Novel umami peptides from two Termitomyces mushrooms and molecular docking to the taste receptor T1R1/T1R3

Wild edible Termitomyces mushrooms are popular in Southwest China and Umami is important flavor qualities of edible mushrooms. This study aimed to understand the umami taste of Termitomyces intermedius and Termitomyces aff. bulborhizus. Ten umami peptides from aqueous extracts were separated using a Sephadex G-15 gel filtration chromatography. The intense umami fraction was evaluated by both sensory evaluation and electronic tongue. They were identified as KLNDAQAPK, DSTDEKFLR, VGKGAHLSGEH, MLKKKKLA, SLGFGGPPGY, TVATFSSSTKPDD, AMDDDEADLLLLAM, VEDEDEKPKEK, SPEEKKEEET and PEGADKPNK. Seven peptides, except VEDEDEKPKEK, SPEEKKEEET and PEGADKPNK were selectively synthesized to verify their taste characteristics. All these ten peptides had umami or salt taste. The ten peptides were conducted by molecular docking to study their interaction with identified peptides and the umami taste receptor T1R1/T1R3. All these ten peptides perfectly docked the active residues in the T1R3 subunit. Our results provide theoretical basis for the umami taste and address the umami mechanism of two wild edible Termitomyces mushrooms.