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This work suggested that L. nobilis oil could be used as a potential fungicide to control the post-harvest disease caused by A. alternata.

It is difficult to preserve fresh shiitake mushroom (Lentinula edodes (Berk.) sing) partly because of the rapid deterioration of texture (softening or lignification). In this study, we developed a storage model in which tissue softening was induced to analyse the relationship between changes in firmness and alterations in cell wall chemical components as well as their metabolism. The results showed that the treatment group accumulated more CO2 and contained less O2 because of the poorer permeability in package. The contents of glucan and chitin in the treatment group decreased from 241.3 ± 13.2 mg g−1 and 46.3 ± 1.2 mg g−1 to 157.3 ± 11.2 mg g−1 and 18.0 ± 1.0 mg g−1 (P < 0.05) with the accumulation of CO2. The activities of major cell wall degradation‐related enzymes were enhanced in the softening model, and the expression levels of major genes that encode enzymes related to cell wall degradation were upregulated. Our results suggested that the softening of shiitake mushrooms induced by high CO2 was associated with the degradation of polysaccharides and glycosaminoglycan and that these changes were systematically regulated by alterations in the activities and expression levels of related enzymes and genes.

Summary Fresh shiitake mushrooms (Lentinula edodes) are prone to texture softening and quality decline during storage. We investigated the effects of prestorage ultrasonic treatment on the textural changes of the mushrooms during storage. We monitored physiological parameters, such as respiration intensity, weight loss, cell wall composition and resistance‐related enzymes activity. The hardness of the ultrasonic‐treated (40 kHz, 80 W L−1, 20 min) mushrooms after 12 days of storage (0.461 N) was significantly higher than the untreated control group (0.286 N). The weight loss and respiration intensity of the ultrasonic‐treated group were significantly lower, whereas the cell wall contents, including glucan and chitin, were significantly higher. The ultrasonic‐treated mushrooms also had higher phenylalanine ammonia lyase, superoxide dismutase and catalase activities. Thus, ultrasound preserves the texture of mushrooms by reducing metabolic rate, maintaining cell wall compositions, activating the activity of SOD and maintaining the activity of PAL and CAT.

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