Udayasekhara Rao P, Deosthale Y G
National Institute of Nutrition, Indian Council of Medical Research, Hyderabad.
Plant Foods Hum Nutr. 1988;38(1):35-41. doi: 10.1007/BF01092308.
White and brown ragi (Eleusine coracana) varieties were analysed for tannin, phytate phosphorus, total phosphorus, iron, ionisable iron, zinc and soluble zinc content. White ragi had no detectable tannin while in brown varieties it ranged from 351 to 2392 mg per 100 g. Germination brought about a progressive decrease in tannin and phytate phosphorus and an increase in ionisable iron and soluble zinc content of grain ragi. Both in raw and germinated grain, ionizable iron was significantly higher in white than in brown varieties. While ionisable iron was inversely correlated with the level of tannin and phytate phosphorus, soluble zinc was negatively correlated with phytate phosphorus. After extraction of tannin, ionisable iron of brown ragi rose by 85%. On the other hand, in white varieties, addition of tannin extracted from brown ragi, resulted in a 52-65% decrease in ionisable iron content. These studies indicated that poor iron availability in ragi as judged by its low ionisable iron content was due to the presence of tannin in the grain.
对白色和棕色龙爪稷（龙爪稷）品种的单宁、植酸磷、总磷、铁、可离子化铁、锌和可溶性锌含量进行了分析。白色龙爪稷未检测到单宁，而棕色品种中每100克单宁含量在351至2392毫克之间。发芽使龙爪稷籽粒的单宁和植酸磷含量逐渐降低，可离子化铁和可溶性锌含量增加。无论是未发芽还是发芽的籽粒，白色品种中的可离子化铁含量均显著高于棕色品种。可离子化铁与单宁和植酸磷水平呈负相关，而可溶性锌与植酸磷呈负相关。提取单宁后，棕色龙爪稷的可离子化铁含量提高了85%。另一方面，在白色品种中，添加从棕色龙爪稷中提取的单宁后，可离子化铁含量降低了52%至65%。这些研究表明，根据其低可离子化铁含量判断，龙爪稷中铁的利用率低是由于籽粒中存在单宁。
