Pasteurization of carrot juice by high voltage pulsed electric fields with square wave pulse and quality change during storage

In this study, carrot juice was treated with high voltage pulsed electric fields (PEF) and the changes in its physical and chemical properties during storage at 4°C and 25°C were investigated. The sterility for bacteria, yeast and mold in carrot juice increased with increasing electricfield strength and treatment temperature. While yeast and mold were completely inactivated at 65 kV/cm with a treatment time of 200 μs in a continuous PEF treatment system, bacteria were reducedby four log cycles. The results also showed that square wave pulse treatment was more effective for inactivating microorganisms than exponential decay pulse, and this effect was more apparent for carrot juice of lower pH. Although we observed significant changes in physical and chemical properties such as soluble solid content, pH, acidity, color, and carotene retention when the PEF treated samples were stored at the ambient temperature (20°C), no significant physical and chemicalchanges were found at the cold storage temperature (4°C) during 28 days of storage. The results indicate that the PEF treated carrot juice is appropriate for commercial refrigerated storage.