大米小包装储藏过程中脂类及微观结构的变化  

Lipid and Microstructure Changes of Small Packaged Rice During Storage

作　　者：王立峰[1] 陈超[1] 杨精华[1] 陈静宜[1] 汪海峰[1] 鞠兴荣[1] 

机构地区：[1]南京财经大学食品科学与工程学院/江苏省现代粮食流通与安全协同创新中心/江苏高校粮油质量安全控制及深加工重点实验室,210023

出　　处：《中国农业科学》2015年第9期1807-1817,共11页Scientia Agricultura Sinica

基　　金：江苏省科技支撑计划项目(BE2012764);江苏省农业科技自主创新资金项目(CX(13)3088);江苏省高校优势学科建设工程资助项目

摘　　要：【目的】由于胚乳失去保护,大米在储藏过程中易发生陈化、霉变等问题,致使其品质劣变甚至丧失食用价值。通过测定储藏过程中大米游离脂肪酸、总酸含量、脂肪酸组成和含量,观察大米横断面胚乳细胞、淀粉颗粒微观结构,探讨大米品质劣变原因,为大米储藏技术提供参考。【方法】以粳稻99号大米为对象,进行人工模拟储藏试验:采用编织袋、自然密闭缺氧、抽真空3种包装方式,置于温度为15、25和30℃(60%湿度)的人工气候箱中储藏180 d,每个月进行一次品质指标测定;测定大米储藏过程中脂肪酸值、总酸值的变化,利用气相色谱分析脂肪酸组成及含量变化,利用扫描电镜观察大米横断面胚乳细胞形态,探索脂类及横断面胚乳结构导致大米品质陈化的机理及品质劣变后淀粉颗粒微观形态的变化规律。【结果】1储藏过程中,编织袋及自然密闭缺氧包装的大米游离脂肪酸及总酸含量皆呈现急剧上升趋势,当品质劣变严重时两者含量反而下降;抽真空包装的大米游离脂肪酸及总酸含量均保持在较稳定的水平,且储藏温度对其含量影响不显著;2脂肪酸组成中含量最多的是亚油酸、油酸和棕榈酸,这3种脂肪酸含量占总脂肪90%以上。包装方式及储藏温度对各脂肪酸组成影响不同。除了花生酸(C20:0)及二十二烯酸(C22:1)外,其余脂肪酸受包装方式影响较大;而储藏温度仅与豆蔻酸(C14:0)和山嵛酸(C22:0)有显著性关系,对其余脂肪酸影响不大。脂肪酸变化规律符合:高不饱和脂肪酸含量随温度升高而降低,多不饱和脂肪酸与饱和脂肪酸及单不饱和脂肪酸间呈现显著负相关,具体表现为硬脂酸(C18:0)与亚油酸(C18:2)、亚麻酸(C18:3);油酸(C18:1)与亚油酸、亚麻酸皆呈现明显的"此消彼长"现象。3新鲜大米淀粉粒以复粒形式存在,形状较大,表面有较厚的膜,排列整齐有序,两侧以片状的细胞间�Objective]Due to the loss of protection of endosperm, rice prones to aging during storage, mildew and other issues, which resulted in edible quality deterioration or even lost edible value. The aim of this study was to explore the reasons for the deterioration of rice quality by measuring the content of total acids and free fatty acids, changes in fatty acid composition and content, microscopic structure of cross-sectional endosperm cells or starch granules of rice, and to provide reference for storage technology of rice.[Method]The No. 99 japonica rice packaged in woven, natural airtight anoxia and vacuum was simulated storaged in artificial climate chamber at a temperature of 15, 25, and 30℃ under 60% RH for 180 d, then the quality indicators and morphology of rice were measured every month. The aging mechanism of rice and variation of starch granules morphology caused by lipids and cross-sectional structure of endosperm after deterioration were explored by determining the variation of fatty acid and total acid value, the changes of fatty acid composition and content were analyzed by gas chromatography, and the cross section of rice endosperm cell morphology was observed by scanning electron microscopy.[Result]It was found from the study that the free fatty acids and total acid contents of rice packaged in woven and natural airtight anoxia increased sharply in initial process while decreased with a serious deterioration of the quality. The free fatty acids and total acid contents of rice packaged in vacuum maintained at a relatively stable level while the storage temperature had no significant effect on its content. The most abundant fatty acids were linoleic acid, oleic acid and palmitic acid,which accounted for more than 90% of total fats. Packaging methods and storage temperature had a great impact on various fatty acids. In addition to arachidonic acid （C20：0） and docosenoic acid （C22：1）, the other kinds of fatty acids were greatly influenced by packaging methods. The storage temperature had a

关 键 词：大米 脂肪酸 总酸 气相色谱 胚乳细胞 

分 类 号：TS210.1[轻工技术与工程—粮食、油脂及植物蛋白工程]