The Influence of Melatonin Treatment in the Vinification of Feteasca Neagra and Cabernet Sauvignon Wines on the Profile of Polyphenolic Compounds and Antioxidant Activity

Abstract

Until recently, the main antioxidant role among wine constituents was attributed to polyphenolic compounds, but once the presence of melatonin in wines was confirmed, an interesting new field of research opened up due to its possible synergistic effects with other antioxidants in the winemaking process, which may lead to a change in the profile of polyphenolic compounds and antioxidant activity. In order to investigate the evolution of active principles from the phenylpropanoid metabolism associated with the synergistic effects of melatonin, for the first time, a melatonin treatment was performed in the pre-stage of the different winemaking processes of Feteasca Neagra and Cabernet Sauvignon wines with different melatonin concentrations. After comparing the acquired results for the evolution of the polyphenolic compound profile and antioxidant activity of treated wines, we ascertained an increase in the antioxidant compound concentrations, especially in resveratrol, quercetin, and cyanidin-3-glucoside, directly proportional to the used melatonin concentration; an intensification in activity of PAL and C4H enzymes; and the modification in the expression of specific anthocyanin biosynthesis genes, especially UDP-D-glucose-flavonoid-3-O-glycosyltransferase. It was also shown that the application of melatonin in the pre-stage of the winemaking process can be successfully used to obtain red wines with increased antioxidant activity (almost 14%).

Winemaking Technologies for the Production of Cabernet Sauvignon and Feteasca Neagra Wines Enriched with Antioxidant Active Principles Due to the Addition of Melatonin

“…Melatonin may have a synergistic effect with other antioxidants naturally present in wines [ 28 ] and may enhance the production of antioxidant compounds in the winemaking process. The exogenous administration of melatonin in must at the initial stage of the vinification process allows for the biosynthesis of polyphenolic compounds via phenylpropanoid metabolism and stimulates the activity of the enzymes phenylalanine ammonia lyase and cinnamic acid 4-hydroxylase to considerably modify the expression of specific genes for anthocyanin biosynthesis [ 29 ]. However, the research is still in an early stage, and it has not established what level of melatonin should be used and which winemaking process should be applied for the different grape varieties to improve red wines with antioxidant compounds.…”