Combined drying method of microwave and hot air for rice based on glass transition

Abstract

The invention provides a microwave-hot air combined compound type rice drying method based on glass transition, and belongs to a grain drying technology. According to the method, a glass transition technology is combined with a microwave-hot air combined drying technology, in the condition that the moisture gradient between the inner and the outer of a rice grain is less than or equal to 6%, microwaves are used for rapidly heating the rice grain, the rice is dried by hot air when reaching the rubber state, and thus the operation is completed; and according to the method, the rate of cracking at a waist of the rice is reduced, the drying time is saved, the drying efficiency is improved, and the drying energy consumption is reduced.

Description

technical field [0001] The invention belongs to the grain drying technology, and mainly relates to a rice microwave and hot air combined compound drying method based on the glass transition theory. Background technique [0002] The main components of rice are starch and protein, among which starch accounts for about 70%. It will become a rubber state. In the rubber state, the moisture diffusion coefficient and expansion coefficient of rice are large, the elastic modulus is small, and the deformation ability is high, and the state transition temperature is negatively correlated with the moisture content. After a large number of experiments, the glass transition temperature of each variety of rice has a linear correlation, and the glass transition temperature is about 50°C when the moisture content of the rice moisture base is 14.5%. The moisture content of newly harvested rice is relatively high, generally about 22%-30%. Direct storage will cause rice germination, mildew, an...

AI Technical Summary

Problems solved by technology

The hot air drying method still has problems such as high rice cracking rate, high energy consumption, and no obvious improvement in the whole rice rate in the post-processing process.