鲜食玉米酚类化合物含量及体外功能活性研究

The Content and in Vitro Functional Activity of Phenolic Compounds in Fresh Corn

选择‘天紫23’‘西星黄糯6号’和‘京科糯2000’3个不同颜色的代表性品种,探讨鲜食玉米籽粒在鲜食期和完熟期多酚类化合物及体外功能活性的差异。结果表明,鲜食玉米籽粒中的酚酸类物质大多以结合态形式存在,黄酮和花色苷类物质则主要以游离态形式存在,且鲜食期的多酚含量均高于完熟期。鲜食期多酚提取物的羟基自由基清除率、DPPH自由基清除率和总还原能力均显著(P<0.05)高于完熟期,且多数游离酚表现出高于结合酚的抗氧化活性。3个品种鲜食期游离态和结合态酚类物质的α-淀粉酶抑制率分别是完熟期的1.3~1.5倍和1.4~1.8倍,对α-葡萄糖苷酶的抑制率则分别为1.1~1.5倍和1.5~8.1倍。鲜食玉米多酚提取物对胆酸钠的结合能力最高,游离酚和结合酚分别在172.99~219.92μmol/100 mg DW和362.48~417.16μmol/100 mg DW,3个品种鲜食期的胆酸盐结合能力均高于完熟期,结合态多酚表现了更强的胆酸盐结合能力。

Three representative varieties with different colors,‘Tianzi 23',‘Xixing Huangnuo 6'and‘Jingkenuo 2000',were selected to investigate the differences in polyphenolic compounds and in vitro functional activities of fresh maize grains at fresh feeding stage and complete ripening stage.The results showed that most phenolic acids existed in the bound form,while flavonoids and anthocyanins mainly existed in the free form,and the content of polyphenols in the fresh feeding stage was higher than that in the complete ripe stage.The hydroxyl radical scavenging rate,DPPH radical scavenging rate and total reducing power of polyphenol extract at fresh food stage were significantly higher than those at complete ripe stage(P<0.05),and most free phenols showed higher antioxidant activity than bound phenols.The α-amylase inhibition rates of free and bound phenolic substances in the fresh feeding stage were 1.3~1.5 times and 1.4~1.8 times of those in the ripe stage,and theα-glucosidase inhibition rates were 1.1~1.5 times and 1.5~8.1 times,respectively.The binding capacity of fresh corn polyphenol extract to sodium cholate was the highest,with the free phenol and bound phenol ranged from 172.99μmol/100 mg DW to 219.92μmol/100 mg DW and 362.48μmol/100 mg DW to 417.16μmol/100 mg DW,respectively.The binding capacity of the three varieties at fresh feeding stage was higher than that at complete ripe stage.The bound polyphenols showed stronger cholate binding ability.