a n t o p e r a t i o n l i m i t s t h e i r range of a p p l i c a b i l i t y . R e l i a b l e measurements of t h e e f f l u e n t from a b lancher o r flume i n an o p e r a t i n g p l a n t r e q u i r e s t ak ing da ta over a per iod of t i m e long enough t o encompass t h e range of v a r i a t i o n s that i n e v i t a b l y occur. Other r e p o r t s on the measurement of b lancher e f f l u e n t f o r convent iona l as w e l l as new blanching techniques (Lund, 1974; Ral l s and Mercer, 1974; Bomben, e t a l . , 1975) w i l l be used as a b a s i s f o r comparison i n t h i s r e p o r t .

Product q u a l i t y w a s ano the r c o n s i d e r a t i o n i n e v a l u a t i n g t h e ope ra t ion of t h i s p i l o t p l a n t . Qua l i ty w a s measured i n t h r e e ways: (1 ) t o t a l ae rob ic coun t , ( 2 ) sensory e v a l u a t i o n by t h e duo- t r io t es t , and ( 3 ) chemical a n a l y s i s of pe rox idase , a s c o r b i c a c i d and ch lo rophy l l conversion.

Economic cr i ter ia w i l l e v e n t u a l l y determine whether t h e i d e a s i n v e s t i - ga t ed i n t h i s work w i l l be commercially adopted. The economic c o n d i t i o n s

22

of an i n d i v i d u a l f r e e z i n g p l a n t are unique because of l o c a t i o n , a v a i l a b i l i t y of c a p i t a l , c o n d i t i o n of e x i s t i n g b l anche r s , and o t h e r i n d i v i d u a l economic c o n s i d e r a t i o n s . The economic c a l c u l a t i o n s t h a t were done f o r t h i s r e p o r t s i m p l y compared f i x e d and v a r i a b l e o p e r a t i n g c o s t s under what w a s cons idered reasonable o p e r a t i n g cond i t ions f o r fou r a l t e r n a t i v e s : v i b r a t o r y sp i r a l b lancher -cooler , convent iona l water b l anche r , h y d r o s t a t i c steam b lanche r , and hot-gas b lancher .

Analvsis of P ro to type Design and Opera t ions

An o b j e c t i v e of t h e exper imenta l runs w a s t o observe how t h e v i b r a t o r y conveyors moved t h e vege tab le s i n t h e h e a t e r , h o l d e r , and c o o l e r . Although v i b r a t o r y conveyors are used i n vege tab le p rocess ing , t hey have r a r e l y been used t o convey v e g e t a b l e s through a b lancher (Commercial Mfg. Co., 1975) , and t h i s work was t h e f i r s t t o use s p i r a l v i b r a t o r y conveyors f o r t h i s purpose. Previous work (Brown, e t a l . , 1974) showed that c i r c u l a r v i b r a t o r y conveyors gave flows approximating plug flow of t h e v e g e t a b l e s , t he reby i n s u r i n g uni- form re s idence t i m e f o r t h e v e g e t a b l e s i n a b lancher . The s p i r a l conveyors use$ i n the p i l o t p l a n t gave uniform conveying a l s o as long as t h e i r conveying s u r f a c e was covered wi th vege tab le s . s epa ra t ed i n t o hea t ing and holding s t e p s , any small nonuniformity of h e a t i n g i n t h e h e a t e r s p i r a l w a s equa l i zed i n t h e ho lde r where vege tab le s p i l e d up f o r temperature e q u i l i b r a t i o n and enzyme i n a c t i v a t i o n .

Because t h e blanching w a s

The d e s i g n c a p a c i t y of t h e p i l o t p l a n t of 907 k g / h r 1 t o n / h r ) w a s 3 8 c a l c u l a t e d assuming a bulk d e n s i t y of 641 kg/m

t i m e of 1 min. i n t h e h e a t e r , 1 min. i n t h e h o l d e r , and 2 min. i n th? c o o l e r . S ince bulk d e n s i t i e s can be as small as 400 kg/m (25 l b / f t ) f o r b r o c c o l i s p e a r s and blanching times f o r l a r g e b r u s s e l s s p r o u t s can be as long as 6 minutes , t h e a c t u a l c a p a c i t y depended on t h e v e g e t a b l e being blanched. I n R u n s SB-9 t o SB-13 t h e p i l o t p l a n t f a r exceeded i t s des ign c a p a c i t y ; snap beans, whose bulk d e n s i t y i s about 561 kg/m3 (35 l b / f t 3 ) , were f ed t o the b lancher a t over 5000 k g / h r i s about 641 kg/m (40 l b / f t ), but r equ i r ed blanching t i m e s l onge r than t h e 2 minutes used f o r t h e des ign feed ra te , a l s o exceeded t h e des ign c a p a c i t y i n some runs (LB-1, 7 , 8, 9, and 16) . Brusse l s s p r o u t s , c a u l i - f l ower , and b r o c c o l i , a l l of which have lower bulk d e n s i t i e s and longe r blanching t i m e s than those used f o r des igning the conveyors, had feed rates below t h e des ign capac i ty . The a c t u a l c a p a c i t y of t h e p i l o t p l a n t f o r t h e s e l a t te r v e g e t a b l e s could not be a c c u r a t e l y e s t a b l i s h e d f o r reasons mentioned la te r i n this r e p o r t .

(40 l b / f t ) and a r e s idence

3

2.5 t o n s / h r ) . Lima beans , whose bu lk d e n s i t y 5

The blanching t i m e s f o r snap beans i n the p i l o t p l a n t ( h e a t i n g and ho ld ing ) s u f f i c i e n t t o produce a nega t ive peroxidase were g e n e r a l l y less than those on the product ion l i n e . These s h o r t e r blanching t i m e s were achieved because t h e p i l o t p l a n t had s e a l e d ends , t h u s i n s u r i n g t h a t t h e h e a t e r w a s maintained a t 100°C, and because the hea t ing and holding s e c t i o n s a s s u r e d a uniform temperature among t h e i n d i v i d u a l p i e c e s l e a v i n g t h e holder . Steam b lanche r s w i th unsealed ends, such a s t h e one used f o r steam flow measurements on t h e product ion l i n e , may have a c o n s i d e r a b l e v a r i a t i o n i n tempera ture a long t h e i r l e n g t h because of a i r e n t e r i n g through t h e feed and

23

d i s c h a r g e ends. In a d d i t i o n , t h e b e l t i n a convent iona l steam blancher i s of t e n h e a v i l y loaded , which causes t h e vege tab les w i t h i n a blancher t o exper ience a d i f f e r e n t temperature t rea tment .

The holder was n o t l a r g e enough t o provide adequate c a p a c i t y f o r b r u s s e l s s p r o u t s . A t t h e feed rates shown i n Table 3 f o r Runs BS-1 t o BS-4, t h e h e a t e r was not f u l l y loaded g i v i n g some nonuniformity i n blanching t i m e s . I n Run BS-5, when a more f u l l y loaded h e a t e r w a s t r i e d , t h e holder became overloaded. The blanching t i m e of 4.2 minutes (1.8 minutes h e a t i n g + 2.4 minutes hold ing) was t h e maximum p o s s i b l e i n t h e p i l o t p l a n t . Although t h e b r u s s e l s s p r o u t s processed i n t h e s e experiments showed n e g a t i v e peroxidase t e s t s , t h e e x a c t t i m e of blanching was u n c e r t a i n because of t h e underloaded h e a t e r and t h e very slow conveying v e l o c i t y i n t h e h o l d e r (10 sec. on; 40 sec. o f f ) . To provide proper c o n d i t i o n s f o r blanching b r u s s e l s s p r o u t s , t h e s i z e of t h e holder would need t o be increased s u f f i c i e n t l y t o accomodate a f u l l y loaded hea t ing s p i r a l .

Broccol i s p e a r s tended t o br idge and block t h e 15 cm x 23 cm ( 6 i n . x 9 i n . ) e n t r a n c e s and e x i t s of t h e h e a t i n g and cool ing s p i r a l s i f t h e f e e d rate was above 240 kg/hr . Thus a g a i n t h e h e a t e r s p i r a l could n o t be loaded a t i t s f u l l capac i ty . For unobstructed f low of b r o c c o l i through t h e proto- t y p e , t h e s e e n t r a n c e s and ex i t s would have t o be en larged . The blanching t i m e of 3.5 minutes used on t h e b r o c c o l i product ion l i n e could n o t be achieved i n t h e pro to type because t h e holder could n o t convey b r o c c o l i a t t h e heavy loading r e q u i r e d t o a t t a i n a long res idence t i m e i n t h e holder . A t t h e low v i b r a t i o n ampli tude (0.32 cm) and t h e long t i m e o f f ( 4 0 s e c . ) t h e h e a v i l y loaded holder conveyor could n o t move t h e b r o c c o l i . A t h i g h e r v i b r a t i o n ampli tudes ( 0 . 6 4 cm o r l a r g e r ) o r l i g h t e r l o a d i n g s (on cont inuous ly) t h e b r o c c o l i could be moved by t h e conveyor, bu t of course t h e s e c o n d i t i o n s gave a s h o r t e r holding t i m e . p o s s i b l e w i t h a longer holder .

Adequate holding t i m e w i t h b r o c c o l i would be

Caul i f lower moved uniformly and without d i f f i c u l t y through a l l conveyors i n t h e p i l o t p l a n t . However, t o use t h e s p i r a l conveyors a t f u l l c a p a c i t y and t o provide f o r a longer holding t i m e (convent iona l blanching times = 3.5 min.) , a l a r g e r ho lder would be necessary.

Because of t h e equipment l i m i t a t i o n s mentioned above, t h e c a p a c i t y of t h e p i l o t p l a n t f o r b r u s s e l s s p r o u t s , c a u l i f l o w e r and b r o c c o l i could not be determined i n these tests. The tests d i d e s t a b l i s h t h a t t h e v i b r a t o r y conveyors could move t h e s e v e g e t a b l e s and t h a t adequate blanching and cool ing could be achieved i n t h e prototype; however, e s t a b l i s h i n g t h e exact s i z e s of t h e holder and f e e d and d i s c h a r g e openings needed so that t h e pro to type could handle t h e s e v e g e t a b l e s cont inuous ly and r e l i a b l y would r e q u i r e f u r t h e r te s t i n g .

