Original article Effect of different precooking methods on chemical composition and lipid damage of silver carp (Hypophthalmichthys molitrix) muscle Mahmood Naseri, 1 Masoud Rezaei, 1 * Sohrab Moieni, 2 Hedayat Hosseni 3 & Soheil Eskandari 4 1 Department of Fisheries, Tarbiat Modares University, Noor, P.O. Box 46414-356, Mazandaran, Iran 2 Department of Food Science and Technology, School of Agriculture, Tehran University, Tehran, Iran 3 National Nutrition and Food Technology Research Institute, Shaheed Beheshti University, Tehran, Iran 4 Bureau of Food and Drug Laboratories, Tehran, Iran (Received 3 March 2010; Accepted in revised form 11 June 2010) Summary The influence of three precooking methods (steaming, oven-baking and microwave-cooking) on the chemical composition and lipid quality of silver carp fillets was evaluated. The changes in protein, fat and moisture were found to be significant for all the treatments (P £ 0.05). The iron content in the samples subjected to steam-cooking increased; however, the other precooking methods did not change the mineral contents (P ‡ 0.05). The free fatty acid content of the fillets did not change by the different precooking methods, while thiobarbituric acid (TBA) values increased for oven- and microwave-cooked fillets and remained constant in the steam-cooked samples. Conjugated diene and browning colour formation levels significantly increased in the oven-baked fillets. Oven-baking and microwave-cooking marginally affected the fatty acid composition of the silver carp. On comparing the raw and precooked fillets, steam-cooking was found to be the best precooking method on retaining nutritional constituents. Keywords Fatty acid composition, minerals, oxidation, precooking, proximate composition, silver carp. Introduction Seafood products have attracted considerable attention as a source of high amounts of important nutritional components to the human diet (Ackman, 1989). Seafo- ods have high protein content, low saturated fat and also contain vitamins and minerals. Mineral compo- nents such as magnesium, calcium, zinc, iron and phosphorus are essential for human nutrition (Erkan &O ¨ zden, 2007). However, in recent years, the fishing sector has suffered from dwindling stocks of traditional species as a result of dramatic changes in their availability. This has prompted fish technologists and the fish trade to pay more attention to aquaculture techniques as a source of fish and other seafood products (Aubourg, 2001). Silver carp (Hypophthalmichthys molitrix) is an extensively cultured species. Aquaculture production of silver carp is the highest of any finfish species in the world; especially important in the Asia-Pacific region that has an annual global production of nearly 4.2 million metric tons. (Gheyas et al., 2009). Accordingly, the consump- tion of value-added products of this species has recently increased. Assurance of both the quality and safety of seafood will be a major challenge faced by humans in this new century (Aubourg et al., 2005). In this sense, wild and farmed fish species are known to deteriorate after death because of the action of different factors that can be summarised as microbiological growth, endogenous enzyme activity, nonenzymatic lipid oxidation and browning. The relative incidence of each damage mech- anism will depend on the kind of technological process applied (Aubourg, 2001; Horner, 1997; Pigott & Tucker, 1987). Canning belongs to the most important means of fish preservation (Horner, 1997; Aitken & Connell, 1979). As with any other treatment, canning should be designed to retain as much as possible of all the nutritional constituents present in the initial matter to serve human nutrition (Aubourg, 2001). The extensive heat treatment involved in canning steps substantially alters the nature of the raw material so that, in effect, a product with different characteristics is formed. Precooking is a critical thermal process before retort- ing and designated to destroy pathogenic micro- organisms, endogenous enzymes, secure certain *Correspondent: Fax: +98 122 6253499; e-mail: rezai_ma@modares.ac.ir International Journal of Food Science and Technology 2010, 45, 1973–1979 1973 doi:10.1111/j.1365-2621.2010.02349.x Ó 2010 The Authors. International Journal of Food Science and Technology Ó 2010 Institute of Food Science and Technology