Efeito da idade e do período de despesca do pirarucu (Arapaima gigas) na caracterização físico-química da carne e desenvolvimento de mantas salgadas e secas

Abstract

Known as the pirarucu in Brazil and paiche in Peru, Arapaima gigas is one of the world’s largest freshwater fish. This species provides excellent industrial yields and has mild-flavored meat, light coloring, soft textures, a boneless fillet, traditionally sold in the domestic market as a dry salted product, and usually portrayed as the “Brazilian cod.” Several factors, directly and indirectly, influence the chemical composition of fish, including intrinsic determinants such as genetics, morphology, physiology, age, body weight, and extrinsic factors including climatic factors, food, production water quality, among others. Given the above, this study aimed to characterize the raw materials of the pirarucu blanket in different-aged animals given climatic variation (rainy and dry periods) and develop salting technology to suggest a protocol that complies with Brazilian legislation. For this, four harvests were carried out in two excavated tanks, obtaining five specimens per harvest per tank, with the animals being 18-, 24-, 25-, and 30-months old. The animals were slaughtered and processed in a local slaughterhouse, and the blankets were characterized according to their biometric indices, proximate composition, caloric value, instrumental color, fatty acid profile, lipid nutritional quality indices, freshness via total volatile nitrogen bases, pH in 24 h, water activity, water retention capacity, drip loss, cooking loss, and shear force. Collagen was quantitatively determined in the pirarucu skin, muscles, and scales, and dry salt blankets were developed only once and under refrigeration using 24-month-old specimens in a composite rotational design with two independent variables (salt concentration and salting time) in fourteen trials whose dependent variables were moisture, ash, water activity, and sodium chloride. There was a statistically significant difference in head weight, average daily gain, blanket compactness index, proximate composition, caloric value, total volatile nitrogen bases, shear force, pH in 24 h, water activity, and collagen in the pirarucu skin. It was found that the younger the fish, the better the Kleiber index and the worse the total length and its correlation with the other indices; both the age and weight of the animal influenced the proximate composition and physicochemical characterization, while the fatty acid profile only correlated with age. It is concluded, therefore, that the particularity of the studied region, where there is no significant variation in temperature and there is only a change in rainfall that directly interferes in the quality of the breeding water, such as the difference in age and weight of the evaluated animals, all influenced, even if in varying degrees, the analyzes and indices carried out showing that it is possible to determine a raw material that expresses the best that a species can produce. In this sense, it was possible to determine the best protocol for the creation and processing of pirarucu aiming both an increase in fish farming of this species and also to meet an increasingly demanding and globalized consumer market. Therefore, it is suggested to carry out the dry salting in a period of 24 h with 21.6% of coarse salt, which complies with Brazilian legislation.