Citric acid treatment maintains fresh-cut sweet potatoes storage quality by reducing browning levels and increasing antioxidant capacity

Fresh-cut sweet potatoes are popular among consumers for their freshness and convenience. However, rapid browning and oxidative damage under stress significantly degrade their storage quality. This study aims to evaluate the effects of citric acid (CA) treatment on maintaining the quality of fresh-cut sweet potatoes during storage and to explore the underlying mechanisms. Fresh-cut sweet potatoes were immersed in 1% (w/v) CA for 10 min, with water treatment as the control (CK), and stored at 4 degrees C for 8 d. Physicochemical parameters were evaluated every 2 d. After 8 d of storage, CA-treated samples exhibited significantly lower total colony count (3.34 lg CFU g(-1)), soluble sugar content (1.52%), and lignin content (2.62 OD280 g(-1)) compared to the CK group (P < 0.05), and better maintained color values. Additionally, CA treatment inhibited the increase in browning-related enzyme activities (phenylalanine deaminase, polyphenol oxidase, peroxidase) and the accumulation of browning products (total phenolics, soluble quinones), resulting in a browning index 8.15% lower than the CK group at the end of storage. The CA-treated fresh-cut sweet potatoes also exhibited lower malondialdehyde content (0.58 <mu>mol g(-1)) and lipoxygenase activity (3.19 U g(-1)), while showing higher activities of antioxidant enzymes such as catalase and ascorbate peroxidase, and enhanced free radical scavenging capacity, indicating that CA treatment helps mitigate cutting-induced oxidative stress. In conclusion, our findings highlight the significant potential of CA treatment in preserving the storage quality of fresh-cut sweet potatoes and provide new insights into its regulatory mechanisms.