Hostname: page-component-78c5997874-t5tsf Total loading time: 0 Render date: 2024-11-05T09:26:37.634Z Has data issue: false hasContentIssue false
  • English
  • Français

Reversibility of shrinkage of mineral acid casein curd as a function of ionic strength, pH and temperature

Published online by Cambridge University Press:  01 June 2009

Cheng Tet Teo ,
Peter A. Munro  and
Harjinder Singh
Cheng Tet Teo
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
Harjinder Singh
Affiliation:
Department of Food Technology, Massey University, Palmerston North, New Zealand
Get access Rights & Permissions [Opens in a new window]

Summary

Mineral acid casein (MAC) curd was subjected to a range of ionic strength, pH and temperature conditions to explore their effects on curd water-holding capacity, particularly the reversibility of shrinkage. The shrinkage of MAC curd on whey removal during the washing stage of casein manufacture could be attributed almost completely to the reduction in ionic strength and not specifically to either calcium or lactose removal. This shrinkage on whey removal during washing could not be reversed by adding whey back to the curd to attain the original ionic environment. In this sense it was irreversible. The pH during formation of MAC curd was more important than later pH adjustments in controlling curd water-holding capacity. The effect of a high precipitation pH in creating a tough, compact curd could not be reversed by subsequently decreasing the pH. However, the effect of a low precipitation pH in creating a soft, open curd could be partly reversed by subsequently increasing the pH. MAC curd shrank by 45% when the temperature was increased from 20 to 80°C. This temperature-dependent shrinkage was virtually fully reversible on cooling. It is suggested that the water-holding capacity of casein curd is governed largely by hydrophobic interactions and that once such interactions have occurred they cannot easily be disrupted by small changes in either pH or ionic strength.

Type
Original Articles
Information
Journal of Dairy Research , Volume 63 , Issue 4 , November 1996 , pp. 555 - 563
Copyright
Copyright © Proprietors of Journal of Dairy Research 1996

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

Bell, D. J., Hoare, M. & Dunnill, P. 1983 The formation of protein precipitates and their centrifugal recovery. In Downstream Processing, pp. 1–72 (Ed. Fiechter, A.). Berlin: Springer (Advances in Biochemical Engineering / Biotechnology 26)CrossRefGoogle Scholar
Bringe, N. A. & Kinsella, J. E. 1991 Effects of cations and anions on the rate of the acidic coagulation of casein micelles: the possible roles of different forces. Journal of Dairy Research 58 195–209CrossRefGoogle Scholar
Bringe, N. A. & Kinsella, J. E. 1993 Calcium chloride, temperature, preheat treatments and pH affect the rate of acid-induced aggregation of casein. Food Hydrocolloids 7 113–121CrossRefGoogle Scholar
Dalgleish, D. G. 1983 Coagulation of renneted bovine casein micelles: dependence on temperature, calcium ion concentration and ionic strength. Journal of Dairy Research 50 331–340CrossRefGoogle Scholar
Hobman, P. G. 1978 A model for predicting the water required to wash casein curd. New Zealand Journal of Dairy Science and Technology 13 229–235Google Scholar
Jablonka, M. S. & Munro, P. A. 1986 Effect of precipitation temperature and pH on the continuous pilot-scale precipitation of acid casein curd. New Zealand Journal of Dairy Science and Technology 21 111–123Google Scholar
Jablonka, M. S. & Munro, P. A. 1987 Mechanical properties of lactic, mineral acid and rennet casein curds from commercial plants. New Zealand Journal of Dairy Science and Technology 22 67–74Google Scholar
Mulvihill, D. M. 1989 Caseins and casemates: manufacture. In Developments in Dairy Chemistry—4. Functional Milk Proteins, pp. 97–130 (Ed. Fox, P. F.). London: Elsevier Applied ScienceGoogle Scholar
Munro, P. A. & Tan, B. K. 1984 Inclusion of gas in casein and leaf protein precipitate particles and its effect on particle density. Journal of Chemical Technology and Biotechnology 34B 279–290CrossRefGoogle Scholar
O'meara, G. M. & Munro, P. A. 1982 The precipitation and shrinkage of acid casein curd: a preliminary study. New Zealand Journal of Dairy Science and Technology 17 147–159Google Scholar
Patel, M. C., Lund, D. B. & Olson, N. F. 1972 Factors affecting syneresis of renneted milk gels. Journal of Dairy Science 55 913–918CrossRefGoogle Scholar
Pearce, K. N., Johnstone, R. J. & Maccoll, A. J. 1987 Computer simulation of continuous multi-stage countercurrent washing of casein curd. Neiw Zealand Journal of Dairy Science and Technology 22 49–66Google Scholar
Swaisgood, H. E. 1992 Chemistry of the caseins. In Advanced Dairy Chemistry—1. Proteins, pp. 63–110 (Ed. Fox, P. F.). London: Elsevier Applied ScienceGoogle Scholar
Teo, C. T., Munro, P. A., Singh, H. & Hudson, R. C. 1996 Effects of pH and temperature on the water-holding capacity of casein curds and whey protein gels. Journal of Dairy Research 63 83–95CrossRefGoogle Scholar
Zadow, J. G. 1971 Some theoretical aspects of casein washing. Australian Journal of Dairy Technology 26 9–17Google Scholar