干燥方式对香菇品质特性及微观结构的影响

为了分析常用的3种干燥方式对香菇干制品品质的影响,以新鲜整香菇为原料,采用三段式微波真空冷冻干燥(three-stage microwave vacuum freeze drying,TS-MVFD)、冷冻干燥(freeze drying,FD)、热风干燥(hot airdrying,HAD)技术干燥加工,探讨不同干燥方式下香菇干制品的干燥特性、营养成分、微观结构,并通过标度法定量分析3种香菇干制品复水熟制后的感官特性。结果表明,香菇脱水至水分质量分数低于13%,TS-MVFD、FD与HAD的干燥时间分别为5、14 h和8 h。复水120 min后,TS-MVFD香菇干制品复水比(7.1)明显高于FD(6.0)、HAD(4.4)样品;复重系数(91.40%)、菌盖色泽和总糖(60.21 g/100 g)、粗多糖(7.41 g/100 g)、游离氨基酸(3.44 g/100 g)含量与FD香菇干制品差异不大;FD香菇截面呈多孔性的蜂窝状网状结构,微孔分布均匀;TS-MVFD香菇微观结构与FD相似,而且微孔孔径稍大;HAD香菇截面结构层叠,细胞壁坍塌严重。复水熟制后,TS-MVFD香菇样品的风味、口感明显优于HAD和FD干燥产品。综上,TS-MVFD是一种有推广价值的香菇干燥方式。

Effects of Drying Methods on the Quality Characteristics and Microstructure of Shiitake Mushrooms(Lentinus edodes)

In this study,fresh intact shiitake mushrooms(Lentinus edodes)were used to investigate effects of three drying methods three-stage microwave vacuum freeze drying(TS-MVFD),freeze drying(FD),and hot air drying(HAD)on drying characteristics,nutrient composition and microstructure of dried mushrooms and sensory characteristics of rehydrated mushrooms determined by quantitative scale analysis.The results showed that TS-MVFD,FD and HAD took 5,14 and 8 hours to dehydrate mushrooms to a moisture content of less than 13%,respectively.After 120 min of rehydration,the rehydration rate of TS-MVFD-dried mushrooms(7.1)was significantly higher than that of FD(6.0)and HAD(4.4)dried samples.The rehydration coefficient(91.40%),cap color,content of total sugar(60.21 g/100 g),crude polysaccharide(7.41 g/100 g)and free amino acid(3.44 g/100 g)of the TS-MVFD dried mushroom were no significant difference when compared with FD dried mushroom.The microstructure of TS-MVFD dried samples was similar to that of FD dried samples,except for slightly larger micropore diameter.The cross-sectional structure of HAD dried samples was stacked with the cell wall collapsing seriously.After rehydration and cooking,the flavor and taste of TS-MVFD dried mushroom samples were significantly better than those of HAD and FD dried products.Therefore,we believe that TS-MVFD will become a popular drying method for shiitake mushrooms.