Effects of cooking methods on the proximate composition and mineral contents of rainbow trout (Oncorhynchus mykiss)

The effects of different cooking methods (frying, boiling, baking, grilling, microwave cooking) on proximate composition and mineral contents of rainbow trout (Oncorhynchus mykiss Walbaum 1792) were determined. Mean moisture, protein, ash and fat contents of raw fish were 73.38 +/- 0.015, 19.8 +/- 0.035, 1.35 +/- 0.012 and 3.44 +/- 0.013%, respectively. The changes in dry matter, protein and ash contents were found to be significant for all cooking methods. The increase in fat content of fried samples was found to be significant but not those samples cooked by other methods. The Mg, P, Zn and Mn contents of fish cooked by almost all methods significantly decreased. The Na and K contents in microwave cooked samples increased, the Cu content increased in fried samples. Losses of mineral content in boiled fish were higher than those of fish cooked by other methods. On comparing the raw and cooked fish, the results indicated that cooking had considerable affect on the proximate composition and mineral contents. Baking and grilling were found to be the best cooking methods for healthy eating. (C) 2003 Elsevier Ltd. All rights reserved.