Table 1 shows t h a t i n those runs wi th snap beans where t h e feed rate exceeded t h e d e s i g n c a p a c i t y , t h e cooled v e g e t a b l e tempera tures exceeded 27°C (80"F) , which w a s t h e d e s i g n product temperature . In t h e snap bean and l i m a bean r u n s done a t t h e d e s i g n c a p a c i t y , t h e cooled product temperature w a s g e n e r a l l y a t o r below 27°C. w a s dependent on t h e wet-bulb temperature of t h e ambient a i r . The low

The a c t u a l temperature i n any given run

24

t empera tures achieved wi th c a u l i f l o w e r and b r o c c o l i were t h e r e s u l t of t h e low conveyor l o a d i n g s and t h e very low wet-bulb temperatures of t h e ambient a i r . Figure 6 shows t h e r e s u l t s of measurements of a i r v e l o c i t i e s as a f u n c t i o n of d i s t a n c e above a conveyor f l i g h t . It c l e a r l y shows t h a t most of t h e a i r w a s n o t being aimed a t t h e product. This c o n d i t i o n gave adequate cool ing when t h e p i l o t p l a n t was opera ted a t i t s d e s i g n c a p a c i t y s i n c e o n l y a s i n g l e l a y e r of product w a s on the c o o l e r conveyor; whereas a t t h e h igher feed r a t e s t r i e d i n Runs SB-9 t o SB-13, t h e c o o l e r conveyor had m u l t i p l e l a y e r s of product. An a i r d i s t r i b u t i o n system, which aimed t h e a i r d i r e c t l y a t t h e product , would g i v e more a i r f low over t h e product and thereby i n c r e a s e t h e rate of cool ing and g i v e a h igher c o o l e r c a p a c i t y . Air could be d i r e c t e d a t t h e product by using s l o t t e d t u b e s extending from t h e e x i s t i n g a i r holes ou t t o t h e edge of t h e f l i g h t s .

The c o o l e r w a s opera ted w i t h product f lowing upward dur ing t h e 1975 season and downward dur ing t h e 1 9 7 6 season. The c o o l e r opera ted s a t i s f a c - t o r i l y wi th snap beans i n e i t h e r mode of o p e r a t i o n (Runs SB-1 t o SB-3 were up-flow), b u t i t had more c a p a c i t y i n down-flow o p e r a t i o n . The c o o l e r could move l i m a beans upward, but t h e f low w a s e r r a t i c , and sometimes t h e l ima beans could n o t be moved a t a l l by t h e conveyor. This problem w a s in te rmi t - t e n t , and no s i n g l e cause f o r i t s occurence was determined a l though t h e fol lowing c h a r a c t e r i s t i c s were observed: (1) The longer t h e l ima beans were blanched, t h e more s lowly t h e y tended t o move on t h e conveyor. ( 2 ) Stems, pods, and u n d e r s i z e beans c o l l e c t e d on t h e s u r f a c e of t h e c o o l e r conveyor. ( 3 ) I f dur ing a run t h e l i m a beans stopped moving i n t h e c o o l e r and then t h e c o o l e r w a s washed down wi th water, t h e c o o l e r could a g a i n convey t h e l i m a beans. Despi te t hese problems t h e c o o l e r i n up-flow w a s opera ted con- t i n u o u s l y w i t h l i m a beans without washing f o r over f i v e hours (Run LB-14). None of t h e s e problems were encountered when c o o l i n g l i m a beans i n t h e down-flow mode (Runs LB-16 and -17).

The c o o l e r could n o t cont inuous ly convey upward blanched b r u s s e l s s p r o u t s , blanched c a u l i f l o w e r o r blanched b r o c c o l i ; i t was a b l e t o convey upward r a w b r u s s e l s s p r o u t s and raw b r o c c o l i but n o t raw c a u l i f l o w e r . Changing t h e a n g l e of v i b r a t i o n from 45" t o 30" from t h e h o r i z o n t a l d i d not make t h e s e v e g e t a b l e s move up t h e c o o l e r . The c o o l e r had no d i f f i c u l t y i n conveying any of t h e s e v e g e t a b l e s downward. From t h e s t a n d p o i n t of d e s i g n , t h e only disadvantage of n o t being a b l e t o convey upward i n t h e cool ing s p i r a l i s some l o s s i n compactness s i n c e t h e o v e r a l l h e i g h t of t h e equipment must be h igher f o r down-flow (Figure 2 and 4 ) .

The c leaning of t h e p i l o t p l a n t w a s e a s i l y accomplished a f t e r every run. The smooth s t a i n l e s s s teel s u r f a c e s of t h e conveyors were e a s i l y c leaned w i t h c o l d water, and t h e s p r a y system could e a s i l y be f lushed with d e t e r g e n t . Clean-in-place equipment would appear t o be e a s i l y incorpora ted i n t h e design. descr ibed la te r i n t h i s r e p o r t , show t h a t t h e s a n i t a t i o n of t h e des ign i s w e l l w i t h i n accepted l i m i t s .

Microbio logica l a s s a y s of v e g e t a b l e s l e a v i n g t h e c o o l e r ,

25

12 1 1 I I t I

0 3rd FLIGHT FROM BOTTOM

IT FROM BOTTOM I

0 6th FLlG I \

10

8

6

4

2

0 5 10 15 20 25 30 35 40 45 0

DISTANCE ABOVE COOLER CONVEYOR SURFACE (cm)

Figure 6 . Air velocity distribution over cooler spiral conveyor.

26

Material Balances and Wasteload

Tables 4, 5 , and 6 show t h e character is t ics of t h e l i q u i d e f f l u e n t from t h e p i l o t p l a n t and t h e r e s u l t s of a material ba l ance on t h e d i f f e r e n t vege- t a b l e s e n t e r i n g and l eav ing t h e p i l o t p l a n t f o r each of t h e runs . I n t h e case of l i m a beans , t h e t h r e e measurements made on t h e p roduc t ion l i n e are a l s o shown i n Table 5. The Appendix (Tables 5 , 6 and 7 ) g i v e s t h e r e s u l t s of t h e wastewater a n a l y s e s f o r each of t h e runs . A t o t a l volume of e f f l u e n t of less t h a n 0.5 l i t e r c o l l e c t e d du r ing a run w a s cons ide red n e g l i - g i b l e , and t h i s small amount of e f f l u e n t i s i n d i c a t e d by h y d r a u l i c l o a d s preceeded by a "less than" s i g n (<) . Table 7 shows t h e means of t h e v a l u e s i n Table 4, 5 , and 6 grouped by v e g e t a b l e v a r i e t y . When t h e r e were a s u f f i - c i e n t number of runs t o make i t a p p l i c a b l e , a 95% conf idence l i m i t w a s c a l c u l a t e d .

The v a r i a t i o n s i n h y d r a u l i c was te load and o rgan ic was te load f o r a g iven v e g e t a b l e appeared t o be p r i m a r i l y because of v a r i a t i o n s i n t h e r a w v e g e t a b l e v a r i e t y and ma tu r i ty . Table 7 i n d i c a t e s t h a t f o r snap beans t h e v a r i e t y made a s i g n i f i c a n t d i f f e r e n c e i n t h e wasteload. Within a g iven v a r i e t y of snap beans (Tables 1, 4 & 7) t h e v a r i a t i o n s i n was te load are n o t l a r g e w i t h t h e excep t ion of Run SB-12, which w a s a s h o r t d u r a t i o n p re l imina ry run. On t h e o t h e r hand, l i m a beans showed no d i s t i n g u i s h a b l e c o r r e l a t i o n between v a r i e t y and was te load . L i m a beans d i d however have l a r g e v a r i a t i o n s i n wasteload among r u n s of a g i v e n v a r i e t y (Tables 2, 5 and 7 ) . Comparisons between Runs LB-15 (36.09% t o t a l s o l i d s , Kingston v a r i e t y ) and LB-16 (38.70% t o t a l s o l i d s , Kingston v a r i e t y ) and LB-13 (41.6% t o t a l s o l i d s , Br idge ton v a r i e t y ) and LB-14 (35.92% t o t a l s o l i d s , Bridgeton v a r i e t y ) i n d i c a t e d t h a t l i m a beans wi th h ighe r s o l i d s con ten t produced less wasteload. One would expec t t h a t a lower volume of e f f l u e n t would be produced dur ing t h e b lanching of a d r i e r o r more mature ( h i g h e r s o l i d s c o n t e n t ) r a w v e g e t a b l e [Lund (1974) and Bomben, e t a l . (1973) l . There were n o t enough runs done wi th b r u s s e l s s p r o u t s , c a u l i f l o w e r o r b r o c c o l i t o make o b s e r v a t i o n s about v a r i a t i o n s i n was te load .

The material ba lances c a l c u l a t e d i n Tab les 4 , 5, 6 and 7 were done t o trace t h e l o s s of s o l i d s and weight du r ing b lanching and coo l ing . Bomben, e t a l . (1975) demonstrated that d i f f e r e n t methods of coo l ing l e d t o d i f f e r - ences i n y i e l d and s o l i d s l o s s . The y i e l d i s impor t an t i n v e g e t a b l e f r e e z i n g s i n c e f rozen v e g e t a b l e s are s o l d by weight . Air c o o l i n g obv ious ly reduces t h e h y d r a u l i c l oad a s compared t o flume c o o l i n g , b u t a t t h e expense of a lower v e g e t a b l e y i e l d . Y ie lds of g r e a t e r than 100% are p o s s i b l e s i n c e the v e g e t a b l e s can abso rb more l i q u i d i n c o o l i n g t h a n w a s l o s t i n b lanching . S o l i d s l o s s i s a measure of t h e n u t r i e n t s t h a t are l eached from a v e g e t a b l e a s i t i s blanched and cooled. Measurements on t h e p roduc t ion l i n e were made o n l y f o r l i m a beans , but i t w a s n o t p o s s i b l e t o measure a c c u r a t e l y t h e y i e l d , so that s o l i d s l o s s i s t h e o n l y material ba l ance comparison p o s s i b l e between commercial p rocess ing and t h e p i l o t p l a n t . Table 7 c l e a r l y shows f o r l i m a beans t h e advantages i n s o l i d s r e t e n t i o n and was te load r educ t ion p o s s i b l e w i t h t h e p i l o t p l a n t as compared t o t h e p roduc t ion l i n e .

