Fraksinasi protein susu kedelai selama fermentasi yoghurt=fractionation of soymilk protein during yoghurt fermentation

ABSTRAK Recent medical and nutritional research have revealed the strong potential of soy foods for lowering blood cholesterol levels and the incidence of heart disease and cancer. It has been developed yoghurt-like fermented product from soymilk. Flavor and texture are critical aspects of consumer acceptability of yoghurt. One of the factors influence yoghurt texture is degree of proteolysis. The effect of soymilk fermentation into yoghurt by Streptococcus thermophilus and Lactobacillus bulgaricus on the changes of protein fractions in relation to the formation of yoghurt texture was investigated. The studies were conducted in different ways of starter addition and the difference of the length of fermentation. The analysis involved protein fractions analysis by SDS-PAGE and textures analysis by Lloyd\u27s Instrument. Changes in protein fractions occurred during this fermentation, formed smaller protein fractions. It seem that the formation of the smaller protein fractions had roled by these bacteria. Changes of protein fractions led to the changes of the soymilk textures from liquid becomes semisolid textures. The addition of S. thermophilus at the beginning of incubation was found to change textures rapidly which were detected in the harder textures than others. The soymilk already had peptides. Keywords: protein fractions â SDS-PAGE â soymilk â texture