Effect of domestic processing and cooking methods on total, hcl extractable iron and in vitro availability of iron in spinach and amaranth leaves.

Abstract

Spinach (Spinacia oleracia) and amaranth (Amaranthus tricolor) leaves were stored in polyethylene bags and without packing for 24 and 48 hours in a refrigerator at 5 degrees C and 30 degrees C in polyethylene bags. The fresh leaves were also dried (oven and sun), blanched (5, 10 and 15 min) and cooked in an open pan and a pressure cooker. The processed leaves were analysed for total iron, its availability and antinutrient content. The iron content of these leaves varied from 26.54 to 34.14 mg/100 g, dry weight and its HCl-extractability and in vitro availability were 62.11-67.18% and 3.03-3.97% of total respectively. Drying and storage had no significant effect on total iron content, HCl-extractability and availability (in vitro), while blanching and cooking resulted in significant improvement of iron availability, and a significant reduction in oxalic acid content, while only blanching significantly reduced phytic acid and polyphenol contents. Thus cooking and blanching are good ways to improve HCl-extractability and in vitro availability of iron.