Commercial Scale Pulsed Electric Field Processing of Tomato Juice

Abstract

Effects of commercial scale pulsed electric field (PEF) processing on the quality of tomato juice were studied and compared with those of thermal processing. Tomato juice was prepared by hot break at 88 °C for 2 min or by cold break at 68 °C for 2 min and then thermally processed at 92 °C for 90 s or PEF processed at 40 kV/cm for 57 μs. Thermally processed, PEF processed, and unprocessed control juices were packed into 50 mL sterilized polypropylene tubes in a sanitary glovebox and stored at 4 °C for 112 days. Both thermally and PEF processed juices showed microbial shelf life at 4 °C for 112 days. The lipoxygenase activities of thermally and PEF processed juices were 0 and 47%, respectively. PEF processed juice retained more ascorbic acid than thermally processed juice at 4 °C for 42 days (p < 0.05). No significant differences were observed in the concentration of lycopene, °Brix, pH, or viscosity between thermally and PEF processed juices during the storage (p > 0.05). Sensory evaluations indicated that flavor and overall acceptability of PEF processed juice were preferred to those of thermally processed juice (p < 0.05). Keywords: Pulsed electric field; thermal processing; tomato juice; shelf life; ascorbic acid