The concentrations of iron, calcium, zinc and phytate in cereals and legumes habitually consumed by infants living in East Lombok, Indonesia

Abstract

There is a paucity of analysed data on contents of minerals and phytate in Asian complementary foods. Thus, cereals and legumes ( n=27) consumed by Indonesian infants were analysed for iron, zinc and calcium using flame Atomic Absorption Spectrophotometry and for phytate using high performance liquid chromatography (HPLC). Results (per 100 g dry weight) showed unfortified cereals had lower concentrations of zinc (1.5–3.2 mg/100 g vs. 3.2–5.8 mg/100 g), iron (0.3–5.4 mg/100 g vs. 2.9–17.4 mg/100 g), calcium (5–48 mg/100 g vs. 41–926 mg/100 g) and phytate (hexa- and penta-inositol phosphates; 70–246 mg/100 g vs. 177–1042 mg/100 g) than legumes and lower phytate: mineral molar ratios. Tempe had the lowest concentration of phytate (236–366 mg/100 g vs. 763–1042 mg/100 g), and the lowest molar ratios of phytate: zinc (6.3–12.6 vs. 14.3–21.1) and phytate: iron (1.6–4.0 vs. 5.0–11.3) compared to other soybean products. Milling increased concentrations of iron and calcium in rice (1.2 vs. 0.4 mg/100 g, p=0.002; and 8.1 vs. 5.1 mg/100 g, p=0.029, respectively); but reduced zinc (1.6 vs. 1.7 mg/100 g, p=0.013). Boiling increased calcium concentrations in rice and rice flour (5.1–16.7 mg/100 g, p=0.004; and 8.1–31.4 mg/100 g, p<0.001, respectively); whereas frying decreased iron concentrations in tempe (13.3–6.1 mg/100 g, p=0.038). When expressed per infant portions, fortified cereals and tempe were the best sources of zinc, iron, and calcium, because of their relatively high mineral and low phytate contents.