title: Evolution of polyphenols and organic acids during the fermentation of apple cider.
abstract: BACKGROUND
  Polyphenols and organic acids are important constitutes in the cider because they greatly contribute to organoleptic quality. The determination of their changes is important for monitoring the fermentation process for purposes of quality control. In this study, the evolution of polyphenols and organic acids was monitored throughout the cider fermentation process. The samples were taken periodically and the polyphenols and organic acids contents were determined using HPLC methods.
  
  
  RESULTS
  The contents of polyphenols and organic acids were in constant change. After fermentation, the content of (+)-catechin, (-)-epicatechin, chlorogenic acid, cinnamic acid, p-coumaric acid, gallic acid, caffeic acid, ferulic acid, rutin and phloridzin decreased by different degrees, while protocatechuic acid increased after fermentation. The content of organic acids was also affected by fermentation. Malic acid, lactic acid, quinic acid, pyruvic acid and citric acid showed different levels of increase, but succinic acid content decreased.
  
  
  CONCLUSIONS
  The contents of polyphenols and organic acids were affected by fermentation. Their changing profiles during fermentation process were dependent on the type of phenolic compounds and organic acids studied.
authors.affiliation: College of Food Science and Engineering, Northwest A&F University, Yangling, Shaanxi, 712100, China.
authors.forename: Mengqi
authors.initials: M
authors.lastname: Ye
authors.forename: Tianli
authors.initials: T
authors.lastname: Yue
authors.forename: Yahong
authors.initials: Y
authors.lastname: Yuan
mesh_terms: D001628:Beverages / Q000032:analysis*; D002264:Carboxylic Acids / Q000737:chemistry / Q000378:metabolism*; D005285:Fermentation; D005516:Food Microbiology; D006863:Hydrogen-Ion Concentration; D027845:Malus / Q000737:chemistry*; D059808:Polyphenols / Q000737:chemistry / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000378:metabolism
chemical_list: D002264:Carboxylic Acids; D059808:Polyphenols
keywords: apple wine; changing profile; fermentation; organic acids; polyphenols