Submitted to: Food and Bioprocess Technology
Publication Type: Peer reviewed journal
Publication Acceptance Date: 8/30/2013
Publication Date: 10/1/2013
Publication URL: http://handle.nal.usda.gov/10113/58928
Citation: Guo, M., Jin, Z.T., Geveke, D.J., Fan, X., Sites, J.E., Wang, L. 0203. Evaluation of microbial stability, bioactive compounds, physicochemical properties, and consumer acceptance of pomegranate juice processed in a commercial scale pulsed electric field system. Food and Bioprocess Technology. DOI:10.1007/s11947-013-1185-6. Interpretive Summary: Raw pomegranate juice was processed in a commercial scale pulsed electric filed (PEF) processing system. Effect of PEF processing on microbial stability, color, total soluble solid, pH, sediment, antioxidant ability, total phenolic content, anthocyanin, and sensory properties after the treatments and during storage at 4 degree C for 12 weeks were studied and compared to thermally processed juice. This study demonstrated that PEF processed pomegranate juice had similar microbiological shelf-life as thermally processed juice while had similar quality, nutritional, and sensory values to the unpasteurized juice.
Technical Abstract: This paper investigated the feasibility for pasteurizing raw pomegranate juice in a commercial scale pulsed electric field (PEF) system. The juice was processed in a commercial scale PEF processing system at 35 and 38 kV/cm for 281 µs at 55 degree C with a flow rate of 100 L/h. Effect of PEF processing on microbial stability, color, total soluble solid, pH, sediment, antioxidant ability, total phenolic content, anthocyanin, and sensory properties after the treatments and during storage at 4 degree C for 12 weeks were studied and compared to thermally processed juices. PEF treatments significantly inhibited the growth of total aerobic bacteria, which remained at less than 2.5 log CFU/ml during the 12-week storage. No yeast and mold were detected (less than 0.69 log CFU/ml) in the PEF-treated juices during storage up to weeks 10 and 12, which is similar to the thermally processed juice. There were no significant differences in pH and total soluble solid between the PEF processed juice and unprocessed juice. PEF processing did not alter the contents of total phenolics and anthocyanin as compared to unprocessed juice. PEF processing had significantly less impact on the color of pomegranate juice than thermal processing. PEF treated juice had the same consumer satisfaction scores as the unprocessed juice, which were significantly higher than thermally processed juice samples. There was no significant difference between the two PEF treatments in all results. This study demonstrated that PEF technology extended microbial shelf-life and preserved the major quality and nutritional characteristics of pomegranate juice, and hence, is technically feasible for commercialization in the juice industry.