Characterization of the volatile organic compounds and sensory properties of fermented soymilks as affected by carbohydrates and starter cultures

Abstract

Soymilks were fermented by two starter cultures and with different levels of added glucose or lactose respectively. GC-MS, HS-GC-IMS and GC × GC-TOFMS were compared and the latter reported much more volatile organic compounds (VOCs). The VOCs profiles of the fermented soymilks were divided into four groups using principal component analysis and hierarchical clustering analysis. Based on the variable importance in the projection value greater than 1.0 and one way ANOVA (P < 0.05), 22 VOCs were respectively identified as the critical differential VOCs in starter culture A and B fermented soymilk, and the concentrations of the critical differential VOCs changed in different patterns in response to the addition of carbohydrates. Four significant metabolic pathways were involved via the metabolite set enrichment analysis, including the glycolysis/gluconeogenesis, pyruvate metabolism. Among critical differential VOCs, there were 11 and 13 aroma-active compounds with odor activity values greater than 1.0, for starter culture A and B fermented soymilks respectively. The deductive sensory properties of the fermented soymilks as affected by carbohydrate addition were evaluated. This study provides experimental and theoretical bases for improving flavor quality of fermented soymilks.