The effect of commercial pasteurization and sterilization on the vitamin B1 and riboflavin content of milk as measured by chemical methods
Houston, J.; Kon, S.K.; Thompson, S.G.
Jour Dairy Res 11(1): 67-70
Fluorimetric tests for vitamin B1 and riboflavin were applied both to pasteurized and to sterilized milk. The total aneurin of milk was measured after incubation with takaphosphatase and with pepsin. Riboflavin was detd. at first by the method of Whitnah, Kunerth and Kramer (Jour. Amer. Chem. Soc. 59: 1153. 1937) but it was often observed that the apparent riboflavin content of pasteurized milk was higher than that of the corresponding raw milk. This was attributed to the presence in milk of riboflavin-protein complexes which break down on heating but are little affected by treatment with trichloroacetic acid in the cold. In view of these observations, the method of Emmerie (Zeitschr. Vitaminforsch., 7: 244, 1938) was used in the later trials. In pasteurized milk, the loss of total vitamin B1 was approx. 10%, whereas no loss in riboflavin was detected. In the case of sterilized milk, the processing resulted in losses of total B1 ranging from 45.6 to 57.6%. However, no appreciable loss in riboflavin occurred. The results secured in these expts. are in good agreement with previously published results secured by biol. tests.