Abstract: Umami peptides from a decoction of white Hypsizygus marmoreu were separated and purified by sequential ultrafiltration (UF), gel filtration chromatography (GFC) and reversed-phase high performance liquid chromatography (RP-HPLC) combined with sensory evaluation and were identified by ultra-performance liquid chromatography-mass spectrometry (UPLC-MS/MS). The identified peptides were synthesized and their taste characteristics were evaluated by sensory evaluation. The results showed that six umami peptides were identified, namely ELELQ, ELQSGNTY, NYNGGY, EAKVY, VANGGGFGAA, and SLLQPL, whose threshold values were 0.16, 0.19, 0.31, 0.38, 0.44, and 0.63 mg/mL, respectively. The molecular masses of the six peptides were all below 1 000 Da. The synthetic peptides had umami-enhancing effects. As seen from the dose-response curves of umami taste for the synthetic peptides in the presence of monosodium glutamate solution, their umami-enhancing effects were significantly different from each other (P < 0.05), among which NYNGGY and ELELQ were prominent umami enhancers. The synthetic peptides were all able to enhance the umami, salty and sweet taste of chicken soup, and ELELQ, NYNGGY and ELQSGNTY were the most effective in improving the taste of chicken soup.

Key words: white Hypsizygus marmoreu; umami peptides; separation and purification; mass spectrometry identification; sensory evaluation