Use of Ultra High Pressure Homogenization to sterilize grape must

Abstract

Ultra-High Pressure Homogenization Sterilization (UHPHS) allows the sterilization of fluid foods at low temperatures or even in refrigeration. UHPHS is a continuous technique that allows to process 10,000 L/h with a single pump working at 300 MPa with an imbalance of 1 MPa (Ypsicon EP2409583). During the process, fluid temperature increases less than 5 ∘C. The technique is sensory gentle not affecting molecules formed by covalent bonds so aroma and pigments are unaltered. During the process of white musts, the complete elimination of yeasts, bacteria and spores can be achieved and the must may remain unfermented for several months-years if stored in amicrobic conditions. The technique is also effective in the destruction of polyphenol oxidase (PPO) enzymes. Final size particle is 100–300 nm allowing to increase the availability of yeast assimilable nitrogen and opens the opportunity to nano-encapsulate flavours. Destruction of PPOs and elimination of microorganisms help to reduce sulphites in wines. UHPHS facilitates the use of new biotechnologies such as the use of non-Saccharomyces yeasts and yeast-bacteria co-inoculations by enabling a better implantation of the starters in absence of competition with wild grape microorganisms.