Kojima N, Wallace D, Bates G W
Am J Clin Nutr. 1981 Jul;34(7):1392-401. doi: 10.1093/ajcn/34.7.1392.
The solubilization of iron from cooked pinto beans was examined using an improved in vitro methodology. The iron content of the beans was found to exist in three populations: 1) that which is spontaneously soluble upon incubation; 2) that which can be mobilized by chelating or reducing agents; and 3) that which is more firmly bound to the insoluble bean residue. These fractions constitute approximately 25, 45, and 30%, respectively, of the bean iron content when using consecutive 30-min incubations at pH 2 and 6. Ascorbic acid is maximally effective in iron mobilization under acidic conditions and acts via iron reduction. Citric acid is maximally effective near pH 6. The combination of ascorbic acid and citric acid leads to the solubilization of 70% of the iron content of the beans. Orange juice also leads to maximal soluble iron, predominantly in the Fe2+ state. Tea severely decreases iron solubility in the system. Only 3% of the iron content of spinach is solubilized by 10 mM ascorbic acid. Whole spinach suspension and the insoluble spinach residue are able to remove iron from solution that was previously solubilized from beans.
采用一种改进的体外方法研究了熟斑豆中铁的溶解情况。发现豆类中的铁含量存在于三个部分：1）孵育时自发溶解的部分；2）可被螯合剂或还原剂动员的部分；3）与不溶性豆残渣结合更紧密的部分。当在pH值为2和6的条件下连续孵育30分钟时，这些部分分别约占豆类铁含量的25%、45%和30%。在酸性条件下，抗坏血酸在铁动员方面效果最佳，其作用方式是铁还原。柠檬酸在pH值接近6时效果最佳。抗坏血酸和柠檬酸的组合可使豆类中铁含量的70%溶解。橙汁也能使最大量的铁溶解，主要以Fe2+状态存在。茶会严重降低体系中铁的溶解度。10 mM抗坏血酸只能溶解菠菜中铁含量的3%。完整的菠菜悬浮液和不溶性菠菜残渣能够从先前从豆类中溶解出来的溶液中去除铁。
