以香菇为原料,通过单因素试验测定不同切片厚度、热风温度及装载量条件下香菇的干基含水率、水分比及干燥速率变化,通过三因素三水平的响应面试验对热风干燥的工艺参数进行优化,比较香菇在热风干燥前后可溶性蛋白质、总酚含量及1,1-二苯基-2-三硝基苯肼(1,1-diphenyl-2-picrylhydrazyl,DPPH)自由基清除率的变化.结果表明:单因素试验中切片厚度在3～12 mm、热风温度在50～70℃、装载量在5～15 g/dm范围时香菇干基含水率、水分比及干燥速率较合适;响应面试验优化后各工艺参数的最佳组合为切片厚度4.99 mm、热风温度55.21℃、装载量7.88 g/dm2;经热风干燥后香菇的可溶性蛋白质及游离氨基酸含量无显著下降,而总酚含量及DPPH自由基清除率都较干燥前显著降低,说明热风干燥可以较好保留香菇中可溶性蛋白质和游离氨基酸含量,但对香菇总酚含量及抗氧化活性的破坏较大.%The one-factor-at-a-time method was used to investigate the effect of slice thickness,hot air temperature and loading amount on the hot air drying characteristics of shiitake mushrooms including moisture content on a dry basis,moisture ratio and drying rate.The drying parameters were optimized by response surface methodology with a three-variable,three-level experimental design.The changes in soluble protein content,total phenolics and 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging capacity before and after hot air drying were compared.The results showed that slice thickness,hot air temperature and loading amount in the range of 3-12 ram,50-70 ℃ and 5-15 g/din2,respectively were suitable for moisture content on a dry basis,moisture ratio and drying rate.The optimized drying parameters obtained by response surface methodology were as follows:slice thickness,4.99 mm;hot air temperature,55.21 ℃;and loading amount,7.88 g/dm2.The phenolics and DPPH scavenging capacity but not soluble protein or free amino acid contents of shiitake mushrooms were significantly decreased after hot air drying.These results indicate that hot air drying can maintain the contents of protein and free amino acids,but severely destroy the total phenolics and antioxidant activity of shiitake mushrooms.
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