Dense phase carbon dioxide treatment of mango in syrup: Microbial and enzyme inactivation,and associated quality change

Dense phase carbon dioxide (DPCD) has been mainly explored as a new non-thermal pasteurization method for liquid foods. However, it's pasteurization efficacy absolutely needs to be further investigated for solid-liquid food mixtures, such as mango in syrup. This study aimed to investigate pasteurization and enzyme inactivation effects for DPCD treatment, and evaluate quality changes by comparing with traditional thermal pasteurization (TP) method. Optimal DPCD treatment (20 MPa, 60 °C, 30 min) was determined by conducting single factor and orthogonal experiments. Staphylococcus aureus CICC 10384 and Escherichia coli CICC 10003, which were selected as representative gram-positive and gram-negative pathogens in mango in syrup, could be completely inactivated by the optical DPCD treatment with initial concentrations of >8-log CFU/mL. Polyphenol oxidase and peroxidase activities could be completely inactivated after the optimal DPCD processing. Less adverse effect on pH and color, and higher amounts of vitamin C and total phenols of samples were observed after DPCD treatment when compared with TP treatment. The shelf-life of mango in syrup treated with DPCD was estimated to be <86 days (25 °C) based on an accelerated shelf-life testing (ASLT). This study demonstrated that DPCD treatment can be considered as a promising pasteurization technology for solid-liquid mixtures without exceedingly influencing their quality attributes.