High pressure carbon dioxide pasteurization of fresh-cut carrot

High pressure carbon dioxide treatment (HPCD) was applied for the pasteurization of fresh-cut carrot. The inactivation kinetics of the natural microbial flora were determined as a function of the treatment conditions (8 or 12 MPa, 22, 35, 40, 45 °C, 5–45 min) to investigate the more feasible process conditions to assure a microbial stability to the product. Further, the effect of HPCD treatment on the qualitative aspects of the product in terms of enzymatic activity (polyphenol oxidase (PPO), peroxidase (POD), pectin methylesterase (PME) and polygalacturonase (PG)), bioactive composition (phenol, flavonoid, carotenoid, ascorbic acid content and antioxidant capacity), texture, pH and tritatable acidity (TA) were measured. A storage study at refrigerated conditions (4 °C) for 4 weeks was also performed to monitor the microbial and qualitative stability of the product. The results showed that 12 MPa, 40 °C, 15 min were effective to inactivate the natural microbial flora and assure the microbial and enzymatic stability of the product for 4 weeks. Bioactive compounds content, antioxidant capacity, and enzyme stability were all preserved with the exception of the texture which exhibited a significant reduction up to 90% compared to the control, and the ascorbic acid content which was reduced down to 40%.

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► HPCD partially inactivated the natural microbial flora and enzymes in fresh-cut carrot.
► Bioactive compounds and antioxidant capacity of the samples were preserved.
► 90% texture reduction was observed for the samples treated at 12 MPa, 40 °C, 15 min.
► HPCD did not seem to be feasible as innovative technique to pasteurize fresh-cut carrot.