Antioxidant Compounds and Antioxidant Activities of Fermented Black Rice and Its Fractions

Abstract

본 연구는 흑미(복합)발효물 및 분획물의 항산화 성분(총페놀, 총플라보노이드 및 proanthocyanidin)을 측정하였고 또한, 다양한 in vitro 모델을 이용하여 항산화 활성을 평가하였다. 항산화 활성은 DPPH 라디칼 소거능, ABTS 라디칼 소거능, reducing power 및 FRAP을 이용하였고 아질산염 소거능도 평가하였다. 저분자 분획물은 흑미(복합)발효물 및 고분자 분획물에 비해 유의적으로 높은 항산화 활성을 나타내었다. 흑미(복합)발효물 및 분획물 중에서, 저분자 분획물의 총페놀, 총플라보노이드 및 proanthocyanidin 함량은 각각 <TEX>$109.2{\pm}2.9$</TEX> mg GAE/g, <TEX>$39.4{\pm}0.8$</TEX> mg RE/g 및 <TEX>$32.9{\pm}1.4$</TEX> mg CE/g으로 흑미(복합)발효물 및 고분자 분획물에 비해 높은 함량을 보였고 이들 항산화 성분들은 저분자 분획물의 항산화 활성과 유의적인 상관관계를 보였다. 건강증진에 대한 소비자들의 높은 관심도를 고려해 볼 때, 흑미(복합)발효물 및 분획물은 건강기능식품, 건강증진 및 의약품 소재로서 이용이 가능할 것으로 사료된다. The aim of this study was to determine the total phenol, total flavonoids, and proanthocyanidin contents of fermented black rice and its fractions, as well as to assess the antioxidant activities. Antioxidative activities were assessed in various in vitro models using 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), reducing power, ferric ion reducing antioxidant power (FRAP), and nitrite scavenging activity (Griess reagent assay). Our results show that the antioxidant activity was significantly higher in the low-molecular fraction of fermented black rice than in the other samples (p<0.05). Among the fermented black rice and its fractions, the low-molecular fraction had the highest total phenol (<TEX>$109.2{\pm}2.9$</TEX> mg GAE, gallic acid equivalent/g), total flavonoids (<TEX>$39.4{\pm}0.8$</TEX> mg RE, rutin equivalent/g), and proanthocyanidin (<TEX>$32.9{\pm}1.4$</TEX> mg CE, catechin equivalent/g) contents, which correlated strongly with its antioxidative activity. Considering the high consumer demand due to the beneficial health effects, fermented black rice and its fractions can be utilized to develop functional food, as well as health-promoting and pharmaceutical agents.