27

TABLE 4. YIELD, SOLIDS LOSS & L I Q U I D WASTELOAD FOR SNAP BEANS

Run No. Yie ld S o l i d s Hydraul ic BOD T OC ss Loss Load

(% 1 ( % > (L /kkg 1 (kg / kkg 1 (kg/ kkg 1 (kg/kkg 1

SB-1 P SB-2 P SB-3 P SB-4 P SB-5 P SB-6 B SB-7 P SB-8 P SB-9 P SB-10 P SB-11 P SB-12 P SB-13 P SB-14 B SB-15 B SB-16 P SB-17 B SB-18 P SB-19 B SB-20 B SB-21 B SB-22 B SB-23 B SB-24 C SB-2 5- B SB-26 P SB-27 C SB-28 C SB-29 B SB-30 C SB-31 C SB-32 B SB-33 B SB-34 P SB-35 C SB-36 C SB-37 C

86.5 98.5 97.2 96.7 99.4 96.4 99.7 98.7 98.5 95.6

96.3 96.0

98.7 98.5

99.5 99.1 99.1 96.8 96.1

101.6 98.8 95.1 99.8 96.4 95.8 95.5 98.2 95.8 94.1 94.9 90.6 98.6 99.4 98.8

100

102

102

-- 0.71 0.68 0.62

0.18

0.76 1.1 0.50 2.2

--

0.21

1.2 1.0 --

1.4 --

1.9 0.85 0.29 0.94 1.6 1.4 1.3 1.8 1.7 1.7 1.6 1.4 0.41 0.89

51 32 29 33

5.7 8.5 23 38 15 79 (0.6

7.6 <o. 3 35 43 <0.6 c0.6 <O. 6 <O. 6 34 <O. 6 C0.6 47 27 13 23 41 39 34 53 58 61 60 51 13 27

--

0.80 0.52 0.44 -- -- A

-- 0.59 0.90

0.85 0.98

--

--

1.2 0.34 0.57

0.62 0.31 0.29 0.28

0.06

0.29 0.43 0.22 0.95

--

0.42 0.46

0.49 -- --

0.63 0.29 0.13 0.36 0.52 0.49 0.50 0.59 0.52 0.50

0.56 0.18 0.37

0.14 0.16

0.15 -- --

0.20 0.090 0.041 0.11 0.14 0.13 0.14 0.20 0.15 0.16

0.15 0.057 0.12

--

2 8

TABLE 5. YIELD, SOLIDS LOSS & L I Q U I D WASTELOAD FOR LIMA BEANS

Run No. Yie ld S o l i d s Hydraul ic BOD TOC ss Loss Load

(2 1 ( % I (L/kkg) (kg/kkg) (kg/kkg) (kg/kkg)

LB-1 P LB-2 P LB-3 P LB-4 P LB-5 P LB-6 P LB-7 P LB-8 B LB-9 B LB-10 c

P i l o t P l a n t

89.2 0.70 47 0.89 0.67 0.50 Run s topped because c o o l e r was unable t o move beans 83.2 -- 42 0.65 0.58 0.22 Run s topped because c o o l e r w a s unable t o move beans

90.9 -- 39 0.77 0.54 0.42 94.1 0.49 2 8 0.83 0.51 0.40 92.1 0.052 4.6 0.098 0.064 -- 0.15 7.9 -- 0.16 0.14

Run s topped because c o o l e r w a s unable t o move beans

II I 1 II II II 11 II I t I 1

0.041

0.20 LB-11 C -- LB-12 C 93.2 0.37 LB-13 C 92.9 0.15 LB-14 C 92.1 0.79 LB-15 C 92.0 1.2 LB-16 B 83.9 LB-17 C 90.8

-- --

LB PL-1 b lanching * 1.7 c o o l i n g 0.52

b lanching 1.6 LB PL-2

c o o l i n g 1.2 LB PL-3

b lanching 1.6 c o o l i n g 0.48

11 20

40 60 <O. 7 10

8.2

Product ion Line

550 53 0

4 60 7 80

370 31 0

-- 0.20 0.17 - 0.39 0.35 0.24 0.15 0.12 0.79 0.99 1.9 1.5 1.8

-- -- -- T-

-- -- --

3.2 1.8 0.85 0.91 0.38 0.15

3.8 1 .7 0.85 1.0 0.41 0.15

3.2 1.8 0.68 1.0 0.44 0.12

-

*Yield cou ld n o t be a c c u r a t e l y measured on t h e p roduc t ion l i n e .

29

TABLE 6. Y I E L D , SOLIDS LOSS AND LIQUID WASTELOAD FOR BRUSSELS SPROUTS, CAULIFLOWER AND BROCCOLI

Run No. Yie ld S o l i d s Hydraul ic BOD T OC ss Loss Load

B r u s s e l s Sp rou t s

-- -- -- <3 13s-1 P 102 <3 BS-2 P

BS-3 P 88.7 0.29 1 5 0.27 0.15 0.052 BS-4 P 94.4 0.65 41 0.59 0.31 0.093 BS-5 P Run s topped

-- -- -- - -- --

Caul i f lower

Brocco l i

-- -- -- -- -- <11 B-1 P B-2 P 103 0.33 11 0.25 0.15 0.091

P roduc t Q u a l i t y

Table 8 shows t h e r e s u l t s of t h e t o t a l a e r o b i c coun t s done on v e g e t a b l e s l e a v i n g t h e coo le r . The coun t s on a l l t h e l i m a bean samples taken from t h e p i l o t p l a n t were much lower than those of product taken from t h e product ion l i n e , and t h e s e coun t s were f a r below t h e a c c e p t a b l e lo5 c o l o n i e s / g i n d i c a t e d by Sharf (1966). I n most o f t h e runs wi th snap beans t h e coun t s on t h e cooled v e g e t a b l e s from t h e p i l o t p l a n t were much h i g h e r t han t h e product ion l i n e (Run No. SB-24 t o -36). These runs were a l l done w i t h t h e product f lowing downward i n t h e c o o l e r , and an i n c l i n e d b e l t had t o be used t o e l e v a t e t h e cooled v e g e t a b l e s from t h e e x i t of t h e c o o l e r t o a c o l l e c t i o n b i n ( F i g u r e 5 ) . In r u n s SB-24 t o -36, samples were taken from t h e v e g e t a b l e s l e a v i n g t h e i n c l i n e d b e l t e l e v a t o r ; however i n Run SB-37, samples were taken d i r e c t l y from t h e e x i t of t h e s p i r a l c o o l e r , and t h e c o u n t s ob ta ined on those samples were much lower t h a n t h o s e of p rev ious r u n s and about t h e same as t h e product ion l i n e . Runs LB-11 t o LB-15 were done wi th product f lowing upward i n t h e c o o l e r , and t h u s d i d n o t r e q u i r e an i n c l i n e d - b e l t e l e v a t o r . Samples f o r LB-17, BS-3, BS-4 and C-1 were a l s o taken d i r e c t l y from t h e ex i t of t h e down f low coo le r . The h igh coun t s when us ing t h e i n c l i n e d b e l t e leva- t o r d r a m a t i c a l l y p o i n t o u t t h e d i f f i c u l t y i n keeping b e l t conveyors c l e a n a s opposed t o v i b r a t o r y s p i r a l conveyors. I n a l l cases where v e g e t a b l e s were taken d i r e c t l y from t h e s p i r a l conveyors , t h e coun t s were lower t h a n , o r about t h e same a s , t h e c o u n t s of v e g e t a b l e s taken from t h e product ion l i n e ; fu r the rmore , t h e coun t s on t h e v e g e t a b l e s from t h e p i l o t p l a n t showed

30

TABLE 7. MEANS OF YIELDS, SOLIDS LOSSES AND LIQUID WASTELOADS WITH 95% CONFIDENCE LIMITS

Yie ld S o l i d s Hydraul ic BOD TOC ss Loss Load (% (L/kkg) (kg/kkg) (kg/kkg) (kg/kkg

Snap Beans

Galagreen 97.2i-O.4 Apennine 96.6T1.2 Ramones 99.470.7 -

L i m a Beans

Kingston 90.5+2.3 Bridge t o n 89.4T7.7 s-4 91.3T1.0 -

Product i on Line blanching- * cool ing- blanching + cool ing

Brusse l s Sp rou t s 95.0+9.6 -

Caul i f lower 97.2

Brocco l i 103

0.83W.09 27.0+2.6 0.53i-O.10 1.51TO. 07 39.8T6.8 0.98TO. 12 no t enough e f f l u e n t f o r sample

0.50i-O.18 0.37TO. 53 0.05y

1.64+0.06 0.7330.58 2.37

0.47

--

0.33

2 7.9+9.6 0.9Oi-O. 61 24 T 15 0.56TO. 42 18 T - 27 0.44-

460 + 130 3.37+0.49 540 340 0 .983 .09

1000 4.35

15 + 1 4 0.43 -

11 0.25

0.36i-O.03 0.53TO. - 02

0.55i-O.23 0.47TO. 32 0.30-

1.74+0.07 0.4 150.04 2.15

0.23

--

0.15

0.0 84+0.0 1 7 0.15 T0.02 -

0.54 +0.28 0.16+0.07 0.23-

0.79+0.14 0 . 1 4 3 .02 0.93

0.073

0.091

*Yield could no t be a c c u r a t e l y measured on t h e product ion l i n e .

