Influence of the mannoproteins of different strains of Starmerella bacillaris used in single and sequential fermentations on foamability, tartaric and protein stabilities of wines

Aim: In this work, seven strains of Starmerella bacillaris were analysed for their ability to release polysaccharides during alcoholic fermentation (AF), both in single-strain and in sequential AF together with Saccharomyces cerevisiae. Methods and Results: A synthetic polysaccharide-free must was used to characterise the mannoproteins (MPs) released. The MPs were quantified, characterised in terms of carbohydrate composition, and tested to assess their ability to reduce protein and tartrate instabilities and their ability to affect the foaming properties of wine. Conclusions: All the tested strains in sequential AF increased the total MPs production. Moreover, the strains affected the MPs properties in different ways regarding tartaric and protein stabilities. The MPs released in sequential AF by some S. bacillaris strains showed a significant effect on protein stabilisation and tartaric stability. An effect on the foamability was found for MPs obtained in single-strain AFs of S. bacillaris. Significance and impact of the study: An improvement in wine stability can be achieved using the sequential AF.