Characterization of polysaccharides from oenological byproducts by a novel multiple reaction monitoring mass spectrometry method

A robust analytical method based on derivatization with 1-phenyl-3-methyl-5-pyrazolone (PMP) and subsequent analysis by HPLC-MS/MS-multiple reaction monitoring (MRM) has been developed and validated for the quantification of monosaccharides in different oenological byproducts (commercial mannoproteins, wine lees and grape pomace extracts). This methodology overcomes most of the limitations associated with the conventional techniques most commonly used in oenology. Method validation demonstrated good precision and accuracy, with low limits of detection (LOD) and quantification (LOQ). Mannose and glucose were identified as the main monosaccharides in commercial mannoprotein extracts and wine lees extracts (53–97%), while galacturonic acid, arabinose, and galactose (~34% each) dominated in white grape pomace polysaccharide extract, indicating the presence of homogalacturonans (HG) and polysaccharides rich in arabinose and galactose (PRAGs). These results highlight the important structural and compositional variability among oenological extracts, whether commercially available or obtained in the laboratory, reinforcing the need for a robust methodology to determine their composition. Hence, the validated method presented here can be a valuable tool to enhance the understanding of such extracts by providing key chemical information that is crucial for assessing their applicability and technological properties. • HPLC-MS/MS-MRM method has been validated for monosaccharide analysis. • Validated method allowed the characterization of polysaccharides in wine byproducts. • Method overcomes key limitations of conventional oenological techniques.