[Change in food proteins during technological processing]

Changes in protein fractions of casein during production of milk-protein concentrates (casecite and casein hydrolysate) were studied by double disk-electrophoresis in poly-acrylamide gel. Significant changes were observed during casein treatment with pancreatin at pH-6.6-7.0. beta-casein was subjected to the highest proteolytic decomposition, it was separated into two fractions attended by isolation of a great number of positively charged fractions of gamma-casein. The amount of beta-casein, as compared to freshly-precipitated casein, diminished by 3.5 and 11.7%, depending on the decomposition degree. Increment of the portion of positively charged fractions correlated with increased bitter flavor. The method of double disk-electrophoresis in polyacrylamide gel can be recommended for the regulation of the hydrolysis process during food production.