Evaluation of the umami in edible fungi and study on umami extraction of Agaricus bisporus

The purpose of this research is to identify the best edible fungi among eight species of edible fungi, and to study the best enzymatic hydrolysis reaction conditions in order to enhance the umami taste of edible fungi. The free 5'-nucleotides and amino acids in eight kinds of edible fungi were determined by high performance liquid chromatography (HPLC), and the equivalent umami concentration (EUC) values were calculated. Combined with the sensory evaluation, it was found that the EUC value of Agaricus bisporus was the highest, which was 826.551±20.057 g/100 g, and with a good umami taste. Enzymatic hydrolysis was conducted to further release umami substances in edible fungi, and the best effect was found under the enzyme mixtures of cellulase and Protamex™ by EUC values and sensory evaluation. Through the single-factor experiments and orthogonal tests, taking EUC value, sensory evaluation, degree of hydrolysis and soluble solids content as indexes, the optimal conditions for enzymatic hydrolysis were at 50°C, a solid-liquid ratio of 1:10, a pH of 5.5, a total enzyme mixtures addition of 4000 U/g, and a cellulase hydrolysis time of 60 min followed by the addition of a Protamex™ hydrolysis for 150 min. The final enzymatic hydrolysate had an intensive saltiness and umami taste with an EUC value of 1619.05±3.38 g/100 g.