Proximate Composition of Raw and Cooked Thai Freshwater and Marine Fish

Proximate composition and non-protein nitrogen (NPN) were determined in eight freshwater and eight marine fish species which are commonly consumed in Thailand. Appropriate household cooking methods, i.e., boiling, steaming, roasting and frying were used for fish preparation. All fresh fish investigated were high in protein, 17–22 g/100 g. Wide variation in protein content, 16–32 g/100 g, between species and methods of cooking was observed. On average, a serving of cooked fish (1/2 cup, 80 g) provided 16 g protein, amounting to 33% of Thai Recommended Daily Intake (Thai RDI). Fish, in general, contained NPN at the level of less than 15% of total nitrogen, except 22% in raw, salted and sun-dried snake skin gourami. Fat content varied between species; freshwater fish, 0·6–14 g/100 g and marine fish, 0·5–9·2 g/100 g. Comparatively, marine fish varieties had lower fat content than freshwater fish. Boiling and steaming did not alter the percentage fat of the cooked fish, 0·5–15·5 g/100 g, while roasting and frying showed a relative increase in fat values of the cooked products, 7–23 g/100 g. On average, a serving of fried fish provided 7–18 g of fat which equals 11–28% of Thai RDI.