If there is a small amount of egg yolk in the egg white, it can't be killed. It can be killed by using the egg beater for a long time, and manual ones can't be killed basically. Because egg yolk contains soybean lecithin and vegetable oil, it can both have the effect of demulsification, which will affect the time spent. If only a little, it may also be polyurethane foaming if the time spent at a high speed is a little longer. If the amount of egg yolk is too much, it cannot be spent.
 Protein is composed of 90% water and 10% protein, and that little protein is the primary condition for killing. The protein shows a roll shape, and after hard mixing, it will extend and worry about each other. In addition, mixing will make the liquid produce many fine bubbles, and the protein chain will produce a stable network structure outside the bubbles. Later, it will become more and more robust. The bubbles generated by mixing will be wrapped in the protein web, and the protein foam will be produced.
 In the example course of cake making, it is often stipulated that the protein must not have egg yolk, and the basin and electric egg beater must be free of water and oil stains, because egg yolk and vegetable oil will immediately fuse with the protein molecular structure, thus affecting the production of protein chain, so that the egg white net outside the bubble cannot be produced, so it is necessary to separate the protein and egg yolk, In case it is impossible to kill.
 How to deal with unsuccessful protein sending:
 Sometimes carelessness in making birthday cakes for so many years can also lead to unsuccessful egg whites. The reason may be that the egg yolk has infiltrated (the egg yolk may be scattered when the egg yolk is separated) or whether you are careful to mix water. If you are too lazy, you can also throw in all the raw materials to make a simple Qifeng cake.
 It is also very simple to use raw eggs, milk, and oil low gluten flour to grind the unsuccessful protein super simple sponge cake.
 First, add the unsuccessful protein to the egg yolk, and then grind it again. If you don't know how much sugar should be added, you can add 30 grams of salt to three eggs and 40 grams of salt to four eggs according to my method. By analogy, it is always sugar to add protein and egg yolk, not just egg yolk.
 When you feel that you can't bubble again, add oil and use the electric egg beater to kill again. In the same way, add 30 grams of oil to three eggs, 40 grams to four eggs, and then add milk or water, which is the same way as above.
 Finally, add wheat flour and mix it together in the same way. The temperature is 130 ℃ for 20 minutes. It is safe. Because the level of unsuccessful protein is different for everyone, the temperature needs to be adjusted by yourself. If it is not yellow enough, then add temperature and time. This is the final product. The bottom is a bit crisp and also very loose, It's no different from the successful version.
 There is also a simple method, which is to add egg yolk to the protein that is not successfully milled, stir it evenly, add salt free butter, add yeast, add some dried blueberry and wheat flour that is added with sifting powder, mix it at the same time until it becomes a thick paste, pour it into a baking pan with tin foil, scrape it, bake the middle and high layers at 160 degrees for 10 minutes, and cook it according to its own electric oven, Qifeng cake, which is crisp outside and soft inside, appears.
 This is the end of the problem about protein sending. If it fails, there are ways to save it.