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Oscillatory rheological study of the effects of pH and salts on gel development in heated whey protein concentrate solutions

Published online by Cambridge University Press:  01 June 2009

Qingnong Tang ,
Owen J. McCarthy  and
Peter A. Munro
Qingnong Tang
Affiliation:
Department of Food Technology, Massey University, Palmerston North, New Zealand
Owen J. McCarthy
Affiliation:
Department of Food Technology, Massey University, Palmerston North, New Zealand
Peter A. Munro
Affiliation:
Department of Food Technology, Massey University, Palmerston North, New Zealand
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Summary

The 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.

Type
Original Articles
Information
Journal of Dairy Research , Volume 62 , Issue 3 , August 1995 , pp. 469 - 477
Copyright
Copyright © Proprietors of Journal of Dairy Research 1995

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References

REFERENCES

Brandenberg, A. H., Morr, C. V. & Weller, C. L. 1992 Gelation of commercial whey protein concentrates: effect of removal of low-molecular-weight components. Journal of Food Science 57 427–432CrossRefGoogle Scholar
Clark, A. H. & Lee-Tuffnell, C. D. 1986 Gelation of globular proteins. In Functional Properties of Food Macromolecules, pp. 203–272 (Eds Mitchell, J. R. and Ledward, D. A.). London: ElsevierGoogle Scholar
De Wit, J. N. 1989 Functional properties of whey proteins. In Developments in Dairy Chemistry—4. Functional Milk Proteins, pp. 285–321 (Ed. Fox, P. F.). London: Elsevier Applied ScienceGoogle Scholar
Doi, E. 1993 Gels and gelling of globular proteins. Trends in Food Science & Technology 4 1–5CrossRefGoogle Scholar
Egelandsdal, B. 1980 Heat-induced gelling in solutions of ovalbumin. Journal of Food Science 45 570–573, 581Google Scholar
Foegeding, E. A., Kuhn, P. R. & Hardin, C. C. 1992 Specific divalent cation-induced changes during gelation of β-lactoglobulin. Journal of Agricultural and Food Chemistry 40 2092–2097CrossRefGoogle Scholar
Gault, P. & Fauquant, J. 1992 [Heat-induced gelation of β-lactoglobulin. Influence of pH, ionic strength and presence of other whey proteins.] Lait 72 491–510CrossRefGoogle Scholar
Hines, M. E. & Foegedino, E. A. 1993 Interactions of α-lactalbumin and bovine serum albumin with β-lactoglobulin in thermally induced gelation. Journal of Agricultural and Food Chemistry 41 341–346Google Scholar
Kuhn, P. R. & Foegeding, E. A. 1991 Mineral salt effects on whey protein gelation. Journal of Agricultural and Food Chemistry 39 1013–1016Google Scholar
Langton, M. & Hermansson, A. -M. 1992 Fine-stranded and particulate gels of β-lactoglobulin and whey protein at varying pH. Food Hydrocolloids 5 523–539CrossRefGoogle Scholar
Morr, C. V. & Ha, E. Y. W. 1993 Whey protein concentrates and isolates: processing and functional properties. Critical Reviews in Food Science and Nutrition 33 431–476CrossRefGoogle ScholarPubMed
Mulvihill, D. M. & Kinsella, J. E. 1987 Gelation characteristics of whey proteins and β-lactoglobulin. Food Technology 41 (9) 102, 104, 106, 108, 110–111Google Scholar
Stading, M. & Hermansson, A. -M. 1991 Large deformation properties of β-lactoglobulin gel structures. Food Hydrocolloids 5 339–352Google Scholar
Tang, Q., McCarthy, O. J. & Munro, P. A. 1993 Oscillatory rheological study of the gelation mechanism of whey protein concentrate solutions: effects of physicochemical variables on gel formation. Journal of Dairy Research 60 543–555CrossRefGoogle Scholar
Taylor, S. M. & Fryer, P. J. 1992 [Rheology of whey protein concentrates upon heating: influence of the non-protein fraction on gel strength.] Entropie 168 57–64Google Scholar
Varunsatian, S., Watanabe, K., Hayakawa, S. & Nakamura, R. 1983 Effects of Ca++, Mg++ and Na+ on heat aggregation of whey protein concentrates. Journal of Food Science 48 42–46, 70Google Scholar
Xiong, Y. L. 1992 Influence of pH and ionic environment on thermal aggregation of whey proteins. Journal of Agricultural and Food Chemistry 40 380–384CrossRefGoogle Scholar