Application of supercritical carbon dioxide for the preservation of strawberry juice: Microbial and physicochemical quality, enzymatic activity and the degradation kinetics of anthocyanins during storage

Abstract

Abstract Supercritical carbon dioxide (SCCD) was applied for strawberry juice preservation. SCCD under selected parameters was effective for microflora and enzyme inactivation. For storage studies samples preserved at 30 and 60 MPa, at 45 °C for 30 min were selected. Yeasts and moulds were not detected after SCCD treatment in these conditions, whereas TMC was ~ 1.7 log CFU/g. Polyphenol oxidases were inactivated, whereas peroxidases decreased by ~ 85%. SCCD treatment resulted in the hydrolysis of sucrose and ~ 30% losses of vitamin C, which was totally decomposed after the 4th week of storage. Anthocyanins were not affected by the SCCD process and the kinetic rate constant of degradation during storage ranged from 2.12 × 10 − 2 to 3.10 × 10 − 2 (days − 1 ), and the half-time from 22.4 to 32.7 days, depending on the monomer and pressure applied. Overall, SCCD treatment seems to be a promising technique to obtain high quality strawberry juice as a safe alternative to non-pasteurized juices. Industrial relevance Strawberries are highly appreciated for their nutritional quality, colour and taste. Strawberry compounds, i.e. anthocyanins and vitamin C, are heat sensitive. These nutrients as well as colour are degraded when the fruits are processed using high temperature treatment. Supercritical carbon dioxide (SCCD) is an interesting method among the innovative non-thermal technologies for the preservation of fruit products. In this study, the data proved that SCCD processing is a promising non-thermal alternative to pasteurization to preserve fresh cloudy strawberry juice.