Influence of ultra-high pressure homogenization (UHPH) in the fermentability of Tempranillo musts by Saccharomyces and non-Saccharomyces

Ultra-high-pressure homogenization eliminates native microbiota in grapes. The microorganism's inactivation occurred at 300 MPa which reduce the size of all particles, including microorganisms, to the nanometric scale. Tempranillo musts were evaluated to see whether the physical-chemical and microbiological properties are optimal for conducting alcoholic fermentations using yeast starters, both Saccharomyces and non-Saccharomyces. To assess the ability of musts to be fermented, oenological parameters, aromatic volatile compounds, and chromatic properties of wines have been measured. The elimination of yeasts with UHPH treatments allowed the implantation of non-Saccharomyces yeast starters. For instance, L. thermotolerans produce 2 g/L lactic acid which avoided pigment loss when used in a consortium with T. delbrueckii strains. The possibility of having a sterile must without heat markers with required nutritional quality for yeast starters to be used is one of the features that makes UHPH interesting to be used in the winemaking industry.