Abstract: Objective: To investigate the effect of 60Co-γ irradiation on the quality of harvested Morchella angusticeps during cool storage. Methods: M. angusticeps was irradiated with different absorbed doses of 60Co-γ (1.64, 2.18, 2.43 and 2.93 kGy), and the sensory quality and physiological and biochemical indexes of the control and irradiated samples during cold storage were evaluated. Orthogonal partial least square discriminant analysis (OPLS-DA) was used to establish a discriminant model for irradiation treatment based on the physiological and biochemical indexes of M. angusticeps, and the significantly differential indexes between the control and irradiation groups were identified using variable importance in the projection (VIP). Results: The patterns of changes in the sensory quality and physiological and biochemical characteristics of M. angusticeps irradiated with different doses of 60Co-γ were different during storage at 4 ℃. After five days of storage, the activity of catalase and the contents of total phenols and flavonoids in the 1.64 and 2.18 kGy irradiation groups were increased, malondialdehyde content and the activities of polyphenol oxidase and peroxidase were reduced, and browning and softening were retarded as compared to the control group. The dose of 1.64 kGy provided better preservation of the quality of M. angusticeps (P < 0.05). On the contrary, the doses of 2.43 and 2.93 kGy increased the quality deterioration of M. angusticeps at the end of storage. The developed discriminant model could distinguish the differences between the control and irradiation treatments effectively. The activities of catalase and peroxidase were identified as significantly differential indexes. Conclusion: 60Co-γ irradiation at doses of 1.64 and 2.18 kGy can delay the quality deterioration significantly and prolong the shelf life of M. angusticeps, the dose of 1.64 kGy being more effective. The OPLS-DA model could effectively distinguish between the different treated sample groups.

Key words: Morchella angusticeps; 60Co-γ irradiation; storage quality; orthogonal partial least squares-discriminant analysis