Chinese ancestors actually discovered how to make tofu. This is one of the most miraculous discoveries in history. As the saying goes, "add brine to tofu, and one thing will reduce one thing." Otherwise, we would still only have tofu until now. You can drink soy milk. How does this brine turn the soy milk into tofu curd and then condense it into tofu?
What exactly is brine? How does it turn soy milk into tofu?
General brine is actually easy to be misunderstood, because the marinade used in many braised dishes is also called brine. That kind of brine is made from various edible spices and is not discussed in this article. The real brine is Brine is salt brine, which is a brine block formed by the crystallization of the mother liquor remaining in the salt pond after evaporation and cooling after salt production from seawater or salt lake water. The main ingredients are magnesium chloride, sodium chloride, potassium chloride, calcium chloride, magnesium sulfate and magnesium bromide.
Braised cubes
Braised cubes are also very salty. Mixing them with tofu and eating them in small amounts can supplement trace elements, but they must not be taken in excess, as they can cause poisoning and are very irritating to the skin and mucous membranes. It is strong and has an inhibitory effect on the central nervous system. If people accidentally take it, they will experience nausea and vomiting, dry mouth, abdominal distension, diarrhea, dizziness, headache and other symptoms!
How do you order tofu with brine?
Grind the soybeans, wash them in water, dissolve the protein, and then boil them in the water. Of course, not boiling, but bubbling slightly! After skimming off the foam that floats to the surface, what’s left is a large pot of mostly protein and water! At this time, the soy protein pellets are surrounded by water and are constantly moving. They cannot come together and form a "colloid"!
Soy protein has free carboxyl and amino groups on its surface. The effect of these groups on water causes the surface of the protein particles to form a colloidal substance with a water film of the same charge. The repulsive force isolates the particles from each other and prevents them from sticking together into agglomerates!
Brine is mainly magnesium chloride (MgCl2). These solutions are electrolyte solutions and will form many charged particles (positive ions and negative ions) in the water. The hydration of these ions takes away the water film of the protein, making The protein is isolated, and the positive and negative ions in the magnesium chloride electrolyte suppress the repulsion due to the charges on the protein surface, causing the particles to agglomerate with each other, thus turning into lumps of bean curd!
Of course, this takes a certain amount of time. The waiting time at this time is called squatting, also called swelling or nourishing milk. The peptide chain of the protein in the soy milk with brine just ordered and between the peptide chains. It takes time to form a uniform and orderly three-dimensional structure between the peptide chain and water molecules. It is not advisable to stir and vibrate at this time, otherwise the tofu rate will be low or the tofu cannot be formed.
It has condensed into clumps
Of course, the role of salt brine can only form tofu. The next tofu needs further processing, that is, pressing, filtering out the water, and then Press it on gauze and squeeze out excess water to form tofu!
Brine tofu is just a process of colloid sedimentation, not a chemical reaction.
A few tofu delicacies
Besides brine, what other things can turn soy milk into tofu?
The tofu we usually eat includes old tofu and tender tofu. Each has its own preference for radish and green vegetables. Old tofu is made from brine, while tender tofu is made from gypsum. We learned above that as long as it meets the conditions for protein aggregation, other substances can also be used as "catalysts" for tofu!
Gypsum that meets this requirement can be calcium sulfate! There is also glucono-delta-lactone, which is called lactone tofu! Even white vinegar can be used, and some friends can also use lemon juice to make tofu, so many friends who like pure natural ingredients use lemon juice to make tofu! There are also tutorials online, and friends who are interested can learn about it!
Of course, the principle of changing the pH value is slightly different, but adding acid will make the protein colloid particles approach the isoelectric point (soy protein is Glycinin, beta-Conglycinin, and the isoelectric point is about PH5 (left or right), the net charge of the colloidal particles decreases and the repulsive force becomes smaller, making it easier to agglomerate into clusters. In fact, the result is the same.
Extended reading: Yuba (Tofu Skin)
Tofu skin is made by boiling soy milk without boiling the pot, and then the soy protein cools and forms a crust on the surface. The production process is much simpler than tofu. Experienced friends will pull out a few tofu skins before making tofu. Of course, if you pull too many tofu skins, the rate of tofu production will decrease, but in one operation, two kinds of delicious food are worth trying!
The bean curd that sticks out from the edge of the pot is the tofu skin, just pick it up with chopsticks
The bean curd is a must-have for making spring rolls, soup, or meat rolls. of raw materials! You may not have the courage to try making tofu, but tofu skin is too simple. Next time, boil the soy milk and put it in a big pot. You can also prepare a few chopsticks or get a few longer clean bamboos, and then find a place to dry. , let it dry!
Finally, sodium chloride solution is also an electrolyte solution. It can also be used to order tofu, but the amount must be large, and the tofu will be salty to death!