Whey Protein Isolate as potential filler for Blue

Stock

Eduard Hernàndez BaladaERRC Research Liaison Committee

April 29th, 2008

Main GoalTo assess the feasibility of using Whey Protein Isolate, an abundant, inexpensive and readily available by-product of the cheese industry and gelatin, a byproduct of the meat industry rich in collagen, as alternatives to petroleum-based fillers.

From US Dairy Export Council web site From GEA filtration web site

Flow Diagrams of Whey Protein Isolate and Gelatin Production

Introduction – Experimental – Results – Conclusions – Future work

Introduction

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Why using WPI with a dash of gelatin?…

T C T C T C

3 % 1.5 % 0 %

C: Control (no mTGase)

T: Test ( 2 U mTGase/g protein)

Amount of gelatin

Biopolymer composition: 10% (w/w) WPI, 2 U mTGase/g protein (Test), 1% (w/w) DTT

Introduction

Introduction – Experimental – Results – Conclusions – Future work

• Can Whey Protein Isolate (WPI) and Gelatin be used as filling agents for leather?

• What is the role exerted by microbial transglutaminase (mTGase) pretreatment of the blue stock (B.S.)? How does it contribute on the quality and appearance of the finished leather?

• Do these fillers work effectively on both shoe upper and upholstery leather?

• Can the filling process be optimized by cutting back on parameters such as time, float percentage, and concentration of reactants?

• Does the quality of the original B.S. (e.g. spring break, veininess…) affect the outcome of the filling process?

Questions…

Experimental

Introduction – Experimental – Results – Conclusions – Future work

Upholstery B.S.

Control → untreated

Test 1 → treated with 2.5% (w/w) WPI + 0.25% (w/w) gelatin

Test 2 → pretreated with 2.5% (w/w) mTGase, followed by 2.5% (w/w) WPI + 0.25% (w/w) gelatin

Shoe upper B.S.

Control → untreated

Tests → treated with 5% (w/w) WPI + 0.5% (w/w) gelatin

Pretreated with 0, 2.5 and 5% (w/w) mTGase

Note: Weights calculated with respect to the weight of B.S.

Experimental

Introduction – Experimental – Results – Conclusions – Future work

Blue Stock

Neutralization with 4 % (w/w)

NaHCO3

Addition of mTGase solution

(various concentrations)

Addition of WPI + gelatin solution (various concentrations)

200% Float – 16 rpm

Weights calculated with respect to the weight of B.S.

Retan-Color-

Fatliquor

Drain

Tumble 1h @ RT

Drain

1 h @ RT

5 h @ 45°C

DrainWash

x 2

Results- Upholstery

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)Introduction – Experimental – Results – Conclusions – Future work

Effect of mTGase pretreatment on protein uptake

About 50% of the enzyme is taken up within 30 minutes. The curve levels off thereafter.

Total protein uptake (100%) was achieved within three hours for B.S. pretreated with mTGase. For samples that did not undergo the enzymatic pretreatment, the protein pick-up leveled off at ~ 90% after 3-4 hours.

A 5% of the absorbed protein washes out if the blue stock was not pretreated with mTGase. This percentage lowers to 4% if blue stock was pretreated with mTGase solution.

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Results - Upholstery

Introduction – Experimental – Results – Conclusions – Future work

Effect of mTGase pretreatment on protein uptake• One may consider that the absorption of protein by the blue stock follows a first order reaction kinetics, where k is the reaction rate coefficient.

y = 0.3653x - 1.7999

R2 = 0.8297

y = 1.3767x - 2.4396

R2 = 0.9559-7.00-6.00-5.00-4.00-3.00-2.00-1.000.001.002.003.00

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Time (h)

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0% mTG

2.5% mTG

Linear (0% mTG)

Linear (2.5% mTG)

• 0% mTGase → k = 0.3653 h-1

• 2.5% mTGase → k = 1.3767 h-1

X ~4

Introduction – Experimental – Results – Conclusions – Future work

Results – UpholsteryHandle

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Butt Belly Neck

Control Test1 Test2

Fullness

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Butt Belly Neck

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Butt Belly Neck

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Butt Belly Neck

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Control → untreated

Test 1 → 2.5% (w/w) WPI + 0.25% (w/w) gelatin

Test 2 → 2.5% (w/w) mTGase, followed by 2.5% (w/w) WPI + 0.25% (w/w) gelatin

Results – Upholstery

Introduction – Experimental – Results – Conclusions – Future work

Spring break of the original B.S. was very severe. The grain break of samples that did not undergo the enzymatic pretreatment did not improve significantly. However, the pebble size was decreased.

Break of samples that underwent the enzymatic pretreatment was somewhat improved, specially in the butt and belly areas, and not significantly in the neck area.

