Yeasts Used As Fining Treatment To Correct Browning in White Wines

Abstract

White wine was subjected to several fining treatments using baker's yeast at concentrations of 0.5, 1, 2, 3, 4, and 5 g/L. At all these concentration levels, the yeasts decreased the color of the wine in different degrees. The wine samples treated with the higher yeast concentration were subjected to analysis of phenolic compounds by HPLC and found to exhibit significantly decreased contents of vanillic, syringic and c-coutaric acids, and procyanidins B2 and B4, and colored compounds eluted at high retention times. The efficiency of the yeast-based fining treatment (1 g/L) was compared with traditional treatments such as those involving the use of activated charcoal or PVPP, which were employed at the usual concentrations in Sherry winemaking. This yeast treatment was found to provide results similar to those of the activated charcoal treatment in terms of A(420). Likewise, significant differences in the degree of retention of various phenols were observed among the three treatments compared. Finally, the wine samples obtained with the different treatments were subjected to a sensory panel. All the wines were found to exhibit improved color, aroma, and flavor with respect to the untreated samples, although the treatment using yeast at 1 g/L provided the best results in terms of aroma.

Effect of alcoholic fermentation in the content of phenolic compounds in cider processing

“…An increased surface provided by interstitial spaces favors the adsorption. The surface of yeast cell in the wine fermentation is higher than 10 m 2 .L -1 of the must and some phenolic acids, flavan-3-ol derivatives procyanidins B2 and B4 (Bonilla et al, 2001), phenolic volatiles (Chassagne et al, 2005), colored products formed from phenolics oxidation or condensation reactions can be adsorbed by yeast during the fermentation (red and white wines) (Razmkhab et al, 2002;Mazauric and Salmon, 2005). Another pathway for phenols, with change in the color of the wine involves the direct condensation of the phenols with the acetaldehyde produced by yeasts in fermented drinks (LopezToledano et al, 2004).…”

Oxygen in Must and Wine: A review

“…An interesting observation made by Bonilla et al (2001) is that yeast reduces the brown colour of oxidised white wine. The brown colour of an oxidised white wine was reduced with a higher yeast dosage (ranging from 1-5 g/L), which was compatible to PVPP or activated charcoal fining.…”

“…The yeast thus seems to have a preference for these compounds, which absorb in the yellow/brown spectrum, with the cell walls being the active absorbing area. These reactions proceed very slowly under the acidic conditions in wine and probably play more of a role in browning if the wine contains higher levels of flavanols, and after it has been racked from the yeast lees (Bonilla et al, 2001;Lopez-Toledano et al, 2002b;Lopez-Toledano et al, 2004). The addition of yeast at lower concentrations also improved the aroma of the oxidised wine.…”

Alternatives to Isinglass for Beer Clarification

“…The recent introduction of mandatory allergen labeling in the European Union and the United States of America has stimulated further research on novel alternatives. In the wine industry, clarification or stabilization agents such as gelatin, ovalbumin, wheat glu-ten, activated charcoal, potassium caseinate and polyvinylpolypyrrolidone (PVPP) are used 2,10,17 . The relevance of these materials or other novel alternatives to brewing has not been considered thoroughly to date, and to our knowledge, there are no direct alternatives to isinglass being used routinely in commercial breweries.…”