Janghorbani M, Weaver C M, Ting B T, Young V R
J Nutr. 1983 May;113(5):973-8. doi: 10.1093/jn/113.5.973.
Radiozinc (65Zn) was used to assess the efficiency of incorporation of the label into soybean seeds by means of a noncycling hydroponic system. It was found that 21.3 and 27.6% of the applied dose was incorporated into the mature seeds when the tracer was applied during vegetative or flowering stages of growth cycle, respectively. The latter method was adapted to labeling with the stable isotope 70Zn, and quantitative incorporation of this isotope was investigated within and among hydroponic culture pots each containing four plants. It was found that on the average 17.7% +/- 3.0% of the applied dose was recovered in the mature seeds harvested from each pot. The mass isotope enrichment ratio for 70Zn: 68Zn in these seeds was 2.93 +/- 0.38 (mean +/- SD) compared with the natural ratio of 0.0343, indicating a high degree of stable isotope enrichment. Results of soybean fractionation studies showed that the enrichment was somewhat higher in the defatted meal fraction as compared with the full-fat, the hull, and the whole seed, indicating somewhat preferential translocation of the applied stable isotope in the protein. Despite this small but observable difference, all fractions were highly enriched with 70Zn. The data from this study indicated that noncycling hydroponic culture may be effectively employed to intrinsically label soybeans with the stable isotopes of zinc for use in human feeding trials dealing with the issues of zinc availability. A 100-g portion of such labeled seeds provided 38-43 g protein and 490-620 micrograms 70Zn in various processed products for use in human feeding studies.
利用非循环水培系统，采用放射性锌（65Zn）来评估标记物掺入大豆种子的效率。结果发现，当在生长周期的营养期或开花期施加示踪剂时，分别有21.3%和27.6%的施用量被掺入成熟种子中。后一种方法适用于用稳定同位素70Zn进行标记，并研究了这种同位素在每个装有四株植物的水培花盆内和花盆间的定量掺入情况。结果发现，从每个花盆收获的成熟种子中，平均回收了17.7%±3.0%的施用量。与天然比值0.0343相比，这些种子中70Zn:68Zn的质量同位素富集比为2.93±0.38（平均值±标准差），表明稳定同位素高度富集。大豆分级研究结果表明，与全脂、种皮和整粒种子相比，脱脂粕部分的富集程度略高，这表明施用的稳定同位素在蛋白质中有一定的优先转运。尽管存在这种微小但可观察到的差异，但所有部分都高度富集了70Zn。本研究的数据表明，非循环水培可有效地用于用锌的稳定同位素对大豆进行内在标记，以用于涉及锌有效性问题的人体喂养试验。100克这种标记种子在各种加工产品中可提供38 - 43克蛋白质和490 - 620微克70Zn，用于人体喂养研究。
