米糠中不同存在形态酚类物质的抗氧化活性研究

Study on the Antioxidant Activity of Different Forms of Phenolic Compounds in Rice Bran

摘要:

本文测定了米糠中的游离酚、可溶酯型酚、可溶苷型酚和不溶酯型酚和不溶苷型酚的含量。并测定了其体外抗氧化能力，其中包括Fe3+还原力的测定、DPPH、超氧阴离子以及ABTS自由基清除率的测定实验等。实验结果表明，米糠中游离酚、可溶酯型酚、可溶苷型酚、不溶酯型酚和不溶苷型酚含量分别为44.70、80.81、63.84、128.63、95.46 mg GAE/100g。不同存在形态的酚对不同体系有不同的抗氧化效果：其中Fe3+还原能力可溶酯型酚最好，IC50值为37.62 μg/mL；DPPH自由基清除能力不溶苷型酚最好，当浓度为16.33 μg/mL时，清除率可以达到93.56% ；超氧阴离子自由基清除能力可溶酯型酚最好，当浓度为9.66 μg/mL时，清除率可达91.12%；ABTS自由基清除能力不溶酯型酚较好，当不溶酯型酚浓度为64.05 μg/mL时，清除率可达91.19%。结果表明，米糠富含多酚，具有较好的抗氧化能力。

Abstract:

In this study, the contents of different forms of polyphenol, viz. free, soluble ester, soluble glycoside, insoluble ester, and insoluble glycoside forms, in rice bran were investigated. The in vitro antioxidant activities, including the Fe3+ reducing capacity and 2,2-diphenyl-1-picrylhydrazyl (DPPH), O2-, and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) radical scavenging activities, were evaluated. The results showed that the polyphenol content in free, soluble ester, soluble glycoside, insoluble ester, and insoluble glycoside form in rice bran were 44.70, 80.81, 63.84, 128.63, and 95.46 mg GAE/100 g, respectively. Polyphenols existing in the different forms in rice bran had different antioxidant effects on different systems. Compared to other polyphenols, the polyphenols in the soluble ester form had the strongest Fe3+ reducing capacity (IC50: 37.62 μg/mL). The polyphenols in the insoluble ester form exhibited the best DPPH radical scavenging ability; the DPPH scavenging rate was 93.56% at an insoluble ester concentration of 16.33 μg/mL. The polyphenols in the soluble ester form showed the strongest O2- scavenging capability; the O2- scavenging rate was 91.12% at a soluble ester concentration of 9.66 μg/mL. The polyphenols in the insoluble ester form showed good ABTS scavenging capability, and the ABTS scavenging rate was 91.19% at an insoluble ester concentration of 64.05 μg/mL. These results indicated that rice bran was rich in polyphenols, which had relatively good antioxidant abilities.