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标题：Effects of pH Variation and NaCl on In Vitro Digestibility of Cow's Milk Proteins in Commercially Available Infant Formulas
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作者：Kentaro SAKAI ; Kenji YOSHINO ; Mohammed A. SATTER 等
期刊名称：Journal of Nutritional Science and Vitaminology
印刷版ISSN：0301-4800
电子版ISSN：1881-7742
出版年度：2000
卷号：46
期号：6
页码：325-328
DOI：10.3177/jnsv.46.325
出版社：Center for Academic Publications Japan
摘要：Allergenicity and antigenicity of food proteins are generally dependent on their heat-stability and resistance to digestive enzymes. Using the methods of SDS-PAGE and immunoblots, we assessed peptic-digestibility of major milk proteins (casein, β-lactoglobulin and α-lactalbumin) in commercially available infant formulas in acidic pH range (pH 1.5 to 4.0), and we also investigated the effect of NaCI on peptic-digestibility of cow's milk proteins at pH 2.0. The profile of peptic-digestion of casein was similar at pH range from 1.5 to 3.5 where the intact protein of casein rapidly disappeared, whereas slow digestibility of the pro-tein was found at pH 4.0. β-Lactoglobulin and α-lactalbumin were digested at pH range from 1.5 to 2.5 and were almost entirely resistant to peptic digestion at over pH 3.0. In the presence of NaC1 at pH 2.0, casein showed a good digestibility by pepsin similar to that in the absence of NaCl, in contrast to β-lactoglobulin and a-lactalbumin both having their peptic-digestibility decreased in the presence of 0.2M NaCl. As the state of the stomach in new born infants shows low amounts of secretary pepsin and out of optimum pH of peptic activity, low digestibility of β-lactoglobulin and α-lactalbumin in cow's milk based infant formulas at over pH 3.0 is supposed to be responsible for their allergenicity.
关键词：infant formula;cow's milk;digestibility;pepsin