Content of phytic acid and HCl-extractability of calcium, phosphorus and iron as affected by various domestic processing and cooking methods

ICPL-87, the high yielding cultivar of pigeon pea (Cajanus cajan) released by ICRISAT (International Crop Research Institute for Semi-Arid Tropics), India was subjected to various domestic processing and cooking methods, i.e. soaking (6, 12, 18 h, 30degreesC), soaking (12 h) and dehulling, ordinary as well as pressure cooking and germination (24, 36 and 48 h, 30degreesC). The unprocessed seeds of this variety contained considerable amounts of phytic acid, (857 mg per 100 g). This was reduced significantly (P<0.05) by 628%, 30%, 4-32%, 4-36%, 35-45% in soaked, soaked-dehulled, ordinary as well as pressure cooked and germinated seeds, respectively. Except for soaking and dehulling, the remaining processing and cooking methods did not lower the contents of total calcium, phosphorus and iron. HCl-extractability of these dietary essential minerals, an index of their bioavailability, was enhanced significantly when the pigeon pea seeds were processed and cooked, possibly due to reduction in phytate content, which is known to chelate the minerals. A significant and negative correlation between the phytic acid and HO-extractability of minerals further strengthens these findings. (C) 2002 Elsevier Science Ltd. All rights reserved.