Optimizing UV-C treatment for postharvest quality preservation of sea grapes (Caulerpa lentillifera)

Abstract

Sea grapes (Caulerpa lentillifera) have a limited shelf life of approximately 3–5 d at room temperature and are highly prone to microbial contamination, which restricts their commercial potential and nutritional benefits. To address this, the present study evaluated the effects of UV-C treatment at varying exposure times and doses (0–60 s and 0–0.057 kJ m⁻², respectively) on the postharvest quality of sea grapes during 1, 3, and 5 d of storage. The parameters assessed included physical appearance and morphology, color characteristics, total chlorophyll content (TCC), weight loss, total phenolic content (TPC), antioxidant capacity, and microbiological attributes. Results showed that prolonged storage led to darkening and surface wrinkling, along with increased weight loss. However, UV-C treatment effectively mitigated these degradations compared to untreated samples. Additionally, UV-C exposure slightly enhanced TPC and antioxidant activity, while substantially suppressed total microbial count (TMC) and total yeast and mold count (TYMC) of sea grapes compared to untreated samples. A scoring system integrating physical, chemical, and microbiological parameters identified 30 s of UV-C exposure (0.028 kJ m⁻²) as the optimal treatment condition, offering a balanced improvement across all evaluated attributes. Overall, UV-C treatment demonstrated promising potential as a non-thermal method to extend the shelf life of sea grapes by maintaining visual quality and inhibiting microbial growth.