Evaluation of umami taste components of mushroom (Suillus granulatus) of different grades prepared by different drying methods

Suillus granulatus is a valuable wild edible mushroom with a strong umami taste. Different grades of S. granulatus were dried by different methods, including natural air drying (ND), hot air drying (HAD), vacuum drying (VD), and freeze drying (FD). Results showed that VD samples of all grades had the highest equivalent umami concentration (EUC) value (P < 0.05). The second grade of ND samples showed the highest EUC value (P < 0.05). The first grade of HAD samples showed the highest EUC value (P < 0.05). The third grade of FD samples showed the highest EUC value (P < 0.05). The third grade of VD samples had a higher EUC value than the other grades of samples dried by VD. Electronic tongue results indicated no significant differences between samples of all grades dried by all methods. Thus, umami taste components are affected by drying method and grade. VD is an appropriate drying method for all sample grades. ND, HAD, and FD are suitable for second-, first-, and third-grade samples, respectively.