Microbial, physicochemical and sensory properties of UV-C processed orange juice and its microbial stability during refrigerated storage

The effect of the UV-C light on quality characteristics (microbiological, physicochemical and sensorial) and microbial stability of orange juice (OJ) during storage (4 and 10 degrees C) were investigated and the results were compared with untreated and heat treated (at 90 degrees C, 2 min) juice. UV-C treatment (36.09 kJ/L dose) of OJ resulted in 2.8 log and 0.34 log reductions in aerobic plate count and yeast & mould count, respectively. Also, a 5.72 log reduction in Escherichia coli ATCC 25922 after UV-C treatment (36.09 kJ/L dose) was achieved, which indicates an acceptable reduction of a potential pathogen in juices. Ascorbic acid content as a major quality parameter of OJ did not change significantly after the UV-C treatment (36.09 kJ/L dose). Differences between untreated and UV-C treated (48.12 kJ/L dose) OJ were small in terms of organic acids, antioxidant capacity and phenolics. Based on sensory analysis results, no significant differences were detected between fresh and UV-C treated juices, and UV-C treated OJ was preferred more than the heat treated juice. UV-C treatment partially extended the shelf life of fresh juice during storage at the refrigerated conditions. (C) 2012 Elsevier Ltd. All rights reserved.