TABLE 8. TOTAL AEROBIC PLATE COUNTS ON VEGETABLES LEAVING COOLER

(Colonies /g)

Hours Af te r S t a r t of Run Product ion 1 2 3 4 5 L ine

Snap Beans

4 SB-24 7.9 x 10 SB-27 6.4 x l o 5

5 4

SB-28 1.5 x 10 SB-30 9.2 x 10

SB-35 4.8 x lo5 5 3

SB-36 9.2 x 10 SB-37 1.2 x 10

SB-31 1.9 lo5

L i m a Beans

LB-11 2.0 x lo3 2 3

LB-12 7.0 x 10 LB-13 1.2 x 10 LB-14 5.1 x lo2 LB-15 7.3 x lo2

4 LB-17 3 . 8 x 10

4 BS-3 1.4 x 10 BS-4 3.8 lo5

4 3.5 x 10 9.8 l o 4 1.4 lo5 1.0 l o 5 1.6 lo5 4.3 lo5

5 2

2.9 x 10 6.1 x 10

1.5 l o 3 7.5 x lo2 8.3 i o 2 7.0 x lo2

2 4

5.0 x 10 4.3 x 10

3 2.0 x 10 1.7 lo5

4

5

3.2 x 10

1.0 x 10 1.3 lo5

5 2.2 l o 5 6.0 10

30

20

3 6.2 x 10

2 2.1 x 10 7.0 x lo2

--

1.0 x l o 2

3.7 x l o 2

4 7.2 x 10 4.6 x l o 2 5.8 x lo2

5.0 x lo2

3 1.3 lo3 2.0 103 1.1 10

6 5.0 x lo2

1.5 x 1 0

1.4 lo5 1.1 x 10 5

Cau l i f lower

c-1 4.9 lo4

32

no tendency t o i n c r e a s e wi th t i m e , as demonstrated by Run LB-14, which cont inued f o r over f i v e hours .

Table 9 g i v e s t h e r e s u l t s of s enso ry comparisons (duo- t r io ) of product from t h e p i l o t p l a n t w i th t h a t from t h e product ion l i n e . The r e s u l t s are r e p o r t e d as t h e number of judgements c o r r e c t l y i d e n t i f y i n g t h e sample t h a t w a s i d e n t i c a l t o t h e c o n t r o l (% c o r r e c t ) . The c o n t r o l f o r a comparison w a s e i t h e r t h e p i l o t p l a n t o r product ion l i n e sample. Judges were a l s o asked t o s ta te which sample t h e y p r e f e r r e d . P r o b a b i l i t i e s are from t h e Binomial P r o b a b i l i t y Table.

TABLE 9. SENSORY EVALUATION OF SNAP BEANS AND LIMA BEANS BY DUO-TRIO TEST

% Pre fe rence f o r P i l o t P l a n t

% Cor rec t Sample Run Number

T o t a l Number of Judgments

SNAP BEANS

SB-1 SB-2 SB-3 SB-28 SB-3 6

36 36 34 40 40

61 61 53 68* 78**

42 44 68 65* 58

LIMA BEANS

LB-7 LB-8 LB-9 LB-10 LB-11

41 40 41 38 40

66* 65* 80* * 63 63

54 67* 63 32* 55

* P r o b a b i l i t y < 0.05 **Probabi l i ty < 0.01

---

The senso ry e v a l u a t i o n showed t h a t i n some cases a s i g n i f i c a n t d i f f e r - ence could be d e t e c t e d i n t h e tas te o r t e x t u r e of t h e product because of p rocess ing i n t h e p i l o t p l a n t as compared t o p rocess ing i n t h e product ion l i n e . I n those cases of snap beans where s i g n i f i c a n t d i f f e r e n c e s could be d e t e c t e d , t h e judges , c i t i n g b e t t e r f l a v o r o r t e x t u r e , p r e f e r r e d t h e sample from t h e p i l o t p l a n t . This b e t t e r f l a v o r o r t e x t u r e could have been e i t h e r t h e r e s u l t of t h e s h o r t e r blanching t i m e s o r less l o s s of s o l i d s i n t h e p i l o t p l a n t as compared t o t h e product ion l i n e . I n t h e case of l i m a beans, t h e p r e f e r e n c e s of t h e pane l were n o t a s c o n s i s t e n t , and i n one case (LB-10) t h e pane l p r e f e r r e d l i m a beans taken from t h e product ion l i n e . Some of t h e d i f f e r e n c e s found by t h e judges i n t h e l i m a bean samples probably came from

33

t h e f a c t t h a t t he l i m a beans f o r t h e p i l o t p l a n t could no t be c o l l e c t e d a f t e r t h e f i n a l wash p r i o r t o b lanching , and t h u s con ta ined more of t h e s a l t absorbed i n t h e f l o t a t i o n g rade r . I n g e n e r a l it appea r s s a f e t o con- c lude t h a t t h e p i l o t p l a n t had no adve r se a f f e c t on t h e taste, t e x t u r e o r appearance of v e g e t a b l e s , and i n some cases, i t improved t h e f l a v o r and t e x t u r e .

Table 10 g i v e s t h e r e s u l t s of t h e ana lyses f o r t o t a l s o l i d s , pe rox idase , a s c o r b i c a c i d and c h l o r o p h y l l convers ion of p i l o t p l a n t and product ion l i n e samples. The numbers are averages of two o r t h r e e a n a l y s e s done on 50 t o 100 g of vege tab le s . Ascorbic a c i d i s r e p o r t e d wi thout account ing f o r d i f f e r e n c e s i n moi s tu re between t h e f rozen v e g e t a b l e s from t h e product ion l i n e and those from t h e p i l o t p l a n t .

The r e s u l t s of peroxidase test are repor t ed i n two ways. In those cases where a raw vege tab le sample w a s a v a i l a b l e a t t h e t i m e of a n a l y s i s , a resi- dua l peroxidase w a s determined; o therwise t h e t i m e f o r a c o l o r change i n t h e test s o l u t i o n i s r epor t ed . For t h e c o n d i t i o n s used i n t h i s t e s t , adequate blanching w a s shown by less than 6% r e s i d u a l peroxidase o r no c o l o r change i n more than 210 sec. Except f o r one sample of b r u s s e l s s p r o u t s taken from t h e product ion l i n e ( B S - 3 ) , a l l samples shown i n Table 10 were adequate ly blanched. dase i n a c t i v a t i o n , t h e c r i t e r i o n being t e x t u r e i n s t e a d . S ince i n most cases t h e p i l o t p l a n t used s h o r t e r blanching times, t h e peroxidase c o n t e n t s of v e g e t a b l e s t h a t were processed i n i t were h i g h e r , bu t i n no case d i d t h e p i l o t p l a n t no t blanch s u f f i c i e n t l y . I n one of t h e runs w i t h b r u s s e l s s p r o u t s (BS-4), t h e p i l o t p l a n t v e g e t a b l e s were s e r i o u s l y overblanched because of t h e d i f f i c u l t i e s , desc r ibed ea r l i e r , i n ma in ta in ing c o n s t a n t ho ld ing t i m e s w i th t h e ho lde r o p e r a t i n g a t a ve ry s low conveying v e l o c i t y .

L ima beans are commonly blanched longe r t h a n necessa ry f o r peroxi-

Gene ra l ly , t h e a s c o r b i c a c i d con ten t of t h e v e g e t a b l e s processed i n t h e p i l o t p l a n t w a s h ighe r than t h a t of t h e v e g e t a b l e s t aken from t h e produc- t i o n l i n e (Table l o ) . Some of t h e s e d i f f e r e n c e s can be accounted f o r by d i f f e r e n c e s i n t o t a l s o l i d s between t h e samples , bu t i n some cases (SB-2, -3, -28, - 3 6 ) t h e vege tab le s processed i n t h e p i l o t p l a n t d i d indeed have more r e t e n t i o n of a s c o r b i c a c i d . This r e t e n t i o n could have been t h e r e s u l t of bo th s h o r t e r blanching t i m e s and less l each ing .

Ascorbic a c i d i s l o s t bo th by l each ing and thermal deg rada t ion , bu t an i n c r e a s e i n c h l o r o p h y l l convers ion i s s o l e l y a measure of t he rma l degrada- t i o n . A s exp la ined p rev ious ly , t h e conveying v e l o c i t y i n t h e l i m a bean runs wi th product f lowing upward i n t h e c o o l e r w a s sometimes s low and errat ic , and t h e h e a v i l y loaded conveyor gave an e x c e s s i v e l y s low coo l ing rate. Th i s s lower coo l ing ra te caused h i g h e r c h l o r o p h y l l convers ions t h a n those on the product ion l i n e (Table 10, runs LB-12, 13, 14, and 15). I n t h o s e l i m a bean runs wi th up-flow where t h e c o o l e r had s h o r t e r r e s idence times and less loading (LB-8 and -11) and t h e down-flow run (LB-17), no s u b s t a n t i a l d i f f e r e n c e s between c h l o r o p h y l l convers ions i n t h e p ro to type and product ion l i n e samples appeared. The pro to type samples of snap beans, i n e i t h e r up-flow o r down-flow, had lower c h l o r o p h y l l conve r s ions t h a n d i d t h e product ion l i n e samples , i n d i c a t i n g t h a t t h e p ro to type , when o p e r a t i n g

34

TABLE 10. CHEMICAL ANALYSES OF VEGETABLES

Blanch & Cool Residua 1 Ascorbic * Chlorophyl l TS P i l o t P i l o t Peroxidase Acid Conversion

R u n R a w P i l o t Prod. P l a n t P l a n t P i l o t Prod. P i l o t Prod. P i l o t Prod. No. TS P l a n t Line Yie ld S o l i d s P l a n t Line P l a n t Line P l a n t Line

(%I ( % > (%> (Z ) Loss (%) ( % I (70) (mg/100 g > (mg/100 g > ( % > (%I

SNAP BEANS

SB-1 10.76 11.20 10.35 86.5 -- 2.1 1.6 14.1 13.9 SB-2 10.75 10.75 -- 98.5 0.708 1.1 0.5 15.1 13.4 SB-3 10.75 10.40 -- 97.2 0.707 1.5 0.5 14.1 13.4 SB-28 9.35 9.09 -- 99.4 1.56 402sec** 595sec** 11.7 9.8 SB-36 10.97 10.23 -- 99.4 0.412 300sec** 800sec** 14.0 11.8

w cn LB-8 40.65 41.71 34.60 LB-11 40.86 39.74 36.49 LB-12 40.72 40.13 36.01 LB-13 41.60 40.71 38.03 LB-14 35.92 35.62 34.80 LB-15 36.09 36.07 34.82 LB-17 41.82 39.29 --

16.8 16.8 13.8 14.1 13.8 14.1 18.2 -- 11.9 --

LIMA BEANS

92.1 0.052 0.0 0.0 18.7 16.7 13.0 14.5 -- 0.202 0.0 0.0 26.7 23.8 11.9 13.9

93.2 0.372 0.0 0.0 27.2 24.0 17.2 10.8 92.9 0.148 0.0 0.0 20.6 19.7 15.6 13.0 92.1 0.794 0.0 0.0 19.1 20.3 19.1 11.3 92.0 1.22 0.0 0.0 24.6 25.7 18.9 8.0 90.8 -- >1500sec** >1500sec** 23.7 7.0*** 13.5 55.2***

BRUSSELS SPROUTS

BS-3 13.91 13.42 -- 88.7 0.293 330sec** llOsec** 62.0 69.6 55.6 37.2 BS-4 13.15 12.42 -- 94.4 0.645 1000sec** 290sec** 75.5 66.0 75.6 43.8

*Ascorbic a c i d ana lyses were n o t c o r r e c t e d f o r d i f f e r e n c e s i n t h e amount of water i n t h e vege tab les . **Time f o r c o l o r change i n peroxidose test; no c o l o r change i n > 210 sec o r < 6% r e s i d u a l peroxidase

i n d i c a t e s adequate blanching. ***Sample may have been l e f t a t room tempera ture t o o long be fo re f r e e z i n g .

p r o p e r l y , could r a p i d l y b lanch and cool v e g e t a b l e s . The h igh c h l o r o p h y l l convers ion shown f o r b r u s s e l s s p r o u t s i n Run BS-4 r e s u l t e d from t h e condi- t i o n s of overb lanching d i scussed ear l ier .

