New Processes for New Products Impact of protein modification designed functionalities as food ingredients E. Allen Foegeding Department of Food, Bioprocessing and Nutrition Sciences North Carolina State University USA
Molecular Function Interfacial properties *Foams and Emulsions Network formation *Gels and films Soluble particles (heat stability) *Beverages
Modifications Soluble aggregates ŁDenaturation and aggregation Hydrolysis Deamidation Glycosylation Add other polymers
Angel Food Cake Form Foam (200 ml) Ł10% protein Ł12% Sugar Blend in: Ł33 g cake flour Ł75.8 g powdered sugar Bake
Stability of the wet foam Egg white bubbles remains stable Whey protein isolate bubbles destabilize 120 100 # Bubbles/ mm 2 Area 80 60 40 20 0 100%W 1 50%W 50%E 1 100% E 100%W 2 50%W 50%E 2 0 2.5 5 7.5 10 E.A. Foegeding, unpublished data. Time Elapsed (min)
Expansion of cakes during cooking (Pernell et al., 2002, J. Food Sci., 67, 2945) Normalized peak height (cm) 10 8 6 4 2 0 2% EWP 5% EWP p10% EWP 10% WPI 15% WPI r20% WPI 120 100 80 60 40 20 Temperature ( o C) -2 0 0 2 4 6 8 10 12 14 16 Time (min)
Problem in cake structure Loss of bubble stability during baking 100% Egg White 75% Egg White & 25% WPI
Properties of Foams FORMATION Ł Foamability Effectiveness of gas encapsulation (Wilde and Clark, 1996) PHYSICAL PROPERTIES Ł Air phase volume (overrun) and bubble size Ł Rheological Shear moduli and yield stress STABILITY Ł Drainage Ł Coalescence Ł Disproportionation
Yield Stress (s o ) -Vane Technique Height Diameter Yield Stress (σ o ) (bubble size, air phase volume, interfacial tension and/or rheology)
Egg White vs. Whey Protein Isolate (Pernell et al., 2000, Journal of Food Science, 65, 110) 200 Egg White Mean yield stress (Pa) 150 100 50 WPI 0 0 5 10 15 20 25 30 35 Whipping time (min)
Hydrolysis to improve foaming Davis et al., 2005, J. Colloid and Interface Science, 288, 412 Extensive hydrolysis with Alcalase Improved yield stress and did not decrease overrun Yield Stress (Pa) 140 120 100 80 60 40 20 controls 90C/15min 75C/30min % Overrun 1400 1200 1000 800 600 400 200 0 Beta-lg Alcalase WPI 0 Beta-lg Alcalase WPI
Does it work in a cake? 400 300 Cake Volume (ml) 200 100 0 5% hydro 10% hydro 10% EWP 10% blg 10% WPI
What happened during baking? WPI batters destabilize during the entire process 25 o C 35 o C 45 o C 55 o C 100% WPI 75% EWP/ 25% WPI 100% EWP Egg white batters remain stable during the entire process
Lesson: Functionality is the entire process! Improved wet Foam functionality But did not improve Thermal stability Protein/sugar foam Blend in wheat starch and protein (flour) Angel Food Cake Heat to expand air cells, set the protein/starch network and remove moisture
Whey proteins in Beverages Stability *No visible phase separation Clarity *Clear like soft drinks Flavor *No off-flavors *Low astringency Nutrition & Health *No changes in biological properties 1 2 3 4.6 6 7 14 Beverage ph Clear Stable Astringent Opaque Not stable Less astringent
General Approach Inhibit denaturation or alter aggregation ŁAddition of charged polysaccharides (dextran sulfate) ŁAddition of β- or α s -casein to act as molecular chaperones
A G = increasing DS concentration ph 5.6 Dextran Sulfate (DS) A* B C D E* F* G* ph 5.8 A B C D E F G* 6% β-lactoglobulin ph 6.0 Heated at 85 C for 15 min * = Gel ph 6.2 A B C D E F G* Vardhanabhuti, B. and Foegeding, Unpublished data A B C D E F G*
Effect of dextran sulfate M w at ph 6.0 2 OD 400 1.5 1 G G G G G G DS 5k DS 10k DS 100k DS 500k 0.5 0 0 0.05 0.1 0.15 0.2 DS:BLG weight ratio Vardhanabhuti, B. and Foegeding, Unpublished data
Effect of NaCl 2.0 Gel Gel Gel Gel Gel Gel Gel OD 400 1.5 1.0 0.5 Gel Gel control 0.005 0.01 0.02 0.05 0.1 0.2 0.0 0 10 30 NaCl (mm) Vardhanabhuti, B. and Foegeding, Unpublished data DS effect removed
Caseins as Molecular Chaperones: Previous investigations Study ph Temp. ( o C) Time (min) Whey components (%) *1 7.0 70 5 a-lac (0.2) b-lac (0.2) Caseins (%) Total protein (%) a s -casein (0.6) 1.0 *2 7.1 70 480 b-lac (0.5) a s -casein (0.5) 1.0 *3 6.0 85 10 Whey protein isolate (0.5) a s1 /b-casein (0.5) 1.0 *1 Bhattacharyya and Das, J. Biol. Chem. (1999), vol. 274, p. 15505 *2 Morgan et al., J. Agric. and Food Chem. (2005), vol. 53, p. 2670 *3 O Kennedy and Mounsey, J. Agric. and Food Chem. (2006), vol. 54, p. 5639 TOO LOW!
