Ultraviolet radiation as a potential non-thermal preservation method for sugarcane juice: microbial safety, quality retention, and shelf-life extension

This study explored ultraviolet (UV) treatment effects on sugarcane juice at doses of 0.00–149.76 J/cm2. The most effective dose (149.76 J/cm2) was selected for balancing microbial reduction (≈ 2–3 log) with quality attribute of preservation and compared to pasteurized and untreated samples. A first-order kinetic model accurately described microbial reduction (R2 = 0.9039–0.9057; k = 0.0093–0.0442 day–1). Physicochemical properties showed no significant differences (P > 0.05) between treatments. UV treatment enhanced total phenolic content (TPC), total flavonoid content (TFC), and antioxidant activity (2,2-diphenyl-1-picrylhydrazyl [DPPH] and ferric reducing antioxidant power [FRAP] assays), compared to pasteurization (P ≤ 0.05). During refrigerated storage (4°C), pH, total soluble solids, L*, TPC, TFC, DPPH, and FRAP decreased, while titratable acidity, a*, and microbial counts increased, particularly in untreated juice samples. UV-treated juice achieved 6 days shelf life versus 4 days for controls, based on microbial limits (5 log CFU/mL total plate count; 4 log CFU/mL yeast and mold). Pasteurized juice showed no microbial growth over 12 days. Compared with pasteurization, UV-C irradiation better preserved bioactive compounds, although limited penetration in turbid juice samples requires further study.