Gelatina e astaxantina de resíduo do salmão (salmo salar l): extração, caracterização e aplicação para a produção de filmes antioxidantes

Abstract

The salmon, Salmo salar L. is one of the fish species most imported in our country. The fish processing industries generate large amounts of waste. In salmon processing waste materials represent more than 60% and when disposed of improperly can cause great harm to the environment. Collagen is the main protein of connective tissue and is the most abundant protein in mammals, birds and fish. A commercial collagen used is gelatin, obtained by partial hydrolysis of collagen. Coatings and films are edible types of protection that can be applied in a food. Proteins are among the major macromolecules found in edible films. The salmon muscle, also had no destination, then the alternative is astaxanthin extraction of it, closing a production cycle with the full use of fish and product innovation. The aim of this study is to extract gelatin from skin and salmon carcass (Salmo salar L.), astaxanthin extract of the same fish muscle and produce films from the extracted gelatins incorporated with astaxanthin. For the extraction of gelatin were performed essentially five steps (demineralization, acid and alkali treatments alternately and extraction in distilled water under heating). The extracted gelatin was characterized as the chemical composition, minerals, water activity (Aw), gel strength, color, extraction yield, differential scanning calorimetry (DSC), thermogravimetric (TGA), infrared spectroscopy (FTIR), distribution molar mass and scanning electron microscopy (SEM). The formulation of the film was made with 3% fish gelatin and 5% glycerol (dry basis) varying the amount of astaxanthin and tannic acid extract. The films were obtained by casting and characterized according to their permeability to water vapor, opacity, color and morphology (SEM). The films were presented with good looks, homogeneous and manageable, with good transparency and moisture between 10.5 and 12%. The addition of astaxanthin with tannic acid was effective in reducing the permeability to water vapor (PVA), which was reduced significantly. The extraction of the gelatin from this residue may be a new alternative, because it displays characteristics favorable to a good quality gelatin, mainly due to good gel strength; low water activity; Low moisture and ash content; high protein content; next color to white and good thermal properties for uses up to 200ºC. The application of gelatin as in film production was effective when added tannic acid as cross-linking.