Skins, scales and bones are the major by-products of the fish-processing industry. These by-products are not
regarded as ordinary saleable products and are usually discarded causing a heavy environmental impact. However, marine
by-products are a good source of collagen that could be extracted and further enzymatically hydrolyzed to liberate
interesting bioactive peptides. Collagen-derived peptides may exhibit interesting antioxidant activity, potent
antihypertensive activity, antimicrobial activity against different strains of bacteria, protective effect on cartilage, capacity
to stimulate bone formation, and also other interesting activities (e.g., satiety, calciotropic, or opioid). The bioactive
properties of collagen-derived peptides, and also their resistance to protein digestion, make them potential ingredients of
health promoting foods.