Complementação da composição aminoacídica da gelatina extraída da pele de tilápia do Nilo (Oreochromis niloticus) com proteína miofibrilar

Abstract

Nile tilapia (Oreochromis niloticus) is one of the main fish species cultivated in Brazil, accounting for about 41% of national fish farming. One of the biggest problems in the fishing chain is the large amount of waste generated after filleting, which can reach 70%. Various products can be obtained from coproducts of fish such as protein isolates, gelatine, collagen and others. The objective of this work was to perform the amino acid complementation of gelatin meal extracted from the Nile tilapia skin with myofibrillar protein meal extracted from the mechanically separated meat (CMS) of this fish, for later use as a nutritional supplement. The centesimal composition of the proteins under study (gelatine flours and myofibrillar protein) was determined. Amino acid complementation was performed according to the chemical score of the extracted gelatine meal with the myofibrillar protein to obtain a protein mixture of high nutritional quality. The centesimal composition of the gelatin meal was 86.4% protein, 4.19% lipid, 7.12% moisture and 2.12% ash. For myofibrillar protein meal, the contents were 87.25% of proteins, 6.82% of lipids, 4.18% of humidity and 1.72% of ashes. It was verified by determination of the chemical score of the gelatin flour protein that isoleucine was considered the limiting amino acid of this product. After this evaluation, it was determined that for gelatin flour to become balanced in terms of essential amino acids, it is necessary to add 58.12 g (33.42%) of myofibrillar protein meal to 115.74 g (66.57%) of gelatine flour, which increases the isoleucine content of the blend to a level equal to that found in the FAO standard protein. It was possible to obtain the gelatine flours extracted from the skin of the Nile tilapia and the myofibrillar protein and to determine their centesimal composition. From the study of the chemical score of amino acids and the centesimal composition it was possible to complement the protein quality of the gelatine meal through the addition of myofibrillar protein flour, obtaining a mixture with quantities of essential amino acids correct for human nutrition according to FAO. This mixture, due to its protein value and amino acids present, could be used in the elaboration of a nutritional supplement.