Yeast derivatives: a promising alternative in wine oxidation prevention?

Oxidation processes constitute a main problem in winemaking. Oxidation result in color browning and varietal aroma loss, which are key attributes of wine organoleptic quality. Despite the mechanisms involved in wine oxidation have been extensively reviewed, the protection of wine against oxidative spoilage remains one of the main goals of winemaking. Moreover, oxidation of young white wines become particularly critical mostly when low levels of SO₂ are used. SO₂ is indeed one of the most efficient wine antioxidants used to prevent oxidation and microbial spoilage. However, intolerances caused by SO₂ have led to the reduction of its concentration in wines. In a competitive global winemaking market strategy, it is crucial to reduce or even eliminate the use of SO₂ and to search for new healthier strategies. In the last decade, Yeast Derivatives (YDs) were proposed as a new strategy to control wine oxidation. These products are obtained from yeasts by autolytic or hydrolytic processes and dried to obtain the commercial products. The aim of this work was to carry out a preliminary investigation of YDs with different composition on (i) their capacity to prevent oxidation of white wine in comparison with conventional treatment with SO₂ and (ii) to evaluate their impact on wine quality.

2 YDs were used for all the experiments: a YD_R naturally rich in reducing compounds and a YD_L naturally rich in lipids. White wines vinified with no sulfite additions were supplemented with one of the YD and submitted at low and high oxidation: 4 mg/L and 8 mg/L of dissolved O₂ respectively. A Pyroscience optical O₂ sensor was used for the dissolved oxygen monitoring. Wines analyses were performed after the complete oxygen consumption: wine analysis (Foss), color (CIELab), glutathione (GSH, HPLC-fluo), ethanal (GC-MS), redox potential (cyclic voltammetry), sensorial analysis. These results were compared with those obtained for wines with no antioxidant treatment and with SO₂ addition.

Results showed that yeast derivatives and SO₂ permit to reduce the O₂ consumption rate of 55 and 60% respectively than the untreated control without antioxidant. In comparison with the control wines, YD have an impact on color but they allow the reduction of wine browning. Voltammetry analyses showed that the wines treated by YD have a voltammetric profile suggesting that they are more resistant to oxidation than the untreated control. This behavior is comparable to wines treated with SO₂. In addition, wines treated with YD present a lower ethanol amount than the control and SO₂ wines. The YD naturally rich in reducing compounds show better preservation of wine’s GSH content. Finally, during wine sensorial analysis, the tasters prefer wines treated with YD than wine without treatment.

This work opens new perspectives for the development of yeast preparations usable as alternatives or as complements to sulfites and allows the improvement of white wines oxidative stability.

Poster presented at Macrowine virtual (June 23-30, 2021)