Abstract: In order to study the effect of different drying methods on the umami taste components in different parts of the fruiting body of Suillus granulatus, the contents of non-volatile components in the mushroom samples after natural drying (ND), hot air drying (HAD), vacuum drying (VD) and vacuum freeze drying (FVD) were determined. The umami taste was evaluated by equivalent umami concentration and umami taste scores from an electronic tongue. The results suggested that among four drying methods, HAD provided the highest umami amino acid content (18.49 mg/g) and equivalent umami concentration (EUC) (113.18 g/100 g) in Suillus granulatus tube, the highest umami amino acid content in pileus (15.11 mg/g) and the highest EUC value in stipe (27.66 g/100 g) (P < 0.05). After vacuum drying, the soluble sugar content of Suillus granulatus tube (26.35%) and stipe (23.25%), the umami amino acid content (10.04 mg/g) of stipe, the umami nucleotide contents of tube, pileus and stipe (3.63, 3.06 and 2.84 mg/g) and the EUC value (39.51 g/100 g) of stipe were all significantly higher than those from the other three drying methods (P < 0.05). After vacuum freeze drying, the soluble sugar content (30.29%) and the contents of sweet amino acids (16.90 mg/g) and non-taste-active amino acids (16.23 mg/g) in Suillus granulatus pileus, the sweet amino acid content (16.74 mg/g) of stipe, and the bitter amino acid content (27.66 mg/g) of tube were all significantly higher than those from the other three drying methods (P < 0.05). After natural drying, the umami taste score (11.46) and bitter amino acid content (21.13 mg/g) of Suillus granulatus pileus and the contents of bitter amino acids (37.48 mg/g) and non-taste-active amino acids (17.44 mg/g) in stipe were all significantly higher than those from the other three drying methods (P < 0.05). Therefore, during the deep processing of S. granulatus into umami seasonings, hot air drying is suitable for S. granulatus tube and stipe, while vacuum drying is suitable for S. granulatus pileus.

Key words: Suillus granulatus, drying methods, umami taste components, chemical analysis, electronic tongue