抹茶对贮藏期间薏仁米脂质氧化的影响

目的：利用天然物质抹茶延长薏仁米货架期。方法：以新鲜薏仁米为原料，经过不同剂量抹茶茶粉处理，测定贮藏期间薏仁米的水分含量、脂肪酸值、过氧化值、丙二醛含量等各项指标及菌落总数和脂质氧化关键酶的变化。结果：经不同剂量抹茶茶粉处理均会抑制薏仁米贮藏期间脂肪酸值、过氧化值、丙二醛含量以及脂肪酶和脂肪氧化酶活性的上升，减少水分的消耗及微生物的生长繁殖。抹茶对薏仁米的保藏效果存在一定程度的剂量依赖性，但添加质量分数为0.05%和0.08%的抹茶茶粉处理的保藏效果差异较小。贮藏4个月后，与自封袋组相比，添加质量分数为0.05%的抹茶茶粉处理组中薏仁米的脂肪酸值、过氧化值和丙二醛含量分别降低了31.60%，30.77%，44.83%，脂肪酶和脂肪氧化酶活性分别降低了23.05%，28.74%，且游离脂肪酸组成和含量与新鲜薏仁米更相似。结论：抹茶能有效抑制薏仁米贮藏期间脂质氧化，延长其货架期。

Effects of matcha on lipid oxidation during storage of coix seed

Objective: This study aimed to study the effect of matcha on lipid oxidation during the storage of coix seed. Methods: The fresh coix seeds were used as raw material and treated with matcha tea powder in different doses. The changes in water content, fatty acid value, peroxidation value, malondialdehyde content, total number of colonies and key enzyme of lipid oxidation were determined during the storage of coix seeds. Results: The treatment with different doses of matcha powder could inhibit the increase of fatty acid value, peroxide value, malondialdehyde content, lipase, and lipoxygenase activities, and reduce water consumption and microbial growth during storage of coix seeds. The preservation effect of matcha on coix seeds was dose-dependent to a certain extent, but the difference in the preservation effect of adding matcha tea powder with a mass fraction of 0.05% and 0.08% was small. After 4 months of storage, compared with the self-sealing bags group, the fatty acid value, peroxide value and malondialdehyde content of coix seeds in the treatment group with the addition of 0.05% matcha powder were decreased by 31.6%, 30.77% and 44.83%, respectively. The activities of lipase and lipoxygenase decreased by 23.05% and 28.74%, respectively, and the composition and content of free fatty acids were more similar to those of fresh coix seeds. Conclusion: Matcha could effectively inhibit lipid oxidation during storage of coix seeds and extended shelf life.