A simple method for total quantification of mannoprotein content in real wine samples

Abstract

Mannoproteins released by yeast cells throughout the winemaking process contribute in several ways to improve wine quality. For this reason, some winemaking practices have been developed in order to increase the mannoprotein content of wine. However, monitoring of mannoprotein content of wine during these processes, or even mannoprotein quantification in the final wines, is an analytical problem not easily solved so far. Here, we report a simple and accurate method for mannoprotein quantification in wines. The method involves isolation of wine polysaccharides by size exclusion chromatography, acid hydrolysis, elimination of acid by weak anionic exchange solid phase extraction, and analysis of monosaccharides by ion exclusion HPLC. Advantages over previously existing methods include low sample volumes, possibility of parallel processing for multiple samples, absence of precipitation steps, and clear distinction between mannoproteins and other wine polysaccharides.