Hostname: page-component-586b7cd67f-tf8b9 Total loading time: 0 Render date: 2024-11-23T05:38:55.015Z Has data issue: false hasContentIssue false

Rheology of whey protein concentrate solutions as a function of concentration, temperature, pH and salt concentration

Published online by Cambridge University Press:  01 June 2009

Qingnong Tang
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
Owen J. McCarthy
Affiliation:
Department of Food Technology, Massey University, Palmerston North, New Zealand

Summary

Rheological properties of whey protein concentrate (WPG) solutions were studied in steady shear, using a Bohlin VOR Rheometer, as a function of concentration, temperature, shear rate, shearing time, pH, salt type, salt concentration and solution age. At 22 °C and pH 7, the WPC solutions exhibited Newtonian behaviour up to a concentration of 10% total solids, pseudoplastic behaviour between 10 and 30% and time-dependent shear thinning at 35% and above. The apparent viscosity of solutions at 22 °C and pH 7 was linearly related to concentration up to 8%. The effect of temperature on apparent viscosity in the range 5–60 °C was closely described by the Arrhenius equation. The viscosities of WPC solutions were independent of solution age in the pH range 4–8 at all concentrations up to and including 20%, the precise pH range narrowing as concentration increased. At pH values above or below this range apparent viscosity became dependent on both pH and solution age, the age effect becoming more marked at higher WPC concentrations. Apparent viscosity at pH 7 increased markedly with both CaCl2 concentration and solution age at concentrations above 0·6 M-CaCl2, the age effect in this case increasing with CaCl2 concentration. In contrast, NaCl concentrations of up to 0·8 M-NaCl had little effect on apparent viscosity. The rheological behaviour of WPC solutions changed from time-independent to time-dependent shear thinning at high concentration, at extreme pH values, at high CaCl2 concentration (after ageing) and on heating to above ∼ 60 °C. This change is considered to be caused by the formation of structure in solutions; a 40% solution (at 22 °C and pH 6·75) exhibited classic thixotropic behaviour in a step–shear rate experiment.

Type
Original Articles
Copyright
Copyright © Proprietors of Journal of Dairy Research 1993

