Effects of pulsed electric fields on the quality of fruit juices

The influence of pulsed electric fields (PEF) on some physical, chemical properties and enzyme inactivation of orange, tomato and grape juice was investigated in this study. Treatment parameters were 3 µs pulse duration, 400 pps frequency, 24 kV/cm electric field strength and 0 (control), 524, 655, 786, 917 and 1048 µs treatment time. Results indicated that pH, ? Brix, conductivity, titratable acidity, color (L*,a*,b* and chroma), total phenolic substances, total anthocyanin content and FT-IR spectra of juice samples were not significantly changed (p>0.05). Increased treatment time did not change total antioxidant activity of tomato juice, however total antioxidant activity of orange and grape juice was decreased (p?0.05). Also total color difference of all juice samples was increased and hue value was not significantly change without decrease in grape juice. Moreover, pectin methylesterase activity of orange juice, lipoxygenase activity of tomato juice and polyphenol oxidase activity of grape juice was significantly decreased with increased treatment time (p?0.05). It was concluded that PEF application depending on increased treatment time can be successfully used to process orange, tomato and grape juice samples without adversly affecting some important quality parameters and with inactivation of enzymes. The potential of PEF to pasteurize juices needs to be studied further with microbial inactivation and sensory studies