Effect of different cooking methods on total fat and fatty acid composition of Cape Snoek (Thyrsites atun)

Abstract

Cape snoek (Thyrsites atun) is a valuable commercial marine fish species and an important source of protein and long chain omega-3 polyunsaturated fatty acids (LCn-3PUFA), especially among the lower-income population of South Africa. The influence of microwave cooking, oven baking and steaming on total fat and fatty acid composition of Cape snoek was investigated. All cooking methods resulted in an increase of the total fat content when compared to the raw (3.88% ± 0.73) snoek samples. Microwave cooking and steaming resulted in the total fat content of samples to increase to 5.09% ± 0.69, and 5.61% ± 0.97, respectively. Oven baking resulted in the highest increase in total fat (6.66% ± 0.41). Although steaming and oven baking resulted in a marginal reduction in ecosapentaenoic acid (EPA), docosahexaenoic acid (DHA), and alpha-linolenic acid (ALA), respectively, none of the cooking methods had any significant (P > 0.05) effect on the EPA, DHA, and ALA concentrations. None of the cooking methods had any significant effect on the n-6:n-3 ratio (0.12 ± 0.01 for raw snoek samples). There was no significant change in the saturated fatty acid (SFA) concentration between raw and any of the samples from the three cooking methods. Only microwave cooking resulted in a significant increase in the monounsaturated fatty acid (MUFA) concentration, while steaming significantly reduced the PUFA concentration and the PUFA/SFA ratio. Microwave cooking, followed by oven baking, seemed to be the better of the three cooking methods for preservation of PUFA.