© All Rights Reserved *Corresponding author. Email: hasnah@fsk.ukm.my Tel: (603) 9289 7511; Fax: (603) 2694 7621 International Food Research Journal 20(5): 2873-2880 (2013) Journal homepage: http://www.ifrj.upm.edu.my Shimi, G. and * Hasnah, H. Nutritional Science Programme, School of HealthCare, Faculty of Health Sciences, Universiti Kebangsaan Malaysia, Jalan Raja Muda Abdul Aziz, 50300 Kuala Lumpur, Malaysia Does cooking affect the phytate content in local soy based dishes? Abstract This study aimed to determine the effect of cooking on phytate content and the inhibitory effects of phytate on the bioavailability of minerals in eight Malaysian soy based dishes. Phytate was analyzed by using anion-exchange chromatography while minerals were analyzed by using Atomic Absorption Spectrophotometer. Molar ratios were obtained by dividing the mole of phytate to minerals. Phytate content was reduced in cooked dishes compared to the raw ones but it was not significantly different (P > 0.05). Raw, cooked and whole dish soy products contained 257.14-900.00, 182.14-803.57 and 289.29-910.71 mg/100 g phytate, respectively. Boiling and steaming have reduced most phytate content in the food samples. Molar ratios for phytate/minerals in these samples (phytate/Ca >0.17; phytate/Fe >1) indicated that phytate content inhibited the absorption of calcium and iron. However, the ratio for Ca × phytate/Zn in all samples was less than 200 which showed that phytate did not affect the bioavailability of zinc. Introduction The emergence of interest in healthier nutrition in the recent years has given a greater trend towards the use of plant food products with multiple functional properties. Soybean (Glycine max) is an ancient legume which is traditionally used to make both fermented and non-fermented foods. It is the staple food for the Asian populations (Omoni and Aluko, 2005). Nowadays, soybean products have attracted a lot of interest due to their health benefits to nutrition and health (Paucar-Menacho et al., 2010). On an average, Asians consume 20 to 80 g of soy foods daily which consisted of tofu, miso and tempeh (Omoni and Aluko, 2005). The Food Consumption Statistics for Malaysia (2006) reported that tempeh and bean curd intakes among the Malaysian population were 6.91 g/ day and 19.40 g/day, respectively. This showed that Malaysians do consume soy products in their daily intake. Many studies have highlighted the importance of the nutritional values in soy products. Soy bean and its by-products are excellent sources of nutritionally basic macro- and micro-minerals, even though their availability may be seriously compromised by the presence of phytic acid, polyphenols and oxalate or the particular structure of soybean proteins (Giami, 2002; Karr-Lilienthal et al., 2004; Rani et al., 2008). Soy beans are different from other legumes in terms of higher in fat and protein but lower carbohydrate contents (Messina and Messina, 2010). On the average, dry soy bean contains about 40% protein, 20% oil, 35% soluble and insoluble dietary fiber and 5% ash (Jooyandeh, 2011). Phytate (InsP6) is a compound that exists in plant food like legumes, cereals, nuts, oil seeds. It has both beneficial and detrimental effects on human health (Horner et al., 2005). Phytic acid has long been considered as an anti-nutrient due to its ability to complex with several metal ions such as iron, zinc, and calcium, thus reducing their bioavailability (Horner et al., 2005; Mejborn and Tetens, 2011). Therefore, many food processing and preparation techniques are the main efforts made to decrease the amount of phytate in foods (Egli et al., 2002). Apparently, the cause of mineral deficiency in Malaysia was due to its low bioavailability in the diet. Phytate was one of the factors that affect the bioavailability. The incidence of anemia due to deficiency of iron was nearly one million cases (969,645); osteoporosis as a result of calcium deficiency is 2,421,432 cases while data on Zn status in Malaysia is not available (Norhaizan and Nor Faizadatul, 2009). The intake of phytate in Malaysia is not available due to the lack of database on phytate content in local food. Although the phytate content in other Asian foods might be available, some factors such as differences in cooking methods, food processing techniques and the variety of food consumed by Malaysians compared to other countries may attribute to the unsuitability of data being used to assess the phytate intake of Malaysians. Therefore, this study Keywords Phytate Calcium Iron Zinc Molar ratio Article history Received: 27 January 2013 Received in revised form: 10 April 2013 Accepted: 12 April 2013