## 1 Introduction  
Reactive oxygen species (ROS) derived from molecular oxygen are indispensable cellular components in organisms that take part in cell signaling and homeostasis during physiological processes [1]. However, excess ROS during oxidative stress can result in oxidative damage to cell membranes, proteins, and DNA. Those damage will cause increased issues in a series of chronic diseases including hepatopathy, atherosclerosis, and diabetes [1, 2]. In addition, radical mediated oxidation can cause deterioration in food products, which is a main concern during food processing and storage. This concern is because the toxic and smelly secondary metabolites produced by lipid peroxidation can negatively influence normal functions within the human body [3; 4]. Therefore, chronic diseases and food spoilage caused by excess ROS arouse widespread public concern because they could result in great damage to public health and food industries. At present, chemically synthesized antioxidants have been generally applied to biomedical products, daily cosmetics, and foodstuff industries [5]. However, the general public have an increasing awareness of food safety and the potential toxicity of chemical preservatives and antioxidants, which has urged researchers to develop new approaches to exploit innoviously natural antioxidants [6]. Antioxidant peptides (APs) derived from food waste can promote human health through decreasing the risk of chronic diseases related to oxidative stress. In addition, APs can effectively delay food deterioration caused by lipid peroxidation [2; 7]. Therefore, APs have been proposed as a perfect alternative to chemical antioxidants due to their bioactivities, safety, and nutritional properties [2]. As reported by Food and Agriculture Organization of the United Nations (FAO) in 2016, the quantity of global fish production is about \(1.71\times 10^{8}\) tons. Commercial fish processing generates a large amount of fish by-products, which cause heavy processing and environmental problems [2]. Therefore, collagens and peptides, with excellent physicochemical properties and antioxidant activity, have been prepared using seafood by-products including skin [8; 9], bone [5; 10], head [11; 12], scale [6], and dark muscle [13]. [PERSON] et al. researched the structural and rheological properties and the enhanced wound-healing ability of collagen-based gel obtained from cuttlefish skin, and the results indicated that cuttlefish collagen-based gel might be useful as a wound healing agent [9]. Previous reports have indicated that collagen hydrolysate and peptides from cod skin can protect mice skin from ultraviolet radiation-induced damage including wrinkle formation and destruction, through suppressing the depletion of endogenous antioxidant enzyme and inhibiting the expression of NF-kB and pro-inflammatory cytokines mediated by NF-kB [14]. In addition, the peptides have shown high moisture retention and absorption abilities. [PERSON] et al. [3; 12] reported that APs including GVPLT, GPGGFI, FIGP, WEGPK, GPP, and GSGGL from protein hydrolysate of bluefin leatherjacket head and skin exhibited high scavenging activities on superoxide anion radical (O\({}_{2}^{-}\bullet\)), hydroxyl radical (HO\(\bullet\)), and 2,2-Diphenyl-1-picrylhydrazyl radical (DPPH\(\bullet\)). WEGPK and FGP could effectively inhibit the peroxidation of unsaturated fatty acids. Their antioxidant activities are related to their molecular structures, such as small molecular sizes, amino acid (AA) sequences, and the ratios of hydrophobic and aromatic AAs [6]. In addition, collagens and APs from marine organisms have also shown strong activity and potential application value [15]. [PERSON] et al. reported that collagen-derived peptides from _Chondrosia reinformis_ might be used in drug and cosmetic formulations for damaged or photoaged skin repair because it could stimulate and increase cell growth and proliferation, scavenging ROS, and protect cells from UV-induced death [16]. [PERSON] et al.