Scavenging of ROS After Eugenol Treatment as Mechanism of Slowing Down Membrane Lipid Metabolism to Maintain the Surface Color of Fresh-Cut Yam

The effects of eugenol emulsion (EUG) on the browning of fresh-cut yam during storage and its inhibition mechanism were studied. The EUG treatment group had a significant anti-browning ability, and the 1.5% EUG treatment group had the best effect. During the whole storage period, the activities of peroxidase (POD) and phenylalanine ammonia-lyase (PAL) decreased significantly after 1.5% EUG treatment, especially on day 4, when the activity of POD and PAL was 3.2% and 23% of that of the control group, respectively. Molecular docking experiments showed that EUG inhibited PAL activity by binding to the active center of PAL, a key browning enzyme. A decrease in total phenol content was also observed. In addition, after EUG treatment, catalase (CAT) activity was significantly increased, preventing the accumulation of reactive oxygen species (ROS)-H 2 O 2 . EUG inhibited membrane lipid metabolism, 1.5% EUG delayed the emergence of lipoxygenase activity peak, and malondialdehyde (MDA) content decreased by 75.67% compared with the control on 4 d. In comparison with control, EUG increased the scavenging capacity of DPPH, ABTS, and iron-reducing antioxidant capacity (FRAP). The mechanism may be that EUG enhances antioxidant capacity, thereby reducing ROS-induced membrane lipid metabolism, therefore, lowering the synthesis and oxidation of phenolic compounds, and ultimately inhibiting browning.