热蒸汽烫漂联合热风微波耦合干燥香菇的工艺优化

本文基于热风干燥探究了不同热蒸汽烫漂预处理时间(0、60、120、180、240 s)对香菇干燥特性及色泽的影响。单因素实验确定最优的预处理时间后,基于热风微波耦合干燥研究间歇比(2、3、4、5、6)对香菇干燥特性、能耗及干品品质(色泽、收缩模式、香菇多糖)的影响,并获得热风微波耦合干燥香菇的最优工艺。结果表明:热蒸汽烫漂处理后可缩短约0%~30%的干燥时间,烫漂180 s时效果最佳;热风微波耦合干燥间歇比越小,干燥时间越短,能耗越小,随着间歇比的增加,香菇多糖含量先减小后增大;在干燥过程中,香菇片厚度比与水分比呈二次函数关系,间歇比为2~6时,热风微波耦合干燥的拟合度为0.83~0.97,模型拟合良好;在微波间歇比为2(1 min:1 min,t_on:t_off)时,产品色差较小,香菇多糖含量最高,能耗最低。结果表明180 s热蒸汽烫漂联合热风微波耦合干燥,在间歇比为2时,能够实现对香菇的快速干燥,并保证较好的干品品质。

Optimization of the Technology of Hot Steam Blanching Coupled with Hot Air-microwave Combined Drying Process of Shiitakes

The influence of different heat steam treatment time (0, 60, 120, 180, 240 s) on the drying characteristics and color of shiitakes were explored in this study. The single factor test was carried out to determine a better pretreatment time. Drying experiments were performed in order to investigate the effect of hot air-intermittent microwave combined drying on the characteristics, energy consumption and quality (color, shrinkage mode, lentinan) at different pulse ratios (2, 3, 4, 5, 6). The optimal drying process was achieved. Results showed that hot steam blanching resulted in decreasing the drying time by 0%~30%, and the best quality was obtained at the blanching time of 180 s. In addition, by increasing the pulse ratio from 2 to 6, samples drying time and energy consumption decreased. The content of lentinan decreased initially, and then increased with the increment of the pulse ratio. The thickness ratio was related to the humidity ratio as a quadratic function during the drying process. The fitting coefficient was 0.83~0.97 when the pulse ratio was between 2 to 6, and the quadratic function fitted well. In fact, less color change, better maintenance of lentinan and less the energy consumption was achieved with the microwave intermittent ratio was 2 (1 min:1 min, t_on:t_off). Overall, 180 s hot steam blanching coupled with hot air-microwave combined drying achieved rapid drying and optimized the quality of dried shiitakes when the pulse ratio was 2.