Effect of intermittent microwave drying on biophysical characteristics of rice

作者：Fengying Xu, Zhen Chen, Mushui Huang, Changyou Li, Weibiao Zhou · 发表于：Journal of Food Process Engineering · 年份：2017 · DOI：10.1111/jfpe.12590 · 被引用次数：32 · 研究领域：Food Drying and Modeling、Food composition and properties、Microencapsulation and Drying Processes

Abstract The dehydration performance of intermittent microwave drying and its effect on the biophysical characteristics of rice (Oryza sativa L.) were quantified. Three pulse ratio levels (PR2, PR3, and PR5) were tested. Two dehydration performances (temperature and drying rate) and seven biophysical quality indices (moisture content, microstructure, glass transition temperature, color, hardness, crack percentage, and germination) of rice were measured. Different semi‐empirical moisture ratio models were optimized to fit the experimental data. The results showed that the temperature of rice treated by PR2, PR3, and PR5 were significantly different from each other during the process. The rice temperature dried by PR5 was the lowest and it tended to be constant at the late stage. The average drying rates of rice treated by PR2, PR3 and PR5 were 0.568, 0.437, 0.265% w.b. gg −1 .min −1 , respectively. With the increase of pulse ratio, the porosity of kernel glume cross section and the glass transition temperature of dried rice decreased. The moisture content changed significantly ( p < .05). However, the hardness and color of rice showed no significant differences ( p < .05). The crack quality and germination rate of dried rice treated by PR5 were significantly higher than those of the other treatments (p < .05). Page model was found to be the most fitted model. By considering the drying performance and quality, PR5 was the most suitable microwave drying treatment for ri...