This research investigated the impacts of various drying methods, including hot-air drying, hot-air-microwave drying, heat-pump drying, vacuum-freeze drying, microwave-vacuum drying, and multi-stage hot-air drying, on the physicochemical properties, antioxidant capacity and flavor profile of Lentinus edodes powder (LEP). The results demonstrated that vacuum-freeze-dried LEP was superior to LEP produced using the other drying methods in terms of physicochemical properties such as water absorption index, expansion ratio, and color. Moreover, vacuum-freeze-dried LEP had the highest total phenolic content (1.345 mg/g) and strongest antioxidant capacity in terms of 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical and 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) cation radical scavenging capacity. In contrast, microwave-dried LEP showed the lowest antioxidant capacity. Analysis by electronic nose and gas chromatography-ion mobility spectrometry (GC-IMS) revealed that the major volatile compounds in the six LEPs included sulfur-containing compounds, aldehydes, alcohols, ketones, and esters, and there were significant differences in the aroma profiles of these LEPs. Notably, heat-pump-dried LEP exhibited the highest levels of alcohols and esters. Hot-air-dried LEP exhibited the highest levels of aldehydes. Vacuum-freeze drying was conducive to retaining aroma compounds. The results of electronic tongue analysis indicated that hot-air-microwave dried LEP had high umami and low bitterness. These findings could provide a theoretical foundation for the development and application of LEP as a food ingredient.

In this study, the effects of the extracts from mulberry leaves, rosemary, cinnamon, grape seeds, green apples and cloves on the color, oxidative stability and flavor characteristics of oil-fried shiitake mushroom were investigated. It was found that these natural extracts improved the brightness of oil-fried shiitake mushroom and significantly inhibited its browning. The content of melanoid, the Maillard reaction product, was decreased by treatment with each of the extracts, which shared a similar trend with the change in the degree of browning. The natural extracts also significantly improved the antioxidant capacity and inhibited the oxidation reaction of oil-fried shiitake mushroom. Clove extract resulted in the largest decrease in peroxide value (74.36%), while green apple extract resulted in the greatest decrease in thiobarbituric acid reactive substances (TBARS) value (17.54%). Clove, rosemary and grape seed extracts significantly inhibited protein oxidation. Treatment with green apple extract minimized the free radical content. The umami and saltiness were significantly increased by treatment with clove, rosemary or mulberry leaf extract. All six natural extracts increased the levels of nitrogen and oxygen compounds, hydrocarbons, alcohols, aldehydes, and ketone. Seventeen differential volatile compounds, such as methyl 2-methoxybenzoate and isoamyl 2-methylbutyrate, were identified among the six treatment groups and the control group. These results provide a theoretical basis for the application of natural extracts in oil-fried edible mushrooms.