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

Abstract

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 °C) were investigated and the results were compared with untreated and heat treated (at 90 °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.