Synergistic photodynamic inactivation of Escherichia coli using curcumin-trehalose photosensitizer under blue visible light on fresh-cut dragon fruit (Hylocereus undatus)

There is a growing need for sustainable and effective packaging solutions that ensure microbial safety and extend the shelf life of fresh-cut fruit without compromising their nutritional quality. This study aimed to investigate the efficiency of curcumin-trehalose (CUR-TRE) complex as a novel photosensitizer (PS) with blue visible light (455 nm) in inactivating Escherichia coli O157:H7 on fresh-cut dragon fruit. The results showed that 100 µM CUR-TRE was the optimum concentration in inhibiting E. coli O157:H7 cells to 3.0 × 10 1 CFU/mL, achieving a 6.52 log reduction when exposed to blue visible light for 30 min. Furthermore, photodynamic treatment on E. coli -inoculated fresh-cut dragon fruit with 100 µM CUR-TRE resulted in a log reduction greater than 3.47. Subsequently, the visual quality of fruit was better preserved in CUR-TRE treated samples with less change in fruit color compared to the control fruit and those treated only with CUR, TRE, or EtOH under both dark and light conditions during the ambient storage at 25 ℃. In addition, CUR-TRE-PDI treatment delayed the weight loss of fresh-cut dragon fruit to 33 % compared to the untreated control (88 %) after 20 d of storage. They also had the best retention of total phenolic content, total flavonoid content, DPPH, and vitamin C levels of fresh-cut dragon fruit throughout the entire storage. In particular, PPO and POD activity levels were substantially inhibited with 1.20 U/g and 0.72 U/g, respectively, after 20 d of storage. Taken together, these observations imply that CUR-TRE-PDI treatment exhibits a high potential in the photodynamic field by extending the shelf life of dragon fruit. • Curcumin-Trehalose (CUR-TRE) as a photosensitizer for PDI in fresh-cut dragon fruit. • CUR-TRE photodynamically inhibited Escherichia coli growth. • PDI with CUR-TRE showed higher antibacterial efficacy than CUR alone. • PDI ensures quality retention and enzymatic stability in dragon fruit during storage. • Insight into a novel postharvest strategy to extend the shelf life of dragon fruit.