两种香米在不同温度储存过程中理化性质和食用品质的变化

以‘稻花香二号’和‘茉莉’大米为对象，从理化性质、质构特性、蒸煮特性和糊化特性4 个角度分析了香米在15 ℃、室温（约20～25 ℃）和37 ℃储存过程的品质变化，以期为优质大米的实际储存和流通过程提供理论依据。结果表明，在不同温度储藏期间，香米的各品质特性均发生明显改变，且温度越高，变化幅度越大。其中，‘茉莉’大米在储存过程中的水分质量分数、蛋白质量分数、巯基质量分数、L*值、a*值、米汤pH值的下降幅度以及硬度的增加幅度均大于‘稻花香二号’大米。‘稻花香二号’大米的直链淀粉质量分数、b*值和膨胀率增加幅度均大于‘茉莉’大米。香米在储藏期间，黏着性不断下降，而吸水率和糊化温度不断提高。香米在15 ℃条件下回复性变化不显著，而在其他温度条件下显著上升（P＜0.05）。‘稻花香二号’大米的弹性总体变化不显著，而‘茉莉’大米呈下降趋势。‘茉莉’大米在储藏期间咀嚼性更稳定。结合咀嚼性、峰值黏度和崩解值分析，37 ℃分别储藏120 d和180 d后，‘稻花香二号’大米和‘茉莉’大米的食味性达到最佳，且储藏结束后‘茉莉’大米的食味性高于‘稻花香二号’大米。

Variations in Physicochemical Properties and Eating Quality of Two Fragrant Rice Varieties during Storage at Different Temperatures

The quality changes of two fragrant rice varieties of ‘Daohuaxiang 2’ and ‘Jasmine’ during storage at 15 ℃, room temperature (20–25 ℃) and 37 ℃ were analyzed in terms of physicochemical, texture, cooking, and gelatinization characteristics. The results showed that pronounced changes in all quality characteristics were seen at all storage temperature, being more pronounced at higher temperature. During storage, ‘Jasmine’ rice presented greater decreases in water content, protein content, sulfhydryl content, the color parameters L* and a*, and pH, as well as a greater increase in hardness than did ‘Daohuaxiang 2’ rice. The increases in amylose content, b* value, and swelling rate were greater for ‘Daohuaxiang 2’ rice than ‘Jasmine’ rice. The adhesiveness decreased, while the water-absorbing capacity and gelatinization temperature increased for both varieties. While no significant change was observed in the resilience during storage at 15 ℃, a significant increase was found at other storage temperatures (P < 0.05). The elasticity of ‘Daohuaxiang 2’ rice did not significantly change overall, whereas ‘Jasmine’ rice showed a downward trend. The chewiness of ‘Jasmine’ rice was more stable than that of ‘Jasmine’ rice. Taking into account chewiness, peak viscosity, and breakdown, ‘Daohuaxiang 2’ and ‘Jasmine’ rice had the best taste after storage at 37 ℃ for 4 and 6 months, respectively, and the taste value of ‘Jasmine’ rice after storage was higher than that of ‘Daohuaxiang 2’ rice.