Influence of Wine pH and Ethanol Content on the Fining Efficacy of Proteins from Winemaking By-Products

Wine color and limpidity are important aspects of consumer preferences. The alteration of these parameters can damage wine's appearance but also its mouthfeel characteristics due to its relationship with attributes such as bitterness and astringency. Fining is a practice usually used in enology to modulate undesirable wine organoleptic attributes. However, there are several factors that influence this technique. In this study, the influence of wine pH and ethanol content on grape seed protein fining efficacy has been assessed. Wine clarification, total phenolic and flavanol contents, antioxidant activity, and chromatic parameters have been investigated before and after fining process. The most noticeable clarifying effects were observed for the experimental wines with a lower pH and ethanol content. Control of these factors will make it possible to modulate the main organoleptic properties of the wine, also avoiding the addition of large amounts of fining agents and thus providing greater versatility to wineries during winemaking. Furthermore, our findings indicated that grape seed protein is a potential alternative to other plant-based fining proteins commonly used in winemaking. Its effects on clarification and color quality have been found to be comparable to those of potato protein and significantly better than those of pea protein.

Automated summary

Wine color and limpidity are crucial factors for consumers, as they can affect both appearance and mouthfeel characteristics. This study examined the impact of wine pH and ethanol content on the effectiveness of grape seed protein fining. Experimental wines with lower pH and ethanol content displayed the most significant clarifying effects. Controlling these factors allows for the modulation of organoleptic properties without the need for excessive fining agents, enhancing wineries' flexibility during winemaking. Additionally, grape seed protein demonstrated comparable and superior clarifying and color quality effects when compared to potato and pea proteins, making it a potential alternative in winemaking.