Effect of cooking methods on total and heme iron contents of anchovy (Engraulis encrasicholus) Sadettin Turhan * , N. Sule Ustun, T. Bogachan Altunkaynak Department of Food Engineering, Ondokuz Mayis University, 55139 Kurupelit, Samsun-Turkey Received 11 November 2003; received in revised form 8 January 2004; accepted 8 January 2004 Abstract The effects of cooking methods (electric oven, grill, microwave, and boiling) on total and heme iron contents of anchovy (Engraulis encrasicholus) were investigated. Effects of cooking methods on total and heme iron contents of anchovy were statistically significant (P < 0:05). The highest total and heme iron losses were found in grilled samples (52.6%, 70.4%), and the lowest were found in boiled samples (11.2%, 30.4%). Boiling was the most suitable method in terms of both total and heme iron contents of anchovy. Ó 2004 Elsevier Ltd. All rights reserved. Keywords: Total iron; Heme iron; Cooking methods; Anchovy 1. Introduction Seafoods, especially darker flesh fish, are reasonably good sources of iron, supplying 1–2 mg/100 g muscle (Kinsella, 1988). There are two types of dietary iron, based on different mechanisms of absorption: nonheme and heme. Heme iron is found only in meat, fish and poultry, while nonheme iron is found in all plant and animal products (Clark, Mahoney, & Carpenter, 1997; Kalpalathika, Clark, & Mahoney, 1991; Schricker, Miller, & Stouffer, 1982). The importance of meat iron depends on its heme iron content. Heme iron has a high bioavailability, ranging from 15% to 35% (Kalpalathika et al., 1991) and is not affected by other dietary con- stituents (Carpenter & Mahoney, 1992; Clark et al., 1997; Schricker et al., 1982). Nonheme iron, on the other hand, has a low bioavailability, ranging from 2% to 20% (Kalpalathika et al., 1991) and is influenced greatly by a variety of enhancing and inhibiting com- ponents in the diet (Carpenter & Mahoney, 1992; Clark et al., 1997; Schricker et al., 1982). However, cooking degrades the highly available heme iron into the less available nonheme iron (Buchowski, Mahoney, Car- penter, & Cornforth, 1988; Carpenter & Mahoney, 1992; Carpenter & Clark, 1995; Clark et al., 1997; Han et al., 1993; Jansuittivechakul, Mahoney, Cornforth, Hendricks, & Sisson, 1986; Kalpalathika et al., 1991; Schricker & Miller, 1983). Not much information is available on the degradation mechanism of heme iron, but it is suggested that increases in nonheme iron may be due to release of iron from heme iron complexes by ox- idative cleavage of the porphyrin ring (Buchowski et al., 1988; Schricker & Miller, 1983). Besides, its lower bio- availability, nonheme iron is of interest, because it acts as a catalyst for the rapid development of oxidized fla- vour in cooked meats (Chen, Pearson, Gray, Fooladi, & Ku, 1984; Igene, King, Pearson, & Gray, 1979). Some researchers (Buchowski et al., 1988; Carpenter & Clark, 1995; Gall, Otwell, Koburger, & Appledorf, 1983; Han et al., 1993; Kongkachuichai, Napatthalung, & Charoensiri, 2002; Lombardi-Boccia, Dominguez, & Aguzzi, 2002; Schricker & Miller, 1983) have studied the effects of heat on amounts of total and heme iron in meat. Gall et al. (1983) reported that cooking (baking, broiling, deep frying, microwaving) did not significantly affect the concentration of iron. According to Chen et al. (1984), both final temperature and rate of heating in- fluenced release of nonheme iron from meat pigment * Corresponding author: Tel: +90-362-4576020; fax: +90-362- 4576034. E-mail address: sturhan@omu.edu.tr (S. Turhan). 0308-8146/$ - see front matter Ó 2004 Elsevier Ltd. All rights reserved. doi:10.1016/j.foodchem.2004.01.026 Food Chemistry xxx (2004) xxx–xxx www.elsevier.com/locate/foodchem Food Chemistry ARTICLE IN PRESS