Effects of ultraviolet-C treatment in Teflon®-coil on microbial populations and physico-chemical characteristics of watermelon juice
2013
Feng, Mei | Ghafoor, Kashif | Seo, Bohyun | Yang, Keunyong | Park, Jiyong
The efficacy of UVC radiation for inactivation of bacteria (aerobic, coliform) and yeast/mold in watermelon juice using helix Teflon®-coil was investigated. Changes in microbial load, pH, °brix, color (L*, a*, and b*), lycopene, and phenolics in juice, after UVC treatment were evaluated for 37days of storage at 5±1°C. Microbial inactivation was dependent on the UVC intensity between 2.7 and 37.5J/mL. UVC treatment inactivated all (2.6logCFU/mL) coliform bacteria. UVC (37.5J/mL) reduced total aerobes and yeast/mold by 1.47 and 0.99logCFU/mL, respectively. The microbial load in treated juice remained lower than 6.0logCFU/mL until the 31st day of storage. UVC treatment resulted in no-significant effects on pH, °brix, color change, lycopene, and phenolics, the values of which remained consistent with those of a control until 25th day of storage. UVC treated juice had lower b* (yellowness) and higher a* (redness) colors than untreated juice.Watermelon juice is a potential health food and strategies to increase its shelf-life with minimal or no damage to nutritional components are crucial for obtaining more commercial benefits. Our study suggests that a Teflon®-coil UVC system can be effectively used as a non-thermal method for microbial inactivation in watermelon juice and to improve the product shelf-life with no significant effects on different physico-chemical and nutritional characteristics.
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