Open AccessInfluence of Thermal Processing on Free and Bound Forms of Phenolics and Antioxidant Capacity of Rice Hull (Oryza sativa L.)
Author(s) -
Min Young Kim,
Nara Yoon,
Yoon Jeong Lee,
Koan Sik Woo,
Ho Kim,
Junsoo Lee
Publication year - 2020
Publication title -
preventive nutrition and food science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.498
H-Index - 24
eISSN - 2287-8602
pISSN - 2287-1098
DOI - 10.3746/pnf.2020.25.3.310
Subject(s) - chemistry , hull , gallic acid , oryza sativa , antioxidant , food science , flavonoid , polyphenol , catechin , husk , methanol , botany , organic chemistry , biochemistry , materials science , biology , composite material , gene
The objective of this study was to evaluate the effects of heat treatment on the phenolics and antioxidant activity of rice hull. Heat treatment was performed at temperatures 80∼140°C for 1∼5 h, and the heated rice hull was extracted with 80% (v/v) methanol in an ultrasonic bath. The highest total polyphenol and flavonoid content (10.68 mg gallic acid equivalents/g and 1.83 mg catechin equivalents/g, respectively) occurred in rice hull heated at 130°C for 5 h. During heat treatment, the content of free phenolic acids increased compared with that of the bound phenolic acids. The highest 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) radical scavenging activity and reducing power was observed in rice hull heated at 140°C for 3 h. The highest OH radical scavenging activity was 75.30% in rice hull heated at 140°C for 5 h. These results suggested that heat treatment was an efficient method to enhance the antioxidant characteristics of rice hull.