Efeito dos métodos de cocção sobre a composição química e perfil lipídico de filés de Tilápia do Nilo (Oreochromis niloticus Linnaeus 1757)

Abstract

In this work, the effects of different cooking methods of Nile tilapia fillets on their chemical composition, cholesterol content and total fatty acids, were studied. Cooking methods evaluated were water boiling (WB), frying in soybean oil (SO), broiling in an electric oven (EO), cooking in a microwave oven (MO) and a control group (raw fillets). The experiment was conducted as a completely randomized design, with the fish (two fillets/fish) considered as the experimental unit, and seven experimental units were used per treatment. Dry matter increased (P<0.05) in cooked fillets (23.27 % WB, 25.44 % EO, 31.93 % MO and 33.44 % SO) when compared with raw fillets (20.61 %). Total lipids were higher (P<0.05) in SO fillets (17.36 %), than in all the other treatments (6.94 % WB, 9.80 % EO, 8.66 % MO and 5.92 % raw fillets). All cooking methods increased (P<0.05) cholesterol content of the fillets (46.89 mg/100g WB, 46.46 mg/100g EO, 54.78 mg/100g SO and 57.28 mg 100g-1 MO) when compared with raw fillets (33.00 mg/100 g). Relative to all the other treatments, FO fillets had (P<0.05) lower values for saturated and monounsaturated fatty acids, and a higher percentage of polyunsaturated fatty acids. Overall, water boiling results in an increase in dry matter due to water loss in the cooking process, with higher concentration of the remaining constituents. Cooking by oil frying leads to the incorporation of oil in the fillets, with an increase in total lipids and a change of the fatty acid profile in fried fish.