Method of using papain to extract collagen from aquatic animals

A process of extracting collagen from skins of fish selected from the group consisting of Lates calcarifer (barramundi) and Oreochromis nilotica (red tilapia) using papain, comprising:

• a) homogenizing the fish skin with sodium hydroxide;
• b) obtaining a suspension from step (a);
• c) stirring the suspension for at least 24 hours;
• d) centrifuging the suspension from step (c) for at least 20 minutes;
• e) separating a precipitate from step (d);
• f) homogenizing the precipitate from step (e) with alkaline solution;
• g) stirring the precipitate from step (f) for at least 24 hours and for at least 3 repeats;
• h) washing the precipitate with water and acetic acid solution;
• i) stirring the precipitate from step (h) with papain at a working temperature of 5° C. for at least 24 hours;
• j) separating a papain-treated precipitate from step (i);
• k) centrifuging the papain-treated precipitate from step (j) for at least 20 minutes;
• l) separating collagen fibers from the centrifuged papain-treated precipitate of step (k);
• m) introducing the collagen fibers into a sodium chloride solution;
• n) collecting the collagen fibers from step (m) and centrifuging the collagen fibers for at least 20 minutes;
• o) separating the resulting collagen pellet;
• p) freeze-drying the collagen fibers from step o;
• wherein the collagen yield of said skins is between 14 and 40% by weight.