Polysaccharide content of extracts obtained from unfermented skins from red varieties

¹ Instituto Tecnológico Agrario de Castilla y León, Ctra Burgos Km 119, 47071 Valladolid, Spain
² Instituto de Ciencias de la Vid y el Vino (Universidad de La Rioja, Gobierno de La Rioja, CSIC), Finca de La Grajera, Ctra. Burgos 6, 26007 Logroño, Spain

Abstract

Grape pomace is one of the main by-products generated by wine industry and contains several bioactive compounds such as polysaccharides. They are contained in the cell walls of the grape skins. The variety can be an important factor influencing the polysaccharide content of grapes. Actually, there is great interest in the revaluation of by-products and their incorporation into the production process. Therefore, the aim of this work was to evaluate the polysaccharide content of different extracts obtained from unfermented pomaces of different red grape varieties from Castilla y León. Eight different grape varieties were studied. The polysaccharides from grape pomace was obtained following a flash extraction process and the total polysaccharide content and the molecular weight distribution were estimated by High-Performance Size-Exclusion Chromatography with a Refractive Index Detector. Statistically significant differences were found in the content of total polysaccharides by grape variety varying between 112 and 200 mg/g. Only high and low molecular weight polysaccharide fractions were detected. All varietal extracts presented higher percentage of low molecular weight polysaccharides (50.8-64.3%) than of high molecular weight (35.7-49.2%).