Revestimento para filé de peixe submetido à fritura utilizando hidrocoloides reforçados com alfa-tocoferol e micropartículas de casca de ovo

Abstract

Fish consumption is recommended for human health, as it is a very nutritious food that can contribute to the preservation of cardiovascular diseases. The Nile tilapia is among the most produced and consumed fish worldwide, because, in addition to the characteristics of easy cultivation and good adaptation to environmental conditions, it is a tasty food and low cost compared to other species of fish. Many methods of preparation can be used, one of them is frying, this can interfere with the benefits making the food harmful to health, due to the absorption of oil in fish during preparation, and frying is the method most used by consumers. Therefore, alternatives have been sought for the reduction of oil absorbed by foods subjected to frying, such as the use of coatings before the preparation process. Coatings can reduce the migration of oils to food, serving as a barrier to lipid absorption during frying. Soy protein isolate and pectin coatings have been used for application in deep-fried foods; eggshell powder is promising for food fortification. Therefore, the use of coatings has been studied. This study aimed to develop polymeric coatings and characterize them for application in tilapia fillets submitted to frying, as an alternative to reduce the migration of oil in the fillets during the frying process. Soybean protein isolate (SPI) and pectin (PEC) coatings were developed with the addition of α-tocopherol acetate (α-TOC) and eggshell powder (PCO), and referred to as control (SPI+PEC), (SPI+PEC/PCO/α+PEC), (PCO+SPI); by the casting method blends were made for characterization. The experiment was divided into two stages. In the first, the characterization of the blends and analyzed color, thickness, antioxidant activity (DPPH), rate of water vapor permeability (TPVA), moisture and solubility, thermogravimetric analysis (TGA), infrared spectroscopy with Fourier transform (FTIR) and scanning electron microscopy (SEM). Subsequently, in the second stage, the application of the coatings by immersion in Nile tilapia fillets and then subjected to frying. Analyzes of lipid content, fatty acids, lipid oxidation, moisture and, finally, statistical analyzes were performed. The results showed that the blends with the addition of eggshell powder and α-tocopherol presented lower value for TPVA, and the blends SPI + PEC/ ESP obtained the lowest permeability, that is, the addition of these materials provided a barrier to water vapor in SPI+PEC blends. In TGA it was possible to observe that ESP reduced mass loss and thermal degradation of the blends. In the second stage, as results of the application, it was possible to observe that coatings that had lower TPVA reduced the moisture losses of the fillets to the oil during frying. The coatings acted as a barrier in the migration of oil in the fillets during frying, reducing the lipid content in the coated fillets. These results suggest that the coatings have potential for application in foods subject to frying.