UV-C treatments on fresh-cut green onions enhanced antioxidant activity, maintained green color and controlled 'telescoping'

To maintain high quality and to extend the shelf life of minimally processed green onions (Allium cepa L.), the potential benefit of UV-C treatment for different doses was evaluated. Fresh-cut green onions treated with UV-C for 0 (K, non-treated), 3 (UV-C3), 5 (UV-C5), 10 (UV-C10) and 15 (UVC 15 ) min were stored at 5 o C for 15 days. Antioxidant activity, electrolyte leakage, color, weight loss, visual quality and inner leaf extension ‘telescoping’ were measured at 1, 5, 10 and 15 d of storage. DPPH free radical scavenging activity of fresh-cut green onions was increased by UVC treatments, especially higher doses. The highest antioxidant activity was measured in onions treated with UV-C 15 (87.75%) while it was lowest in onions of K (82.14%) and UV-C 10 (81.95%). In contrast to antioxidant activity, electrolyte leakage was lowest in control group and it was getting high with the higher doses of UV-C. UV-C treatments for high doses increased antioxidant activity but these doses caused tissue deterioration. L* values of white leaf sheath of fresh-cut green onions were maintained higher in onions treated with UV-C5 and UV-C10 than in the other UV-C treatments and K. Color values a* and b* of the hollow green tissues of onions in K, UV-C 3 and UV-C 5 treatments increased during the storage. Decay percentage and inner leaf extension ‘telescoping’ of onions were effectively controlled by UV-C 15 treatment.