title: Evaluation of polyphenolic content and antioxidant activity in two onion varieties grown under organic and conventional production systems.
abstract: BACKGROUND
  Onions contain a number of bioactive compounds, in particular polyphenols. They are rich sources of such compounds in the human diet and offer significant health benefits to the consumer. Demand for organic crops is steadily increasing partly based on the expected health benefits of organic food consumption. The current study examines the influence of organic and conventional crop management practices on bioactive polyphenolic content of onion.
  
  
  RESULTS
  We examined the effect of conventional, organic, and mixed cultivation practices on the content of total phenolics, total flavonoids and antioxidant activity in two varieties of onion grown over 4 years in a split-plot factorial systems comparison trial. Levels of total phenolics and total flavonoids showed a significant year-on-year variation and were significantly different between organic and conventional production systems. The levels of total phenolics, total flavonoids and antioxidant activity in general were significantly higher (P < 0.05) under fully organic compared to fully conventional management.
  
  
  CONCLUSIONS
  Organic cultivation practices resulted in significantly higher levels of potential bioactive compounds in onion. © 2016 Society of Chemical Industry.
authors.affiliation: Teagasc Food Research Centre, Ashtown, Dublin, 15, Ireland.|University College Cork, Western Road, Cork, Ireland.
authors.forename: Feiyue
authors.initials: F
authors.lastname: Ren
authors.affiliation: Teagasc Food Research Centre, Ashtown, Dublin, 15, Ireland.
authors.forename: Kim
authors.initials: K
authors.lastname: Reilly
authors.affiliation: Teagasc Food Research Centre, Ashtown, Dublin, 15, Ireland.
authors.forename: Michael
authors.initials: M
authors.lastname: Gaffney
authors.affiliation: University College Cork, Western Road, Cork, Ireland.
authors.forename: Joseph P
authors.initials: JP
authors.lastname: Kerry
authors.affiliation: Teagasc Food Research Centre, Ashtown, Dublin, 15, Ireland.
authors.forename: Mohammad
authors.initials: M
authors.lastname: Hossain
authors.affiliation: Teagasc Food Research Centre, Ashtown, Dublin, 15, Ireland.
authors.forename: Dilip K
authors.initials: DK
authors.lastname: Rai
mesh_terms: D000383:Agriculture / Q000379:methods*; D000975:Antioxidants / Q000032:analysis*; D058870:Food, Organic / Q000032:analysis; D019697:Onions / Q000737:chemistry* / Q000254:growth & development; D058871:Organic Agriculture; D010084:Oxidation-Reduction; D010936:Plant Extracts / Q000032:analysis*; D059808:Polyphenols / Q000032:analysis*
chemical_list: D000975:Antioxidants; D010936:Plant Extracts; D059808:Polyphenols
keywords: antioxidants; conventional; flavonoids; onion (Allium cepa L.); organic; phenolics