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Rice Industrial By-products Management forOil Extraction and Value Added Products

By

MIAN KAMRAN SHARIF

B.Sc. (Hons.) Agri. Major Food Technology (UAF)M.Sc. (Hons.) Food Technology (UAF)

A dissertation submitted in partial fulfillment of requirements for the degree of

DOCTOR OF PHILOSOPHY

IN

FOOD TECHNOLOGY

NATIONAL INSTITUTE OF FOOD SCIENCE AND TECHNOLOGY

UNIVERSITY OF AGRICULTUREFAISALABAD, PAKISTAN

2009


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To

The Controller of Examinations,

University of Agriculture,

Faisalabad.

The members of the Supervisory Committee find the thesis submitted by Mr.

Mian Kamran Sharif (Regd. 96-ag-1478) satisfactory and recommend that it be

processed for evaluation by External Examiner(s) for the award of degree.

CHAIRMAN(Dr. Masood Sadiq Butt)

MEMBER(Prof. Dr. Faqir Muhammad Anjum)

MEMBER(Dr. Haq Nawaz)


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DEDICATED

TO

HAZRAT MUHAMMAD(Peace Be Upon Him)

&my parents

who taught me to be responsible and professional in any field


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ACKNOWLEDGEMENTS

I am extremely thankful to ALMIGHTY ALLAH (The Merciful) whoblessed to complete this piece of research work presented in this study. I presentmy humble gratitude from the deep sense of heart to the HOLY PROPHETMUHAMMAD (Peace Be Upon Him), that without him the life would havebeen worthless.

I expand my deepest appreciation to my affectionate supervisor,Dr. Masood Sadiq Butt,Associate Professor, National Institute of Food Scienceand Technology, University of Agriculture, Faisalabad for his great help,illuminating guidance, and consistent encouragement during planning,execution, and final presentation of this piece of research work

With a deep emotion of gratitude, I express the sincere thanks to

Prof. Dr. Faqir Muhammad Anjum, Director General, National Institute Food

Science and Technology, University of Agriculture, Faisalabad for his

sympathetic attitude and cooperation in the preparation and finalization of this

manuscript.

I am also grateful to my committee member,Dr. Haq Nawaz, AssociateProfessor, Institute of Animal Nutrition and Feed Technology for hiscompassionate attitude and kind cooperation provided during my researchproject.

I also thank my friends and fellow students, who made my busy andboring life more interesting. I am also grateful to Mr. Tauseef Sultan, Mr.Muhammad Nasir, Miss Saima Hafeez Khan, Mr. Akmal Nazir, Mr. KashifKhan, Muhammad Issa Khan and Dr. Mumtaz Shaheenwho helped me dayand night for final presentation of this dissertation.

Finally I would like to convey my sincere admiration to my father MianMuhammad Sharif, mother, brother, Sisters and my wife who were alwaysvery kind to provide moral and financial support during the track of this study.

(Mian Kamran Sharif)


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TABLE OF CONTENTS

S. No. Contents Page #

List of Abbreviations iAcknowledgement iiList of Tables viiList of Figures xiList of Appendices xiiAbstract xiii

1. INTRODUCTION 12. REVIEW OF LITERATURE 82.1. Rice bran: an overview 82.1.1. Physiology and general characteristics 82.1.2. Anti-nutritional factors 92.1.3. Dietary fiber 112.2. Processing of rice bran 122.3. Rice bran oil and its components 142.3.1. Current status 142.3.2. General characteristics 152.3.3 Effective components 162.3.4. Utilization 212.3.5. Economic Feasibility 222.4. Hypocholesterolemic effects of rice bran and rice bran oil 22

2.4.1. Rice Bran 222.4.2. Rice Bran Oil 252.4.3. Cholesterol-lowering mechanisms 302.5. Supplementation in baked products 322.5.1. Bread 332.5.2. Cookies 353. MATERIALS AND METHODS 373.1. Materials 373.2. Rice bran processing 373.2.1. Rice bran stabilization 37

3.2.2. Denaturation of anti-nutritional factors 383.3. Stabilization and anti-nutritional appraisal 383.3.1. Lipase activity 383.3.2. Peroxide value 383.3.3. Thiobarbituric acid no. 383.3.4. Haemagglutinin-lectin activity 393.3.5. Trypsin inhibitor activity 39


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3.3.6. Phytates 392.4. Raw Materials Analysis 393.4.1. Proximate analysis 393.4.2. Mineral analysis 403.5. Rice bran oil 41

3.5.1. Extraction 413.5.2. Refining 413.5.3. Yield 413.5.4. Quality of refined rice bran oil samples 413.5.5.

Antioxidants potential42

3.5.6.Fatty acid profile

43

3.6.Selection of best treatment

43

3.7. Efficacy studies for safety evaluation 43

3.7.1.Experimental plan

44

3.7.2.Analysis of serum profile

45

3.7.2.1. Liver function tests 453.7.2.2. Renal function tests 453.7.2.3. Lipid profile 453.8. Product development 46

3.8.1. Preparation of rice bran oil cookies 463.8.1.1 Quality attributes of cookies 463.8.1.1.1. Physical analysis 463.8.1.1.2 Proximate analysis 473.8.1.1.3. Total acidity 473.8.1.1.4. Thiobarbituric acid no. 473.8.1.1.5. Sensory evaluation 473.8.2. Preparation of rice bran supplemented flours 473.8.3. Analysis of rice bran supplemented flours 483.8.3.1. Proximate analysis 483.8.3.2. Mineral analysis 483.8.3.3. Dietary fiber 483.8.3.4. Thiobarbituric acid no. 493.8.3.5. Dough rheological studies 493.8.4. Preparation of rice bran supplemented cookies 503.8.5. Preparation of rice bran supplemented leavened pan bread 503.8.6. Analysis of rice bran supplemented cookies and bread 513.8.6.1. Physical analysis 51


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3.8.6.2. Mineral analysis 513.8.6.3. Dietary fiber 513.8.3.4. Sensory evaluation 513.9. Statistical Analysis 524. RESULTS AND DISCUSSIONS 53

4.1 Stabilization and anti-nutrition appraisal 534.1.1. Lipase activity 544.1.2. Peroxide value 564.1.3. Thiobarbituric acid no. 564.1.4. Haemagglutinin-lectin activity 574.1.5. Trypsin inhibitor activity 594.1.6. Phytates 594.2. Raw materials analysis 604.3. Rice bran oil 634.3.1. Refining 63

4.3.2. Yield 634.3.3. Quality evaluation 634.3.4. Fatty acid profile of RBO 684.3.5. Antioxidants potential 714.3.5.1. Oryzanol 714.3.5.2. Tocopherols and tocotrienols 734.3.6. Selection of best sample 744.4. Efficacy studies 754.4.1. Physical parameters of rats 754.4.1.1. Feed intake 75

4.4.1.2. Water intake 754.4.1.3. Gain in body weight 784.4.1.4. Organ weight 794.4.2. Renal and Kidney functioning tests 814.4.3. Serum biochemical profile 814.4.3.1. Cholesterol 834.4.3.2. High density lipoprotein (HDL) 884.4.3.3. Low density lipoprotein (LDL) 914.4.3.4. Triglycerides (TG) 914.4.3.5. Glucose 954.4.3.6. Serum proteins 974.5.

Product development99

4.5.1. Preparation of rice bran oil cookies 994.5.1.1. Physical analysis 994.5.1.2. Proximate analysis 1024.5.1.3. Total acidity 1074.5.1.4. Thiobarbituric acid no. 107


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4.5.1.5. Sensory evaluation 1094.5.2. Preparation of rice bran supplemented flours 1154.5.2.1. Proximate analysis 1164.5.2.2. Mineral analysis 1244.5.2.3. Dietary fiber 127

4.5.2.4. Thiobarbituric acid no. 1294.5.2.5. Dough rheological studies 1324.5.2.5.1. Mixographic studies 1324.5.2.5.2. Farinographic studies 1364.5.3. Preparation of rice bran supplemented cookies 1414.5.3.1. Physical analysis 1424.5.3.2.

Mineral analysis145

4.5.3.3. Dietary fiber 1474.5.3.4. Sensory evaluation 147

4.5.4. Preparation of rice bran supplemented leavened pan bread 1544.5.4.1. Mineral analysis 1544.5.4.2. Dietary fiber 1574.5.4.3. Sensory evaluation 1594.5.4.3.1. External characteristics 1594.5.4.3.2. Internal characteristics 1655. SUMMARY 175

RECOMMENDATIONS 180LITERATURE CITED 181APPENDICES 206


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LIST OF TABLES

S. No. Title Page #

1. Utilization of RBO in cookies 46

2. Rice bran supplemented flours used in study 48

3. Treatments used for preparation of rice bran supplemented cookies 50

4. Treatments used for preparation of leavened pan bread 51

5. Mean squares for FFA, POV and TBA no. of rice bran samples 55

6. Effect of stabilization on FFA, POV and TBA no. of rice bransamples

55

7. Effect of storage on FFA, POV and TBA no. of rice bran samples 558. Anti-nutritional factors in rice bran samples 58

9. Proximate composition of fullfat rice bran samples and commercialstraight grade flour

62

10. Mineral analysis of rice bran samples 62

11. Proximate composition of defatted rice bran samples 62

12. Yield of rice bran oil from different bran samples 65

13. Quality characteristics of rice bran oil samples 65

14. Fatty acid composition of rice bran oil samples 70

15. Mean squares for antioxidants in rice bran oil samples 72

16. Mean squares for physical parameters of different groups of rats 76

17. Mean squares for organs weight of different groups of rats 80

18. Effect of diets on organs weight of different groups of rats 80


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19. Organs weight of different groups of rats during study periods 80

