Potential of pulsed light treatment to pasteurize pomegranate juice: Microbial safety, enzyme inactivation, and phytochemical retention

The study explores the pasteurization condition of pomegranate juice using pulsed light (PL) treatment within a fluence domain of 312-2988 J cm(-2). A 5-log reduction (microbial safety) in Escherichia coli ATCC 43888, aerobic mesophiles, yeasts & molds count in the juice was obtained at 761.4 J cm(-2) (2.7 kV for 90 s). The thermal treatment attaining the equivalent lethality was 95 degrees C for 2 min. A complete inactivation in enzyme activity (polyphenol oxidase and peroxidase) along with microbial safety was attained for the treatments at 2988 J cm(-2) (PL) and 95 ?/3 min (thermal treatment). The thermally pasteurized sample (95 degrees C/3 min) showed 30 and 37% depletion in phenolic compounds and antioxidant capacity, respectively, with only 34% vitamin C in the juice. The equivalent PL pasteurized (2988 J cm(-2)) juice retained 97%, 94%, and 83% phenolics, antioxidants, and ascorbic acid, respectively. The PL-pasteurized sample's quality attributes and sensory profile were on par with high-pressure and pulsed electric field pasteurized juices from the literature. In turn, PL treatment of the pomegranate juice at 2988 J cm(-2) satisfies the criteria for all the stakeholders such as microbial safety (manufacturers demand), enzymatic stability (retailer's demand), and phytochemical retention (consumers demand).

Automated summary

This study investigated the pasteurization condition of pomegranate juice using pulsed light treatment and achieved a significant reduction in microorganisms. Pulsed light treatment at the equivalent lethality as thermal treatment retained more nutrients while ensuring enzyme activity and microbial safety.