稻谷烘干过程中的水分扩散特性与品质特性  

Moisture diffusion characteristics and quality characteristics of rice during drying

作　　者：徐凤英[1] 黄木水 陈震[1] 李长友[1] 

机构地区：[1]华南农业大学南方农业机械与装备关键技术省部共建教育部重点实验室,广州510642

出　　处：《农业工程学报》2016年第15期261-267,共7页Transactions of the Chinese Society of Agricultural Engineering

基　　金：国家自然科学基金资助项目(31371871;31071583)

摘　　要：为深入研究稻谷高效均匀化烘干过程中的水分扩散与质量转变耦合特性,该文测定了玉香油粘稻谷经50、65、80℃分别烘干时的水分有效扩散系数;检测了以上3种温度分别烘干稻谷的色差、籽粒颖壳断面孔隙率与分形维数及玻璃化转变温度,考察了已烘干稻谷的含水率、硬度、爆腰率、发芽率等过程品质差异。结果表明:玉香油粘稻谷烘干过程的有效水分扩散系数为3.576×10-8e15 684/Tm2/s;随烘干温度增加,籽粒颖壳断面的孔隙率由鲜谷的0.39±0.06依次降为0.22±0.09、0.17±0.04、0.13±0.05,但烘干稻谷的分形维数、色差、玻璃化转变温度则较其鲜谷波动增加;已烘干稻谷的含水率、硬度、爆腰率、发芽率组间差异显著(P<0.05)。50℃烘干稻谷的爆腰率、发芽率性能优,宜选为稻谷烘干常用工艺温度,研究结果为稻谷高效均化烘干提供了理论与基础数据参考。Traditionally, researches of rice drying methods are only focused on moisture diffusion characteristics and quality characteristics respectively. But the questions how both of those characteristics affect the multilayer structure moisture diffusion of grain, how their structure forms, and how the physiological-biochemical quality converts under high temperature thermal are ignored. Thus, the cooperative improvement mechanism of rice drying characteristics and quality is difficult to reveal. In order to study coupling characteristics among balanced efficient mechanical drying feature, moisture diffusion characteristics, microstructure, chromatic aberration, and physiological-biochemical characteristics for rice grain, this paper analyzed the relationship among moisture diffusion equations and its effective moisture diffusion coefficient, Arrhenius factor, and activation energy for short column rice grain. By methods of separately measuring and fitting, the paper investigated the dewatering characteristics of continuous drying process at 50, 65, and 80 ℃ for Yuxiangyouzhan rice, compared the effective moisture diffusivity of continuous drying at the 3 different temperatures, and studied the Arrhenius factor and activation energy. Then, the porosity and the fractal dimension of rice shell were compared under intermittent drying at 50, 65, and 80 ℃.Furthermore, the moisture and the maximum heat flux were compared for Yuxiangyouzhan rice at different drying stages, as well as their start temperature, midpoint temperature, end temperature of glassing converting, and specific heat. Finally, the hardness, crack percentage, germination rate, and moisture content were studied for fresh rice in the interval drying process at the 3 different temperatures, as well as the heat flux, fractal dimension, hardness, and cracked germination effect. The results showed that the moisture effective diffusivity of rice grain significantly increased with drying temperature. When continuously drying at 50, 65, and 80 ℃, the moisture

关 键 词：干燥 温度 分形 稻谷 水分扩散特性 品质特性 水分有效扩散 

分 类 号：S375[农业科学—农产品加工]