Optimization of the supercritical CO2 pasteurization process for the preservation of high nutritional value of pomegranate juice

This work aims to develop a high-pressure pasteurization process for pomegranate juice by supercritical CO2 (SC-CO2). The process was optimized in a mutibatch-system through Design of Experiment (DoE) and Response Surface Methodology. The optimized SC- CO2 process (12.7 MPa, 45 °C, 40 min) was compared with conventional thermal pasteurization (90 °C, 1 min) and High Hydrostatic Pressure process (600 MPa, 3 min) for the microbiological inactivation and the change in quality parameters of total phenols content (TPC), antioxidant activity (AAt) and colour, up to 28 days of storage at 4 °C. SC-CO2 treated juice was microbiological stable during the entire shelf life as well as colour and TPC. The antioxidant activity showed a significant (p < 0.05) decrease during the storage period, however this evidence was observed also for the thermal and high hydrostatic processed samples. Overall, SC-CO2 process is a promising technology for the development of innovative pasteurization technologies for high nutritional juice.