Effects of Different Processing Methods on Umami Taste and Antioxidant Capability of Water Extracts of Morchella esculenta

This study was aimed to compare the effects of thermal treatment (70, 90 ℃) and non-thermal treatment (room temperature, ultrasound treatment, homogenization and high hydrostatic pressure) on the umami taste and antioxidant capability of water extracts of Morchella esculenta. The content of 5’-nucleotide (5’-CMP, 5’-UMP, 5’-XMP, 5’-GMP, 5’-IMP and 5’-AMP) and free amino acid (17 kinds) in these extracts were analyzed by high performance liquid chromatography and amino acid analyzer respectively, and their corresponding value of Equivalent Umami Concentration (EUC) were calculated. Antioxidant properties of each water extract of Morchella esculenta were comprehensively evaluated by DPPH, FRAP and ABTS methods. Except for the treatment of RT (room temperature), other treatment on finely pulverized Morchella esculenta powder (P2 or P3, 35.52 and 6.28 μm, respectively) increased the contents of total 5'-nucleotides while decreased the contents of umami amino acids and total free amino acids (FAA) in their corresponding water extract. Therefore, the EUC values of the Morchella esculenta extracts were changed from 106.58 g MSG/100 g~493.97 g MSG/100 g to 74.70 g MSG/100 g~364.35 g MSG/100 g. Compared with the room temperature treatment, other treatments improved the EUC value of the water extracts. However, thermal treatment decreased the antioxidant capacity of the extract, and non-thermal treatment of HHP displayed the highest EUC value and ideal antioxidant effect. Especially, the original Morchella esculenta powder without superfine grinding had the highest EUC value and the best antioxidant capacity after HHP treatment, which might be suitable for the further processing of Morchella esculenta.