E f f l u e n t Genera t ion and S team Consumption of Blanchers

Table 11 compares t h e wastewater produced by v a r i o u s b lanching tech- n iques . The d a t a r e p o r t e d by Bomben, e t a l . (1975) w a s from s m a l l scale t e s t s , and inc luded cool ing . The d a t a r e p o r t e d by Lund (1974) and Ralls and Mercer (1974) w a s t aken e i t h e r i n p i l o t p l a n t s o r commercial p roduct ion l i n e b l a n c h e r s , and they do n o t i n c l u d e coo l ing .

The o r g a n i c wasteload f o r snap beans and l i m a beans from t h e s p i r a l v i b r a t o r y b lancher -cooler was e s s e n t i a l l y t h e same as t h a t found by Bomben, e t a l . (1975) i n t h e i r small scale tes ts of conven t iona l steam blanching and a i r c o o l i n g w i t h condensate spray . The h y d r a u l i c l o a d from the v ib ra - t o r y b lancher -cooler p i l o t p l a n t w a s less t h a n t h a t from t h e small scale tes ts done by Bomben, e t a l . (1975) probably because t h e p i l o t p l a n t used a l a r g e r r a t i o o f a i r t o v e g e t a b l e s and t h u s had more e v a p o r a t i o n du r ing coo l ing .

The r e s u l t s of o t h e r work done on a p i l o t p l a n t o r p roduc t ion l i n e scale shown i n Table 11 do n o t i nc lude t h e was te load from c o o l i n g , and t h e r e f o r e they cannot be d i r e c t l y compared t o t h e r e s u l t s of t h i s work. Except f o r hot-gas b lanching , t h e v i b r a t o r y s p i r a l b lancher -cooler g e n e r a l l y produced about t h e same o r less o rgan ic was te load f o r bo th b lanching and coo l ing t h a n d i d t h e o t h e r s f o r blanching a lone . It should a l s o be noted t h a t i n t h e case of snap beans , t h e work c i t e d h e r e (Lund, 1974; Ral l s and Mercer, 1974) w a s blanching f o r canning , and t h u s t h e beans were hea ted t o lower tempera tures ; a lower product tempera ture probably produced less was te load .

S ince b lanching i s t h e major sou rce of o r g a n i c was te load i n most v e g e t a b l e p rocess ing p l a n t s ( R a l l s and Mercer, 1973) , r e d u c t i o n o r e l i m i - n a t i o n of i t s was te load w i l l have a major e f f e c t on t h e p l a n t e f f l u e n t . Even though i t e l i m i n a t e s e f f l u e n t comple te ly f o r snap beans , hot-gas blanching does n o t do t h i s f o r a l l v e g e t a b l e s ( R a l l s and Mercer, 1974). I n a d d i t i o n t h i s technique i s dependent on i n c r e a s i n g l y scarce n a t u r a l g a s a s a h e a t sou rce , which w i l l probably prec lude i t s be ing used commercially. The s m a l l h y d r a u l i c l oad from t h e v i b r a t o r y s p i r a l b lancher -cooler would s i g n i f i c a n t l y reduce t h e volume of p l a n t wastewater t h a t had t o be t r e a t e d .

T a b l e 12 g i v e s t h e steam use f o r v a r i o u s b lanching systems. The ca lcu- l a t i o n s f o r t h e t h e o r e t i c a l steam requirement and f o r t h e steam equ iva lence of hot-gas b lanching are shown i n t h e Appendix (Tab le A-8). s p i r a l blancher-cooler h a s t h e h i g h e s t steam e f f i c i e n c y , t h e r e b y showing t h e e f f e c t i v e n e s s of i t s seals a g a i n s t steam leakage and i t s double w a l l i n s u l a t i o n . The low e f f i c i e n c y of conven t iona l steam b lanche r s i s r e a d i l y a p p a r e n t , and even w i t h t h e newly des igned h y d r o s t a t i c steam b lanche r s , t h e e f f i c i e n c y i s low as compared t o the v i b r a t o r y s p i r a l blancher-cooler . Although t h e hot-gas blanching p i l o t p l a n t h a s a h i g h e r e f f i c i e n c y than

The v i b r a t o r y

36

TABLE 11. WASTELOAD PRODUCED BY DIFFERENT BLANCHING TECHNIQUES

Blanching Technique Hydraul ic Load

(L/kkg)

Organic Load BOD TOC ss

V i b r a t o r y S p i r a l Blancher-Cooler*

0.36 0.55

0.084 0.54

Snap beans (Galagreen) 27 L i m a beans (Kings ton) 2 8

0.53 0.90

Water Blanching w i t h Air/Water Spray Cooling*

L ima beans (Kings ton) 1000 2.15 0.93 --

S t e a m Blanching and A i r Cooling w i t h Cond. Spray +

0.37 0.60

Snap beans (Galagreen) 50 L i m a beans (Kings ton) 40

Steam Blanching +

and Water Cooling

1.5 2.8

Snap beans (Galagreen) 5100 L ima beans (Kings ton) 5100

Steam Blanching wi thou t Cooling**

120 240

0.55 3.5

0.02 -- Snap beans L i m a beans

Water Blanching wi thou t Cool ine

U Snap beans Snap beans** L ima beans**

0.61 -- 600

340 820

3.2

0.65 --

-- Hot-Gas Blanch- i n g wi thou t Cooling U

< 0.01 Snap beans 0.06 < 0.01 --

*This work 'Bomben, e t a l . (1975)

**Lund ( 1974 ) u R a l l s and Mercer (1974)

37

TABLE 12. ENERGY USE I N BLANCHING

Steam Blanching Technique Requirement E f f i c i e n c y

(kg/kkg) (%I

The o ret i cal* 134 100

Vib ra to ry Blancher-Cooler** 158 85

Convent iona l Steam** Blancher

+ H y d r o s t a t i c S team B 1 anc he r

Hot-Gas Blanching* (steam e q u i v a l e n t )

2580 5

500 27

240 56

60 Conventional Water Blancher ff --

*See Appendix, Table A-8

'Ray (1975) and Layhee (1975) **This work

*Estimated us ing in fo rma t ion g iven by Lazar and Rasmussen (1964)

commercial steam b l a n c h e r s , i t s e f f i c i e n c y i s s u b s t a n t i a l l y lower than that of t h e v i b r a t o r y s p i r a l blancher-cooler. No measurement of t h e steam con- sumption of t h e water b l anche r s i n t h e p roduc t ion l i n e was made, n o r w a s i t p o s s i b l e t o f i n d any steam consumption measurements f o r water b l anche r s r e p o r t e d i n t h e l i t e r a t u r e . The e f f i c i e n c y r e p o r t e d i n Table 12 f o r water b l anche r s w a s e s t i m a t e d from remarks made by Lazar and Rasmussen (1964). Gene ra l ly , i t appea r s r easonab le that t h e e f f i c i e n c y of water b l a n c h e r s would be h i g h e r t h a n t h a t of conven t iona l steam b l a n c h e r s since water b l a n c h e r s have less s u r f a c e area f o r h e a t l o s s and they do no t d i s c h a r g e a s much steam t o t h e su r round ings a t t h e f e e d and d i scha rge .

Cos t E s t i m a t e s

Table 13 shows t h e c a p i t a l c o s t of f o u r b l anche r s . S ince conven t iona l steam b lanche r s are u s u a l l y cus tom- fab r i ca t ed , a c c u r a t e purchase c o s t s could n o t be ob ta ined ; t h e r e f o r e , i t w a s dec ided no t t o i n c l u d e t h i s type of b l anche r i n t h e c o s t a n a l y s i s . The h y d r o s t a t i c steam b l a n c h e r can be viewed as an improved v e r s i o n of a conven t iona l steam b l a n c h e r , and except f o r steam e f f i c i e n c y , i t s c o s t i s probably s imilar t o t h a t of conven t iona l steam b lanche r s . Except f o r the hot-gas b l a n c h e r , equipment purchase c o s t s were based on equipment manufac tures ' p r i c e q u o t a t i o n s f o r a c a p a c i t y of k . 5 kkg/ h r ( 5 t o n s / h r ) of snap beans (2.0 minute b lanching t ime) . The purchase c o s t

38

TABLE 13. CAPITAL INVESTMENT FOR BLANCHERS AND COOLERS

I t em+ Vib ra to ry Water H y d r o s t a t i c Ho t -Ga s S p i r a l Blanc h e r Steam B 1 anc he r B 1 anc he r - Cooler

B 1 anc he r

1. Equipment purchase $108,000 $1 6,000 $ 87,000 $12 7,000 c o s t

2. Del ivery 5,000 1,000 4 , 000 6,000

3. I n s t a l l a t i o n 22,000 3,000 17,000 25,000

4 . Floor space 4,000 2,000 9,000 25,000

5. I n d i r e c t c o s t s 35,000 6,000 30,000 46,000

$1 74,000 $28,000 $1 47,000 $229,000

+ 1.

