Influence of Must Clarification Technique on the Volatile Composition of Albariño and Treixadura Wines

Abstract

Clarification of the musts is carried out to remove particles that cause turbidity, oxidizable polyphenols, and eliminate excess of proteins. However, an excessive clarification of the musts can lead to the reduction of volatile compound concentrations and, as a consequence, modify the sensorial properties of the wines. Therefore, in this study, the influence of two pre-fermentation clarification techniques (static settling and flotation) on the concentrations of volatile compounds has been assessed in Albariño and Treixadura wines. Fermentations were performed at an industrial scale. Volatile compounds have been identified and quantified by gas chromatography (FID and mass spectrometry detection) and expert panelists assessed the sensory properties of the final wines. The results showed effects of the clarification techniques on the volatile composition of wines from both varieties. Flotation significantly increased the concentrations of benzyl alcohol in Treixadura wines, whereas this technique increased the concentration of 1-hexanol, octanoic acid, and furfural in Albariño wines, but without exceeding the corresponding perception thresholds. Panelists tended to score higher the wines coming from flotation, which, together with the shorter application time, makes this technique suitable for clarifying the musts of these two white varieties.

The Valorization of Spanish Minority Grapevine Varieties—The Volatile Profile of Their Wines as a Characterization Feature

“…Regarding the fermentative compounds, different factors will have different influences, such as the sanitary degree of the grape, the maturity level, the cleanliness level of the must and the possible clarification techniques employed, the fermentation temperature, the type of yeast, nutrients, the oxygen level, as well as possible pre-fermentative and fermentative deviations [33][34][35][36][37][38][39]. Some of these factors are highly dependent on the liters of vinification, with it sometimes being quite difficult to control small volumes or microvinifications, which is the main type of vinification in this study.…”

Impact of must clarification treatments on chemical and sensory profiles of kiwifruit wine

“…Some solid particles in the juice can significantly influence the aroma composition and organoleptic properties of fruit wines 8 , 9 . These substances can be effectively removed by clarification of the freshly pressed juice 10 , which is a crucial aspect of the brewing technology for white wine. The colour of fruit wines is quantified in the equidistant L*a*b* colour space, however, clarity is often denoted by their turbidity values, expressed in nephelometric turbidity units (NTU).…”

“…The turbidity in turn affects the volatile compound content. Wines fermented using low turbidity must tend to exhibit elevated levels of C6, C7, and C8 fatty acids, which have the potential to enhance the fermentation aromas of the wine 10 . In contrast, fermentation involving high turbidity must result in wines containing reduced ethyl ester levels and increased levels of isobutanol and isoamyl alcohol 11 , 12 .…”

“…Turbidity also influences the release of macromolecules from the S. cerevisiae ; juice clarification inevitably eliminates important nutrient sources (unsaturated and saturated fatty acids, nitrogenous compounds, and polysaccharides) that are used by the yeast during the alcoholic fermentation (AF) process 10 . In low-turbidity juices, yeast tends to yield more extracellular and cell wall polysaccharide compounds during AF 8 , which directly affect the taste and sweetness of the wine, albeit making a limited contribution to the nutritional value 9 .…”