Processamento dos cortes comerciais e aproveitamento dos resíduos de Beijupirás (Rachycentron canadum) cultivados e selvagens

Abstract

The cobia (Rachycentron canadum) is the only species of marine fish cultivated commercially in Brazil with great potential for mariculture. The present study evaluated the processing and utilization of the residues of cultured and wild cobia. The study consisted of three studies. The first study made an analysis of the yield and quality attributes of the main commercial cuts of the cobia cultivated on the north coast of São Paulo, according to different weight classes, in order to suggest the slaughter weight of these animals, allowing an optimization in the production and product standardization. The cobia used in this study came from a commercial marine fish culture located on Búzios Island, Ilha Bela, São Paulo. We collected 18 cobias with weights between 1,115 and 3,975 kg, which were divided into three weight classes: (T1 = from 1,001 to 2,000 kg); (T2 = from 2,001 to 3,000 kg) and (T3 = from 3,001 to 4,000 kg). Five types of commercial cuts were made and their yields calculated according to the weight classes (T1, T2 and T3). Analyzes of centesimal chemical composition, physical-chemical pH and BNVT, as well as microbiological analysis were performed to evaluate the freshness and sanity of the fillet samples. Sensory analyzes of acceptance and purchase intention were performed in the class T2 and T3 fillets. In the second study, the characterization and utilization of the residues generated from the processing of the cultured cobia was carried out, obtaining coproducts of high added value destined for human consumption, from simple and low-cost methodologies. The residues were obtained from the same fish used in the first study. The generated residues were weighed and the yield was calculated according to the weight classes. The heads and carcasses of the cobias cultivated according to the weight classes (T1, T2 and T3) were utilized from the cooking and manual removal of meat adhered to the bones denominated CMNS (manually separated meat). The CMNS of the head, the carcass and the shavings were used in the elaboration of ball and pasty pate. Analyzes of the chemical composition of CMNS centesimal of the head of the carcass and of the shavings, as well as of the products elaborated with this residue were carried out. Microbiological analyzes of CMNS of head, carcass and shavings were carried out in order to evaluate the sanity of the samples. Sensory analyzes of acceptance, purchase intention and acceptability index were performed in the elaborated co-products. The skin of the cobias was used to obtain gelatine, where five extraction methodologies were tested in order to evaluate the best yield obtained. The third study was carried out in order to compare the yield of fillet and fillet residues of wild and cultivated cobia in the same weight class, in order to evaluate if there are differences between wild and cultivated animals. The six-cultured fish used in this study were the same fish used in the first study of the T2 weight class. The other six wild fish in the same T2 weight range were purchased from local commerce in the municipality of Itarema, state of Ceará. The fish were filleted and the yield calculation was performed. In the first study, eutrophicated whole fish yields (EIRP) did not differ statistically between 86.70% (± 0.93) and 85.92% (± 1.67) between the T1 and T2 classes respectively. For RPEC, RFCP, RFSP and RFSPV did not present statistical difference between classes T2 and T3. The results of the chemical composition showed that the chemical components differed statistically in the weight classes T1 9 and T2, except for ash. Among the weight classes T2 and T3, no statistical differences were found between the chemical components of cobia fillets. Regarding the microbiological and freshness analyzes (BNVT and pH), the samples of cobia fillet of classes T1, T2 and T3 were in accordance with the standards established by Brazilian legislation, and with an excellent state of freshness. The results of the sensorial evaluation indicated an excellent acceptance of the steaks with an overall impression of 7.84 (± 1.21) and 7.96 (± 1.32) respectively for the classes T2 and T3. In the second study, the results of the centesimal chemical composition of the residues and co-products showed high nutritional value, especially in relation to high protein and lipid content. Microbiological analysis indicated that residues (shavings, CMNS of head and carcass) were in accordance with the standards established by Brazilian legislation and suitable for use in the preparation of co - products for human consumption. The sensorial analyzes of the elaborated co-products showed excellent sensory acceptance, with a high degree of acceptability and purchase intention, thus demonstrating great market potential. The highest yield of gelatine extracted from cobia skin was 14.61%, indicating high yield and relevant biotechnological potential of this residue. In the study, the results obtained allowed to conclude that there were no significant differences in the yield of fillet, viscera, head and skin between the wild and cultivated cobias. However, significant differences were observed for carcass yield and tummy titer.