Abstract:To enrich protein nutrition types, reduce cost and enhance flavor of the current milk flavors, soybean protein isolate was used to partially replace cream to build a mixed substrate. Two novel milk flavors were developed based on the mixed substrate by fermentation in combination with two different enzymatic hydrolysis methods. Meanwhile, the organoleptic properties, main metabolites, and volatile compounds were determined for the two milk flavors. The results showed that the flavor prepared by one-step enzymolysis combined with fermentation was more associated with higher levels of free fatty acids and medium-long chain volatile acids, which led to rancid and astringent flavor; while the flavor prepared by two-step enzymolysis combined with fermentation accumulated higher concentrations of polypeptides and amino acids, short-chain volatile acids, 3-hydroxy-2-butanone, benzaldehyde, furfural, and δ-dodecanone, which led to higher sensory evaluation score and regarded as the proper meth