Lynch S R, Dassenko S A, Cook J D, Juillerat M A, Hurrell R F
University of Kansas Medical Center.
Am J Clin Nutr. 1994 Oct;60(4):567-72. doi: 10.1093/ajcn/60.4.567.
The inhibitory effect of soybean protein isolates on nonheme-iron absorption was studied in 34 human subjects. Iron absorption was measured by using an extrinsic radioiron label in liquid-formula meals containing hydrolyzed corn starch, corn oil, and either egg white or a series of soybean-protein derivatives. The unmodified soybean-protein isolate markedly inhibited iron absorption. Percentage absorption was 19-fold higher when an extensively enzyme-hydrolyzed preparation with very little phytate was used as the protein source. Both the glycinin (11S) and conglycinin (7S) fractions of soybean protein were inhibitory to iron absorption. Dephytinization removed the inhibitory effect of the glycinin but not of the conglycinin fraction. We conclude that there are two major inhibitors of iron absorption in soybean-protein isolates, phytic acid and a protein-related moiety contained in the conglycinin (7S) fraction.
在34名人体受试者中研究了大豆分离蛋白对非血红素铁吸收的抑制作用。通过在含有水解玉米淀粉、玉米油以及蛋清或一系列大豆蛋白衍生物的液体配方膳食中使用外源性放射性铁标记来测量铁吸收。未改性的大豆分离蛋白显著抑制铁吸收。当使用植酸盐含量极低的高度酶解制剂作为蛋白质来源时，铁的吸收百分比高出19倍。大豆蛋白的大豆球蛋白（11S）和伴大豆球蛋白（7S）组分均抑制铁吸收。脱植酸作用消除了大豆球蛋白的抑制作用，但未消除伴大豆球蛋白组分的抑制作用。我们得出结论，大豆分离蛋白中有两种主要的铁吸收抑制剂，即植酸和伴大豆球蛋白（7S）组分中含有的一种与蛋白质相关的部分。
