Non-thermal hydrodynamic cavitation processing of tomato juice for physicochemical, bioactive, and enzyme stability: Effect of process conditions, kinetics, and shelf-life extension

Abstract

Fresh tomato juice was processed by hydrodynamic cavitation (HC) at 5 to 15 psi pressures for 5–30 min. A full factorial design was applied to optimize the HC treatment of tomato juice quality. Optimal conditions were recorded at 10 psi for 10 min, which showed no significant (p < 0.05) change in lycopene content to that of freshly obtained unprocessed tomato juice (control). After processing, the retention of 93% ascorbic acid and 96.6% of total phenolic compounds (TPC) was observed. Similarly, sedimentation and viscosity were mildly affected by HC processing (89.2 and 94.4% of values in the treated sample, respectively). While pH, total soluble solids (TSS), titratable acidity (TA) of HC treated sample remained unchanged (p < 0.05). The results were also compared with the conventional thermally processed tomato juice (90 °C for 90 s). Although thermal treatment resulted in the inactivation of 92.2% of pectin methylesterase and a 5 log reduction in total plate counts, it also showed significant reductions in ascorbic acid (61.4%), TPC (72.3%), and physical properties (37.7% of SI and 83.2% viscosity). However, HC processing could achieve a maximum of 4.9% inactivation of PME and 1 log reduction at high treatment conditions, respectively (15 psi for 30 min). The shelf-life study showed more retention of bioactives and better physicochemical properties in tomato juice samples stored at 4 °C for 15 days than the control. Sensory evaluation revealed that the overall acceptability of the optimized HC treated (0.714) sample was better than the thermally treated sample (0.591). The observed results concluded that HC-treated tomato juice was comparatively better than thermally-treated tomato juice in retaining bioactive compounds. Consequently, HC constitutes a promising approach in food processing to improve and retain the beneficial properties of tomato juice.