The Effect of Proanthocyanidins on Growth and Alcoholic Fermentation of Wine Yeast under Copper Stress

Abstract

Proanthocyanidins (PAs) derived from the grape skin, as well as from grape seeds, grape stems, are an important group of polyphenols in wine. The aim of this study was to understand the effect of PAs (0.1, 1.0 g/L) on growth and alcoholic fermentation of 2 strains of Saccharomyces cerevisiae (commercial strain FREDDO and newly selected strain BH8) during copper-stress fermentation, using a simple model fermentation system. Our results showed that both PAs and Cu(2+) could pose significant inhibition effects on the growth of yeast cells, CO2 release, sugar consumption, and ethanol production during the initial phase of the fermentation. Compared to PAs, Cu(2+) performed more obvious inhibition on the yeast growth and fermentation. However, adding 1.0 g/L PAs increased in the vitality and metabolism activity of yeast cells at the mid-exponential phase of fermentation in the mediums with no copper and 0.1 mM Cu(2+) added, shortened the period of wine fermentation, and decreased the copper residues. It indicated that PAs could improve the ability of wine yeast to resist detrimental effects under copper-stress fermentation condition, maintaining cells metabolic activity, and fermentation could be controlled by manipulating PAs supplementation.

Effects of Copper Pollution on the Phenolic Compound Content, Color, and Antioxidant Activity of Wine

“…Three different copper content ranges, including low copper contents, 0 mM (also as a control group) and 0.05 mM (3.2 mg/L); medium copper contents, 0.15 mM (9.6 mg/L), 0.20 mM (12.8 mg/L), 0.25 mM (16.0 mg/L), 0.30 mM (19.2 mg/L, on the verge of the maximum limits), and 0.35 mM (22.4 mg/L, slightly above the maximum limits); and high copper contents, 0.5 mM (32 mg/L), 1.0 mM (64 mg/L), and 1.5 mM (96 mg/L) were used to analyze the effects of copper pollution on the phenolic compound content, color, and antioxidant activity of wine based on the maximum tolerance limit for copper residue in the OIV and EU (20 mg/L) and the actual copper content in grape must observed during wine production [ 2 , 4 , 5 , 9 , 12 , 13 , 14 , 15 , 16 ]. Different levels of copper pollution observed during wine production and representing both current and future values were simulated using this graded copper series.…”

“…Copper (Cu) is one of the heavy metals of greatest concern in the wine industry [ 1 , 2 , 3 , 4 , 5 ]. Long-term use of copper fungicides (mainly the Bordeaux mixture), which increases the copper levels in soil and grape berries [ 5 , 6 , 7 ], and the use of copper winemaking equipment [ 8 ], and copper sulfate or copper citrate additives to eliminate H 2 S [ 9 , 10 ] may also increase the copper contents in grape must and wine.…”

Investigation of the Copper Content in Vineyard Soil, Grape, Must and Wine in the Main Vineyards of Romania: a Preliminary Study

“…Copper (Cu) is one of the heavy metals of great concern in the wine industry (Jia et al, 2015;Sun et al, 2017;Sun et al, 2018). It should be emphasized that Cu is an essential element for plants and, by definition, it is necessary for an organism to function properly, since it plays key roles in several biochemical and physiological processes connected to plant growth and development (Yruela, 2005).…”