关键词: 大米；储藏；品质变化；气相色谱-离子迁移谱；动力学模型

Abstract: To investigate the effects of storage temperature on the quality of rice, the pattern of changes in quality indexes of ‘Liaoxing’ rice under different storage temperatures (15, 20–25, 37 ℃) was studied, and a kinetic model that fitted the experimental results to describe each quality index was determined, aiming at providing reference for predicting quality changes during rice storage. The results showed that higher storage temperature had a more significant effect on the surface morphology of rice endosperm. Rice showed inferior quality after being stored at high temperature (37 ℃) for 300 days. The physicochemical properties, appearance, texture, cooking and pasting properties of rice changed greatly during storage, and the higher the storage temperature, the greater the change. According to fatty acid values and catalase activity, the storage period of rice stored at 15 ℃, room temperature (around 20–25 ℃) and 37 ℃ was less than 240, 180, and 120 days respectively, and the quality of rice deteriorated beyond this period. The results of gas chromatography-ion mobility spectrometry (GC-IMS) indicated that the concentrations of 1-butanol, dimethyl disulfide, cyclohexanone increased with the increase in storage temperature, thus indicating that these substances may be crucial to produce off-odor during the storage of rice. Principal component analysis showed that rice at different storage temperatures had significant differences in odor components. Zero-order kinetic models could better describe the changes of fat content, swelling rate, pH of rice soup, solid content of rice soup, lipase activity, fatty acid value and catalase activity, while first-order kinetic models could better describe the changes of thiol content and water absorption during rice storage.

Key words: rice; storage; quality change; gas chromatography-ion mobility spectrometry; kinetic model