Chemical Synthesis of Proanthocyanidins in Vitro and Their Reactions in Aging Wines

Abstract

Proanthocyanidins are present in many fruits and plant products like grapes and wine, and contribute to their taste and health benefits. In the past decades of years, substantial progresses has been achieved in the identification of composition and structure of proanthocyanidins, but the debate concerning the existence of an enzymatic or nonenzymatic mechanism for proanthocyanidin condensation still goes on. Substantial attention has been paid to elucidating the potential mechanism of formation by means of biomimetic and chemical synthesis in vitro. The present paper aims at summarizing the research status on chemical synthesis of proanthocyanidins, including non-enzymatic synthesis of proanthocyanidin precursors, chemical synthesis of proanthocyanidins with direct condensation of flavanols and stereoselective synthesis of proanthocyanidins. Proanthocyanidin-involved reactions in aging wines are also reviewed such as direct and indirect reactions among proanthocyanidins, flavanols and anthocyanins. Topics for future research in this field are also put forward in this paper.

Antioxidant phenolic compounds of pomegranate wines produced by different maceration methods

“…He et al . indicated that, throughout the aging process, proanthocyanidines, flavonols and anthocyanins may result in taste and colour alterations in wines through various chemical reactions and they may form polymeric pigments with flavonol‐3‐ols, anthocyanins and flavonols. These compounds are formed through polymerization of proanthocyanidines and condensation of anthocyanins and flavonols.…”

Impact of winemaking practices on the concentration and composition of tannins in red wine

“…Oxygen reacts readily with phenolic substances as reviewed in Oliveira et al (2011). These reactions increase tannins size by incorporating more polymer subunits as well as reducing the water solubility of the tannins because of the cross-linking of subunits through hydroxyl groups (Cheynier 2006, He et al 2008, Poncet-Legrand et al 2010. These reactions increase tannins size by incorporating more polymer subunits as well as reducing the water solubility of the tannins because of the cross-linking of subunits through hydroxyl groups (Cheynier 2006, He et al 2008, Poncet-Legrand et al 2010.…”

“…This can lead to precipitation of tannins and thus sediment forming in the bottle (Waters et al 1994). The main difference is that the number of bonds between subunits that can be broken by exposure to acid is significantly reduced as a result of subunit cross-linking and the incorporation of anthocyanins (He et al 2008). The structural modifications to tannins occur faster at lower pH (Kontoudakis et al 2011, McRae et al 2013.…”

Oligomeric Cocoa Procyanidins Possess Enhanced Bioactivity Compared to Monomeric and Polymeric Cocoa Procyanidins for Preventing the Development of Obesity, Insulin Resistance, and Impaired Glucose Tolerance during High-Fat Feeding

“…The two hydrogens of (+)-and (−)-C are in the trans configuration while the hydrogens of (+)-and (−)-EC are in the cis configuration 31 . Oligomers (2-5 units) and polymers (6 or more units) are chains of these monomers connected via C-C linkages and can be expressed by their DP, which is equivalent to the number of monomeric units present in a given chain 1,[39][40][41] . Cocoa Flavanol Profile.…”