Buchheim W, Welsch U, Huston G E, Patton S
Institute for Chemistry and Physics, Federal Dairy Research Center, Kiel, Federal Republic of Germany.
Pediatrics. 1988 Jan;81(1):141-6.
Freeze-etch electron microscopy was applied to milk fat globules to observe surface details. A remarkable array of filaments, approximately 0.5 micron in length, was seen on human, but not bovine, globules. Heating human globules removed the filaments that were identified as high molecular weight glycoproteins by freeze-etch and gel electrophoretic analysis of the heating medium. Extraction of these globule glycoproteins was slight at 60 degrees C for one minute but substantial and tending to plateau at 80 degrees C for one minute. Such heat-induced alterations of the milk fat globule surface provide an alternative or additional explanation to milk lipase inactivation as the cause of reduced milk fat absorption from heated milk by the preterm infant.
冷冻蚀刻电子显微镜被应用于乳脂肪球以观察其表面细节。在人乳脂肪球上可见一系列显著的细丝，长度约为0.5微米，而在牛乳脂肪球上则未观察到。加热人乳脂肪球会去除这些细丝，通过对加热介质进行冷冻蚀刻和凝胶电泳分析，这些细丝被鉴定为高分子量糖蛋白。在60℃下加热一分钟，这些乳脂肪球糖蛋白的提取量较少，但在80℃下加热一分钟，提取量很大且趋于平稳。乳脂肪球表面的这种热诱导变化为早产儿从加热牛奶中吸收乳脂肪减少的原因提供了另一种或额外的解释，即乳脂肪酶失活。
