Effects of pepper (Zanthoxylum bungeanum Maxim.) leaf extract on the antioxidant enzyme activities of salted silver carp (Hypophthalmichthys molitrix) during processing

•Polyphenols of Chinese pepper leaf extract were determined.•Salted fish with the leaf extract and polyphenols had a lower degree of lipid oxidation.•The leaf extract may increase CAT, SOD and GSH-Px activities in salted fish.•The leaf extract has a potential to prevent oxidative stress. Here we investigated the lipid-protective effects of Chinese red pepper (Zanthoxylum bungeanum Maxim.) leaf (ZML) extract and chlorogenic acid, hyperoside, and quercitrin on salted fish during processing. ZML extract and the polyphenols expressed high total antioxidant capacity and DPPH free radical scavenging activity. Salted fish with the ZML extract had higher endogenous antioxidant enzyme (superoxide dismutase, catalase and glutathione peroxidase) activities, lower peroxide value (PV) and thiobarbituric acid-reactive substance (TBARS) values than that of the control. The negative correlation between the antioxidant enzyme activities and PV, or TBARS values of all samples was observed throughout the entire processing. These results indicated that ZML extract could effectively inhibit lipid oxidation in the salted fish and suggested its potential role in the protection against oxidative stress in processed meat.