20. Mean squares for serum kidney and liver function tests 82

21. Effect of diets on serum kidney and liver function tests in differentgroups of rats

82

22. Serum kidney and liver function tests in different groups of ratsduring study periods

82

23. Mean squares for lipid profile and serum glucose in differentgroups of rats

84

24. Effect of diets on serum lipid profile and glucose (mg/dL) indifferent groups of rats

84

25. Serum lipid profile and glucose (mg/dL) in different groups of ratsduring various study periods

84

26. Mean squares for serum proteins in different groups of rats 98

27. Effect of diets on serum proteins in different groups of rats 98

28. Serum proteins in different groups of rats during study periods 98

29. Mean squares for physical analysis of RBO cookies 100

30. Physical analysis of RBO cookies 100

31. Effect of storage on physical analysis of RBO cookies 100

32. Mean squares for proximate composition of RBO cookies 103

33. Proximate composition of RBO cookies 10534. Effect of storage on proximate composition of RBO cookies 105

35. Mean squares for total acidity and TBA no. of RBO cookies 108

36. Total acidity and TBA no. of RBO cookies 108

37. Effect of storage on total acidity and TBA no. of RBO cookies 108

38. Mean squares for sensory attributes of RBO cookies 111

39. Color scores of RBO cookies 112

40. Flavor scores of RBO cookies 112

41. Taste scores of RBO cookies 112

42. Texture scores of RBO cookies 114

43. Crispness scores of RBO cookies 114

44. Overall acceptability scores of RBO cookies 114

45. Mean squares for proximate composition of supplemented flours 117


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46. Moisture content of supplemented flours 118

47. Crude protein of supplemented flours 120

48. Crude fat of supplemented flours 122

49. Crude fiber of supplemented flours 12350. Ash content of supplemented flours 125

51. Nitrogen free extract of supplemented flours 126

52. Mean squares for mineral content of supplemented flours 128

53. Mineral contents of supplemented flours 128

54. Mean squares for dietary fiber and TBA no. of supplemented flours 130

55. Dietary fiber content of supplemented flours 130

56. TBA no. of supplemented flours 131

57. Mean squares for mixographic characteristics of supplementedflours

134

58. Mixing time of supplemented flours 134

59. Peak height of supplemented flours 135

60. Mean squares for farinographic characteristics of supplementedflours

137

61. Water absorption of supplemented flours 137

62.

Dough development time of supplemented flours 14063. Dough stability of supplemented flours 140

64. Mean squares for physical parameters of rice bran supplementedcookies

143

65. Physical analysis of rice bran supplemented cookies 144

66. Effect of storage on physical analysis of rice bran supplementedcookies

144

67. Mean squares for minerals of rice bran supplemented cookies 146

68.

Mineral contents of rice bran supplemented cookies 14669. Mean squares for dietary fiber of rice bran supplemented cookies 148

70. Dietary fiber content of rice bran supplemented cookies 148

71. Mean squares for sensory attributed of rice bran supplementedcookies

149

72. Color, flavor and taste scores of rice bran supplemented cookies 150


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73. Effect of storage on color, flavor and texture of rice bransupplemented cookies

150

74. Texture, crispness and overall acceptability scores of rice bransupplemented cookies

153

75. Effect of storage on texture, crispness and overall acceptability ofrice bran supplemented cookies

153

76. Mean squares for mineral contents of rice bran supplementedbreads

156

77. Mineral contents of rice bran supplemented breads 156

78. Mean squares for dietary fiber of rice bran supplemented breads 158

79. Dietary fiber of rice bran supplemented breads 158

80. Mean squares for external characteristics of rice bran

supplemented breads

161

81. Volume and crust color scores of rice bran supplemented breads 162

82. Effect of storage on volume and crust color of rice bransupplemented breads

162

83. Symmetry and evenness of bake scores of rice bran supplementedbreads

164

84. Effect of storage on symmetry and evenness of bake of rice bransupplemented breads

164

85. Character of crust scores of rice bran supplemented breads 16686. Effect of storage on character of crust of rice bran supplemented

breads166

87.

88.

Mean squares for internal characteristics of rice bran supplementedbreads

Grains and crumb color scores of rice bran supplemented breads

167

169

89. Effect of storage on grains and crumb color scores of rice bransupplemented breads

169

90. Aroma and taste scores of rice bran supplemented breads 171

91. Effect of storage on aroma and taste of rice bran supplementedbreads

171

92. Texture scores of rice bran supplemented breads 173

93. Effect of storage on texture of rice bran supplemented breads 173


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LIST OF FIGURES

S. No. Title Page #

1 Feed intake in different groups of rats (per rat/day) during sixweeks

77

2 Water intake in different groups of rats (per rat/day) during sixweeks

77

3 Percent decrease in gain in body weight in different groups ofrats (per rat/week) during six weeks

77

4 Percent decrease of cholesterol in different groups of rats 85

5 Percent increase of HDL in different groups of rats 89

6 Percent decrease of LDL in different groups of rats 92

7 Percent decrease of triglycerides in different groups of rats 94

8 Percent decrease of glucose in different groups of rats 96


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LIST OF APPENDICES

S. No. Title Page #

I Composition of salt mixture 206

II Composition of vitamin mixture 207

III Performa for sensory evaluation of cookies 208

IV Performa for sensory evaluation of leavened pan bread 209

V Saturated/unsaturated fatty acids profile of rice bran oil 210

VI Micro-nutrient profile of rice bran oil 211


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LIST OF ABBREVIATION

RB Rice bran

FFRB Fullfat rice branDFRB Defatted rice branUn-RB Unstabilized rice branES-RB Extrusion stabilized rice branPAR-RB Parboiled rice branMW-RB Microwave stabilized rice branRBO Rice bran oilPAR-RBO Parboiled rice bran oilMW-RBO Microwave stabilized rice bran oilES-RBO Extrusion stabilized rice bran oil

NS Normal shorteningCSGF Commercial straight grade flourPOV Peroxide valueTBA no. Thiobarbituric acid no.FFA Free fatty acidsUC Unsaponifiable contentTocols Tocopherol and tocotrienolSD-rats Sprague Dawley ratsNFE Nitrogen free extractCVD Cardiovascular disease

TRF Tocotrienol rich fractionHDL High density lipoprotein cholesterolLDL Low density lipoprotein cholesterolTG TriglyceridesTC Total cholesterolALP Alkaline phosphataseALT Alanine amino transferaseAST Aspartate amino transferaseBRBO Bioactive components from rice bran oilSOV Source of variation

df Degree of freedomwk Weekswb Wet basishr Hourmin Minutes

rpm Revolutions per minutes


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ABSTRACT

Rice bran, one of the main by-products of rice milling industry, has beenrecognized as an excellent source of edible oil, protein, dietary fiber and alliedmicronutrients. In Pakistan, it is under-utilized and generally used in poultryfeed and fuel purposes. It contains about 15-20% edible oil, which could

efficiently be used for bridging the oil deficiency in the country. Current researchwas conducted to utilize indigenous rice bran (RB) for oil extraction as well aspreparation of value-added products. Rice bran samples, stabilized by extrusioncooking, microwave heating and parboiling; were analyzed for lipase activityduring 60 days storage. On the basis of analysis, microwave (MW) stabilizationwas found to be the most effective stabilization technique in controlling lipaseactivity. After stabilization, oil was extracted from bran samples and evaluatedfor physical & chemical characteristics, fatty acid profile and antioxidantpotential. In current study, microwave stabilized rice bran (MW-RB) waspreferred on the basis of better stability (FFA, POV and TBA no.), color of oil and

high antioxidant potential. MW stabilized fullfat rice bran (FFRB); its defattedportion (DFRB) and extracted oil (RBO) were used for efficacy studies andpreparation of value added products. The diets prepared from selectedtreatments alongwith control were fed to four groups of SD-rats for 45 days andevaluated for physical and hematological parameters. The rats fed on RBO diethad the highest feed intake (19.21g/rat/day); water intake (37.81mL/day) andgain in body weight (7.24g per rat/week). Mean squares for organs weight, renaland liver functioning tests exhibited non-significant differences with respect todiets and study periods in different groups of rats. Animals fed on RBO, FFRBand DFRB resulted significant reduction in serum cholesterol, LDL and

triglycerides. It was concluded that experimental diets imparted no adverseeffects on the animal growth and improved serum profile of SD-rats; showingsuitability of RB and RBO for product development. In the 2 ndphase of research,RBO was supplemented in cookies by replacing normal shortening. It wasconcluded that rice bran oil can successfully be used for preparation of cookiesupto 40-60%. Moreover, FFRB and DFRB were mixed separately with commercialstraight grade flour in different proportions and analyzed for chemicalcomposition and rheological behavior to find out the most appropriatecompositions showing suitability for preparation of cookies and leavened bread.Later, cookies and leavened breads were prepared from selected FFRB and DFRBsupplemented flours. On the basis of physicochemical and sensory assay, it wasconcluded that cookies can be supplemented 10-20% and leavened pan breadupto 15% with either type of rice bran without affecting nutritional and sensoryquality attributes. From the present investigation, it is concluded that rice branhas a potential to be used for oil extraction and preparation of value addedproducts. This will not only be helpful to fulfill the countrys edible oilrequirement but also to cope with the protein deficiency in the communities atrisk through bran supplemented value added products.


