The growing awareness in the maximum utilization of meat industrial by-products is one of the main reasons why optimizing the extracting conditions of collagen and gelatin and discovering diverse sources has attracted the consideration of researchers in the last few years. Collagen is commonly isolated from porcine skin, bovine hide and, porcine and bovine bones and use of these by-products are excellent means to reduce the waste refining costs and to create profitable products from low value meat industrial by-products. However, due to socio-religious constraints, the industrial use of collagen or gelatin obtained from non-mammalian species is growing in importance. Collagen is widely used for biomedical, pharmaceutical, classical food and cosmetic applications. In addition to that, an increasing number of new applications and products have been found for collagen in the food industry, such as emulsifiers, foaming agents, colloid stabilizers, biodegradable film-forming materials and microencapsulating agents, along with the rising tendency to substitute artificial representatives by natural ones. In the last decade, a large number of researches have been carried out to extract enzymatically hydrolyzed collagen or gelatin for the production of bioactive peptides. Furthermore, researches have also focused on the effect of oral intake of collagen in both animal and human models, revealing the excellent chronic disease-protecting potential. In this paper, recent evidence on collagen extraction from novel sources, new processing conditions, potential novel or improved applications and their potential role in the prevention of chronic diseases have been critically reviewed and discussed.

collagen, gelatin, bioactive peptides, functional properties, chronic diseases.