Department of Food and Nutrition, Matsuyama Shinonome Junior College, Kuwabara 3-2-1, Matsuyama 790-0853, Japan.
Br J Nutr. 2011 Jul;106(1):73-8. doi: 10.1017/S0007114510005842. Epub 2011 Apr 27.
In the present in vitro study, the effects of pH and ionic strength on the release of iron from pectin and the ability of pectin to reduce ferric iron to ferrous iron were examined. The bioavailability of Fe bound to pectin was evaluated in rats. The amount of Fe released from pectin was at a maximum at pH 2·0 and decreased as the pH value increased. At pH 2·0, the amount of Fe released from pectin increased as the ion length increased; at pH 5·0, ion length had no effect on pectin release. Pectin effectively reduced Fe from the ferric form to the ferrous form. In rats fed a pectin diet, where Fe bound to pectin was the only Fe source, the final Hb concentration using diets containing 4·4-5·7, 7·2 or 11·5 mg Fe/kg diet was equal to the concentration in rats fed diets containing 4·5, 7·6 or 13·5 mg ferrous iron/kg diet, respectively. Hb regeneration efficiencies in rats fed pectin diets were significantly different from rats fed a diet containing 13·5 mg ferrous iron/kg diet. In rats fed a diet with or without pectin, where ferric iron was the only Fe source, pectin increased the final Hb concentration. These results suggest that Fe bound to pectin is utilised by rats.
在本体外研究中，考察了 pH 值和离子强度对果胶中铁释放的影响，以及果胶将三价铁还原为二价铁的能力。评估了与果胶结合的 Fe 的生物利用度在大鼠体内的情况。在 pH 2·0 时，果胶释放的 Fe 量达到最大值，随着 pH 值的升高而降低。在 pH 2·0 时，随着离子长度的增加，果胶释放的 Fe 量增加；在 pH 5·0 时，离子长度对果胶释放没有影响。果胶能有效地将 Fe 从三价形式还原为二价形式。在给大鼠喂食果胶饮食的实验中，果胶结合的 Fe 是唯一的 Fe 来源，在 Fe 含量分别为 4·4-5·7、7·2 或 11·5 mg/kg 饮食的饮食中，最终 Hb 浓度与给大鼠喂食 Fe 含量分别为 4·5、7·6 或 13·5 mg/kg 饮食的饮食中 Hb 浓度相同。喂食果胶饮食的大鼠的 Hb 再生效率与喂食 13·5 mg/kg 饮食的大鼠有显著差异。在给大鼠喂食含或不含果胶的饮食中，当三价铁是唯一的 Fe 来源时，果胶增加了最终的 Hb 浓度。这些结果表明，大鼠利用了与果胶结合的 Fe。
