Preparation of calcium absorption-stimulating whey protein using Amino-carbonyl reaction

为了考察乳清蛋白与葡萄糖-6-磷酸（G6 P）之间Millard反应的最佳条件，将乳清蛋白和G6 P以不同重量比在pH 7.0下溶解，冷冻干燥，在50 ℃和65%相对湿度下孵育，并测量反应产物的布朗宁、蛋白质聚合、磷含量。以下条件是合适的：乳清蛋白与G6 P的比例为1：0.3 ;反应时间小于1天，因为蛋白质的棕色显色和聚合过快，并且孵育0.5或1天制备的乳清蛋白-G6 P缀合物的磷含量高于酪蛋白。使用大鼠检查WPI（乳清蛋白分离物）-G6 P缀合物对钙吸收的影响。大豆蛋白、酪蛋白和WPI-G6 P结合物饮食组的小肠结扎袢中可溶性钙的比例为43.2（± SD）。[)8.7，72.7（±）SY. [)8.0和77.7（]SY. [)9.7，分别。小肠中的可溶性钙在WPI-G6 P结合物饮食组中显著高于大豆蛋白饮食组。这表明WPI-G6 P缀合物溶解钙以防止磷酸钙在小肠中沉淀。大豆蛋白、酪蛋白和WPI-G6 P缀合物饮食组的钙吸收（其通过连接环中<@D145@>D1Ca的消失来估计）为50.7（± SY）。[）17.6，58.5（）SY. ±. [)8.3和72.6（]SY.（19.7）。WPI-G6 P结合物饮食组的钙吸收也高于大豆蛋白饮食组。这些结果表明WPI-G6 P缀合物可用作食品材料。

In order to examined the optimum conditions for the Millard reaction between whey protein and glucose-6-phosphate (G6P) were examined, whey protein and G6P were dissolved at various weight ratios at pH 7.0, freeze-dried, incubated at 50ﾟC and 65% relative humidity, and the browning, polymerization of proteins, the phosphorus content of reaction products were measured. The following conditions were appropriate : the ratio of whey protein to G6P,1 to 0.3 ; reaction time, less than 1 day, because brown color development and polymerization of protein exceed rapidly and the phosphorous content of whey protein-G6P conjugates prepared for 0.5 or 1 day of incubation was higher that of casein. The effect of the WPI (whey protein isolate) -G6P conjugate on calcium absorption was examined using rats. The proportions of soluble calcium in the ligated loop of the small intestine of the soy protein, casein, and WPI-G6P conjugate diet groups were 43.2(]SY.+-。[)8.7,72.7(]SY.+-。[)8.0, and 77.7(]SY.+-。[)9.7, respectively. The soluble calcium in the small intestine was significantly higher in the WPI-G6P conjugate diet group than in the soy protein diet group. This indicated that the WPI-G6P conjugate solubilizes calcium to prevent the precipitation of calcium phosphate in the small intestine. The calcium absorption, which was estimated by the disappearance of <@D145@>D1Ca in the ligated loop, of the soy protein, casein, and WPI-G6P conjugate diet groups was 50.7(]SY.+-。[)17.6,58.5(]SY.+-。[)8.3, and 72.6(]SY.+-。[)19.7, respectively. The calcium absorption was also higher in the WPI-G6P conjugate diet group than in the soy protein diet group. These results suggest that WPI-G6P conjugates are useful as food materials.