Veins on the B.S., which were mostly visible in the butt area, were visible on the flesh side but not on the grain side. However, this fact was observed in all samples, regardless of the treatment. Hence, this observation can be attributed to the Retan-Color-Fatliquor formulation.

Effect on Spring Break

Results – Upholstery

Introduction – Experimental – Results – Conclusions – Future work

Effect on Color

Results – Shoe Upper

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5% mTGase

Introduction – Experimental – Results – Conclusions – Future work

Effect of mTGase concentration on protein uptake

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5% mTGase

The enzyme is picked up very rapidly (within 30 minutes).

As opposed to what was observed for upholstery B.S., a slightly higher pick up of protein was achieved if the B.S. was not pretreated with mTGase (~ 98%) than if it was (from 83 to 91%).

Protein did not wash out if B.S. was pretreated with 5% mTGase. Pretreatment with 2.5% mTGase and no pretreatment at all led to ~ 6% to ~ 8% protein desorption, respectively.

It is important to mention than the 5% mTGase run was carried out with a B.S. that belonged to another lot, and also happened to have a much worse break (hence, the differences observed could be due to variability associated to different hides).

Results – Shoe Upper

Introduction – Experimental – Results – Conclusions – Future work

Effect of mTGase concentration on protein uptake

• 0% mTGase → k = 0.6081 h-1

• 2.5% mTGase → k = 0.4133 h-1

• 5% mTGase → k = 0.3233 h-1

y = 0.3233x - 3.2307

R2 = 0.95y = 0.4133x - 2.6956

R2 = 0.8513

y = 0.6081x - 3.0909

R2 = 0.99370.00

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Time (h)

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5% mTGase 2.5% mTGase 0% mTGase

Linear (5% mTGase) Linear (2.5% mTGase) Linear (0% mTGase)

X ~1.5

X ~1.3X ~2

Results – Shoe Upper

Introduction – Experimental – Results – Conclusions – Future work

Belly - Control Belly - Test

Dramatic improvement in grain break after treatment. In this case, shoe upper leather was pretreated with 2.5% mTGase followed by treatment with 5% WPI + 0.5% gelatin (all weights with respect to weight of blue stock).

Coarse break

Tight break

Results – Shoe UpperIntroduction – Experimental – Results – Conclusions – Future work

Effect on Color

Results – Shoe Upper

Introduction – Experimental – Results – Conclusions – Future work

Belly Butt Neck

Cont.

Test

Results – Shoe Upper

Handle

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Introduction– Experimental – Results – Conclusions – Future work

Butt AreaColor

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Control

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Background – Experimental – Results – Conclusions – Future work

Results – Shoe UpperBelly Area

Handle

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Fullness

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Introduction – Experimental – Results – Conclusions – Future work

Results – Shoe UpperNeck Area

Handle

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Fullness

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ConclusionsIntroduction – Experimental – Results – Conclusions – Future work

Whey Protein Isolate was successfully applied as a filling agent for both upholstery and shoe upper leather.

Even though not demonstrated in this presentation, there is evidence that proves that the addition of small amounts of gelatin to WPI enhances functional properties of the resulting blend.

The protein blend was added to the drum without containing any enzyme. Hence, the preparation of the blend becomes easier and it can be stored for a long period of time without fearing it to become a gel.

The use of a 200% float was proved to be enough to get the proteins taken up on the substrate (blue stock). We have the feeling that when scaling up this operation, and due to a stronger mechanical action, even less float could be used.

The pretreatment of the Blue Stock with mTGase prior to the treatment with WPI and gelatin yield different conclusions for shoe upper and upholstery B.S. Enzymatic pretreatment yielded faster and higher protein uptake for upholstery B.S., whereas this trend was reverse for shoe upper.

ConclusionsIntroduction – Experimental – Results – Conclusions – Future work

Color of the finished leather was “better” for upholstery and shoe upper samples that were treated with the protein blend, either with or without the pretreatment with mTGase.

The grain break of shoe upper B.S. was dramatically improved by using 5% mTGase, followed by 5% WPI + 0.5% gelatin. Cutting half these amounts (2.5% mTGase, followed by 2.5% WPI + 0.25% gelatin), the break was improved but not to the same extent.

In upholstery blue stock, using 2.5% WPI+ 0.25% gelatin with or without mTGase pretreatment did not really improved the grain break. However, other properties such as handle, fullness and color were improved by treating the samples with the above mentioned solution.

Acknowledgments Ellie Brown Lorelie Bumanlag Peter Cooke Gary DiMaio Rafael Garcia Nick Latona Joseph Lee William Marmer Paul Pierlott John Phillips Maryann Taylor

THANK YOU !!THANK YOU !!