Fining of red wines: effects on their analytical and sensory parameters

Aim: The aim of the present study was to examine the influence of protein fining on selected quality parameters of wines made from indigenous Hellenic red grape varieties. Methods and Results: Three different commercial hydrolyzed gelatins and egg albumin were added to two young red wines at three concentrations commonly used in winemaking. The cultivars selected were Hellenic native V. vinifera species used for the production of high quality Appellation of Origin wines (Agiorgitiko and Xinomavro). All the quality parameters studied (anthocyanin concentration, color intensity and hue, ionization degree, total phenolic content, DPPH radical scavenging activity, tannin and polysaccharide concentration, gelatin and HCl indexes, as well as individual phenolic content) were significantly decreased after the addition of the fining agents. The decrease observed was mainly dependent on grape variety, which genetically determines the wine’s phenolic composition, and to a lesser extent on the fining agent used and the dosage applied. In general, treated wines obtained better scores in sensory analysis as compared to untreated ones, although statistically significant differences were only obtained in the Agiorgitiko wine regarding color intensity and hue, acidity, balance, aftertaste, and overall impression. Conclusion: Wine quality parameters after fining were mainly influenced by the wine’s initial phenolic composition, which is determined mostly by grape variety. Significance and impact of the study: The outcomes of such study might be of practical interest to winemakers since they could optimize red wine production technology by selecting the appropriate fining agent according to the specific phenolic profiles of the produced wines and thus improve their quality