2.

3.

4 .

5.

Equipment purchase c o s t s were obta ined from equipment manufactures , except f o r t h e Hot-Gas Blancher whose c o s t w a s t aken from Ralls and Mercer (1974) and c o r r e c t e d t o 1976 p r i c e s by t h e Marsha l l and Stevens Eqiupment Cost Index ( P e t e r s and Timmerhause, 1968). The water b lancher and hot-gas b lancher inc luded an estimate of $5,000 f o r a coo l ing flume.

5% of t h e equipment purchase c o s t .

20% of t h e equipment purchase c o s t . L

Floor space w a s v l a l u e d a t $270/mL. e s t i m a t e d as fo l lows:

F loor space requi rements are

2 2 Vib ra to ry S p i r a l Blancher-Cooler ------ 1 5 m

6m H y d r o s t a t i c Steam Blancher ------------ 33m2

93m2

Water b lancher ........................ Hot-Gas Blancher ......................

25% of t h e t o t a l o f i t e m s 1 t o 4.

39

of t h e hot-gas b lancher w a s based on t h e c o s t s r e p o r t e d by R a l l s and Mercer (1974). Other items i n e s t i m a t i n g d i r e c t f i x e d c a p i t a l were taken as per- cen tages of equipment purc ase c o s t ( P e t e r s and Timmerhaus, 1968). F loor

2 space w a s va lued a t $270/m’ ($25 / f t ). The purchase c o s t s of t h e water b l anche r ( r e e l t y p e ) and hot-gas b lancher inc luded $5,000 f o r a flume c o o l e r . The v i b r a t o r y s p i r a l blancher-cooler and t h e h y d r o s t a t i c steam blancher have t h e c o o l e r a s an i n t e g r a l p a r t of t h e b lancher .

Table 1 4 shows t h e l a b o r , c a p i t a l r e l a t e d , and u t i l i t y and waste treat- ment c o s t s f o r t h e f o u r b l a n c h e r s , as w e l l as t h e b a s i s used f o r c a l c u l a t i n g t h e s e c o s t s . Since t h e open mesh conveyor b e l t s used i n t h e h y d r o s t a t i c and hot-gas b l anche r s probably r e q u i r e more maintenance than t h e conveying sys- terns used i n t h e v i b r a t o r y s p i r a l o r water b l a n c h e r , h i g h e r maintenance c o s t s were used f o r t he former. There were no d a t a a v a i l a b l e f o r t h e was te load of h y d r o s t a t i c steam b lanche r s ; t h e r e f o r e , t h e i r wastewater c o s t s w a s c a l c u l a t e d from the wasteload of conven t iona l steam blanching w i t h flume coo l ing (Table 11). The wa te r use and was te load f o r flume c o o l i n g were added t o t h o s e of water b lanching and hot-gas blanching t o g e t a n o v e r a l l c o s t of water and wastewater f o r t h e s e sytesms.

The l o w c a p i t a l investment needed f o r a water b l anche r i s t h e r eason f o r i t s lowes t c o s t o f o p e r a t i o n . The lower c o s t s of steam, water and wastewater t r ea tmen t f o r t h e v i b r a t o r y s p i r a l b lancher -cooler as compared t o t h e water b lancher and flume were i n s u f f i c i e n t t o compensate f o r t h e lower c o s t s a s s o c i a t e d w i t h c a p i t a l investment . A doubl ing i n t h e combined c o s t of u t i l i t i e s and wastewater t rea tment would g i v e t h e v i b r a t o r y s p i r a l b lancher -cooler an o p e r a t i n g cos t e q u i v a l e n t t o t h a t of t h e water b lancher and flume. c a p i t a l r e l a t e d c o s t s , w h i l e t h a t of t h e h y d r o s t a t i c steam blancher i s because o f c a p i t a l r e l a t e d and steam c o s t s .

The hot-gas b l a n c h e r ’ s h igh c o s t i s a t t r i b u t a b l e most ly t o high

No a t t e m p t w a s made i n t h e s e c a l c u l a t i o n s t o account f o r t h e loss of v e g e t a b l e weight when a i r c o o l i n g i s used. I f f r o z e n vege tab le s ’ are va lued a t $44O/kkg ($0 .20 / lb ) , a 2% l o s s of y i e l d r e s u l t i n g from a i r coo l ing as compared t o flume c o o l i n g (Bomben, e t a l . , 1975) would add t h e e q u i v a l e n t of $8.8O/kkg t o t h e c o s t of b lanching and coo l ing s i n c e f rozen v e g e t a b l e s are marketed by weight . Such a l a r g e p e n a l t y f o r a i r c o o l i n g cannot be economica l ly j u s t i f i e d . A s t a n d a r d o t h e r than weight f o r market ing f rozen v e g e t a b l e s (e .g . number of v e g e t a b l e s per package o r t o t a l s o l i d s per package) would be r equ i r ed t o take f u l l advantage of t h e wastewater reduc- t i o n p o s s i b l e w i t h a i r coo l ing . One should a l s o n o t e t h a t a t a p r i c e of $44O/kkg f o r f rozen v e g e t a b l e s , t h e e n t i r e c o s t of b lanching and coo l ing i s less t h a n 2% of t h e c o s t of product ion . The s m a l l impact of blanching and cool ing on t h e t o t a l c o s t of product ion g i v e s t h e p rocesso r l i t t l e economic i n c e n t i v e f o r c a p i t a l inves tment i n new b lanche r s o r c o o l e r s .

Table 15 g i v e s a comparison of t h e c o s t of t h e v i b r a t o r y s p i r a l b lancher (wi thou t c o o l e r ) and t h e water b lancher (wi thout f lume) a s t h e y would be used f o r canning v e g e t a b l e s . A l l o t h e r c o n d i t i o n s of t h e c o s t c a l c u l a t i o n remain t h e same. The water b lancher s t i l l g i v e s t h e lower c o s t of o p e r a t i o n , and h e r e aga in a doubl ing i n t h e combined c o s t of f u e l , water and wastewater t r ea tmen t would make t h e c o s t o f o p e r a t i n g t h e v i b r a t o r y s p i r a l b lancher

40

TABLE 14. COST OF BLANCHING AND COOLING FOR FREEZING ($/kkg)*

+ Vibra to ry S p i r a l Water Hydro s t a ti c Hot-Gas I t e m B 1 anc he r -C o o 1 er B 1 an c he r Steam B 1 an c he r B 1 an c he r

1. 2.

3. 4. 5.

6. 7. 8. 9.

Opera t ing l a b o r Supe rv i s ion , f r i n g e b e n e f i t s , l a b o r a t o r y , e tc .

Maintenance Lkprecia t i o n Insu rance , t a x e s , o t h e r expenses

Steam E l e c t r i c i t y Water Wa s te wa t e r

T o t a l Cost

0.63 0.41 1.04

Labor Cos t s 0.63 0.63 0.63 0.41 0.41 0.41 1.04 1.04 1.04

C a p i t a l Re la t ed Cos ts 0.69 0.11 1.17 1.82 1.37 0.22 1.17 1.82 1.10 0.18 0.94 1.46 3.16 0.51 3.28 5.10

U t i l i t i e s and Waste Treatment Costs 1.24 1.75 3.91 1.40 0.05 0.01 0.03 0.46 0.00 0.66 0.64 0.64 0.01 1.30

0.15 2.57

0.14 4.72

0.12 2.62

5.50 4.12 9.04 8.76

*Annual product ion - 4.5 kkg/hr x 1 4 h r s /day x 200 days /yr = 12,600 kkg/yr

'1. 1 /4 m a d s h i f t f o r o p e r a t i o n and 1 /4 m a d s h i f t f o r c l e a n i n g (2 s h i f t s / d a y ) w i t h average hour ly wage = $5/hr: $0.57/ ton .

2(2 + 2 ) $5/(14 x 4.5) = $0.63/kkg =

2. Supe rv i s ion , f r i n g e b e n e f i t s , l a b o r a t o r y , s u p p l i e s , e tc . = 65% of opera- t i n g l abor .

3. Maintenance = 5X of d i r e c t f i x e d c a p i t a l / y r f o r v i b r a t o r y s p i r a l and water b l anche r s and 10% of d i r e c t f i x e d c a p i t a l f o r h y d r o s t a t i c steam and hot-gas b l anche r s .

4. Deprec ia t ion = 10% of d i r e c t f i x e d c a p i t a l / y r .

5. In su rance , t a x e s and o t h e r f i x e d expenses = 8% of d i r e c t f i x e d c a p i t a l l Y r

6. Steam = $7.83 kkg of steam ($3.55/1,000 l b s team). S team c o s t f o r Hot-Gas b lancher i n c l u d e s c o s t of g a s ($0.0013/MJ). ( Johnnie and Aggarwal , 1977.

( con t inued)

41

TABLE 14 (cont inued)

7. E l e c t r i c i t y = $0.00389/MJ ($0.018/kw-hr). ( Johnnie and Aggarwal, 1977).

8. Water = $0.13/kL ($0.50/1,000 g a l ) . ( Johnnie and Aggarwal, 1977).

9. Wastewater = $0.018/kL ($0.062/1,000 g a l ) , $O.O22/kg BOD ($O.Ol/lb BOD), These c o s t s are ave rages of v a l u e s r epor t ed $0.044/kg SS ($0.02/ lb SS).

by Carroad (1975). t h e snap bean was te loads shown i n Table 11, wi th t h e a d d i t i o n of flume coo l ing water (4900 l / k k g , 1 . 6 kg/kkg BOD) f o r t h e water and Hot-Gas b l anche r s (Bomben, e t a l . 1975).

To ta l wastewater c o s t i s t h e sum of t h e s e c o s t s f o r

equa l t o t h a t of t h e water b lancher . l e n t t o a 7.2% annual i n c r e a s e f o r t e n y e a r s ) . By removing t h e n e c e s s i t y of c o o l i n g , t h e f i x e d c a p i t a l investment of t h e v i b r a t o r y s p i r a l equipment i s reduced by 53%, whi le f o r t h e water blancher t h e removal of t h e flume reduced the investment by o n l y 28%.

