title: Antioxidant activity of polyphenols of adzuki bean (Vigna angularis) germinated in abiotic stress conditions.
abstract: BACKGROUND
  Adzuki sprouts are one of more valuable but still underappreciated dietary supplements which may be considered as functional food. Sprouting reduces anti-nutritional factors and increases the bioavailability of macro and micronutrients and also affects phytochemical levels. Exposure of plants to abiotic stresses results in change in production of phytochemical compounds. The aim of this study was to assess the content and antioxidant properties of phenolic in adzuki bean seeds germinated in selected abiotic stress conditions.
  
  
  METHODS
  Adzuki bean seeds were germinated in different abiotic stress conditions: thermal, osmotic and oxidative. The content of phenolics in adzuki bean seeds coat extracts and antioxidant activity Fe2+ chelating ability and neutralization of the free radicals generated from DPPH and ABTS were determined.
  
  
  RESULTS
  All applied stress conditions (except for thermal stress) have caused decrease the content of the analysed phenolic fractions. The lowest amounts of polyphenols in extracts of sprouts obtained in oxidative stress conditions were observed. The highest ability to neutralize free radicals generated with ABTS and DPPH have extracts from sprouts germinated under thermal stress 39.94 and 13.20 μmol TEAC/g d.w., respectively. The lowest - sprouts obtained in oxidative stress conditions (18.2 and 9.72 μmol TEAC/g d.w.). The highest ability to chelate Fe2+ has been shown by the extract from adzuki bean seeds coat subjected to thermal stress (7.06 %) and the lowest control extract (3.08%).
  
  
  CONCLUSIONS
  It can be concluded that only thermal stress contributes to the improvement of antioxidant activity of extracts obtained from adzuki bean seeds coat.
authors.affiliation: Department of Biochemistry and Food Chemistry, University of Life Sciences in Lublin, Poland.
authors.forename: Urszula
authors.initials: U
authors.lastname: Złotek
authors.affiliation: Department of Biochemistry and Food Chemistry, University of Life Sciences in Lublin, Poland.
authors.forename: Urszula
authors.initials: U
authors.lastname: Szymanowska
authors.affiliation: Department of Biochemistry and Food Chemistry, University of Life Sciences in Lublin, Poland.
authors.forename: Barbara
authors.initials: B
authors.lastname: Baraniak
authors.affiliation: Department of Biochemistry and Food Chemistry, University of Life Sciences in Lublin, Poland.
authors.forename: Monika
authors.initials: M
authors.lastname: Karaś
mesh_terms: D000975:Antioxidants / Q000032:analysis / Q000494:pharmacology*; D052160:Benzothiazoles / Q000378:metabolism; D001713:Biphenyl Compounds / Q000378:metabolism; D005511:Food Handling / Q000379:methods*; D018525:Germination; D006358:Hot Temperature; D006801:Humans; D009995:Osmosis; D018384:Oxidative Stress; D010636:Phenols / Q000032:analysis / Q000494:pharmacology; D010851:Picrates / Q000378:metabolism; D010936:Plant Extracts / Q000737:chemistry / Q000494:pharmacology; D059808:Polyphenols / Q000032:analysis / Q000494:pharmacology*; D036226:Seedlings / Q000737:chemistry*; D012639:Seeds / Q000737:chemistry; D013312:Stress, Physiological; D013451:Sulfonic Acids / Q000378:metabolism; D000070658:Vigna / Q000737:chemistry*
chemical_list: D000975:Antioxidants; D052160:Benzothiazoles; D001713:Biphenyl Compounds; D010636:Phenols; D010851:Picrates; D010936:Plant Extracts; D059808:Polyphenols; D013451:Sulfonic Acids; C002502:2,2'-azino-di-(3-ethylbenzothiazoline)-6-sulfonic acid; C004931:1,1-diphenyl-2-picrylhydrazyl
keywords: abiotic stress; adzuki bean sprouts; antioxidant activity; polyphenols