Evaluation of the nutritional value, umami taste, and volatile organic compounds of Hypsizygus marmoreus by simulated salivary digestion in vitro

Hypsizygus marmoreus is an edible medicinal mushroom species with a high dietary value. The main purpose of this study was to evaluate the nutritional value, umami taste, and volatile organic compounds (VOCs) of H. marmoreus treated with hot water combined with simulated salivary digestion in vitro. Seafood mushroom (Hm3) had the highest content of moisture, soluble polysaccharides, soluble proteins, and total flavonoids while white Hypsizygus marmoreus (Hm1) had the highest total phenolic content. Moreover, Hm1 had a more noticeable equivalent umami concentration (EUC) value, indicating the umami properties of Hm1 as a food or processing ingredient. Results from E-nose and HS-SPME-GC-MS revealed that the VOCs of Hm1 and brown Hypsizygus marmoreus (Hm2) were relatively similar, which differed substantially from Hm3. Among the 134 VOCs, 24 differential metabolites were identified by OPLS-DA analysis, characterized by VIP > 1, p-value < 0.05, and FC > 2 (pairwise comparisons). Furthermore, 10 biomarkers with VIP > 1 and p-value < 0.05 were identified by PLS-DA analysis based on the total differential metabolites to distinguish different strains of H. marmoreus. These results will benefit future research on the chemistry of H. marmoreus and serve as a guide for breeding, introducing, and using the species more effectively.