Unraveling key non-volatiles responsible for taste differences of Pixian broad bean paste based on sensory analysis and untargeted metabolomics

Besides aroma, the tastes of Pixian Broad Bean Paste (PBBP) are also important, however, they have not yet been thoroughly elucidated. Therefore, this study employed sensory and untargeted metabolomics approaches to investigate taste characteristics, molecular basis and their metabolic pathways of PBBP from three different manufacturers and two grades. Results showed PBBP was predominantly characterized by strong sour, umami and salty tastes, and significant differences were observed in samples from different manufacturers and grades (p < 0.05), especially higher sourness, saltiness and umami in premium PBBP. Based on non-volatiles, 55 key differential metabolites were identified through orthogonal partial least square discriminant analysis (OPLS-DA, P value<0.05, VIP value>1.0) and Pearson correlation analysis (|ρ| > 0.7). These key differential metabolites responsible for taste differences were metabolized by 36 crucial KEGG pathways (P value<0.05, impact value>0.05). These results could expand our understandings of PBBP taste compounds and their metabolisms, and provide theoretical evidences for further quality improvement.