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Chapter-I

INTRODUCTION

Rice (Oryza sativa) is the 2ndleading cereal crop and staple food of half of

the worlds population. It is grown in at least 114 countries with global

production of 645 million tons; share of Asian farmers is about 90% of the total

produce. In Pakistan, rice is the 3rdlargest crop after wheat and cotton. During

fiscal year 2007-08, it was cultivated on an area of 2515 thousand hectares with

production of 5563 thousand tons (IRRI, 2008; GOP, 2008).

In the developing countries, budding dilemma of food crisis, arising due

to lower crop yields and escalating population, needs to utilize each pent ofavailable resources. In order to provide enough food to all people, there is the

holistic approach of using the by-products generated during food processing and

preparations. Rice is being processed in well established industry but the major

apprehension is the utilization of its by-products; rice bran (5-8%) and polishing

(2-3%) that are going as waste. Rice processing or milling produces several

streams of materials including milled rice, bran and husk. In developing

countries, rice bran is considered as a by-product of the milling process andcommonly used in animal feed or discarded as a waste. The potential of

producing rice bran at the global level is 29.3 million tons annually while the

share of Pakistan is worked out to be 0.5 million tons (FAO, 2001; GOP, 2008).

Rice bran, brown outer layer of rice kernel, is mainly comprised of

pericarp, aleuron, subaleuron layer and germ. It contains appreciable quantities

of nutrients like protein, fat and dietary fiber. Furthermore, it contains

substantial amount of minerals like K, Ca, Mg and Fe. Presence of antioxidants

like tocopherols, tocotrienols and - oryzanol also brighten prospects of rice bran

utilization for humans (Gong and Yao, 2001; Moldenhauer et al., 2003).

Although, overall composition and nutritional profile of rice bran holds

significant importance yet presence of anti-nutritional compounds such as


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phytates, trypsin inhibitors, pepsin inhibitors, hemagglutinins and antithiamine

factors prove to be a major hindrance in its possible food applications. Presence

of some higher quantities of lipases render instability to oil fractions as these

enzymes are released during milling and act upon triglycerides thus increasingthe free fatty acid content (Lima et al., 2002; Ahmed et al., 2007).

The effective utilization of rice bran is possible only by deactivating the

lipase enzyme responsible for the hydrolytic degradation of rice bran

constituents (Martin, 1994). Stabilization is an effective treatment turning rice

milling by-products into valuable dietary constituents. Various stabilization

techniques like heat treatment, low temperature storage, chemical treatment,

controlling storage relative humidity, simultaneous milling & extraction andmicrowave heating have evolved to inactivate lipase (Ramezanzadeh et al., 2000;

Lakkakula et al., 2004). These have resulted in emergence of rice bran as an

important by-product of rice milling industry. Heat treatment is effective and

resultant product could be stored at refrigerated temperature upto 16 weeks

without imparting antinutritional effects and allied quality attributes. Microwave

heating is considered as more effective method for the inactivation of lipase,

responsible for rice bran degradation (Ramezanzadeh et al., 1999; Ramezanzadeh

et al., 2000). In rice bran, dipolar water molecules are excited by the

electromagnetic waves and are made to spin. The resultant enhanced kinetic

energy, alongwith friction, produces heat that results in the even distribution of

heat having deleterious effects on lipase activity. Moreover, microwave heat had

little effect on nutritional quality and the functional property of rice bran.

In recent years, rice bran has been recognized as a potential source of

edible oil. It contains 15-20% oil, depending upon degree of milling, variety and

other agro-climatic factors (Marshall and Wadsworth, 1994; Lima et al., 2002).

Globally, during last few decades, efforts were made towards exploiting the non-

conventional sources for oil extraction and value addition; special attention has

been paid towards edible oil/food supplements from food processing by-


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products. Rice bran oil (RBO) holds unique nutritional profile and is of high

nutraceutical worth. Recently, scientists have also shown tremendous interest in

exploring the cholesterol lowering properties of RBO. It is extensively used in

Japan, Korea, China, Taiwan and Thailand as a Premium Edible Oil (Ghosh,2007). In Japan and some western countries, it is more popularly known as a

Heart Oil and acquired the status of Health Food (CAC, 2003). Rice bran and

its oil can be utilized for value addition of cereals based food products to attain

multiple benefits.

RBO contains oleic acid (38.4%), linoleic acid (34.4%), and linolenic acid

(2.2%) as unsaturated fatty acids while palmitic (21.5%) and stearic (2.9%) acids

as saturated fatty acids. A potential advantage of RBO over other oils withsimilar fatty acid composition is its oxidative stability imparted by high levels of

tocopherols, tocotrienols and -oryzanol and its cholesterol lowering ability (Kim

and Godber, 2001; Wilson et al., 2000). It also contains high amount of

unsaponifiable matter i.e. 4.2% including phytosterols. It improves plasma lipid

and lipoprotein profiles by interrupting absorption of intestinal hydrophobic

compounds. RBO also lowers total serum cholesterol and low density lipoprotein

concentrations without effecting high density lipoproteins (Wilson et al., 2000;

2007; Most et al., 2005). The occurrence of peculiar components such as oryzanol

and tocotrienols in RBO are responsible for its hypocholesterolemic worth

(Vissers et al., 2000; Nagao et al., 2001).

Rice bran oil is rich source of natural vitamin E that is complex of eight

chemically distinct molecules: , , and -tocopherol; , , and -tocotrienol.

Palm oil and RBO represent two major nutritional sources of natural tocotrienol

(Sen et al., 2007). Oryzanol is nutritionally and medicinally important constituent

of rice bran oil that reduces cholesterol oxidation. The percentage of oryzanol in

crude RBO ranged from 1.9 to 2.2%. In Japan it is widely used as natural

antioxidant in foods and cosmetics. It has functions similar to vitamin E in

promoting growth, facilitating capillary growth in the skin and improving blood


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circulation along with stimulating hormonal secretion (Luh et al., 1991; Xu and

Godber, 1999; Xu et al., 2001).

Although rice bran has been recognized as an excellent source of vitamins

and minerals yet it has been under-utilized in human diet and in Pakistan 90% isbeing used primarily in animal feeds (Moldenhauer et al., 2003). Proteins are

more concentrated in the rice bran and are unique in their nutritional value,

which is quite comparable with that of its endosperm protein or protein from

any other cereal or legume. The protein of rice bran is highly digestible and

hypoallergenic food ingredient (Helm and Burks, 1996; Tang et al., 2003).

Supplementation of wheat flour with rice bran or its defatted portion

holds potential to uplift the nutritional profile of cereal based food products withspecial reference to protein, lysine and dietary fiber contents. Research

interventions conducted in the past decade highlighted that stabilized full-fat

rice bran up to 20% level and unstabilized full-fat or stabilized defatted rice bran

upto 10% are suitable in various food preparations (Singh et al., 1995). However,

in yeast leavened pan bread formulations, rice bran can be substituted upto 15%

of the wheat flour without affecting loaf volume (Sharp and Kitchens, 1990).

Rice bran is an excellent source of dietary fiber ranging from 20-51%

(Saunders, 1990). Rice bran fiber has laxative effect with increased faecal output

and stool frequencies. Soluble fibers have gained popularity to reduce the

postprandial glycemia in normal and diabetic subjects. It acts like a sponge and

absorbs water in the intestine, mixes the food into gel and there by slows down

the rate of digestion and absorption (Abdul and Yu, 2000). Use of 1g of soluble

fiber can lower total cholesterol by about 0.045mmol/L. Researchers have also

observed 29% less risk of coronary heart disease for each additional intake of 10g

of fiber daily (Rimm et al., 1996; Brown et al., 1999). Possible health claims of

consumption of rice bran and its defatted portion include increased faecal bulk

and reduced blood cholesterol owing to its dietary fiber contents (Abdul and Yu,

2000).


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The research was carried out using indigenous rice cultivar i.e. Basmati

Super. Although lot of research has been carried out on various aspects of rice

bran abroad but in our study we have focused on the local cultivar to explore its

potential for human as little or no effort has been made earlier in Pakistan onextraction of oil form rice bran. There are many factors like soil, environment,

cultural and agronomic practices etc. which have pronounced effects on the grain

quality characteristics. Moreover this work will provide information to the

scientific community, farmers and industrialist about the value addition in rice.

In Pakistan, rice is the 3rdlargest crop after wheat and cotton and it is one of the

major foreign exchange earning crops mainly in the form of Basmati super (upto

40% export) which is liked throughout the world due to its specific aroma.Basmati Super is processed in well established modern mills with production of

good quality rice kernel and bran as a by-product. Other fine rice cultivars and

coarse varieties (for local use) are usually processed through conventional

shellers and bran produced is of poor quality due to more contamination of

endosperm and husk in the resultant bran. So bran of Basmati Super was chosen

due to better quality and relatively higher yield of oil.

Pakistan is confronting with the problem of food security especially in

edible oils. Some of our conventional oil crops like cotton seed,

rapeseed/mustard, sunflower and canola are used for extracting edible oil but

they only account for 29% of domestic requirements (GOP, 2008) and rest is

imported resulting in huge drainage of foreign exchange. During 2007-08,

Pakistan spent US$ 1217 and $ 92.1 millions on the import of palm oil (unsuitable

due to high melting point) and soybean oil from Malaysia and US, respectively.

Rice bran oil (RBO) production is feasible for the region, where bran can be made

available in abundance within stipulated period during rice milling. Rice bran oil

needs no extra land for cultivation. Moreover, its utilization in baked products

will not only explore its functional and nutraceutical role but also contribute

towards value addition in rice sector. Extraction of RBO through solvent and


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utilization of stabilized rice bran and its defatted portion in cereal based food

products could also play an important role in minimizing current food crisis.

