Study on the compositional factors involved in the variable sensitivity ofcaprine milk to high-temperature processing

The heat sensitivity of individual caprine milk displayed considerable vari ation from one sample to another. Compared to heat-unstable milk samples, h eat-stable milk samples were characterised by a higher pH. a lower soluble calcium concentration, a higher phosphorus concentration, and a higher whey protein content. The heat stability of caprine milk showed a marked pH dep endence, but different patterns of heat stability vs. pH were observed betw een heat-stable and heat-unstable samples. Heat-stable milk samples had a m aximum heat stability at pH 6.8, i.e, close to their natural pH, while heat -unstable milk samples had a maximum heat stability at pH 7-7.1, i.e. highe r than their natural pH. The dependence on pH is discussed with respect to both the milk salt balance and the interaction of whey protein with casein. (C) 2000 Elsevier Science Ltd. All rights reserved.