| Edible mushroom are delicious and rich in various nutrients and bioactive substances.Regular consumption of edible mushroom can improve the body's resistance to disease and benefit to human health.However,due to high moisture content and vigorous metabolism,the fruiting body of fresh edible mushroom is sitll metabolize after harvest,resulting in the change of bioactive substances content.In this context,fresh edible mushroom must be timely processed to prevent deterioration.Drying is the primary method to process edible mushroom after harvest.The key to get high-quality dry mushroom is to keep the bioactive ingredients content to the maximum extent during drying.In this work,Lentinus edodes?the largest production mushroom in China?and Pleurotus geesteranus?a wide planting mushroom in recent years?were dried by different drying methods?including hot-air drying,microwave drying,freeze drying and infrared drying?.The indexes including apparent quality,active ingredients content and antioxidant activity were analyzed to determine the best drying method for producing dried products with excellent quality.The results from Lentinus edodes drying tests showed that Lentinus edodes turns black after hot-air drying,and the content of polysaccharide and polyphenol is 21.08mg·g-1 and 5.00 mg·g-1,respectively.Microwave drying takes the least time,but the dried mushroom is black and withered.The content of polysaccharide is determined as 26.39 mg·g-1,but that of polyphenol is only 1.76 mg·g-1.The color and shape of mushroom are maintained well by freeze drying,and the contents of active ingredients do not change greatly,but freeze drying needs much energy and time.The content of polysaccharide and polyphenol is respectively 22.38 mg·g-1 and 6.57mg·g-1in samples dried by infrared drying.Compared with other drying methods,infrared drying maintains bioactive ingredients more effectively and shows the best in vitro antioxidant activity,suggesting that infrared drying is an optimal method for Lentinus edodes drying.The results from Pleurotus geesteranus drying tests showed that only little color difference is determined in dried Pleurotus geesteranus due to its simple structure.The content of polysaccharide in samples dried by infrared drying is 57.19%higher than that in samples dried by hot-air drying.Infrared drying samples also perform the best in antioxidant indexes,suggesting that infrared drying can keep the overall quality of Pleurotus geesteranus.The dried mushrooms are still susceptible to environmental conditions such as oxygen and humidity.To investigate the effects of different packing and storage conditions on the quality of dried Lentinus edodes,they were packed with different packing materials?aluminum foil and plastic bag?in different ways?atmospheric pressure and vacuum condition?,and stored at different temperatures?room temperature and 4oC?.The changes in apparent quality,active ingredients,antioxidant activity and flavor components were monitored during the one-year storage to determine the best storage conditions of dried Lentinus edodes and provide a reference for defining their expiration date and shelf life.The results showed that the storage temperature can significantly affect the quality of dried Lentinus edodes.The variation value of color in samples stored at 4oC is only 3.89%compared with that of samples stored at room temperature,suggesting that low temperature can effectively maintain the apparent quality of dried Lentinus edodes.The loss rate of5'-nucleotide decreases by 48.2%in samples stored at room temperature while it is only 9.65%in samples stored at 4oC.The retention rate of free amino acids in samples stored at room temperature and 4oC is 59.57%and 91.56%,respectively.The content of volatile acids in samples stored at 4oC is 18.45%lower than compared with that of samples stored at room temperature,while the content of alcohols in samples stored at 4oC is 2.98 times compared with that of samples stored at room temperature.Among the quality indicators,the packaging methods mainly affect the apparent quality of dried Lentinus edodes.Vacuum packaging is more effective for the storage of dried Lentinus edodes.The packaging materials mainly affect the apparent quality and early-stage storage of dried Lentinus edodes.In the early stage of storage,the quality of dried Lentinus edodes packaged in aluminum foil is better than that of samples stored in plastic package.However,the quality of dried Lentinus edodes packaged in the two materials turns to be similar in the late stage of storage. |
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