Moreover, RBO as a cooking medium and its meal for supplementation in wheat

flour reckon its prospects in lowering the blood glucose and cholesterol toimprove consumers health.

There are many challenges involved with the utilization of rice bran in

Pakistan. The main challenge is its utilization as feed ingredient due to low price.

Poultry feed mainly comprised of rice bran. This industry procures almost all

barn from rice industry for its utilization throughout the year. As Pakistan is the

6thmost populous country of the world and it population is still increasing with

high rate. Now it is very difficult to feed this population. Utilization of rice branfor human will results in some relief on grain crops because it can be efficiently

supplemented in baked products both in full fat form as well as after oil

extraction. Another challenge was the stability of rice bran during storage.

Although rice bran is considered an excellent source of edible oil but the main

problem is its inherent enzyme system especially lipases which results in

splitting of triglycerides into free fatty acid and make it unfit for human

consumption. Moreover extracted oil will be of poor quality and results in

economic loss during refining process. So in present study, one of the objectives

was to find out the most suitable stabilization technique. For the purpose, rice

bran samples were stabilized through different stabilization techniques like

extrusion, microwave heating and parboiling and stored for two months. On the

basis of lees FFA production, peroxide value and TBA no., microwave technique

was preferred. Microwave heating is considered to be one of the most energy-

efficient and rapid method for heating foods. In rice bran, dipolar water

molecules are excited by the electromagnetic waves and are made to spin. The

resultant enhanced kinetic energy, alongwith friction, produces heat that results

in the even distribution of heat having deleterious effects on lipase activity.

Moreover, microwave heat had little effect on nutritional quality and the


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functional property of rice bran. MW heating is now used at household level so it

is feasible in terms of technical and commercial point of view.

The present project was planned to achieve the following objectives: Utilization of rice industrial by-products for oil extraction and its quality

evaluation

The prospects of blending oil and bran for the preparation of value addedproducts i.e. cookies and leavened pan bread

Efficacy study; to study the effect of selected compositions on feed, waterintake and body weight of Sprague Dawley Rats

To determine the effects of selected compositions of RBO andsupplemented flours on serum bio-chemical profile with special referenceto lipid profile of Sprague Dawley Rats.


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Chapter-II

REVIEW OF LITERATURE

Rice bran, a by-product of rice milling industry, is composed of pericarp,aleurone and subaleurone layers, parts of the germ and small portion of the

starchy endosperm. It is rich in vitamins, minerals, amino acids, dietary fiber,

essential fatty acids and plant sterols like -oryzanol, tocopherol and tocotrienol

having promising health-related benefits. Besides its exceptional nutritional

profile, it is currently used as animal feed and fuel source. The literature

available pertaining to different aspects of the present study has been reviewed

under the following headings:

2.1 Rice bran: an overview

2.2 Processing of rice bran

2.3 Rice bran oil and its components

2.4 Hypocholesterolemic effects of rice bran and its oil

2.5. Supplementation in baked products

2.1. Rice Bran: An Overview

2.1.1. Physiology and general characteristics

Rough rice (paddy) is composed of a white starchy rice kernel tightly

covered by a coating of bran, enclosed in a tough siliceous hull (Lakkakula et al.,

2004). When husk is removed, bran layer comes in direct contact with air,

resulting in the development of off-flavor in brown rice due to its endogenous

lipase. Moreover, the appearance of brown rice is not appealing due to its color

(Saunders, 1990). Hence further processing of rice is required to remove the bran

from brown rice to produce white rice (Hu et al., 1996). It is consumed after

appropriate polishing to give a desired degree of whiteness (Juliano, 1985).

Rice bran constitutes about 10% of the weight of rough rice (Hu et al.,

1996). It is comprised of pericarp, aleurone, sub-aleurone, seed coat, nucellus

along with the germ and a small portion of endosperm (Salunkhe et al., 1992;


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Hargrove, 1994). The percentage and composition of rice bran vary according to

the rice variety, pretreatment before milling, type of milling system and the

degree of milling (Saunders, 1990). Rice bran is light in color, sweet in taste,

moderately oily and has a slightly toasted nutty flavor (Hu et al., 1996). Texturevaries from a fine, powder-like consistency to a flake, depending on the

stabilization process (Barber and Benedito de Barber, 1980).

Rice bran contains 12-22% oil, 11-17% protein, 6-14% fiber, 10-15%

moisture and 8-17% ash. It is rich in vitamins including vitamin E, thiamin,

niacin and minerals like aluminum, calcium, chlorine, iron, magnesium,

manganese, phosphorus, potassium, sodium and zinc (Sunders, 1990; Hu et al.,

1996; Xu, 1998). It also contains a significant amount of nutraceutical compoundsand approximately 4% unsaponifiables, mainly comprised of naturally occurring

antioxidant such as tocopherols, tocotrienols and oryzanol (Ju and Vali, 2005).

Rice bran proteins are of high nutritional value (Kennedy and Burlingame,

2003) and hypoallergenic (Tsuji et al., 2001). These proteins are rich in essential

amino acids, especially lysine, hence can be used as ingredients in food recipes

(Wang et al., 1999). Stabilized rice bran is also a good source of both soluble and

insoluble dietary fiber ranging from 20-51% (Saunders, 1990), which is almost twice

as much as that of oat bran. Rice bran can be used as a stool bulking agent

(Tomlin and Read, 1988) and for the enrichment of some foods (Burton, 2000).

2.1.2. Anti-nutritional factors

The effective utilization of rice bran is possible only by deactivating the

lipase enzyme, responsible for the hydrolytic degradation of bran constituents

and denaturation of anti-nutritional factors. Successful developments in the use

of various techniques to stabilize rice bran have resulted in the emergence of rice

bran as an important by-product of the rice milling industry. The following anti-

nutritional factors exist in rice bran:

2.1.2.1. Lipases


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Lipases (E.C. 3.1.1.3) are enzymes that are primarily responsible for the

hydrolysis of triglycerides into glycerol and fatty acids. Rice bran contains

several types of lipases which results in significant increase of the free fatty acids

(FFA) by hydrolyzing the oil. Rapid increase in the free fatty acid occurs withinhours and reaches 7-8% within 24 hours, followed by about 5% increase per day

(Ramezanzadeh et al., 1999; Rukmani, 2002).

Lipase activity is greatly affected by moisture, temperature, pH, time and

water activity (Dunford and King, 2001; Gangodavilage, 2002). The enzyme was

active up to 40C and the activity declined sharply to 65% at 60C and then

gradually decreased (Bhardwaj et al., 2001). In addition to native lipases, the

microbial lipases also deteriorate the nutritional quality of the oil, making it unfitfor human consumption. The hydrolytic rancidity severely affects the nutritive

value and palatability of rice bran (Rajeshwara and Prakash, 1995).

2.1.2.2. Trypsin inhibitors

Trypsin inhibitors are also endogenous enzymes, which can form stable

complex with proteolytic pancreatic enzymes i.e. trypsin and chemotropysin.

Due to complex formation, the activity of these enzymes decreases. Rice bran

contains trypsin inhibitor (Kratzer and Payne, 1977; Deolankar and Singh, 1979).

Approximately 85-95% trypsin inhibitor activity was found in rice embryo. One

mole of rice bran trypsin inhibitor can inhibit two moles of trypsin.

2.1.2.3. Haemagglutinin-lectin

Haemagglutinin-lectins are toxic globulin proteins present in the rice bran

and agglutinate mammalian red blood cells (Ory et al., 1981). Similarly, lectin is a

glycoprotein and is present in germ portion. It comprised of 27% carbohydrate,

predominantly glucose (Takahashiet al.,1973) while another 10% carbohydrate is

mainly in the form of xylose and arabinose (Indravathamma and Seshadri, 1980).

The lectin also contains a large number of glycine and cystine residues (Tsuda,

1979).

2.1.2.4. Phytates


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Phytates (1,2,3,4,5,6-hexaphosphate of myoinositol) occur in discrete

regions of cereal grains and accounts for 85% of the total phosphorous content of

grains. They reduce the bio-availability and digestibility of nutrients by forming

complexes with minerals, protein, digestive enzymes and amino acids mainlylysine, methionine, arginine and histidine (Jangbloed et al., 1991; Bird, 1998). It is

a rich source of minerals particularly phosphorous, zinc and ferrous (Farrell,

1994). Phytic acid showed strong chelating properties due to its structure

(Ramzan, 2000). Phytates also affect the solubility, functionality and digestibility

of proteins and carbohydrates.

2.1.3. Dietary fiber

Dietary fiber is the edible parts of plants or analogous carbohydratesthat are resistant to digestion and absorption in the human small intestine

with partial fermentation in the large intestine (CAC, 1998). These are plant

food materials that are not hydrolyzed by enzymes secreted by the human

digestive tract but may be digested by micro flora in the gut. These plant food

materials include non-starch polysaccharides such as celluloses, some hemi-

celluloses, gums and pectins as well as resistant starches (DeVries, 2001).

The components of dietary fiber include cellulose, hemicellulose, pectins,

hydrocolloids and lignin. These can be classified into two major categories

depending on their solubility in water. In humans, the structural or matrix fibers

(lignins, cellulose, and some hemicelluloses) are insoluble, whereas the natural

gel-forming fibers (pectins, gums, mucilages, and the remainder of the

hemicelluloses) are soluble. Soluble fiber acts like a gel and insoluble fiber adds

bulk or softens stool. Soluble fiber forms a gelatin like substance in the intestine

and increases the water content in stool. It has been shown that soluble fiber

decreases blood cholesterol and sugar after meals in diabetics (Yeager, 1998).