(A doubl ing i n c o s t s would be equiva-

42

TABLE 15. COST OF BLANCHING WITHOUT COOLING FOR VIBRATORY SPIRAL BLANCHER AND WATER BLANCHER

Vib ra to ry S p i r a l Water B 1 anc he r B 1 anc he r

1. Opera t ing l a b o r 2. Superv i so r , f r i n g e

b e n e f i t s , etc.

3. Maintenance 4. Deprec ia t ion 5. Insurance , t axes ,

e tc .

6. Steam 7. E l e c t r i c i t y 8. Water 9. Wa s te wa t e r

Purchase Cost De l ive ry I n s t a l l a t i o n F l o o r Space I n d i r e c t Cos ts

Labor Cos t s ($ /kkg)

0.63 0.41 1.04

Capi t

0.33 0.65 0.52 1.50

0.63 0.41 1.04

1 Rela ted Cos t s ($ /kkg)

0.08 0.16 0.13 0.37

U t i l i t i e s and Waste Treatment Cos t s ($ /kkg)

1.24 0.01

0.02* 1.27

T o t a l Cost 3.81

F ixed C a p i t a l Inves tmen t ($ )

51,000 2,500

10,200 2, ooo(+)

16 1400 $82 , 100

1.75 0.01 0.02 0.02 1.80

3.21

11,400 60 0

2,300 1 , 700 4,000

$ 2 5 3 m

* Wast load w a s t aken as t h a t of a conven t iona l steam b lanche r . + 7.5m 2

43

REFERENCES

AOAC. 1965. O f f i c i a l Methods of Ana lys i s , 1 0 t h ed. A s s o c i a t i o n of O f f i c i a l A g r i c u l t u r a l Chemists, Washington, D. C. p 308.

ASTM. 1968. Manual on Sensory Tes t ing Methods. American S o c i e t y f o r Tes t ing Methods, STL No. 434.

Bomben, J. L., W. C. D i e t r i c h , D. F. Fa rkas , J. S. Hudson, E. S. D e Marchena, and D. W. Sanshuck. 1973. P i l o t p l a n t e v a l u a t i o n of I n d i v i d u a l Quick Blanching (IQB) f o r v e g e t a b l e s , J. Food sci . 38:590.

Bomben, J. L. , G. E. Brown, W. C. D i e t r i c h , J. S. Hudson, and D. F. Farkas . 1974. I n t e g r a t e d blanching and coo l ing t o reduce p l a n t e f f l u e n t . Proceedings of t h e 5 t h Na t iona l Symposium on Food P rocess ing Wastes, Monterey , CA. EPA-660/2-74-058. U. S. Environmental P r o t e c t i o n Agency , C o r v a l l i s , Oregon. p 120.

Bomben, J. L . , W. C. D i e t r i c h , J. S. Hudson, H. K. Hamilton, and D. F. Farkas . 1975. Y i e l d s and s o l i d s l o s s i n steam b lanch ing , coo l ing and f r e e z i n g vege tab le s . J. Food Sc i . , 40:660.

Brown, G. E. , J. L. Bomben, W. C. D i e t r i c h , J. S. Hudson, and D. F. Farkas . 1974. A reduced e f f l u e n t blanching-cool ing method us ing a v i b r a t o r y conveyor. J. Food Sc i . 38:89.

Car road , P. A. 1975. Economic a n a l y s i s of a nove l method f o r c l ean ing us ing r o t a t i n g rubbe r d i s c s . MBA t h e s i s , U n i v e r s i t y of C a l i f o r n i a , Berkeley.

Commercial Mfg. Supply Co. 1975. Catalog No. 375, Fresno , C a l i f .

D i e t r i c h , W. C . , and H. J. Neumann. 1968. Blanching B r u s s e l s s p r o u t s . Food Tech. 19 (5 ) : 150.

EPA. 1971. Methods f o r Chemical Ana lys i s of Water and Wastes. 16020-- 07/71. Environmental P r o t e c t i o n Agency, C i n c i n n a t i , Ohio.

Johnn ie , C. C., and Aggarwal, D. K. 1977. C a l c u l a t i n g p l a n t u t i l i t y c o s t s . Cher.. Eng . Progr . 73 (1 1 ) : 84.

Layhee, P. 1975. FF l i n e y i e l d s 5 b ig p roduc t ion b e n e f i t s . Food Engin. 47(2):61.

44

Lazar, M. E., D. B. Lund, and W. C. Dietrich. 1971. IQB: A new concept in blanching. Food Tech. 25:684.

Lazar, M. E. and C. R. Rasmussen. 1964. Dehydration plant operations. In "Food Dehydration." Avi Publishing Co., Vol. 2, p 132.

Lund, D. B. 1974. Wastewater Abatement in Canning Vegetables by IQB Blanching. Office of Research and Development. EPA-660/2-74-006. U.S. Environmental Protection Agency, Washington, D.C.

National Canners Association. 1971. Liquid Wastes from Canning and Freezing Fruits and Vegetables. 12060 EDK. Environmental Protection Agency, Washington, D.C.

Peters, M. S. and K. D. Timmerhaus. 1968. Plant Design and Economics for Chemical Engineers, 2nd ed. McGraw-Hill, New York.

Ralls, J. W. and W. A. Mercer. 1973. Low Water Volume Knzyme Deact ration of Vegetables Before Preservation. EPA-R2-73-198. U.S. Environmental Protection Agency, Washington, D.C.

Ralls, J. W. and W. A. Mercer. 1974. Continuous In-Plant Hot-Gas Blanching of Vegetables. EPA 660/2-74-091. U.S . Environmental Protection Agency, Corvallis, Oregon.

Ray, A. 1975. Steam blancher uses 50% less energy. Journal Food Processing, 36(1) p. 64.

Sharf, J. M. 1966. Frozen fruits, vegetables, and precooked frozen foods. In "Recommended Methods for the Microbiological Examination of Foods," 2nd ed. p 97. American Public Health Association, New York.

Soderquist, M. R. 1975. Characterization of Fruit and Vegetable Processing Wastewaters. WRRI-28. Water Resources Research Institute, Oregon State University, Corvallis, Oregon.

Weckel, K. G., R. S. Rambo, H. Eloso, and J. H. von Elbe. 1968. Vegetable Canning Process'Wastes. Res. Rpt. No. 39. College of Agricultural and Life Sciences, Univ. Wisconsin-Madison.

45

APPENDIX

TABLE A-1. EQUIPMENT SETTINGS FOR SNAP BEANS

Run Heater* Number* * Holder Cooler Air Flow No. E c c e n t r i c of Weights T ime E c c e n t r i c a t Blower

3 Weight on Holder on - off Weight S e t t i n g (set) Se t , t ing (m /min)

SB-1 t o SB-3 7 SB-4 t o SB-11 7 SB-12 t o SB-28 7 SB-2 9 6 SB-30 6 SB-31 5 SB-32 t o SB-34 3 SB-3 5 0

On con t inuous ly 7 II

II

7 9

20 - 10 9 On con t inuous ly 9

9 9 9

II

I t

11

150 150 150 150 150 150 150 150

up f l o w i n c o o l e r down f low i n c o o l e r

11 II 1 1 II

1 1 I t 11 I1

II II I 1 11

11 II 1 1 II

11 II 11 II

fl I? II I 1

* A s e t t i n g of 0 gave a v i b r a t i o n ampl i tude of 0.95 an (3 /8 i n . ) , 7 gave 0.64 an (1 /4 i n . ) ** With 1 weight t h e v i b r a t i o n ampl i tude w a s 0.32 c m (1/8 i n . )

TABLE A-2. EQUIPMENT SETTINGS FOR LIMA BEANS

Run He a te r * Number * * Holder Cooler*** Air Flow No. E c c e n t r i c of Weights T ime E c c e n t r i c a t Blower

3 Weight on Holder on - off Weight S e t t i n g (set) S e t t i n g (m /min)

f LB-1 LB-2 t o LB-5 LB-6 t o LB-7 LB-8 t o LB-10 LB-11 LB-12 t o LB-13 LB-14 t o LB-15 LB-16 t o LB-17

On con t inuous ly 5 - 12.5

On con t inuous ly 11

I I

10 - 10 10 - 10 10 - 10

150 150

140 140 150

150

a5

a5

Up f l o w i n II I I II

II 11 II

1 1 II 11

II 11 II

II 11 1 1

II 11 11

Down f low

* A s e t t i n g of 0 gave a v i b r a t i o n ampl i tude of 0.95 cm ( 3 / 8 i n . ) and 7 gave 4.8 mm (3/16 i n . ) ** With 1 weight t h e v i b r a t i o n ampli tude was 0.32 c m (1 /8 i n . )

*** A s e t t i n g of 0 gave a v i b r a t i o n ampl i tude of 0.96 c m ( 3 / 8 i n . ) and 7 gave 6 . 4 mm (1/4 i n . )

c o o l e r 11

II

11

II

II

II

i n c o o l e r

TABLE A-3. EQUIPMENT SETTINGS FOR BRUSSELS SPROUTS, CAULIFLOWER AND BROCCOLI

Run Heater* Number * * Holder Cooler*** Air Flow No. E c c e n t r i c of Weights T i m e E c c e n t r i c a t Blower

3 Weight on Holder on - off Weight S e t t i n g ( s e c 1 S e t t i n g ( m /min)

BS-1 10 BS-2 t o BS-4 10 BS-5 10

B r u s s e l s Sp rou t s

1 10 - 40 9 1 10 - 40 10 1 10 - 30 10

150 150 150

Caul i f lower

c-1 8 1 30 - 15 10 150

Brocco l i

B-1 a -2

10 1 15 - 1 5 IO**** 150 10 1 Continuous IO**** 150

* A s e t t i n g of 0 gave a v i b r a t i o n ampl i tude of 0.95 cm ( 3 / 8 i n . ) and 7 gave 4.8 mm ( 3 / 1 6 i n . )

** With 1 weight t h e v i b r a t i o n ampl i tude w a s 0.32 cm ( 1 / 8 i n . ) *** A s e t t i n g of 0 gave a v i b r a t i o n ampl i tude of 0.96 c m ( 3 / 8 i n . ) and

