Effects of Pulsed Electric Fields on Physicochemical Properties and Microbial Inactivation of Carrot Juice

Carrot juice samples treated with pulsed electric fields (PEF) of electric field intensity of 25 kV/cm and treatment time of 144.6 μs (PEF1) and 433.8 μs (PEF2) and thermal pasteurization (TP) treatment of 90C for 1 min were evaluated for physicochemical properties and microbial inactivation. The PEF1 and PEF2 treated carrot juice retained higher amounts of ascorbic acid, α-carotene, β-carotene and lutein than the TP-treated carrot juice. The PEF-treated carrot juices were not significantly (P > 0.05) different in pH and °Brix compared to the control, while the TP-treated juices were significantly different in °Brix and total acidity compared to the control. The PEF2 was comparable with the TP for inactivation of aerobic bacteria and mold in carrot juice. Practical Applications Pulsed electric field (PEF) can be used as a nonthermal pasteurization method to inactivate microorganisms and enzymes in liquid food and it preserves the physiochemical and sensory properties, and nutritional value of liquid food. Our study showed that PEF treatment was more efficient in preserving some physicochemical and quality properties of carrot juice compared to conventional heat pasteurization.