不同干燥工艺对冬虫夏草品质的影响

Effects of Different Drying Processes on Quality of Chinese Cordyceps

冬虫夏草传统的干燥工艺包括阴凉干燥和热风烘干。真空冷冻干燥是近年来兴起的新加工方法。以冬虫夏草的外观品质、超氧化物歧化酶(SOD)活力、甘露醇及4种甾醇(麦角甾醇、胆甾醇、豆甾醇和谷甾醇)含量为评价指标,研究了不同干燥工艺对冬虫夏草品质的影响。结果表明:不同干燥工艺所得冬虫夏草水分含量均符合《中国药典》一部对冬虫夏草水分的要求。真空冷冻干燥冬虫夏草保持了鲜品的外观形态和色泽,优于阴凉干燥和热风烘干样品;冷冻干燥冬虫夏草SOD活性最高,其次是阴凉干燥处理,热风烘干处理的SOD活性较低;3种干燥工艺中热风烘干冬虫夏草的麦角甾醇、胆甾醇及豆甾醇含量均高于冷冻干燥,而谷甾醇和甘露醇含量无明显差异(P>0.05)。综合外观品质和检测指标的分析,冷冻干燥比传统的热风烘干和阴凉干燥更适用于冬虫夏草的干燥加工。

The traditional drying process of cordyceps includes cool and hot-air drying. The vacuum freeze-drying is one new approach for Chinese cordyceps. Effect of different drying processes on quality of Chinese cordyceps was investigated. The appearance quality, superoxide dismutase( SOD) activity,mannitol and four sterol contents( Ergosterol,Cholesterol,Stigmasterol and Sitosterol) of Chinese cordyceps were used as evaluation indicators for Chinese cordyceps quality. The results showed that the moisture content of Chinese cordyceps obtained by different drying processes conforms to the requirements of the first part of Chinese Pharmacopoeia. The vacuum freeze-dried Chinese cordyceps maintained its fresh appearance and color,which is better than the air-dried and heat-dried products. The SOD activity was highest in the freeze-dried Chinese cordyceps,followed by the air-dried ones and lower in the heat-dried ones. The contents of ergosterol,cholesterol and stigmasterol in hot-air drying Chinese cordyceps were all higher than those in freeze drying,while the contents of sitosterol and mannitol were not significantly different( P >0.05). Based on the analysis of appearance quality and test index,vacuum freeze drying is more suitable than the traditional dry processes for drying Chinese cordyceps.