7 gave 6.4 mm (1 /4 i n . )

10 gave no v i b r a t i o n **** The s e t t i n g was 2.5 cm ( 1 i n . ) beyond 10; 3.8 an (1.5 i n . ) beyond

48

TABLE A-4. MATERIAL BALANCE AND WASTELOAD

Yie ld = Wet Weight of cooled v e g e t a b l e s (kg) (% 1 Wet Weight of raw v e g e t a b l e s (kg)

x 100 S o l i d s l o s s = Hydraul ic l o a d (L/kkg) TS i n e f f l u e n t (%) ( X ) 1000 TS i n raw v e g e t a b l e s ( X )

Hydraul ic load = Weight of e f f l u e n t (kg) looo (L/kg) (L/kkg) Weight of raw v e g e t a b l e s (kg)

BOD = (BOD a n a l y s i s i n mg/L) x h y d r a u l i c (L/kkg) l o a d x ( kg/ kkg 1

TOC and SS were c a l c u l a t e d s i m i l a r l y t o BOD

49

TABLE A-5. EFFLUENT ANALYSES - SNAP BEANS

T o t a l S o l i d s ss TOC BOD Raw E f f l u e n t ' Ef f luent ' r r E f f l u e n t E f f l u e n t E f f l u e n t

SB-1 P SB-2 P SB-3 P SB-4 P SB-5 P SB-6 P SB-7 P SB-8 P SB-9 P SB-10 P SB-11 P SB-12 P SB-13 P SB-14 B SB-15 B SB-16 P SB-17 B SB-18 P SB-19 B SB-20 B SB-21 B SB-22 B SB-23 B SB-24 C SB-25 B SB-26 P SB-27 C SB-28 C SB-29 B SB-30 C SB-31 C SB-32 B SB-33 B SB-34 P SB-35 C SB-36 C SB-37 C

10.76 10.76 10.76 10.35 10.25

9.23 10.65 10.45 10.05 10.98 11.78 12.92 13.54 13.51 9.53

13.31 14.69 14.22 15.59 16.21

9.56 12.67 15.88

9.28 9.49

12.84 10.46

9.35 9.43

10.23 9.90 9.33 8.86 9.84

10.16 10.97 10.75

-- -- -- 2.37 -- 1151

1500 2.43 -- 1.96

3. 18

3.39 3.01 3.63 3.19 Not enough e f f l u e n t f o r sample 3.79 31200 5610 Not enough e f f l u e n t f o r sample 3.39 29700 4140 3.12 28700 3660 Not enough e f f l u e n t f o r sample

-- -- -- -- --

-- -- -- -- --

-- -- -- -- -- -- -- --

1 1 I I I I 1 1 I I

1 1 I I 1 1 11 I I

I I 1 1 I I I I I I

3.99 3 9000 4310 Not enough e f f l u e n t f o r sample

3.87 38900 4300 2.97 28900 32 60 2.89 29700 32 00 4.20 40000 4 600 3.59 35000 3390 3.38 32200 3410 3.80 36000 4000 3.29 30500 3750 2.69 24800 2600 2.46 24600 2 700 2.67 26500 2.81 25700 2920 3.48 32400 43 50 3.54 3 43 00 4300

1 1 I 1 1 1 1 1 1 1

--

12000 9750 9880 86 80

11 500

12300 11 700 14600 12000

14200

12130 10700

-- --

14300

13500 10 700 10500 15300 12900 12100 14600 11250

9000 82 50

10800 13800 13 800

--

*P = pre l imina ry r u n B = ba tch run C = cont inuous run + Using AOAC, 1965

ft Using EPA, 1971

50

TABLE A-6. EFFLUENT ANALYSES - LIMA BEANS

T o t a l S o l i d s ss TOC BOD I

Raw Ef f luen tT E f f l u e n t 7 ' E f f l u e n t E f f l u e n t E f f l u e n t

P i l o t P l a n t

LB-1 P LB-2 P LB-3 P LB-4 P LB-5 P LB-6 P LB-7 P LB-8 B LB-9 B LB-10 C

36.12 5.40 -- 10700 14300 Run s topped -- 4.63 -- 51 80 13800

Run s topped 1 1 II

-- -- 10800 13800 41.29 7.21 -- 14200 18200 40.65 4.53 43000 8900 13800 38.46 7.50 71 500 17400 20200 Run s topped

--

LB-11 C 40.86 LB-12 C 40.72 LB-13 C 41.60 LB-14 C 35.92 LB-15 C 36.09 LB-16 B 38.70 LB-17 C 41.82

LBPL-1 b lanching 36.08 c o o l i n g

LB PL -2 b lanching 35.35 c o o l i n g

LBPL-3 blanching 35.37 c o o l i n g

* P = pre l imina ry run B = b a t c h r u n C = cont inuous run

. PL = product ion l i n e

7.30 71 800 14800 17700 7.72 77 800 17500 19800 7.53 68300 14900 18300 7.11 6 9800 -- 24800 6.65 65400 27200 22800 Not enough e f f l u e n t f o r sample -- -- -- --

Produc t ion L ine

1.14 10400 762 32 40 1.69 3330 2 80 70 8

1.24 12100 1840 3670 0.238 23 90 84 230

1.54 15000 1830 4700 0.542 53 70 388 1400

+ Using AOAC, 1965 +k Using EPA, 1971

18800

15600

19800 2 9400 21200

--

-- --

2 8800 19800 2 82 00

581 0 1700

82 00 5 80

8500 3200

51

TABLE A-7. EFFLUENT ANALYSES - BRUSSELS SPROUTS, CAULIFLOWER AND BROCCOLI

T o t a l S o l i d s ss TOC BOD K a W

Run Number Veget. * + (% 1 (% 1 (mg/L 1 (mg/L 1 (mg/L) (mg/L 1

Brusse l s Sp rou t s

-- -- -- -- -- -- BS-1 P BS-2 P 14.2 Not enough e f f l u e n t f o r sample BS-3 P 14.1 2.76 25800 34 90 9970 BS-4 P 13.2 2.08 20740 2290 7500 BS-5 P Run s topped

-- --

Caulif lower

c-1 P 8.45 Not enough e f f l u e n t f o r sample

Brocco l i

B-1 P 10.1 Not enough e f f l u e n t f o r sample B-2 P 11.8 3.53 33300 8230 13600 --

* Using AOAC, 1965 + Using EPA, 1971

52

TABLE A-8. CALCULATION OF THEORETICAL STEAM FLOW REQUIRED FOR BLANCHING

Condi t ions :

R a w v e g e t a b l e tempera ture - 16°C Blanched vege tab le tempera ture - 88°C Heat of condensa t ion of steam - 2256 kJ /kg

With no h e a t l o s s e s :

Heat i n from condensing steam = h e a t ou t w i t h product

- 134 kg steam - kkg r a w v e g e t a b l e

For Hot-Gas Blancher ( R a l l s & Mercer, 1974) blanching peas:

Steam use = 170 kg/kkg

N a t u r a l g a s = 1.64 m /kkg 3

1.64 x 37300 kJ/m3 = 61100 kJ /kkg steam e q u i v a l e n t = 61100/2256 = 27.1 kg/kkg

6 3 steam e q u i v a l e n t = 91.4 x 10 /(2256 x 10 ) = E l e c t r i c a l power = 91.4 MJ/kkg ( c i r c u l a t i n g f a n )

T o t a l steam e q u i v a l e n t

E f f i c i e n c y =

40.5 kg/kkg

= 170 + 27.1 + 40.5 = 238 kg/kkg

134 x 100 = 56% 238

53

TECHNICAL REPORT DATA (Please read Instructions on the reverse before completing)

REPORT NO. 12. 13. RECIPIENT'S ACCESSIONNO.

UNCLASSIFIED

EPA-600/2-78-206 T I T L E A N D S U B T I T L E

64

VIBRATORY SPIRAL BLANCHER-COOLER

15. REPORT D A T E

AUTHOR^)

E.L.Durkee, D.F.Farkas J.L.Bomben, J.S.Hudson, W.C.Dietrich,

PERFORMING O R G A N I Z A T I O N N A M E A N D ADDRESS USDA- SEA Western Regional Research Center 800 Buchanan Street Berkeley, CA 94710

Industrial Environmental Research Laboratory Office of Research and Development U . S . Environmental Protection Agency Cincinnati , Ohio 45268

2. SPONSORING AGENCY N A M E A N D ADDRESS

5. SUPPLEMENTARY NOTES

September 1978 issuing date 6. PERFORMING O R G A N I Z A T I O N CODE

8. PERFORMING O R G A N I Z A T I O N REPORT N O

10. P R O G R A M E L E M E N T NO.

1BB610 11. C O N T R A C T / G R A N T NO.

S-803312

13. TYPE OF REPORT A N D PERIOD COVERED

FINAL REPORT 7/74-1/77 14. SPONSORING AGENCY CODE

I

EPA/600/12

The objective of this demonstration project was to test the commercial feasi- bility of the vibratory spiral blancher-cooler, a newly designed steam blancher and air cooler that previous small scale tests showed could reduce the wasteload and energy consumption of preparing vegetables for freezing.

The results of these protype tests showed the following:

1. The unit reduced the hydraulic wasteload of conventional blanching and cooling by several orders of magnitude and the organic wasteload by as much as 80%.

2. The steam efficiency of the blancher was 85%, which exceeds by 17 times that measured for a conventional stean blancher.

3 . Sensory tests were done only with the snap-beans and lima beans. Those samples produced by the vibratory spiral blancher-cooler were judged either equal o r superior in flavor and texture to those conventionally blancher and cooler.

__.. 7. K E Y WORDS A N D DOCUMENT A N A L Y S I S

DESCRIPTORS _______

Food Processing Vegetables Freezing Economic Analysis

68 D

Wastewater Characteristi

Process Modification Blanching

I I

5 . DISTRIBUTION S T A T E M E N T (19. SECURITY CLASS (ThisRepor t ) 121. NO. OF PAGES

RELEASE TO PUBLIC

t U S GOIRNMLNTPRlNTlNGORIC[ 1978-657-06011488 54 EPA Form 2220-1 (9-73)

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Cincinnati, Ohio 45268

7%. I

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