title: Antioxidant activity of commercial soft and hard wheat (Triticum aestivum L.) as affected by gastric pH conditions.
abstract: Phenolic compounds from soft and hard wheat and their milling fractions were extracted into distilled deionized water, and their in vitro antioxidant activities were evaluated. Wheat samples were used as such (nontreated) or subjected to pH adjustment (treated) in order to simulate gastrointestinal pH conditions. The total phenolic content (TPC) was determined using Folin-Ciocalteu's procedure. The total antioxidant activity (TAA) was determined using Trolox equivalent antioxidant capacity assay and expressed as Trolox equivalents. The antioxidant activity of wheat extracts was also evaluated using the beta-carotene bleaching assay, scavenging of 2,2-diphenyl-1-picrylhydrazyl radical, and inhibition of oxidation of human low density lipoprotein cholesterol. The TPC, TAA, and antioxidant potential, evaluated using different methods of wheat samples, were significantly increased following gastrointestinal tract-simulated pH changes. Thus, digestion taking place in the gastrointestinal tract in vivo may also enhance the antioxidant properties of the extracts.
authors.affiliation: Departments of Biology and Biochemistry, Memorial University of Newfoundland, St. John's, NL, A1B 3X9, Canada.
authors.forename: Chandrika M
authors.initials: CM
authors.lastname: Liyana-Pathirana
authors.forename: Fereidoon
authors.initials: F
authors.lastname: Shahidi
mesh_terms: D000975:Antioxidants / Q000032:analysis* / Q000494:pharmacology; D004063:Digestion; D004492:Edetic Acid / Q000494:pharmacology; D016166:Free Radical Scavengers / Q000032:analysis; D005744:Gastric Acid / Q000502:physiology*; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D007502:Iron Chelating Agents / Q000737:chemistry; D015227:Lipid Peroxidation; D008077:Lipoproteins, LDL / Q000737:chemistry; D010636:Phenols / Q000032:analysis; D010936:Plant Extracts / Q000494:pharmacology; D014908:Triticum / Q000737:chemistry*; D019207:beta Carotene / Q000737:chemistry
chemical_list: D000975:Antioxidants; D016166:Free Radical Scavengers; D007502:Iron Chelating Agents; D008077:Lipoproteins, LDL; D010636:Phenols; D010936:Plant Extracts; D019207:beta Carotene; D004492:Edetic Acid