b-lactoglobulin & b-casein (BCN) 25 o C 70 o C 75 o C 80 o C 85 o C 90 o C Unheated solutions (25 o C) were clear BCN decreased the turbidity of heated solutions, especially 2% BCN (total protein 8%) Heating at 90 o C produced clearer solutions than at 75 o C Constant 6% (w/v) BLG BCN (%) 0 0.01 0.05 0.2 0.5 1 2 Yong et al, unpublished data
Effect of different caseins 1.60 Maximum linear region OD 400 nm OD 600 nm 1.20 0.80 0.40 0.00 1.60 1.20 0.80 0.40 BLG only BCN1 BCN2 Crude BCN ACN Two lots of BCN produced identical turbidity profiles A crude BCN showed a systematic shift up a s -Casein inhibited turbidity development at 70 o C matched with other studies However, turbidity increased drastically at 75 o C (lost chaperone ability) and formed gel at 90 o C Constant 6% (w/v) BLG 0.00 25 40 55 65 70 75 80 85 90 Temperature ( o C) Yong et al, unpublished data
Molar Mass (SEC-MALS) Cumulative Weight Fraction 1.0 0.8 0.6 0.4 0.2 0.0 10 6 10 7 10 8 10 9 10 10 Molar Mass (g/mol) BLG 75 o C BLG 90 o C BLG-BCN 75 o C BLG-BCN 90 o C BLG-ACN 75 o C BLG-ACN 90 o C Molar mass distribution at 25 o C -Mean 3.0X10 4 Molar mass distribution at 75 o C -BLG-BCN : 4.5x10 6 2.1x10 7 -BLG-ACN : 5.6x10 6 8.2x10 7 -BLG only : 3.2x10 7 1.1x10 9 Molar mass distribution at 90 o C -BLG-BCN : 4.6x10 6 6.3x10 7 -BLG-ACN : 1.9x10 7 4.7x10 8 -BLG only : 2.2x10 7 5.7x10 8 Yong et al, unpublished data
Root Mean Square Radius Cumulative Weight Fraction 1.0 0.8 0.6 0.4 0.2 0.0 R.M.S. Radius (nm) BLG 75 o C BLG 90 o C BLG-BCN 75 o C BLG-BCN 90 o C BLG-ACN 75 o C BLG-ACN 90 o C 10 20 30 50 75 100 200 300 Radius distribution at 75 o C -BLG-BCN : 20 40 -BLG-ACN : 30 63 -BLG only : 55 98 Radius distribution at 90 o C -BLG-BCN : 37 100 -BLG-ACN : 74 210 -BLG only : 48 88 Radius of BLG at 75 o C slightly higher than 90 o C Yong et al, unpublished data
Conclusion β-casein and as-casein showed chaperone effects by altering aggregation of β- lactoglobulin at ph 6 (8% w/v total protein) β-casein was shown to be an effective approach to alter aggregation of β-lactoglobulin over a range of temperatures (70-90 o C) α s -casein lost its chaperone ability at temperatures 75 o C
Thanks to: *Dairy Management Inc. and the Southeast Dairy Foods Research Center for funding *DAVISCO Foods International for donating the proteins Protein Synthesis Units
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