Rendimento e qualidade físico-química da carne mecanicamente separada de tilápia em diferentes classes de peso

Abstract

Tilapia is the most produced fish in Brazil, with its production aimed at the fillet market, which requires animals weighing 800 to 1000 grams. Due to their heterogeneous growth and reproductive precocity, many animals end up not reaching commercial size, being considered waste. Despite this, they are characterized as a high quality raw material and have the potential to be used in human food, through obtaining Mechanically Separated Meat (CMS). Therefore, this work was developed to evaluate the yield and quality of DMI of tilapia in different weight classes, outside the commercial size. The animals were obtained from a commercial farm and transported in thermal boxes to the laboratory. Subsequently, they were washed, weighed, classified by weight and eviscerated for the production of CMS. The weight classes studied were: A (≥ 50 g < 80 g), B (≥ 80 g and < 110 g), C (≥ 110 g and < 140 g) and D (≥ 140 g and < 170 g). Carcass yield and DMI, physicochemical, calcium, water activity, water retention capacity and fatty acid profile analyzes were carried out. After 90 days of storage (-18ºC), the Total Volatile Bases, lipid oxidation and pH of CMS were determined. The highest carcass yield was obtained with weight class D, this variation can be attributed to the difference in size and weight of the fish in both classes. In relation to CMS performance, there was no significant difference between weight classes. Proteins were not affected by weight differences and lipid content increased according to fish size, with an inverse relationship with moisture and ash. The water activity values of tilapia CMS did not show significant differences. In the analysis of water retention capacity, the classes showed high retention with a significant difference, in which class B (45.2%) obtained the highest average WHC, while C (30.8%) presented the lowest result. Regarding the results found for calcium, it was observed that class A (≥ 50 < 80g) obtained the highest result (1.22%), differing significantly from the others. In this study, no significant differences were observed in TBARS and BVT values between different weight classes. Regarding pH, differences were observed between weight classes, however, all of them have values within the maximum limits permitted by legislation. The major fatty acids found in CMS were palmitic acid (C16:0) (31.63 to 37.29%), oleic acid (25.33 to 30.14%), stearic acid (C18:0) (7.10 to 10.31%), linoleic acid (C18:2n-6) (8.19 to 14.46%), palmitoleic acid (C16:1) (31.63 to 37.29%) and margaric acid (C17: 0) (1.14 to 2.27%). The low commercial weight tilapia CMS showed satisfactory yield in all weight classes and physical-chemical quality, with compliance with permitted standards, after 90 days of storage.