Physics The principle of making frozen tofu .

At a temperature of 0, the water in the tofu condenses into ice.

When the temperature is high, the water in the tofu melts away.

Its chemical principle can be simply summarized as two processes: physical coagulation, solidification and chemical acid-base reaction. Tofu, also known as bean curd and fermented bean curd, is a traditional food made with soybeans as the main raw material.

First of all, soybeans are rich in protein and vegetable oils, after heating in soy milk, the protein molecules will be denatured due to high temperature, and form a network structure, under acidic or alkaline conditions, these denatured proteins intersect and gather together, thus forming a solid tofu block.

At the same time, when the coagulant is added, the acid and alkali substances it represents will react chemically with the protein molecules in the soybean milk, resulting in the ionization, unwinding or coagulation of the protein, prompting it to form a lump. At present, the commonly used coagulants mainly include gypsum, brine, vinegar, etc.

In addition, different types of tofu will also add different accessories, such as sea salt, fresh milk, white sugar, etc., to increase the texture and adjust the taste. However, these excipients do not affect the main chemical principle of the production of bean reed liquid curd.

In conclusion, the production of tofu is a very old and interesting process, and its chemical principles involve physical deformation and chemical reactions, which deeply reflect the nutrients and special properties possessed by soybeans.

The physical experiment process of frozen tofu is as follows:Ingredients: 400 grams of frozen tofu, 80 grams of pork belly, 5 grams of green onions, 5 grams of ginger, 2 tablespoons of light soy sauce, 1 tablespoon of dark soy sauce, 1 tablespoon of cooking wine, 1 teaspoon of sugar, appropriate amount of salt.

1. Cut the frozen tofu into small cubes, cut the pork belly into thin slices, cut the green onion into chopped green onions, and shred the ginger.

2. Add a little oil to the banquet pot, add the pork belly and slowly stir-fry the oil until it is slightly charred.

3. Add the silver to the green onion and ginger and stir-fry the fragrance.

4. Add frozen tofu.

5. Stir-fry lightly, dark soy sauce, cooking wine, and sugar evenly.

6. Pour in an appropriate amount of water, bring to a boil, turn to low heat and simmer for 10 minutes.

7. