母乳不要摇？？？！！！

Don't Shake the Milk
Linda J. Smith, BSE, FACCE, IBCLC
Why not?
Because shaking expressed mothers' milk (or boiling or freezing it) denatures the shaped molecules of the protective proteins, leaving only the pieces - the amino acids - the parts. Lactoferrin, lysozyme, and other protective components work their protection magic when they are in their original shaped molecular structure. Some components remain intact, even during freezing, shaking or heating. They not only protect the gut from many kinds of infection, but also prevent inflammation of the gut lining. Even broken up, the separate amino acids are still really good stuff and are digested by the baby as nutrients.
Imagine a set of pop-beads assembled into a necklace or bracelet. When the beads are acting as a bracelet or necklace, they are doing their job as protective elements. When you break apart the beads, you have in your hand many individual chunks of amino acids which are then digested. Cellular components are also susceptible to damage by physical stress. After all, they are living cells. With mother's milk, you get at least two functions for the price of one. With manufactured formula, you only get the individual beads, never the necklace or bracelet. And never the living cells. So, please handle human milk gently, respectfully and kindly. It's far more than perfect food for babies - it's a living tissue and protective shield too.
? 1998 Linda J. Smith, BSE, FACCE, IBCLC
原文在这里：
http://www.bflrc.com/ljs/breastfeeding/shakenot.htm

当然网上还有些不同观点。我过去没有想到这问题，现在仔细想想。。。原因可能是偶初中化学学得太好了，已经养成了摇匀的好习惯而不是shake。美国人说shake的意思是真的shake。如果你想像一下一个立着的奶瓶，shake是上下大幅度震荡，还是很暴力的。事实上由于蛋白质有不同性质，确实有些蛋白会失去活性。原因不是上文里说的分解成氨基酸，而是失去二三级结构，准确地说就是变性了。当然其实我不知道母乳中各种蛋白的特性，所以也不知道具体哪一种会发生这种变性，或者有没有会变性的蛋白。为保险起见，母乳也好，奶粉也好混匀是应该whirling，而不是shake。如果你看见过洗衣机就明白了就是洗衣服一样在水平方向拿瓶子做圆周运动，形成漩涡。这个基本技巧是初中化学课的基本功，所有化学配液都是摇匀的，不能shake。搞生化的同学可能比较容易理解，如果这个摇匀的速度太高，就叫vortex，人手恐怕很难达到，但是如果高速vortex也是可以使有些蛋白，尤其是某些酶失活的。至于为啥shake和高速vortex可以使蛋白变性，原因也很简单，因为蛋白溶解在水中，而水是有部分晶体结构的，高速的vortex或者shake，可以形成shear force，就是侧向剪切力，使蛋白结构破坏。但是肯定不足以破坏蛋白质的一级结构。所以行不成氨基酸。离心确实很暴力，不过由于没有这个侧向剪切力，只有离心力，所以不会使蛋白失活。偶从来没有注意这个问题，嘿嘿，因为没有shake过。。。哈哈，同学们没有好好学初中化学吧？