Changes In Antioxidative Acitivity Of Aromatic Vinegar And The Underpinning Component Variation During Decoction

Vinegar,one of the limited types of acidic seasonings,is popular worldwide and consumed largely.Consumers always accept vinegar as health-promoting food,thus functional foods made of vinegar tend to conquer in the market.Almost all commercial vinegar-based functional foods,to gain enhanced bioactivity,are supplemented with expensive Chinese medicine materials,pearls and so on.However,this would probably mess up the originally beautiful flavor of vinegar and require extra extraction,emulsification to get soluble products with good organoleptic quality,besides skyrocket producing cost.The mechanism underpinning the health-promoting effect of vinegar is actually barely known.Unraveling bioactives of vinegar and their principles by analyzing characteristic manufacture of vinegar not only is scientifically valuable but enables rational development of vinegar-based functional foods and the consequent growing industry.Zhenjiang Aromatic Vinegar is one of representative Chinese viengars that is the seasoning utilized by nearly half of Chinese families.We investigated the component variation of Aromatic Vinegar,including melanoidins,phenolics and short chain fatty acids(SCFA),during its characteristic heating treatment,decoction.That leads to the discovery of vinegar bioactives including melanoidins and their bound phenolics,and the revelation and discussion regarding antioxidative and other health-promoting activities of these vinegar bioacitives as the followings—1.The radical scavenging activity of Aromatic Vinegar is enhanced upon decoction.During decoction free phenolics decrease while melanoidins,the Maillard reaction products,increase.Consequently,vinegar melanoidins contribute more to the antioxidative activity(AA)of the parent vinegar with decoction,and after decoction have become the main antioxidants responsible for about 50%of the AA of the parent vinegar.The aforementioned findings could facilitate the discovery and development of Chinese vinegar advantages.2.The low molecular weight compounds non-covalently bound to vinegar melanoidins(MBC)account for 89%of the AA of vinegar melanoidins.85%of the phenolics in vinegar melanoidins available in upper gastrointestinal tracts is from MBC.Vinegar melanoidins are phenolic reservoir-phenolics in MBC only amounts to about 60%of free phenolics in vinegar.Phenolics in MBC determine the AA available in upper gastrointestinal tracts.All phenolics covalently bound to vinegar melanoidins would be carried to gut microbes,catabolized and absorbed.3.Five new vinegar phenolics have been identified by high-resolution LC-MS/MS,including dihydroxyphenylacetic,hydroxyphenyllactic,hydroxyphenlacetic and phenylaceitic acid and caffeic aicd ethyl ester.Free phenolics decrease while those non-covalently bound to vinegar melanoidins increase,which improves the AA of vinegar melanoidins in upper gastrointestinal tracts.Plenty of vinegar phenolics are covalently bound to melanoidins,whose amount is larger than the total of free and non-covalently bound phenolics.Vinegar melanoidins could carry these covalently bound phenolics to colon where they would modulate the growth and metabolism of microbes and be catabolized into smaller phenolics and SCFA.Overall,decoction increases the vinegar melanoidins;melanoidins become main vinegar antioxidants upon decoction;bound phenolics are antioxidative groups of vinegar melanoidins;decoction alters the amount of bound phenolics and their metabolism and absorption;melanoidins can function as dietary fibers besides antioxidants,combined with the abundant SCFA in vinegar,vinegar probably promotes health via modulating gut microbes.