Cousins R J, Smith K T
Am J Clin Nutr. 1980 May;33(5):1083-7. doi: 10.1093/ajcn/33.5.1083.
The total zinc content of samples of fat-free human and bovine milk was 3.5 and 3.6 micrograms/ml, respectively. The total protein content was 5.3 and 29.0 mg/ml, respectively, Sephadex G-75 gel filtration chromatography of bovine milk revealed no evidence of zinc associated with low molecular weight fractions (less than 2000 daltons). However, chromatography revealed that 10% of the zinc in human milk was associated with these fractions. When the zinc content of these milks was raised by adding Zn2+ in vitro, chromatography of milk from both species revealed the presence of zinc with the low molecular weight fractions. More zinc was associated with these fractions from human milk than from bovine milk. Recovery of zinc was nearly 100% for all columns. It is proposed, based upon these binding data, that the association of zinc with low molecular weight components of milk is related in part to both protein content and composition and the relative zinc concentrations. These binding differences might influence the bioavailability of zinc from milk.
无脂人乳和牛乳样本中的总锌含量分别为3.5微克/毫升和3.6微克/毫升。总蛋白质含量分别为5.3毫克/毫升和29.0毫克/毫升。对牛乳进行葡聚糖G - 75凝胶过滤色谱分析，未发现锌与低分子量组分（小于2000道尔顿）相关。然而，色谱分析显示人乳中10%的锌与这些组分相关。当通过体外添加Zn2+提高这些牛奶的锌含量时，两种牛奶的色谱分析均显示存在与低分子量组分相关的锌。与人乳相比，牛乳中与这些组分相关的锌更多。所有色谱柱的锌回收率接近100%。基于这些结合数据，有人提出，锌与牛奶低分子量成分的结合部分与蛋白质含量、组成以及相对锌浓度有关。这些结合差异可能会影响牛奶中锌的生物利用度。
