CHARACTERIZATION OF BY-PRODUCTS WITH HIGH FAT CONTENT DERIVED FROM THE PRODUCTION OF BOVINE GELATIN

Background: Gelatin is a protein obtained by partial hydrolysis of collagen contained in skins, connective tissue and/or animal bones, which are by-products of the meat industry. The main raw material to produce bovine gelatin is the dermis of the skin, but there is a variation in fat and moisture content depending on the bovine skin origin. As a contribution to the circular economy and sustainability, these by-products with high fat content and the fat released from them during the gelatin production process can be managed for food industries, mainly in the development or formulation of animal feed. Methods: For the initial physicochemical characterization, moisture, fat, protein and ashes content were determined. Once the by-products with high fat content were identified, alteration parameters such as acidity, peroxide and saponification indexes were evaluated. Additionally, thermal, rheological and fatty acid composition characterization was carried out in order to study the possible applications of the by-products. Results and Discussion: The results showed that some of the by-products presented fat content values lower than 15.0%, so the viability of their use is limited. On the other hand, some by-products have more than 30% fat content, however, they can only be removed manually, and the efficiency of this process is low. By-products removed from the supernatant in the extractors presented 99.9 and 98.9% of fat, and there is the possibility of conditioning a mechanical method for their extraction. The determination of alteration and oxidation parameters, thermal and rheological characterization, fatty acid profile and solid fat content were carried out only on these by-products. According to the characterization, these by-products could be valued and used in the formulation of animal feed, however, they present some limitations for some applications such as biodiesel production or food industry.