Similarly, insoluble fiber is effective in increasing feeling of fullness, stool size,

bulk and helps to reduce constipation and hemorrhoids. Good sources of soluble


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fibers include fruits, vegetables, legumes, psyllium seeds and oat bran whereas

whole grains are good sources of insoluble fiber (Matz, 1991).

Fiber supplementation has been used to enhance the fiber content of array

of foods. Traditionally, fiber supplementation has focused on the use of millingby-products of cereal grains like wheat, corn, sorghum and other grains (McKee

and Latner, 2000). Nowadays, fiber supplementation has focused in cookies,

crackers, snack foods, beverages, spices, imitation cheeses, sauces, frozen foods,

canned meats, meat analogues and many other cereal-based products (Hesser,

1994). The WHO recommendation for total dietary fiber intake is above 25 g/day

(WHO, 2003).

The total dietary fiber content in stabilized rice bran ranges from 25 to 40%depending on the product (Carroll, 1990). Rice brans fiber comprised of a

relatively low proportion of soluble fiber (713%) and the rest is insoluble fiber

(Anderson et al., 1990). However, rice bran has high percentage of oil (1223%) as

compared to other bran sources, with 4.2% unsaponifiable matter (Sugano and

Tsuji, 1997). Rice bran oil, possibly because of unsaponifiable fraction or its fatty

acid content, lowers cholesterol levels in hamsters, rats, humans and nonhuman

primates (Sharma and Rukmini, 1986; Seetharamaiah and Chandrasekhara, 1989;

Nicolosi et al.,1991; Kahlon et al.,1992; Purushothama et al.,1995).

2.2. Processing of Rice Bran

The processing of rice bran was carried out to inactivate lipases as well as

other nutritional inhibitors in such a way that their toxicity is ruined without

damaging the protein quality of rice bran. Furthermore, it also destroys the field

fungi, bacteria and insects infestation, so that the bran becomes safe from further

deterioration which alternately enhanced its shelf life.

The greatest restriction to the use of rice bran as a food ingredient is its

instability during storage. Upon milling, the oil is exposed to lipases, causing

rapid breakdown to free fatty acids @ 57% of the weight of oil per day. Hence

due to the naturally occurring enzymatic activity and subsequent hydrolytic


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rancidity, it is necessary to stabilize the rice bran by suitable techniques for

controlling undesirable reactions. Bran, after proper stabilization, can serve as a

good source of protein, essential unsaturated fatty acids, calories, and nutrients

such as tocopherols and ferulic acid derivatives.The commonly used stabilization techniques are thermal and chemical

treatments (Randall et al.,1985; Kim et al.,1987). There are different types of heat

stabilization procedures such as retained moisture heating (Lin and Carter, 1973),

added moisture heating (Saunders, 1986), extrusion cooking (Sayre et al., 1982),

microwave heating (Malekian et al., 2000) and Ohmic or electrical heating

(Lakkakula et al.,2004).

Heat stabilization is accomplished commercially by wet or dry heatingmethods i.e. hot air, drum drying, dry extrusion and microwave (Prabhakar,

1987; Narisullah and Krishnamurthy, 1989). Although hot air drying is an

effective method of stabilization, the non-uniform heating of material in the tray

driers limits its application. Rice bran was stabilized by fluidized bed drying at

90-130C (Fernando and Hewavitharana, 1993). Although fluidization provides

uniform heating of bran; however, high air velocities are required for the process;

making it uneconomical (Narisullah and Krishnamurthy, 1989). The stabilized

rice bran was obtained by drum drying at 156C (Delahaye et al., 2005).

Parboiling also results in stabilization of rice bran by destroying lipase activity

(Narisullah and Krishnamurthy, 1989). An edible acid (0.1-2.0% acetic acid)

having anti-oxidative properties was added to parboiled rice bran to maintain

the stability of the bran for at least 6 months at ambient conditions (Tao, 2001).

The common drawbacks in heat treatment methods

are: severe processing conditions capable of damaging

valuable components, substantial moisture removal and

inability to achieve irreversible inactivation of enzyme. To


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cope with these problems, moist heat treatment is

suggested. Extrusion cooking has been found to produce

stable rice bran by holding at 125-130 C for few seconds,

then at 97-99 C for 3 min prior to cooling (Randall et al.,

1985). Heating in the presence of moisture is more effective

for permanently denaturing lipases (Ramezanzadeh et al.,

1999). Long-term storage studies with extrusion cooking

indicate stability against FFA development upto 4 months

(Carroll, 1990; Randall et al., 1985), in contrast to dry heat

methods. Hence steaming is suitable method of bran

pretreatment with respect to decrease in FFA development

and the oil extractability in small-scale (Amarasinghe and

Gangodavilage, 2004). However, less flexibility and higher

initial and operating costs make the process uneconomical.

Furthermore, moist heat results in agglomeration of bran,

resulting in lumpy bran.

To achieve proper stabilization, every discrete bran particle must have

uniform moisture content, depending upon time and temperature. In recent

years, use of microwave energy as an inexpensive source of heat for thermal

processing of foods has offered an alternative energy source for stabilization of

rice bran. It is considered to be one of the most energy-efficient types and a rapid

method for heating food items (Yoshida et al., 2003). Considering other heat

treatments, microwave heating is efficient, economical, shorter in processing

time, minor effect on the nutritional value and has a little or even no effect on the


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Rice bran contains 15-22% oil by weight (Orthoefer, 1996; Patel

and

Walker, 2004). Crude rice bran oil contains 90-96% of saponifiable and about 4%

unsaponifiable lipids. The saponifiable lipids include 68-71% triglycerides, 2-3%

diglycerides, 5-6% monoglycerides, 2-3% free fatty acids, 2-3% waxes, 5-7%glycolipids and 3-4% phospholipids (McCaskill and Zhang, 1999) whereas the

principal component of the unsaponifiable fraction is -oryzanol (Raghuram and

Rukmini, 1995).

Rice bran oil has excellent fatty acid profile. It has oleic acid (38.4 %),

linoleic acid (34.4%) and linolenic acid (2.2%) as unsaturated fatty acids while

palmetic acid (21.5%) and stearic acid (2.9%) as saturated fatty acids (Rukmini

and Raghuram, 1991). The saturated, monounsaturated and polyunsaturatedfatty acids are in the ratio of approximately 1: 2.2: 1.5 (Shin and Chung, 1998;

Krishna, 2002). Three major fatty acids, palmitic, oleic and linoleic make up 90%

of the total fatty acids of the rice bran oil (Amarasinghe and Gangodavilage,

2004).

2.3.3. Effective components

2.3.3.1. Fatty acids

Dietary fat is a crucial factor in the regulation of cholesterol levels and

there is devastating evidence to support the hypocholesterolemic effects of

vegetable oils rich in polyunsaturated fatty acids, mainly linoleic acid (Grundy,

1994). Growing interest in health benefits of polyunsaturated fatty acids has

focused on providing suitable sources of these constituents. Polyunsaturated

fatty acids include linoleic acid (C18:2n6c), -linolenic acid (ALA, C18:3n3), -

linolenic acid (GLA, C18:3n6), arachidonic acid (AA, C20:4n6), eicosapentaenoic

acid (EPA, C20:5n3) and docosahexaenoic acid (DHA, C22:6n3).

Polyunsaturated fatty acids are required in the body for normal

functioning of nervous, immune & inflammatory, cardiovascular, endocrine,

respiratory and reproductive systems (Certik and Shimizu, 1999). Their presence

on membrane phospholipids can influence cellular activities. Fatty acids also


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alter membrane fluidity and consequently modulating changes in conformation

or function of receptors, transporters and enzymes (Calder, 2003).

Edible oils rich in polyunsaturated fatty acids have been reported to result

in a decrease in total cholesterol, triglycerides, low density lipoproteincholesterol as well as the beneficial high density lipoprotein cholesterol (Schaefer

et al.,1981; Mattson and Grundy, 1985). In rice bran oil, the amount of linoleic

acid is moderate, and proportion of oleic acid is a relatively high. Studies have

indicated that RBO has significant hypocholesterolemic effect in both animals

and humans when compared to other oils, inspite of limited polyunsaturated

fatty acids (Rukmini, 1988; Raghuram et al.,1989). The effect has been attributed

to components like tocotrienols, oryzanol and monounsaturated fatty acid(Mediterranean diet). The study with rats fed on RBO diet demonstrated a

significant reduction in total serum cholesterol, LDL-cholesterol and anincrease

in fecal steroid excretion compared with that of peanut oil diet (Rukmini and

Raghuram, 1991). Different research findings proved that unsaponifiable

fractions in RBO could compensate for its high saturated fats and played a

predominant role in decreasing cholesterol levels (Nicolosi et al.,1991; Wilson et

al.,2000).

2.3.3.2. Unsaponifiable matter

Recently, rice bran oil has received attention because of its unique health

benefits (Nicolosi et al.,1994) attributed by its high level of unsaponifiable matter

(Shin et al.,1997). These are bioactive components with nutraceutical value and

cannot be saponified by caustic treatment (Sugano et al., 1999). The

unsaponifiables are mainly composed of sterols (42-43%), triterpene alcohols (24-

28%) and less polar components such as squalene or tocotrienols (19%)

depending on the type of rice bran and method used to extract and refine the

lipids (Sugano and Tsuji, 1997; Lloyd et al.,2000; Dunford and King, 2001).

