Effects of UV-C Combined with Different Antioxidants on Storage Quality and Flavor of Selenium-Sand Melon Juice

Selenium-sand melon (Cucumis melo L.) juice (SSJ) is valued for its lycopene and organic selenium content, but its shelf-life is limited by heat-labile nutrients and postharvest microbial spoilage. Non-thermal strategies that combine UV-C with natural antioxidants are therefore of interest. This study quantified the individual and interactive effects of UV-C alone or with four antioxidant systems on microbial safety, bioactive retention, and the flavor stability of SSJ under extreme contamination conditions (Escherichia coli D25015 at 5.19 log₁₀ CFU/mL; Mucor circinelloides D11624 at 4.36 log₁₀ CFU/mL). For this, we evaluated the efficacy of five treatments: UV-C alone (Group Z) and UV-C combined with catechin (Group EC, 0.01%), sodium erythorbate (Group K, 0.01%), ascorbic acid (Group VC, 0.1%), and catechin-ascorbic acid (Group HH, 0.005% + 0.05%). Conventional pasteurization (high-temperature short-time, HTST; low-temperature long-time, LTLT) served as controls. UV-C alone (Group Z) preserved lycopene and volatile flavor compounds better than HTST or LTLT. The combined use of UV-C and antioxidants exhibited synergistic effects, with no viable bacteria detected in Group K (sodium erythorbate) within four weeks. UV-C combined with antioxidants offer a scalable, non-thermal strategy that maintains nutritional and sensory quality while achieving pathogen reduction. These findings provide a quantitative framework for clean-label preservation of functional melon beverages.