Effects of UVC-modified gallic acid (UVC-GA) on the quality and cytotoxicity of squid surimi

Fried foods are susceptible to quality deterioration and heterocyclic amine (HCA) formation during high-temperature processing. Conventional antioxidants have limited efficacy, and research on improving the performance of natural antioxidants through photodynamic modification is insufficient. In this study, gallic acid (GA) was irradiated with 225 nm ultraviolet C (UVC) for 6 h to prepare UVC-modified gallic acid (UVC-GA). The effects of UVC-GA on the quality and cytotoxicity of fried squid surimi were then investigated. Results demonstrated that gallic acid was converted into naphthoquinone, o-benzoquinone, and benzoquinone compounds. Compared with unmodified GA, UVC-GA reduced the frying loss by 51.73% and maintained the moisture content at 52.64%. Meanwhile, it improved the tenderness (35.28 N) and color of the product, enhanced the textural properties, and exhibited superior performance over the other seven antioxidants tested. At a concentration of 0.01%, UVC-GA decreased the cytotoxicity against three cell lines (HepG2, HEK293, and SW480) by 40%-60% compared with unmodified GA, indicating preliminary application safety potential based on in vitro experimental data. This study reveals the excellent performance of UVC-GA and provides a scientific basis for the application of modified natural antioxidants in high temperature processed foods. Undeniably, this study has limitations. The conversion rate of GA to quinones is limited, and the cytotoxicity assessment was based solely on in vitro experiments without long-term exposure observation and indicators of cellular barrier function. Therefore, it cannot reflect the metabolic process of UVC-GA in living organisms or the safety of long term intake.