储藏过程中稻谷挥发性风味物质和酶活力变化的研究进展

Research Progress on Changes of Volatile Flavor Substances and Enzyme Activity in Rice During Storage

风味劣变是影响稻谷品质和商品价值的关键问题。稻谷中的挥发性风味物质变化与酶活力变化密切相关,文章综述了稻谷储藏过程中挥发性风味物质和酶活力变化的研究概况,重点讨论了挥发性风味物质种类、香气贡献及前体物质。稻谷中的挥发性风味物质包括烃、醇、酚、醛、酯、酮、杂环类7类化合物,醛类化合物对稻谷整体风味影响最大,杂环类化合物相对含量最多、种类最丰富。除酚类化合物含量下降和酮类化合物含量呈无规律变化外,其余几类化合物的含量、种类均随储藏时间的延长而上升。稻谷储藏过程中风味劣变主要是脂质经脂肪酶(LPS)水解、脂肪氧化酶和脂氧合酶(LOX)氧化成己醛、丙二醛、异戊醇、糠醇等化合物造成的。稻谷储藏过程中,脂肪水解酶、脂肪氧化酶和LOX活性增加后下降,蛋白酶、过氧化物酶(POD)和过氧化氢酶(CAT)的活性呈降低趋势。储藏过程中采用科学的方法来控制酶活力的变化是减缓稻谷陈化的有效措施。

The deterioration of flavor is the key problem that affects the quality of rice and the value of commodity.The changes of volatile flavor substances in rice are closely related to the changes of enzyme activity.In this paper,the changes of volatile flavor substances and enzyme activity in rice storage were reviewed,with emphasis on the types of volatile flavor substances,aroma contributions and precursor substances.The volatile flavor substances in rice include hydrocarbon,alcohol,phenol,aldehyde,ester,ketone and heterocyclic compounds.Aldehyde compounds had the greatest influence on the overall flavor of rice,and heterocyclic compounds had the largest relative content and the most abundant types.Except for the decrease of phenolic compounds and the irregular change of ketone compounds,the contents and types of other compounds increased with the extension of storage time.The deterioration of rice flavor during storage was mainly caused by the hydrolysis of lipase(LPS)and the oxidation of lipid oxidase and lipoxygenase(LOX)to hexals,malondialdehyde,isoamyl alcohol,furfuryl alcohol and other compounds.During the storage of rice,the activities of lip hydrolase,lipooxidase and LOX increased and then decreased,while the activities of protease,peroxidase(POD)and catalase(CAT)decreased.It was an effective measure to slow down rice aging to control the change of enzyme activity by scientific method during storage.