Bioactive peptides have antioxidant, hypoglycemic, anticancer, and immunoregulatory effects. In particular, the nutritional and health benefits and disease regulatory effects of immune-active peptides have attracted widespread attention from researchers. At present, many immunoactive peptides are applied in the research and development of new functional foods and in the clinical treatment of diseases. This article reviews the current progress in the preparation and screening, immunoregulatory effect and functional evaluation of animal-derived immune-active peptides, and discusses future research trends, aiming to provide a reference for the research, development, and application of functional products based on immunoactive peptides.

The present study was carried out to compare the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging capacity, hydroxyl radical scavenging capacity, Fe²⁺ chelating capacity and total antioxidant capacity of crude peptides extracted from western-style fermented ham with phosphate buffer solution and hydrochloric acid solution. Besides, their amino acid compositions were analyzed. The results showed that the mass and purity of phosphate buffer extractable peptides were significantly higher than those extracted with hydrochloric acid. The radical scavenging ability of both samples increased with increasing their concentration from 1 to 5 mg/mL. At a concentration of 5 mg/mL, phosphate buffer extractable and hydrochloric acid extractable peptides scavenged DPPH radical by 26.59% and 30.99%, and hydroxyl radical by 84.07% and 27.49% respectively. The Fe^{2 +} chelating capacity of phosphate buffer extractable peptides was 81.20%, which was significantly higher than that of hydrochloric acid extractable peptides. Their total antioxidant capacity was 68.74% and 46.11% at 5 mg/mL, respectively. For the two samples, the essential amino acids accounted for 44.246% and 41.746% of total amino acids, respectively, and the total amount of basic, acidic and hydrophobic amino acids related to antioxidant activity was 87.560% and 87.618%, respectively. In conclusion, both crude peptides have antioxidant capacity and a certain nutritional value, and phosphate extractable peptides have stronger antioxidant activity and better amino acid composition.