Molecular weight and physico-chemical profiles of commercial mannoproteins selected for pre-bottling: effect on targeted sensory characteristics of young red wines

Commercial yeast mannoproteins (CMPs) are widely used in winemaking for their physico-chemical stabilizing properties. However, their influence on the sensory characteristics of red wines, particularly at specific stages of production, remains poorly understood. The present study aims to address this gap by investigating how the molecular features of five distinct CMPs, when added prior to bottling, modulate key sensory attributes in two commercial qualities of young Cabernet Sauvignon red wines, produced at a pilot winery scale (batches of 50 L). The CMPs differed in their molecular weight distribution, polysaccharide purity, and both polysaccharide and monosaccharide composition, enabling the exploration of structure-function relations in the context of different red wine matrices. CMPs enhanced smoothness (astringency's sub-quality), only in wines with a less pronounced astringency profile, indicating a matrix-dependent interaction effect. This finding was particularly associated with CMPs rich in medium molecular weight (MW) polysaccharides (~43 kDa). In contrast, the modulation of hotness and sweetness depended exclusively on CMPs treatment, indicating direct effects independent of wine matrix. Specifically, hotness decreased across all CMPs treatments (20.8-90.6 kDa), while sweetness exhibited an increase with CMPs containing a higher proportion of oligosaccharide fraction. The study also highlights the need for detailed physico-chemical characterization of CMPs on product labels. Such improvements would support enologists in tailoring sensory outcomes more effectively, especially in light of matrix-dependent responses, and address potential export restrictions related to additives like gum arabic, which was found in one of the CMPs.