Characterization of mannoproteins during white wine (<em>Vitis vinifera</em> L. cv. ENCRUZADO) ageing on lees with stirring in oak wood barrels and in a stainless steel tank with oak staves

Abstract

<p style="text-align: justify;"><strong>Aim</strong>: To compare the evolution of mannoproteins in a white wine submitted to two different stirring of lees processes: in French oak barrels (BA) and in a stainless steel tank equipped with French oak staves (IN).</p><p style="text-align: justify;"><strong>Methods and results</strong>: Total colloids were obtained by ultrafiltration and ethanol precipitation. Mannoproteins were isolated by adsorption on concanavalin-A and molecular weight separation. Sugar residues were characterized by GC analysis of their alditol acetates and protein content was determined according to Lowry method. Wines were submitted to sensory analysis.</p><p style="text-align: justify;"><strong>Conclusion</strong>: Three polysaccharide fractions were isolated from both BA and IN wines. Regarding sensory attributes, the only significant difference between BA and IN wines was the round mouth-feel. The BA wine showed a higher final polysaccharide concentration, which can be related to the rounder mouth-feel.</p><p style="text-align: justify;"><strong>Significance and impact of the study</strong>: This study is a technological approach of a process largely used by white wine producers who want to market a fresh wine produced with stirring of lees with a woody character. It reports the evolution of mannoproteins through four months of ageing on lees with two different stirring processes that can have a direct impact on the cost of the final product.</p>