ABSTRACTButterfat was hydrolyzed with lipases contained in lecithin reverse micelles. The influence of pH, temperature, molar ratio of surfactant to water (R) and surfactant concentration on the hydrolytic reaction indicated linear, quadratic, and interactive effects for reaction systems mediated byR. javanicusandC. rugosalipases. The initial reaction rate was dependent on reaction parameters; however, the degree of hydrolysis was independent of pH. Both enzymes exhibited high thermal stability. The content and composition of milk fat hydrolysates prepared byR. javanicuslipase were most influenced by reaction temperature and R. The optimum conditions for production of free fatty acids, monoacyl‐glycerols, diacylglycerols and specific regio‐isomers were defi