Combination of pulsed electric field processing and antimicrobial bottle for extending microbiological shelf-life of pomegranate juice

Abstract

Pomegranate juice was processed using bench top (7.2 L/h flow rate, 35 kV/cm field strength, 72 µs total treatment time) and pilot scale (100 L/h flow rate, 35 kV/cm field strength, 281 µs total treatment time) continuous pulsed electric field (PEF) processing systems. The treated juice was packaged in PET bottles or PET bottles coated with potassium sorbate and sodium benzoate, and stored at 4 °C for 84 days. Samples were assessed every 7 days for total aerobic bacteria and yeast and mold. Untreated juice had less than one week of shelf-life, while untreated juices in antimicrobial bottles had 56 days. Juices treated with PEF alone had a shelf-life of 21 days (bench scale) and over 84 days (pilot scale). Juices treated with PEF and stored in antimicrobial bottles had a shelf-life over 84 days for both scale tests, which significantly extended the microbiological shelf-life of pomegranate juice. Pulsed electric field (PEF), one of novel non-thermal processing technologies, has been studied intensively worldwide for the last decades. However, most of them were done at laboratory scale and few were at pilot or commercial scale. In addition, PEF processing alone may not provide enough shelf-life of juice as juice industry expects. The work in this paper shows the side-by-side comparison of PEF processing at lab and pilot scales and demonstrates that the combination of PEF with antimicrobial battle packaging significantly extended the shelf-life of juice. The use of a large scale PEF processing system and the combination of antimicrobial packaging provide juice manufacturers an innovate approach for enhancing the safety and extending the shelf-life of juice products.