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Type II collagen is a homologous super-helical structure consisting of three identical α1(II) chains. It is a major component of animal cartilage, and is widely used in the food industry. Type II collagen can be extracted by acids, salts, enzymes, and via auxiliary methods and can be further hydrolyzed chemically and enzymatically to produce collagen peptides. Recent studies have shown that type II collagen and its polypeptides have good self-assembly properties and important biological activities, such as maintaining cartilage tissue integrity, inducing immune tolerance, stimulating chondrocyte growth and redifferentiation, and providing antioxidant benefits. This review focuses specifically on type II collagen and describes its structure, extraction, and purification, as well as the preparation of type II collagen peptides. In particular, the self-assembly properties and functional activities of type II collagen and collagen peptides are reviewed. In addition, recent research advances in the application of type II collagen and collagen peptides in functional foods, food additives, food coating materials, edible films, and carriers for the food industry are presented. This paper provides more detailed and comprehensive information on type II collagen and peptide for their application. [ABSTRACT FROM AUTHOR]

BACKGROUND: Porcine nasal cartilage type II collagen‐derived peptides (PNCPs) may be complexed with calcium to provide a highly bioavailable, low‐cost, and effective calcium food supplement. However, the calcium‐binding characteristics of PNCPs have not yet been investigated. In the present study, calcium‐binding peptides were derived from porcine nasal cartilage type II collagen and the resulting PNCPs‐Ca complex was characterized. RESULTS: The study reveals that the calcium‐binding capacity of PNCPs is closely related to enzymatic hydrolysis conditions. The highest calcium‐binding capacity of PNCPs was observed at a hydrolysis time of 4 h, temperature of 40 °C, enzyme dosage of 1%, and solid‐to‐liquid ratio of 1:10. Scanning electron microscopy and energy dispersive X‐ray spectroscopy revealed that the PNCPs had a pronounced capacity for calcium binding, with the PNCPs‐Ca complex exhibiting a clustered structure consisting of aggregated spherical particles. Fourier‐transform infrared spectroscopy, fluorescence spectroscopy, X‐ray diffraction, dynamic light scattering, amino acid composition, and molecular weight distribution analyses all indicated that the PNCPs and calcium complexed via the carboxyl oxygen and amino nitrogen atoms, leading to the formation of a β‐sheet structure during the chelation process. In addition, the stability of the PNCPs‐Ca complex was maintained over a range of pH values consistent with those found in the human gastrointestinal tract, facilitating calcium absorption. CONCLUSION: These research findings suggest the feasibility of converting by‐products from livestock processing into calcium‐binding peptides, providing a scientific basis for the development of novel calcium supplements and the potential reduction of resource waste. © 2023 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]