Crude rice bran oil contains an unusually high content of unsaponifiables

(3-5%) several times greater than most commonly used vegetable oils where as


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refined oil may contain 0.3-0.9%; because most part is removed during refining

(Rong et al.,1997). The content of the unsaponifiable material in refined RBO is

regulated to be 0.5% under the Japan Agricultural Standard; this value is

considerably higher than that of other vegetable oils (Sugano and Tsuji, 1997).The unsaponifiable fraction in RBO also contains a unique complex of naturally

occurring antioxidant, of which the tocopherols, tocotrienols and oryzanol have

received much attention (Sayre et al., 1988). The amount of -tocopherol is

relatively large (0.1% of the total oil) in rice bran oil compared with other

vegetable oils (Nicolosi et al., 1994).

There are several mechanisms by which unsaponifiables improve serum

bio-chemical profile such as by interrupting the absorption of intestinalcholesterol rather increasing the excretion of fat and neutral sterols (Kahlon et al.,

1996; Nagao et al., 2001) and increased fecal steroid excretion through

interference with cholesterol absorption (Ikeda et al., 1985; Sharma and

Rukumini, 1986).

2.3.3.3. Antioxidants

Any substance that delays or inhibits the oxidation of substrate, inspite of

low concentrations, is called antioxidant. The physiological role of antioxidants is

to prevent damage to cellular components arising as a result of chemical

reactions involving free radicals (Halliwell and Gutteridge, 1995).

Several important nutraceutical compounds can be extracted from rice

bran which contains high levels of phytochemicals having antioxidant activities

(Chen and Bergman, 2005). These phytochemicals include vitamin E comprised

of four homologs (, , and ) of tocopherol & tocotrienols (Jariwalla, 2001;

Birringer et al., 2002) and the -oryzanol (Akihisa et al., 2000; Jariwalla, 2001).

Vitamin E is considered to be the major chain-breaking antioxidant especially in

biological membranes (Ricciarelli et al.,2001).

Rice bran is a rich natural source of vitamin E and -oryzanol (Shanggong

et al.,2007). It contains over 300 mg/kg vitamin E (Shin et al.,1997). Vitamin E is


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pale-yellow and viscous oil (Hu et al., 1996). It protects cell membrane by

blocking the oxidation of the unsaturated fatty acids and acting as a scavenger of

free radicals (Komiyama et al., 1992; Nesaretnam et al., 1998). In addition to

health benefits, antioxidants of rice bran and its oil have a potential use asadditives to improve the storage stability and frying quality of foods (Lloyd et al.,

2000; Nanua et al.,2000; Kim and Godber, 2001). RBO is rich in -oryzanol having

antioxidant properties; their structure includes ferulic acid, a strong antioxidant

(Miller and Rice, 1997; Sierra et al.,2005).

2.3.3.3.1. Oryzanol

Oryzanol is a mixture of ferulate (4-hydroxo-3-methoxycinnamic acid)

esters of sterols (campesterol, stigmasterol and -stigmasterol) and triterpenealcohols (cycloartenol, 24-methylenecycloartanol, cyclobranol); about 9.8gkg-1 is

found in rice bran (Xu and Godber, 2000; Fang et al.,2003; Miller et al.,2003). It

was first isolated from rice bran oil by Kaneko and Tsuchiya in 1954 (Kaneko and

Tsuchiya, 1954) and named because it was first discovered in rice bran oil (Oryza

Sativa L.). The most accessible natural source of -oryzanol is rice (Seitz, 1989). -

oryzanol is a white or slightly yellowish, tasteless crystalline powder with little

or no odor and has a melting point of 137.5-138.5oC (Xu and Godber, 2000). It is

insoluble in water, slightly soluble in diethyl ether and n-heptane and practically

soluble in chloroform (Bucci et al., 2003). Initially, it was reported as a single

component in rice bran (Kaneko and Tsuchiya, 1954.) but now it is known a

mixture of at least 10 components (Xu and Godbar, 1999; Kim et al.,2001).

The concentration of -oryzanol in rice bran oil ranges from 115 to

780ppm, depending on the degree and method of processing (Rogers et al.,1993).

-oryzanol is 13-20 times (w/w) in rice bran than total tocopherols and

tocotrienols (Bergman and Xu, 2003). It has been observed that about 20% of

unsaponifiable fraction in RBO is oryzanol (Rong et al., 1997). Different extraction

methods can result in different levels of these components because some


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tocotrienols and tocotrienol-like compounds are bound to cellular components in

the rice bran (Shanggong et al.,2007).

Complete role of -oryzanol as functional ingredient, has not so far

thoroughly been observed whereas health claims like antioxidant activity (Xuand Godber, 2001), reduction of serum cholesterol (Akihisa et al.,2000; Xu et al.,

2001), reduction of cholesterol absorption (Lloyd et al., 2000), increase of HDL

cholesterol (Cicero and Gaddi, 2001), inhibition on platelet aggregation

(Seetharamaiah et al., 1990), inhibition of tumor promotion (Yasukawa et al.,

1998), and menopausal syndrome treatment (Rogers et al., 1993) have been

investigated. -oryzanol reduces serum cholesterol in rats and hyperlipidemic

humans (Seetharamaiah and Chandrasekhara, 1989; Yoshino et al.,1989). It hasbeen proven that -oryzanol has higher antioxidant activity as compared to

tocols; might be due to the similarity between the structure of -oryzanol and

cholesterol (Xu et al.,2001; Godber et al.,1994).

2.3.3.3.2. Tocols (tocopherols and tocotrienols)

Vitamin E consists of tocopherols and tocotrienols collectively known as

tocols. Humans and animals cannot synthesize this vitamin; they primarily

acquire tocols from plants. Tocopherols and tocotrienols differ in number and

positions of methyl groups on the fused chromonol ring, and the absence and

presence of three double bonds in the isoprenoid side chain. The structural

differences of tocotrienols and tocopherols influence their biological activities

(Qureshi et al.,1996).

Tocotrienol has 3 double bonds within the main body of the molecule at

the 3,7 and 11 positions of the hydrocarbon tail. Just like edible oils with high

level of polyunsaturated fatty acids, the presence of these double bonds give

greater fluidity to tocotrienols and make it much easier for the body to

incorporate them into cell membranes (Yap et al., 2001). The major forms of

tocotrienol are -tocotrienol (5,7,8-trimethyltocotrienols), -tocotrienol (7,8-


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dimethyltocotrienol) and -tocotrienol (8-methyltocotrienol) (Xu and Godber,

1999).

Evans discovered tocopherols in 1922 (Evans and Bishop, 1922). Major

forms of tocopherols in rice bran oil are -tocopherol (5,7,8-trimethyltocol), -tocopherol (7,8-dimethyltocol) and -tocopherol (8-methyltocol) (Xu and Godber,

1999). RBO also contains high concentrations of the tocopherols compared with

other oil seeds (Kao and Luh, 1991). Approximately 1.0% (v/v) of the

unsaponifiable fraction of RBO is -tocopherol. HPLC analysis of RBO showed

that 1g of RBO contains 3.02mg of -tocopherol (Qureshi et al.,2000).

Tocotrienols are present in vegetable oils like palm oil and rice bran oil

(Stephens et al., 1996; Qureshi et al., 2000). Barley, oats, palm, and rice branscontain more than 70% tocotrienols known as tocotrienols/tocotrienol rich

fraction (Raghuram and Rukmini, 1995). Two novel tocotrienols d-P21-T3

(desmethyl tocotrienol) and d-P25-T3 (didesmethyl tocotrienol) have been

identified and isolated from stabilized rice bran (Qureshi and Qureshi, 1993;

Qureshi et al.,2000). RBO is a rich source of tocotrienols ranged from 72-1157ppm

depending upon different bran sources and commercial refining methods.

Approximately 1.7% (v/v) of the unsaponifiable fraction of RBO is tocotrienol

(Deckere and Korver, 1996). HPLC analysis of RBO showed that 1g of RBO

contains 0.5mg of -tocotrienol (Qureshi et al., 2000). It has been observed that

human consumption of 240mg/day of tocotrienols upto two years caused no

adverse effects and they are safe at even much higher levels. The content and

biological activities of tocotrienol are higher than those of tocopherols (Qureshi et

al.,2001).

2.3.3.4. Effect of processing on antioxidants

After stabilization, crude oil is extracted and refined before human

consumption. There was a gradual decrease in sterol content in each step of

refining. It has been reported that 10-70% of the total sterols were lost depending

on processing conditions (Kochhar, 1983). The effect of bleaching, deodorization


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and hydrogenation on -oryzanol content in refined oil has not yet been cleared;

it is considered that -oryzanol is mainly lost after neutralization. Similarly,

tocotrienols are also lost during each step of refining. In some cases, upto 90%

losses have been reported, which demands advance refining techniques.2.3.4. Utilization

Rice bran oil with higher thermal and oxidative stability than sunflower

oil can be used for deep fat frying (Krishna et al.,2005). Blending of other oils

with rice bran oil has also been found to improve the stability of the blend during

frying and storage. The high oxidative stability of RBO makes it preferred oil for

frying and baking applications (McCaskill and Zhang, 1999; Semwal and Arya,

2001). The stabilized oil may be useful as spray oil for crackers, nuts, chips andother snack foods. It extends the shelf-life of snack foods due to high levels of

phytosterols which may impart resistance to thermal oxidation and storage

deterioration (Taylor et al.,1996).

2.3.5. Economic Feasibility

Among the food grains, the production of paddy is the highest next to

wheat. In Asian countries, rice is the principal cereal produced and consumed by

the population. In 2001, the world production of paddy was 597.3 MMTs (FAO,

2001). The worldwide estimated potential of rice bran is 29.87 MMTs. However,

the commercial production of RBO in 2000 was estimated to be about 783

thousand tons, extracted with hexane (Perretti et al.,2003). The total potential of

rice bran oil production in the world worked out to be 4.48 MMTs. The Asian

countries alone contribute about 98.4% (4.41 MMTs) of rice bran oil.

