Quality of shelf-stable low-acid vegetables processed using pressure-ohmic-thermal sterilization

Pressure ohmic thermal sterilization (POTS) involves ohmic heating of foods by applying an electric field under elevated pressure. Experiments were conducted using a custom made POTS apparatus using carrot as the model food. The samples were processed at a target temperature of 105°C at 600MPa and treated for 0, 1, 3, and 5min by regulating the electric field (30V/cm). POTS treated carrot sample quality attributes were compared against those processed using ohmic heating (0.12MPa, 30V/cm, 105°C) and pressure-assisted thermal processing (PATP; 600MPa, 0V/cm, 105°C). Within the experimental conditions of the study, the thermal come-up time of the POTS, Ohmic and PATP were 1.45min, 3.58min and 6.84min respectively. PATP come-up time also included the pre-heating time (≈6min). Results indicate the POTS samples had the least textural damage due to minimal thermal exposure. POTS samples had higher crunchiness index (CI) of 0.76 compared to PATP (CI=0.57) and ohmic heated (CI=0.62) carrots. All the technologies investigated had minimal impact on product color. This study demonstrates the potential to produce high quality shelf stable low-acid vegetable products using POTS.