Hostname: page-component-586b7cd67f-dsjbd Total loading time: 0 Render date: 2024-11-26T15:29:26.533Z Has data issue: false hasContentIssue false

The effect of preheat temperature and urea addition on the seasonal variation in the heat stability of skim-milk powder

Published online by Cambridge University Press:  01 June 2009

Philip M. Kelly
Affiliation:
The Agricultural Institute, Moorepark Research Centre, Fermoy, Co. Cork, Irish Republic

Summary

The manufacture of skim-milk powder with heat stable characteristics was investigated commercially during the course of 8 trials carried out over a 12-month period. Skim-milk was preheated to temperatures ranging from 110 to 130 °C with a 2-min holding time prior to evaporation and drying. The effect of added urea was also examined during each trial run. Heat coagulation times at 120 °C were determined upon reconstitution of the powders to 20% total solids. From February to April the heat stability of the skim-milk powders increased, with the more heat stable samples being obtained at the higher preheating temperatures. Addition of urea increased the heat stability, particularly so in those milks which had been preheated to 130 °C. The presence of added urea during preheating was not found to be necessary as an equal effect on heat stability was observed when urea was introduced at the concentrate stage before drying. Later in the season optimum heat coagulation times were obtained by maintaining preheating temperatures at 118–120 °C.

Type
Original Articles
Copyright
Copyright © Proprietors of Journal of Dairy Research 1982

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

Davies, J. M. 1959 Decrease in the heat stability of milk on forewarming. 15th International Dair Congress, London 3 18591864Google Scholar
DaviesD, T D, T, & White, J. C. D. 1959 Determination of heat-induced changes in the protein stability and chemical composition of milk. 15th International Dairy Congress, London 3 16771685Google Scholar
Griffin, A. T., Hickey, M. W., Bailey, L. F. & Feagan, J. T. 1976 The significance of preheat and ph adjustment in the manufacture of recombined evaporated milk. Australian Journal of Dairy Technology 31 134137Google Scholar
Kelly, P. M. 1977 Effect of some non–protein nitrogen components on the heat stability of skim-milk powders Irish Journal of Food Science & Technology 1 129135Google Scholar
Lyster, R. L. J. 1972 Reviews of the progress of dairy science. Section C. Chemistry of milk proteins. Journal of Dairy Research 39 279318CrossRefGoogle ScholarPubMed
Muir, D. D., Abbot, J. & Sweetsur, A. W. M. 1978 Changes in the heat stability of milk protein during the manufacture of dried skim-milk. Journal of Food Technology 13 4553CrossRefGoogle Scholar
Muir, D. D. & Sweetsur, A. W. M. 1976 The influence of naturally occurring levels of urea on the heat stability of bulk milk. Journal of Dairy Research 43 495499CrossRefGoogle Scholar
Muir, D. D. & Sweetsur, A. W. M. 1977 Effect of urea on the heat coagulation of the caseinate complex in skim-milk. Journal of Dairy Research 44 249257CrossRefGoogle Scholar
Muir, D. D. & Sweetsur, A. W. M. 1978 The effect of concentration on the heat stability of skim-milk. Journal of Dairy Research 45 3745CrossRefGoogle Scholar
Newstead, D. F., Sanderson, W. B. & Baucke, A. G. 1975 The effects of heat treatment and pH on the heat stability of recombined evaporated milk. New Zealand Journal of Dairy Science & Technology 10 113118Google Scholar
Newstead, D. F., Sanderson, W. B. & Conaghan, E. F. 1977 Effects of whey protein concentrations and heat treatment on the heat stability of concentrated and unconcentrated milk. New Zealand Journal of Dairy Science & Technology 12 2936Google Scholar
Rose, D. 1961 Factors affecting the pH-sensitivity of the heat stability of milk from individual cows. Journal of Dairy Science 44 14051413CrossRefGoogle Scholar
Rose, D. 1962 Factors affecting the heat stability of milk. Journal of Dairy Science 45 13051311CrossRefGoogle Scholar
Rose, D. 1963 Heat stability of bovine milk: a review. Dairy Science Abstracts 25 4552Google Scholar
White, J. C. D. & Davies, D. T. 1958 The relation between the chemical composition of milk and the stability of the caseinate complex. IV. Coagulation by heat. Journal of Dairy Research 25 281296CrossRefGoogle Scholar