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

Abstract

RESUMONo presente trabalho foi avaliado o efeito de métodos de cocção na composição química, teor de colesterol e totais de ácidos graxos de filés de Tilápias do Nilo. Os tratamentos foram cozimento em água (CA), fritura em óleo de soja (FO), assado em forno elétrico (FE), assado em forno microondas (MO), e um grupo testemunha (filés crus). O delineamento foi inteiramente casualizado, cada tratamento com 7 peixes e a unidade experimental foi um peixe (2 filés -1 para CA, FE, FO e MO, respectivamente) com relação aos crus (33,00 mg/100g). Os filés FO (P<0,05) apresentaram menores totais de ácidos graxos saturados e monoinsaturados e mostraram maior percentual de ácidos graxos poliinsaturados, quando comparados aos demais grupos. O cozimento aumenta a matéria seca, resultado da perda de água dos filés e aumento na concentração dos demais constituintes. O tratamento frito em óleo causa uma incorporação do meio (óleo de fritura) aos filés e aumenta os lipídeos totais, alterando o perfil de ácidos graxos dos filés de peixes fritos.Termos para indexação: Peixe, ácidos graxos, colesterol. ABSTRACTIn 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.

Effect of cooking with interesterified margarine in the chemical composition of fish

“…The process of cooking with interesterified margarine resulted in a significant reduction (p < 0.05) in the moisture content of the raw material in natura. Ferreira et al (2007) also reported a reduction in moisture content in fillets of Nile Tilapia (Oreochromis niloticus) after cooking in water (76.73%), frying in soybean oil (66.56%), roasting in an electric oven (74.56%) and roasted in a microwave oven (68.07%), compared to fresh (79.39%).…”

“…This was due to interesterified margarine having a high amount of this acid and consequently by its incorporation during cooking. The levels of docosahexaenoic and arachidonic polyunsaturated fatty acids were significantly reduced (p < 0.05) after steaming with interesterified margarine, showing that there was destruction by oxidation or elution to the medium (Ferreira et al, 2007).…”

Chemical composition and lipids classes of the freshwater fish tilapia do Nilo,Oreochomis niloticus

“…precocity, diet, and especially by its wide acceptance by the population (SOUZA et al, 2001, MENEZES, 2006. and(MEURER et al, 2002 andFERREIRA, 2007)…”

Reflexos da utilização de farelo de coco sobre o valor nutricional do filé de tilápia-do-nilo (Oreochromis niloticus Linnaeus, 1857)

“…Os resultados encontrados são superiores (variando de 91,06 a 162 mg.100 g -1 ) àqueles relatados por Ferreira et al (2007), que encontraram o teor de colesterol de 33 mg.100 g -1 para o filé de tilápia-do-nilo in natura criada em tanque de terra e alimentada com ração comercial. Visentainer et al (2005) observaram que o teor de colesterol encontrado em filé de tilápia submetida a diferentes níveis de óleo de linhaça na ração apresentou variação de 58,3 a 75,5mg.100 g -1 de tecido muscular.…”