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 degrees C at 600 MPa and treated for 0, 1, 3, and 5 min by regulating the electric field (30 V/cm). POTS treated carrot sample quality attributes were compared against those processed using ohmic heating (0.12 MPa, 30 V/cm, 105 degrees C) and pressure-assisted thermal processing (PATP; 600 MPa, 0 V/cm, 105 degrees C). Within the experimental conditions of the study, the thermal come-up time of the POTS, Ohmic and PATP were 1.45 min, 3.58 min and 6.84 min respectively. PATP come-up time also included the pre-heating time (approximate to 6 min). Results indicate the POTS samples had the least textural damage due to minimal thermal exposure. POTS samples had higher crunchiness index (Cl) of 0.76 compared to PATP (CI = 0.57) and ohmic heated (Cl = 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. (C) 2013 Elsevier Ltd. All rights reserved.