Proximate compositions, nonvolatile taste components and antioxidant capacities of some dried edible mushrooms collected from Thailand

Four species of mushrooms are commercially available in Thailand, namely Lentinus edodes, Pleurotus eryngii, Pleurotus sajor-caju and Pleurotus djamor and their nutritional compositions, nonvolatile taste components as well as antioxidant capacities were determined. In this research, each mentioned mushrooms were dehydrated by hot air drying prior to analysis. All dried mushrooms were found to be good sources of proteins, with contents varying in the ranges of 21.23-28.23 g/100 g dry weight (dw) while the fat content was very low (1.47-2.57 g/100 g dw). Trehalose (12.97-42.57 mg/g dw) and mannitol (73.2775.53 mg/g dw) were considered as the major mushroom sugar/polyol. Total soluble sugar contents were in the order: L. edodes > P. sajor-caju > P. eryngii and P. djamor. Total content of free amino acids also varied and ranged from 28.46 to 57.09 mg/g dw. Monosodium glutamate (MSG)like components were the highest in P. eryngii (10.72 mg/g dw), and lowest in L. edodes (7.16 mg/g dw) and P. djamor (7.41 mg/g dw). Equivalent umami concentration values (EUC) in four dried edible mushrooms ranged from 200.28 to 299.60 g MSG/100 g dw, and the highest EUC was found in P. eryngii, followed by P. djamor, P. sajor-caju and L. edodes, respectively. In addition, L. edodes contained the highest total phenolic contents (26.63 mg/g dw) as well as antioxidant capacities as evaluated by DPPH radical scavenging activity (DPPH-RSA, 7.58 mg/g trolox dw), 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) radical scavenging activity (ABTS-RSA, 2.19 mg/g trolox dw) and Ferric ion reducing antioxidant power (FRAP, 18.77 mg/g trolox dw). This result obtained revealed that all dried mushrooms contained a relatively strong umami taste and could be used as functional foods with a palatable umami taste or in the formulation of nutraceuticals.