Functionality of Bovive Milk Fat Globule Membrane

我们研究了牛乳脂肪球膜（MFGM）的功能，特别参考了1)MFGM对乳脂球（MFG）的乳化能力，2)MFGM加速肠道对核黄素（RF）的吸收，3)抑制牛奶中脂蛋白脂肪酶（LPL）引起的脂肪分解。1)将25%乳脂和1% MFGM均质于0.01M磷酸盐缓冲液（pH 7.0）中，在19 k rpm和45^0℃下均质1 min，重组MFG乳状液。乳脂含量为25%、MFGM含量为1%、pH值为中性、MFGM添加量增加时乳化剂乳化性能最佳。影响乳清再造的主要因素是乳化时间、MFGM和乳脂含量，以及pH。粘度在pH 5.0和乳化时间4 min时最高，并随着MFGM含量的增加而增加。MFG吸附的MFGM蛋白组成不受主要变量的影响。然而，在酸性pH下，随着MFGM用量的增加，吸附蛋白的量增加。在剥夺RF 4周后，与自由RF相比，谷胱甘肽还原酶活性比（EGRAR, +FAD/-FAD）为3.5，核黄素结合的MFGM（3杯/g日粮）被给予比表面积为15.6 m^2/m^3.2的RF缺乏大鼠。RF饲喂后，第5周EGRAR恢复到1.6 ~ 1.9，体重增加。第5周第1周体重增重：mfgf - rf喂养组50.2<正负>3.8 g，自由rf喂养组40.4<正负>3.9 g，配对喂养组33.1<正负>5.4 g。3组间差异有统计学意义（P< 0.01）。MFGM似乎加速了大鼠肠道对RF的吸收。乳清乳清中分离出与乳清乳清中可溶性糖蛋白（SGP）具有相同免疫功能的乳酸蛋白（LP）。在200 W下超声处理2 min的鲜牛乳中添加LP，可抑制乳源LPL诱导的脂肪分解。在40 mg蛋白质/ml牛奶中，LP的抑制率约为62-67%，而富含LP成分-3的蛋白酶-蛋白胨部分的抑制率为30-43%。LP和SGP似乎通过高度补充MFG表面的能力来抑制LPL的溶脂作用。少

We studied on the functionality of bovine milk fat globule membrane (MFGM) with special reference to 1) the emusifying ability of MFGM in milk fat globules (MFG), 2) the acceleration of intestinal absorption of riboflavin (RF) by MFGM and 3) inhibition of lipolysis due to lipoprotein lipase (LPL) in milk.1) MFG emulsions were reconstituted by homogenizing 25% milk fat and 1% MFGM in 0.01M phosphate buffer (pH 7.0) for 1 min at 19 k rpm and at 45^0C. Maximal emulsifying properties were attained at 25% milk fat, 1% MFGM, neutral pH and the increased amount of MFGM. The major variables influencing the reconstitution of MFG were emulsifying time, MFGM and milk fat contents, and pH. Viscosity was highest at pH 5.0 and at 4 min of emulsifying time, and increased with MFGM content. The composition of MFGM protein adsorbed on MFG was not affected by the major variables. However, the amount of adsorbed protein increased at acidic pH and with the increased amount of MFGM. Diameter of MFG was 0.9 … More -17.4mum and median diameter was 5.0mum and its specific surface area was 15.6 m^2/m^3.2) Riboflavin bound MFGM was administered (3mug/g of diet) TO RF-defficient rats in who glutathion reductase activity ration (EGRAR, +FAD/-FAD) was 3.5, in comparison with free RF, after RF deprivation for 4 weeks. After RF feeding, EGRAR recovered to 1.6-1.9 and body weights increased in the fifth weeks. Gain of body weights for 1 week in the fifth weeks was 50.2<plus-minus>3.8 g for MFGM-RF-fed group, 40.4<plus-minus>3.9 g for free RF-fed group, and 33.1<plus-minus>5.4 g for pair-fed group. Significant differences were found among 3 groups (P<0.0 1). MFGM seemed to accelerate the absorption of RF from the intestine of rats. The peptides from MFGM may act as a signal peptide for the acceleration of the incorporating RF from intestinal mem3) Lactophrin (LP), which is immunologically identical to the soluble glycoprotein (SGP) of MFGM, was isolated from milk whey. LP added in fresh bovine milk sonicated for 2 min at 200 W inhibited the lipolysis induced by milk indigeneus LPL. The ratio of inhibition was about 62-67% for LP and 30-43% for the LP- enriched component-3 fraction of proteose-peptone at 40 mg of protein/ml of milk over the control. LP and SGP seemed to be inhibited the lipolytic action of LPL by a high ability to replenish the surface of MFG. Less