In 2007-08, rice was cultivated on an area of 2515 thousand hectares and

yield was 5563 thousand tons. The estimated production of rice bran oil can be

worked out to be 81577-108760 thousand tons. As for as Pakistan is concerned,

out of the non-conventional oil sources, rice bran oil is the most important in

terms of its potential to augment the availability of oils. Full realization of the


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potential will help in reducing the gap between demand and availability of

indigenous edible oils in the country to a significant extent (GOP, 2008).

2.4. Hypocholesterolemic Effects of Rice Bran and Rice Bran Oil

2.4.1. Rice BranScientific studies support recommendations to increase dietary fiber as

part of hyperlipidemia treatment. The hypocholesterolemic effects of rice bran

have been demonstrated in experimental animals (Sharma and Rukmini 1987;

Seetharamaiah and Chandrashekhara 1989; Kahlon et al., 1992) and humans

(Hundemer et al., 1991; Sanders and Reddy, 1992; Hakala et al., 2002).

The cholesterol lowering effects of rice bran (fullfat), soybean fiber, oat

and barley bran were compared in mice adding 0.06% cholesterol in their diets.

Both rice bran and soybean fiber diet had significantly lower total blood

cholesterol compared with placebo. Rice bran was found to be the most effective

supplement in reducing liver and plasma total cholesterol compared to the

control diet. Moreover, mice consuming rice bran diet, demonstrated higher

HDL to total cholesterol ratios (Hundemer et al.,1991). In another study, rats fed

on rice and wheat bran showed significant reduction in liver cholesterol and

triglycerides. The rice bran diet also increased LDL receptor activity in the liver

more than the wheat bran, hence, effectively lowering plasma cholesterol levels

(Topping et al.,1990).

The cholesterol lowering effects of fullfat and defatted stabilized rice bran,

parboiled rice bran and rice bran in combination with wheat bran were studied

in hamsters fed on fiber diets with 0.5% added cholesterol. The liver cholesterol

concentrations, in particular, were significantly lower in animals consuming

fullfat stabilized rice bran than all other groups (Kahlon et al., 1990).

Rice bran with extremely low -glucan content is known to be as effective

as high-glucan oat and barley bran in lowering serum cholesterol

(Seetharamaiah and Chandrasekhara, 1989; Kahlon et al., 1990; 1992). The

hypocholesterolemic effects of rice bran may be attributed to the unsaponifiable


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fraction of rice bran oil, primarily phytosterol, tocols (tocopherols and

tocotrienols), -oryzanol, triterpene alcohol and other minor compounds

(Sharma and Rukmini, 1987; Yoshino et al.,1989; Nicolosi et al.,1991). In a similar

study, benefits of bran addition from rice, oats, corn and wheat in diets fed tohamsters were evaluated at relatively high cholesterol level (0.3%). Liver

cholesterol concentrations and liver weights were significantly lower for the rice

bran diet than for either the corn or wheat bran diets. Animals fed on rice bran

had significantly lower VLDL levels and the highest HDL to total cholesterol

ratios when compared to all other bran due to greater lipid and sterol excretion

(Kahlon et al.,1998).

Chicks were fed on 60% fullfat rice bran and corn/soy diets with 0.5%added cholesterol. Significant differences were found in total cholesterol,

triglycerides, high-density and low-density lipoprotein cholesterol. Likewise, in a

second study, chicks were fed on fullfat rice bran, defatted rice bran and

corn/soy diets balanced for 18% protein, 14.47% total dietary fiber and 10.78%

lipid with 0.5% added cholesterol. Total cholesterol and triglycerides were

significantly lower in chicks fed on fullfat rice bran diets. Significant differences

were found in HDL values for all diets with fullfat rice bran exhibiting the

highest (155 mg/dL) and corn/soy exhibiting the lowest mean value (114 mg/dL).

Fullfat rice bran appeared to increase HDL and lower LDL in chicks, but did not

always affect TC (Newman et al.,1992). It has already been concluded that rice

bran might lower cholesterol by increasing short chain fatty acid production in

the cecum by hindering cholesterol absorption due to a change in intestinal fluid

viscosity or by directly inhibiting cholesterol synthesis in the liver (Fukushima et

al.,1999).

Rice bran supplementation has been found effective in lowering total

cholesterol and LDL levels in human subjects with moderate

hypercholesterolemia (Hundemer et al.,1991). However, serum cholesterol was

found to be decreased in patients with mild hypercholesterolemia who


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consumed 300g/d unpolished rice or 100g/d stabilized rice bran (Hakala et al.,

2002). Fullfat rice bran was found to be more effective in lowering cholesterol

than isolated rice bran fractions or their combinations (Kahlon et al.,1992).

Rice bran has been found to be equivalent to oat bran in loweringcholesterol. Mildly hypercholesterolemic subjects were fed on treatment diets

(100g/day stabilized rice bran or oat bran) with 300mg/day added cholesterol.

Total cholesterol levels were significantly reduced in both bran diets when

compared to the control (Hegsted et al.,1993). Similarly, changes in plasma lipid

levels were studied in men with slightly above the normal cholesterol levels

providing test diets containing 35g/day of wheat bran, 60g/day of rice bran or

95g/day of oat bran. The varying amounts of the different brans provided aconstant amount of total dietary fiber i.e. 11.8g/day. At baseline level, only oat

bran was effective in reducing plasma cholesterol as compared to other

treatments. However, the highest rise in HDL was associated with the rice bran

diet, resulting in an improved HDL to total cholesterol ratio. Moreover, plasma

triglycerides were also lower in case of rice bran compared to wheat bran diet

(Kestin et al.,1990).

2.4.2.Rice Bran Oil

A number of studies in humans and animals have proved that RBO is

effective in lowering plasma cholesterol levels (Rukmini and Raghuram, 1991;

Lichtenstein et al.,1994). In some cases, RBO lowered plasma cholesterol more

effectively than other vegetable oils rich in linoleic acid (Rukmini and Raghuram,

1991); might be due to occurrence of specific components in RBO, -oryzanol and

perhaps tocotrienols (Nicolosi et al.,1994).

Rice bran oil and its components significantly improve the plasma profile

in rats. Rats were fed on diets containing 10% rice bran oil alongwith an equal

amount of groundnut oil as control diet for 8 weeks. Half of the animals in each

group also had 0.1% cholesterol and 0.05% cholic acid added in place of a portion

of starch. Rats fed on 10% RBO showed significantly lower serum cholesterol,


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LDL-C and VLDL-C plasma levels, both on cholesterol-containing and

cholesterol-free diets. HDL-C was increased, while TG showed significant

decrease (Sharma and Rukmini, 1986). Rice bran oil was found to be superior to

groundnut oil in cholesterol improvement. Significant reduction in serum totalcholesterol and elevated tendency in HDL-cholesterol were found in rats

consuming cholesterol-free diets with 10% rice bran oil as compared to

groundnut oil diets (Seetharamaiah and Chandrasekhara, 1989).

Similarly, in another study, rats were fed experimental diet having 5 and

20% rice bran oil while control group was fed on diets containing same level of

peanut oil (PNO). There was no significant difference with respect to the organ

weights between control and experimental groups. In general, group fed on 20%oil gained more weight than groups fed on 5% oil. The animals having rice bran

oil in their diet showed comparatively lower levels of cholesterol, triglycerides

and phospholipids. On the other hand, animals receiving 20% rice bran oil in

their diet, showed an increase of 20% in HDL-C, within 18 weeks, when

compared to the animals fed with peanut oil. Moreover, LDL-C and VLDL-C

were also found to be lower in rice bran oil fed groups (Purushothama et al.,

1995).

In animal modeling, rice bran oil was blended with safflower and

sunflower in different ratios and fed to rats fed for a period of 28 days. Rice bran

oil plus safflower oil and sunflower oil in 70:30 ratios showed, significantly,

lower levels of TC, TG and LDL-C and increased HDL-C in animals fed on high

cholesterol diet and cholesterol free diet. Faecal excretion of neutral sterols and

bile acids was increased with the use of rice bran oil blends. The high linoleic

acid content of safflower oil, in combination with the micronutrients of the RBO

unsaponifiable fraction, acts synergistically to lower the serum cholesterol level.

Moreover, high content of tocopherols and tocotrienols in rice bran oil may

improve the oxidative stability of the blends (Sunitha et al.,1997).


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The cholesterol lowering effects of rice bran oil and safflower oil were

compared, alone and in combinations, both in cholesterol and cholesterol free

diets. Half of the animals were randomly assigned to cholesterol-free diets in

which one of these two oils, alone or in varying combinations, contributed 10%.The other half were assigned to similar diets with additional 0.5% cholesterol.

Among the animals not fed on dietary cholesterol, total cholesterol levels were

similar between the rice bran oil and safflower oil groups, but HDL levels were

significantly higher in the rice bran oil group, resulting in a higher HDL:total

cholesterol ratio for this test group, although the differences were non-

significant. Rice bran oil and safflower oil in 7:3 ratios in the diet appeared

optimal with respect to cholesterol levels. The average HDL:total cholesterolratio was significantly higher for this group than all other groups (Koba et al.,

2000).

Despite variations in fatty acid profile, rice bran oil has resulted in

reductions in total cholesterol and LDL levels in animals consuming diets

containing rice bran oil. Likewise, LDL levels dropped and HDL levels remained

unchanged or increased in rats fed on diets supplemented with the

unsaponifiable matter from rice bran oil (Sharma and Rukmini, 1987).

