Research On The Purification Of Kokumi Peptides From Agaricus Bisporus And Its Taste Properties

Kokumi is a sort of taste, used to describe flavor characteristics for mouthfulness,complexity, and continuity, also called mouthfulness in China. Agaricus bisporus is highly accepted by consumers, due to its delicious flavor and rich nutrition. It has been reported that kokumi substances are existed in many foods and mainly are peptides. However, peptides from Agaricus bisporus on new taste sensation, such as mouthfulness, complexity, have not been report previously.In this paper, the aqueous' extract was obtained by autoclave, then isolated by ultrafiltration, nanofiltration and gel-permeation chromatogragraphy, identified by ultra-performance liquid chromatography (UPLC) and quadruple-time-of-flight mass spectrometry (Q-TOF-MS) for the highest kokumi taste fraction. The identified peptides were synthesized by solid phase synthesis, explored the taste characteristic using sensory evaluation and electronic tongue.The aqueous extract was prepared by autoclave cooking, the three-factor and three-level orthogonal experiments were used to optimize the high-pressure preparation process according to the content of solids and sensory evaluation. The better conditions as followings:pressure 60 Kpa, cooking time 130 min, fresh agaricus bisporus: water(w/w) 1:2.0, and the extraction rate was as high as 10.06 % and the taste was good in this condition.Then three fractions were achieved, namely fraction U1(< 300 Da), fraction U2(300 Da? Mw ? 3000 Da) and U3 (> 3000 Da), Results of sensory evaluation showed that addition of U2 to model chicken broth, which can enhance its mouthfulness, complexity and a sensation of lingering.U2 was further separated by Sephadex G-15, and then five fractions F1-F5 were obtained and freeze-dried. UPLC-Q-TOF-MS analysis showed Gly-Leu-Pro-Asp(Mw=399.99) and Gly-His-Gly-Asp might act as key molecules to induce kokumi taste.Gly-Leu-Pro-Asp and Gly-His-Gly-Asp were synthesized by solid phase synthesis, and explored taste profile by sensory evaluation. It has found that both of Gly-Leu-Pro-Asp and Gly-His-Gly-Asp have strong kokumi flavor in model chicken broth and the threshold value is 3.75mmol/Land 2.08mmol/L separately. Peptides Gly-Leu-Pro-Asp and Gly-His-Gly-Asp had the strongest umami-enhancing and salty-enhancing with the concentration of 0.3%.