Lactose phosphate and its origin in cheesemaking : a case study

Lactose phosphate (LP), an impurity present in whey and lactose preparations, was found to have a strong impact on lactose crystallisation; however, the literature values for its concentration in milk were small and its origin was unknown. Two hypotheses - microbiological and chemical - were formulated. The object of this study was to develop a new method to directly analyse LP by capillary electrophoresis to test the first hypothesis. The results of the LP analysis of fresh cows' milk, whey and cheese suggested that the metabolism of the lactic acid bacteria produced LP during the cheesemaking process. Sharp increases in LP concentrations were found both in cheese and whey 24 hours after the start of the process compared to fresh milk.