DEVELOPMENT OF COLLAGEN EXTRACTION PARAMETERS FROM NILE TILAPIA SKIN AND EVALUATION OF ITS PROXIMATE COMPOSITION

Brazil ranks fourth among the largest producers of the Nile tilapia species (Oreochromis niloticus) which, if on the one hand, represents a positive economic impact for the country and for food security, on the other hand, represents a great environmental challenge due to the large volume of waste generated in the production process. A solution to this challenge may lie within the circular economy approach, which provides, among other principles, the efficient use of all types of resources, as an alternative to get closer to sustainability. Tilapia skin, for example, a residue from the industrialization process, is a source of collagen and can be exploited by the pharmaceutical, medical and food areas. The objectives of this work were to develop a method of extracting collagen from tilapia skin and to evaluate the centesimal composition of the product obtained, aiming at its use for industrial purposes. For collagen extraction, the skins were washed with distilled water and cut into standardized pieces. To remove the non-collagen proteins, the sections were submerged in 0.8 M NaOH solution in the proportion of 1:7 (w/v) for 2 h, with the solution being changed after 1 h. Then, the samples were rinsed in running water and distilled until they reached neutral pH (5-7) and immersed in 0.5% HCl (v/v) for 1 h, in the same proportion as the base. The skins were washed again in running water and distilled until they reached neutral pH. After washing, they were heated in distilled water (1:2 w/v) at 60° C for 1h 30 min to extract gelatin, which was filtered in gauze and subjected to freeze-drying