Unsaponifiables prepared from rice bran oil were evaluated in

exogenously hypercholesterolemic rats. Animals were maintained for two weeks

on 0.5% cholesterol diet with 10% fat content either rice bran oil, mixture of palm

& safflower oils or palm & safflower oils plus 0.25% of unsaponifiable content

prepared from rice bran oil. Serum and liver total cholesterol concentrations

were significantly lower and HDL levels significantly higher in both groups of

rats consuming the unsaponifiables versus oil without added unsaponifiables.

Higher fecal excretion of cholesterol was noted in the two unsaponifiable groups

as well. It was concluded that the unsaponifiable fraction of rice bran oil acts to

lower cholesterol by interrupting cholesterol absorption in the gut, not by

altering hepatic cholesterol metabolism (Nagao et al.,2001).


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After 12 days, both substances were able to significantly decrease TG as

compared to control animals. It was concluded that the intravenous administered

-oryzanol and cycloartenol ferulic acid ester could accelerate the excretion of

lipids from the blood (Sakamoto et al.,1987).Besides, rice bran oil and -oryzanol supplementation in diets, bioactive

components from rice bran oil (BRBO), have been shown to play a protective role

against the alteration caused by hypercholesterolemic diet. Male Sprague-

Dawley rats were fed for 4 weeks with normal diet, high-cholesterol diet and

high-cholesterol diet supplemented with the concentrated bioactive components

from rice bran oil (BRBO). The high-cholesterol diet increased serum cholesterol

in rats, compared with those fed on the normal diet. Serum high-densitylipoprotein cholesterol was significantly increased in rats of the BRBO group. In

addition, BRBO recovered the activities of serum aspartate amino transferase

which was elevated in rats by a high cholesterol diet. It was found that BRBO has

significant practical value for protecting against the alterations caused by a

hypercholesterolemic diet, and antioxidative ingredients which suppress lipid

peroxidation (Haa et al.,2005).

The hypolipidemic response of rice bran oil was investigated in non-

human primates fed on semi-purified diets containing blends of oils including

rice bran oil at 0-35% Kcals as dietary fat. The study demonstrated that the

degree of reduction of serum total cholesterol (TC) and low density lipoprotein

cholesterol (LDL-C) was highly correlated with initial serum cholesterol levels in

monkeys fed on standard diet. Further, rice bran oil supplementation in the diet,

significantly, influenced serum TC and LDL-C, causing upto 40% reduction in

LDL-C without affecting HDL-C levels when rice bran oil was the sole dietary oil

(Nicolosi et al.,1991).

Similar to animal studies, a range of human studies have shown that rice

bran oil (RBO) is an edible oil of preference for improving serum cholesterol

levels and lipoprotein profiles. The first scientific statement about rice bran oils


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anti-hyperlipidemic property in humans was published in 1970. RBO blended

with corn, safflower and sunflower oil was consumed by healthy young women

for 7 days to evaluate the effect of blending different vegetable oils on serum

cholesterol levels. It was observed that the hypocholesterolemic effect of RBOwas comparable to other vegetable oils such as corn, safflower and sunflower oils

(Suzuki et al., 1970a,b). Furthermore, the blended oil still exerted

hypocholesterolemic effects, even when five eggs were consumed daily for 7

consecutive days. In contrast, there was an increase in HDL-cholesterol after

consumption of the blended oil, and consequently, the atherogenic index was

significantly improved (Tsuji et al., 1989).

The hypocholesterolemic effects of rice bran oil were evaluated inmoderately non-obese hyperlipoproteinemic human subjects fed on rice bran oil

for a longer period. For comparison, the control group continued use of palm or

groundnut oils. The rice bran oil treated patients showed a 16-25% decrease in

plasma total cholesterol and 32-35% in triglycerides after 15-30 days of treatment

as compared to the control group (Raghuram et al.,1989).

The diets of healthy volunteers with normal cholesterol levels were

supplemented with a margarine enriched with rice bran oil sterols to assess the

impact of sterols present in the unsaponifiable fraction of rice bran oil on lipid

profile. The subjects were instructed to continue usual dietary and physical

activities while supplementing their diets with control margarine containing

traces of sterols or one enriched with 2.1g/day of the sterols from rice bran oil for

three weeks each. The enriched margarine, significantly, lowered total and LDL

cholesterol compared to control (Vissers et al.,2000).

Hyperlipidemic subjects were administered -oryzanol (300mg/day) for

three months. A significant decrease in plasma TC and LDL-C was observed in

both hypercholesterolemic and hypertriglyceridemic patients, while a relevant

increase in HDL-C was noted only in the hypercholesterolemic group without

any side effect (Yoshino et al.,1989).


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It seems that rice bran oil and its components are able to safely improve

the plasma lipid pattern of hypercholesterolemic patients. The available data in

humans suggest that rice bran oil (RBO) is an edible oil of preference for

improving plasma lipid and lipoprotein profiles (Sugano and Tsuji, 1997).2.4.3. Cholesterol-lowering mechanisms

The mechanism of action of rice bran and its oil on lipid metabolism is not

yet evident. However, the most probable hypothesis of RBO hypolipidemic

action is its specific content of phytosterols, polyphenols (-oryzanol) and tocols

(tocopherols and tocotrienols). The cholesterol-lowering effects of RBO are

possibly attributable to its relatively high unsaponifiables; physiologically

bioactive in controlling cholesterol levels in subjects. These compounds havebeen found to work synergistically to exhibit hypocholesterolemic effects.

2.4.3.1. Phytosterols (campesterol, -sitosterol and stigmasterol)

The phytosterols present in crude rice bran oil like campesterol, -

sitosterol and stigmasterol, have been proven effective in lowering plasma total

and LDL-cholesterol without affecting HDL-cholesterol due to similarities in

structures of plant sterols and cholesterol (Weststrate and Meijer, 1998).

There are several mechanisms through which plant sterols affect

cholesterol concentration in the body like formation of non-absorbable complex

with cholesterol, altering the size and/or stability of the micelles, interferences

with cholesterol esterification in the mucosal cell and interacting with protein

receptors required in cholesterol absorption (Rong et al., 1997). It is generally

assumed that plant sterols inhibit intestinal absorption of dietary and biliary

cholesterol, because of the structural similarities with cholesterol. Some studies

indicated that plant sterols contributed more hypocholesterolemic effects than

unsaponifiables. In addition, some plant sterols may be more active than others

(Wilson et al., 2000). Among the sterols, -sitosterol has been recognized the


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predominant cholesterol-lowering component (Vissers et al.,2000; Trautwein et

al.,2002).

2.4.3.2. Polyphenols (oryzanol)

There are numerous mechanisms by which oryzanol lowers cholesterollevels such as: (i) cholesterol-esterase inhibition by cycloartenol or by the

inhibition of the accumulation of cholesterol-esters within macrophages or by the

modulation of cholesterol acid esterase and acyl-CoA-cholesterol-acyltransferase

(Rukmini and Raghuram, 1991); (ii) sterol moiety of -oryzanol is partly split off

from the ferulic acid part in the small intestine by cholesterol esterase (Sugano

and Tsuji, 1997); (iii) effect on biliary secretion resulting in increased faecal

excretion of cholesterol and bile acids (Seetharamaiah et al., 1990); (iv) directinhibition of lipid metabolism (Sakamoto et al., 1987); (v) increased fecal

excretion of cholesterol and its metabolites (Wilson et al.,2007) and (vi) oryzanol

exercises its effects on cholesterol metabolism at sites other than the intestine.

2.4.3.3. Tocols (tocopherol and tocotrienol)

In case of tocols, cholesterol lowering mechanisms include: (i) antioxidant

activity that inhibits cholesterol oxidation (Xu et al., 2001); (ii) inhibit HMG-CoA-

R, a key enzyme in the endogenous synthesis of cholesterol, via increasing the

controlled degradation of reductase protein and decreasing the efficiency of the

translation of HMG-CoA-R messenger RNA (Parker et al., 1993; Khor et al.,1995);

(iii) inhibit the activity of 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA)

reductase, the liver enzyme that is critical to the rate at which cholesterol is

synthesized (Khor and Ng, 2000); (iv) inhibit cholesterol synthesis by

suppressing HMG-CoA reductase activity through a posttranscriptional

mechanism in HepG2 cells (Pearce et al.,1992; Parker et al.,1993; Qureshi et al.,

2000) and (v) via decrease in serum total and LDL cholesterol by inhibiting the

hepatic enzymic activity of -hydroxy--methylglutaryl coenzyme A (Qureshi et

al., 2002).

2.5. Supplementation in Baked Products


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Nowadays, people are becoming more conscious about their health &

nutrition. Foods that are convenient with good taste, reasonably priced and carry

a favorable nutritional image are in great demand; bakery products especially

cakes and cookies. Wheat flour is the primary raw material which provides amatrix in which other ingredients are mixed to form dough or batter.

In Pakistan, the predominant use of rice bran is an ingredient in livestock

feed. Considering its importance, value-added processing technologies for rice

bran have been sought by researchers. The products supplemented with rice

bran can play an important role in the existing food crises besides its health

claims.

From a marketing view point, the most available rice bran derivedproduct is the oil (Orthoefer, 1996). Rice bran oil has an impressive nutritional

quality, which makes it suitable for nutraceutical products. It has industrial

potential particularly in snack food preparation because of great frying stability

and with a good fry life and nutty flavor (Sarkar, 1992). Production of margarine

from rice bran oil has health benefits with reduced saturated fats and trans-fatty

acids.

Rice bran fractions can be used to produce acceptable low fat, high fiber

bakery

feasibility of rice bran oil.pdf

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