Determination of contents and antioxidant activity of free and bound phenolics compounds and in vitro digestibility of commercial black and red rice (Oryza sativa L.) varieties.
Black and red rices (Oryza sativa L.) were analysed for total flavonoids and phenolics and the HPLC profile including both free and bound phenolic fractions. Moreover, antioxidant activity and in vitro digestibility was determined. Content of flavonoids and polyphenols as well as antioxidant activity was higher in free phenolic fractions. Bound flavonoids in black rices were not significant contributors to antioxidant activity. The main free phenolics in black rices were ferulic, protocatechuic and trans-p-coumaric acids, while the major free phenolics in red rices were catechin, protocatechuic and caffeic acids. The main bound phenolics in black rices were ferulic and vanillic acids and quercetin, in red rice types, they were ferulic, syringic, trans-p-coumaric acids and quercetin. Newly, the presence of m-coumaric acid in red rices was detected. Steam cooked rices showed very high levels of organic matter digestibility, whereas red rices were significantly more digestible than black rices (p<0.05).
Tomas Bata University in Zlin, Faculty of Technology, Department of Food Analysis and Chemistry, Náměstí T.G. Masaryka 5555, 760 01 Zlín, Czech Republic. Electronic address: Sumczynski@ft.utb.cz.
Daniela
D
Sumczynski
Tomas Bata University in Zlin, Faculty of Technology, Department of Food Analysis and Chemistry, Náměstí T.G. Masaryka 5555, 760 01 Zlín, Czech Republic.
Eva
E
Kotásková
Tomas Bata University in Zlin, Faculty of Technology, Department of Food Analysis and Chemistry, Náměstí T.G. Masaryka 5555, 760 01 Zlín, Czech Republic.
Helena
H
Družbíková
Tomas Bata University in Zlin, Faculty of Technology, Department of Food Analysis and Chemistry, Náměstí T.G. Masaryka 5555, 760 01 Zlín, Czech Republic.
Jiří
J
Mlček
D000975:Antioxidants / Q000032:analysis* / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D003296:Cooking; D005419:Flavonoids / Q000032:analysis / Q000378:metabolism; D012275:Oryza / Q000378:metabolism*; D010636:Phenols / Q000032:analysis* / Q000378:metabolism*; D010936:Plant Extracts / Q000032:analysis / Q000378:metabolism; D059808:Polyphenols / Q000032:analysis / Q000378:metabolism; D011485:Protein Binding / Q000502:physiology; D011794:Quercetin / Q000032:analysis
D000975:Antioxidants; D005419:Flavonoids; D010636:Phenols; D010936:Plant Extracts; D059808:Polyphenols; D011794:Quercetin
Antioxidant activity; Black rices; Free and bound phenolics; HPLC; In vitro digestibility; Red rices