Whey protein interactions in acidic cold-set gels at different pH values

SummaryThe effects of pH and added NaCl or CaCl2 on gel development in heated whey protein concentrate (WPC) solutions were studied by oscillatory rheometry using a Bohlin rheometer, and by qualitative visual and tactile observations. The storage modulus (G′) exhibited maxima at pH values of about 4 and 7, while the phase angle (δ) exhibited minima at the same pH values. At pH 5·5, which lies within the range of the isoelectric points of the whey proteins, G′ was a minimum while δ was a maximum. At pH 7 and 8 G′ increased to a maximum and then decreased as added ionic strength was increased. At pH 4 G′ decreased steadily but slowly with increasing added ionic strength. The effects of CaCl2 were essentially the same as those of NaCl, but occurred at much lower added ionic strength. All the results are discussed in physicochemical terms. The main conclusions were, firstly, that changes in pH and salt concentration both affected gel development by altering the balance between attractive and repulsive protein-protein interactions, and secondly, that the effects of pH, salt concentration and salt type were interactive. Interaction both partly explains the wide variation in gel character and rheological properties among commercial WPC and potentially provides means of tailoring the gelling behaviour of a WPC so that it functions in a desired way in a given food system.

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Quantification of heat-induced casein–whey protein interactions in milk and its relation to gelation kinetics

Colloids and Surfaces B Biointerfaces ◽

10.1016/s0927-7765(03)00048-1 ◽

2003 ◽

Vol 31 (1-4) ◽

pp. 115-123 ◽

Cited By ~ 87

Author(s):

Astrid J Vasbinder ◽

Arno C Alting ◽

Kees G de Kruif

Keyword(s):

Whey Protein ◽

Protein Interactions ◽

Gelation Kinetics

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Effect of casein to whey protein ratios on the protein interactions and coagulation properties of low-fat yogurt

Journal of Dairy Science ◽

10.3168/jds.2015-10794 ◽

2016 ◽

Vol 99 (10) ◽

pp. 7768-7775 ◽

Cited By ~ 15

Author(s):

L.L. Zhao ◽

X.L. Wang ◽

Q. Tian ◽

X.Y. Mao

Keyword(s):

Whey Protein ◽

Protein Interactions ◽

Low Fat

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Whey Protein Interactions: Effects on Edible Film Properties

ACS Symposium Series - Functional Properties of Proteins and Lipids ◽

10.1021/bk-1998-0708.ch010 ◽

1998 ◽

pp. 158-167 ◽

Cited By ~ 3

Author(s):

John M. Krochta

Keyword(s):

Whey Protein ◽

Protein Interactions ◽

Edible Film ◽

Film Properties

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Heat stability of milk: pH-dependent dissociation of micellar κ-casein on heating milk at ultra high temperatures

Journal of Dairy Research ◽

10.1017/s0022029900024481 ◽

1985 ◽

Vol 52 (4) ◽

pp. 529-538 ◽

Cited By ~ 82

Author(s):

Harjinder Singh ◽

Partick F. Fox

Keyword(s):

Whey Protein ◽

Whey Proteins ◽

Heat Stability ◽

Casein Micelle ◽

Casein Micelles ◽

Ph Profile ◽

Ph Values ◽

Maximum Stability ◽

Β Lactoglobulin ◽

Maximum Minimum

SUMMARYPreheating milk at 140 °C for 1 min at pH 6·6, 6·8, 7·0 or 7·2 shifted the heat coagulation time (HCT)/pH profile to acidic values without significantly affecting the maximum stability. Whey proteins (both β-lactoglobulin and α-lactalbumin) co-sedimented with the casein micelles after heating milk at pH < 6·9 and the whey protein-coated micelles, dispersed in milk ultrafiltrate, showed characteristic maxima–minima in their HCT/pH profile. Heating milk at higher pH values (> 6·9) resulted in the dissociation of whey proteins and κ-casein-rich protein from the micelles and the residual micelles were unstable, without a maximum–minimum in the HCT/pH profile. Preformed whey protein–casein micelle complexes formed by preheating (140 °C for 1 min) milk at pH 6·7 dissociated from the micelles on reheating (140 °C for 1 min) at pH > 6·9. The dissociation of micellar-κ-casein, perhaps complexed with whey proteins, may reduce the micellar zeta potential at pH ≃ 6·9 sufficiently to cause a minimum in the HCT/pH profile of milk.

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The use of high hydrostatic pressure to modulate milk protein interactions for the production of an alpha-lactalbumin enriched-fraction

Green Chemistry ◽

10.1039/c7gc03428h ◽

2018 ◽

Vol 20 (2) ◽

pp. 515-524 ◽

Cited By ~ 13

Author(s):

Alice Marciniak ◽

Shyam Suwal ◽

Michel Britten ◽

Yves Pouliot ◽

Alain Doyen

Keyword(s):

Hydrostatic Pressure ◽

Whey Protein ◽

Protein Interactions ◽

High Hydrostatic Pressure ◽

Milk Protein ◽

Protein Solution ◽

Green Method ◽

Alpha Lactalbumin

An innovative and green method for the fractionation of α-lactalbumin with 86% purity from whey protein solution was developed using high hydrostatic pressure as a pretreatment.

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The cheesemaking potential of milk concentrated up to four-fold by ultrafiltration and heated in the range 90–97 °C

Journal of Dairy Research ◽

10.1017/s0022029900029599 ◽

1990 ◽

Vol 57 (4) ◽

pp. 549-557 ◽

Cited By ~ 20

Author(s):

Margaret L. Green

Keyword(s):

Electron Microscopy ◽

Heat Treatment ◽

Whey Protein ◽

Protein Interactions ◽

Heat Denaturation ◽

The Difference

SummaryProperties of interest to cheesemaking were investigated with milks concentrated by ultrafiltration and heated at 90 °C or 95–97 °C for 15 s. The effects of light homogenization before concentration and of addition of CaCl2 after heating were assessed. No changes in casein–fat or casein–whey protein interactions were detected by electron microscopy. The heat denaturation of whey protein increased linearly as the milk became more concentrated. Coagulability by rennet after heat treatment increased with concentration to close to the unheated value in 3·5 to 4-fold concentrates. The decrease in curd firming rate by heat treatment was slightly affected by concentration and addition of CaCl2 restored some of the difference. Heat treatment reduced the rate of whey loss and slightly improved the curd structure but did not affect fat losses. Light homogenization slightly reduced heat denaturation of whey protein and whey loss.

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