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

Bakshi, A. S. & Smith, D. E. 1984 Effect of fat content and temperature on viscosity in relation to pumping requirements of fluid milk products. Journal of Dairy Science 67 11571160CrossRefGoogle Scholar
Bohlin, L., Hegg, P.-O. & Ljusberg-Wahren, H. 1984 Viscoelastic properties of coagulating milk. Journal of Dairy Science 67 729734CrossRefGoogle Scholar
Bottomley, R. C., Evans, T. A. & Parkinson, G. J. 1990 Whey proteins. In Food Gels, pp. 435466 (Ed. Harris, P.). London and New York: Elsevier Applied ScienceCrossRefGoogle Scholar
Cheftel, J. C., Cuq, J.-L. & Lorient, D. 1985 Amino acids, peptides, and proteins. In Food Chemistry, pp. 245369 (Ed. Fennema, O. R.). New York: Marcel DekkerGoogle Scholar
Cheng, D. C.-H. 1987 Thixotropy. International Journal of Cosmetic Science 9 151191CrossRefGoogle ScholarPubMed
Damodaran, S. & Kinsella, J. E. 1982 Effects of ions on protein conformation and functionality. In Food Protein Deterioration – Mechanisms and Functionality, pp. 327357 (Ed. Cherry, J. P.). Washington, DC: American Chemical SocietyCrossRefGoogle Scholar
Dewit, J. N. & Klakenbeek, G. 1984 Effects of various heat treatments on structure and solubility of whey proteins. Journal of Dairy Science 67 27012710CrossRefGoogle Scholar
Dickinson, E. & Stainsby, G. 1982 Rheology. Colloids in Food, pp. 331407. London: Applied Science PublishersGoogle Scholar
Dunnill, P. & Green, D. W. 1966 Sulphydryl groups and the N⇋R conformational change in β-lactoglobulin. Journal of Molecular Biology 15 147151CrossRefGoogle ScholarPubMed
Hermansson, A.-M. 1975 Functional properties of proteins for foods–flow properties. Journal of Texture Studies 5 425439CrossRefGoogle Scholar
Hermansson, A.-M. 1979 Aspects of protein structure, rheology and texturization. In Food Texture and Rheology, pp. 265282 (Ed. Sherman, P.). New York: Academic PressGoogle Scholar
Hillier, R. M., Lyster, R. L. J. & Cheeseman, G. C. 1980 Gelation of reconstituted whey powders by heat. Journal of the Science of Food and Agriculture 31 11521157CrossRefGoogle Scholar
Holdsworth, S. D. 1971 Applicability of rheological models to the interpretation of flow and processing behaviour of fluid food products. Journal of Texture Studies 2 393418CrossRefGoogle Scholar
Kinsella, J. E. 1979 Functional properties of soy proteins. Journal of the American Oil Chemists' Society 56 242258CrossRefGoogle Scholar
Kinsella, J. E. & Whitehead, D. M. 1989 Proteins in whey: chemical, physical, and functional properties. Advances in Food and Nutrition Research 33 343438CrossRefGoogle ScholarPubMed
Kuhn, P. R. & Foegeding, E. A. 1991 Mineral salt effects on whey protein gelation. Journal of Agricultural and Food Chemistry 39 10131016CrossRefGoogle Scholar
Langley, K. R. & Green, M. L. 1989 Compression and impact strength of gels, prepared from fractionated whey proteins, in relation to composition and microstructure. Journal of Dairy Research 56 275284CrossRefGoogle Scholar
Lyster, R. L. J. 1964 The free and masked sulphydryl groups of heated milk and milk powder and a new method for their determination. Journal of Dairy Research 31 4151CrossRefGoogle Scholar
McDonough, F. E., Hargrove, R. E., Mattingly, W. A., Posati, L. P. & Alford, J. A. 1974 Composition and properties of whey protein concentrates from ultrafiltration. Journal of Dairy Science 57 14381443CrossRefGoogle ScholarPubMed
Mangino, M. E., Kim, J. H., Dunkerley, J. A. & Zadow, J. G. 1987 Factors important to the gelation of whey protein concentrates. Food Hydrocolloids 1 277282CrossRefGoogle Scholar
Mulvihill, D. M. & Kinsella, J. E. 1987 Gelation characteristics of whey proteins and β-lactoglobulin. Food Technology 41(9) 102, 104, 106, 108, 110111Google Scholar
Pradipasena, P. & Rha, C.-K. 1977 a Effect of concentration on apparent viscosity of a globular protein solution. Polymer Engineering and Science 17 861864CrossRefGoogle Scholar
Pradipasena, P. & Rha, C.-K. 1977 b Pseudoplastic and rheopectic properties of a globular protein (β-lactoglobulin) solution. Journal of Texture Studies 8 311325CrossRefGoogle Scholar
Rha, C.-K. & Pradipasena, P. 1986 Viscosity of proteins. In Functional Properties of Food Macromolecules, pp. 79120 (Eds Mitchell, J. R. and Ledward, D. A.). London: Elsevier Applied ScienceGoogle Scholar
Sherman, P. 1970 Rheological properties of foodstuffs. In Industrial Rheology with particular reference to foods, Pharmaceuticals and cosmetics, pp. 185321. London: Academic PressGoogle Scholar
Tang, Q., McCarthy, O. J. & Munro, P. A. 1993 Oscillatory Theological study of the gelation mechanism of whey protein concentrate solutions: effects of physicochemical variables on gel formation. Journal of Dairy Research. In pressCrossRefGoogle Scholar
Tung, M. A. 1978 Rheology of protein dispersions. Journal of Texture Studies 9 331CrossRefGoogle Scholar
Van Wazer, J. R., Lyons, J. W., Kim, K. Y. & Colwell, R. E. 1963 Viscosity and Flow Measurement. A Laboratory Handbook of Rheology. New York: InterscienceGoogle Scholar
Xiong, Y. L. & Kinsella, J. E. 1990 The effect of pH, thiol reagent and time on properties of urea-induced whey protein gels. Food Hydrocolloids 4 245248CrossRefGoogle Scholar
Ziegler, G. R. & Foegeding, E. A. 1990 The gelation of proteins. Advances in food and Nutrition Research 34 203298CrossRefGoogle Scholar