White wine processing by UHPH without SO2. Elimination of microbial populations and effect in oxidative enzymes, colloidal stability and sensory quality

Abstract

The use of UHPH sterilization in the absence of SO₂ has been used to eliminate wild microorganisms and inactivate oxidative enzymes. A white must of the Muscat of Alexandria grape variety was continuously processed by UHPH at 300 MPa (inlet temperature: 23-25 °C). The initial microbial load of the settled must was 4-log CFU/mL for both yeast and moulds, and slightly lower for bacteria. After UHPH processing, no microorganisms were detected in 1 mL. UHPH musts remain without fermentative activity for more than 60 days. Concentrations of the thermal markers indicated the absence of thermal damage in the UHPH-treated musts, since 5-hydroxymethylfurfural was not detected. In addition, the must treated by UHPH keeps terpene concentrations similar to those of the untreated controls. A strong inactivation of the oxidative enzymes was observed, with no browning at room temperature for more than 3 days. The antioxidant value of the UHPH-treated must was 156% higher than the control.

Keywords: 2,6-Dimethyl-1,7-octadiene-3,6-diol: Pubchem CID 548927; 5-Hydroxymethylfurfural: Pubchem CID 237332; 8-Hidroxylinalool: Pubchem CID 5280678; Geraniol: Pubchem CID 637566; Linalool: Pubchem CID 6549; Microbial control; Oxidases inactivation; Protein haze; SO(2); Ultra High Pressure Homogenization (UHPH) sterilization; White must; Wine; α-Terpineol: Pubchem CID 17100; β-Citronellol: Pubchem CID 8842.