title: Distribution of phenolic antioxidants in whole and milled fractions of quinoa and their inhibitory effects on α-amylase and α-glucosidase activities.
abstract: Whole grain quinoa and its milled fractions were evaluated for their phenolic composition in relation to their antioxidant properties and inhibitory effects on α-amylase and α-glucosidase activities. Compositional analysis by HPLC-DAD showed that the distribution of phenolic compounds in quinoa is not entirely localised in the outer layers of the kernel. Milling of whole grain quinoa resulted in about 30% loss of total phenolic content in milled grain. Ferulic and vanillic acids were the principal phenolic acids and rutin and quercetin were predominant flavonoids detected in whole grain and milled fractions. Quinoa milled fractions exhibited numerous antioxidant activities. Despite having relatively lower phenolic contents, dehulled and milled grain fractions showed significantly (p ⩽ 0.05) higher metal chelating activity than other fractions. Furthermore, extracts of bran and hull fractions displayed strong inhibition towards α-amylase [IC50, 108.68 μg/ml (bran) and 148.23 μg/ml (hulls)] and α-glucosidase [IC50, 62.1 μg/ml (bran) and 68.14 μg/ml (hulls)] activities. Thus, whole grain quinoa and its milled fractions may serve as functional food ingredients in gluten-free foods for promoting health.
authors.affiliation: Department of Grain Science and Technology, Central Food Technological Research Institute, Council of Scientific and Industrial Research (CSIR), Mysore 570 020, India.
authors.forename: P
authors.initials: P
authors.lastname: Hemalatha
authors.affiliation: Department of Grain Science and Technology, Central Food Technological Research Institute, Council of Scientific and Industrial Research (CSIR), Mysore 570 020, India.
authors.forename: Dikki Pedenla
authors.initials: DP
authors.lastname: Bomzan
authors.affiliation: Department of Grain Science and Technology, Central Food Technological Research Institute, Council of Scientific and Industrial Research (CSIR), Mysore 570 020, India.
authors.forename: B V
authors.initials: BV
authors.lastname: Sathyendra Rao
authors.affiliation: Department of Grain Science and Technology, Central Food Technological Research Institute, Council of Scientific and Industrial Research (CSIR), Mysore 570 020, India. Electronic address: yns@cftri.res.in.
authors.forename: Yadahally N
authors.initials: YN
authors.lastname: Sreerama
mesh_terms: D000975:Antioxidants / Q000032:analysis*; D027465:Chenopodium quinoa / Q000737:chemistry*; D010636:Phenols / Q000032:analysis*; D010936:Plant Extracts / Q000494:pharmacology; D000516:alpha-Amylases / Q000737:chemistry*; D000520:alpha-Glucosidases / Q000737:chemistry*
chemical_list: D000975:Antioxidants; D010636:Phenols; D010936:Plant Extracts; D000516:alpha-Amylases; D000520:alpha-Glucosidases
keywords: Antioxidant activity; Milled fractions; Phenolic compounds; Quinoa; α-Amylase inhibitors; α-Glucosidase inhibitors