发芽糙米热风和微波干燥特性及品质研究

Effects of Hot Air Drying and Microwave Drying on Characteristics and Quality of Germinated Brown Rice

摘要:

本文以糙米为原料，将糙米发芽后进行热风干燥和微波干燥，通过比较热风干燥与微波干燥对发芽糙米干燥特性、主要营养成分、酶解力、硬度及色泽的影响，建立干燥数学模型，为微波干燥品质预测与干燥条件的控制提供依据。基于Fick扩散定律建立的干燥模型与Page方程可分别很好地拟合发芽糙米的热风与微波干燥曲线。随着热风温度的升高或微波比功率的增大，干燥速度常数和水分有效扩散系数都呈逐渐增大的趋势，发芽糙米的热风干燥活化能为55.76 kJ/mol。干燥条件对发芽糙米的主要营养成分含量、酶解力及硬度都有显著的影响。微波干燥条件下发芽糙米的还原糖、游离氨基酸及γ-氨基丁酸含量较低。发芽糙米在干燥过程中发生了褐变反应，颜色以黄色为主，微波干燥得到的发芽糙米的红度高于热风干燥。

Abstract:

Germinated brown rice (GBR) was dried using hot air or microwaves and effects the drying characteristics, main nutritional content, enzymatic hydrolysability, hardness, and color of the dried GBR were analyzed. Drying mathematical models were established to provide a basis for the prediction of microwave drying and the control of drying conditions. The drying model based on Fick's laws of diffusion and Page equation fit the hot air drying and microwave drying curves of GBR well. The drying rate constant and moisture effective diffusivity increased with the increase in hot air temperature or microwave power per gram. The activation energy of hot air drying of GBR was 55.76 kJ/mol. Drying conditions significantly affected the content of main nutritional content, enzymatic hydrolysability, and hardness. The contents of reducing sugar, free amino acid and γ- aminobutyric acid of GBR treated by microwave drying were relatively low. Browning reaction during the drying process changed the color of the GBR to yellow, while the redness value after microwave drying was higher than that after hot air drying.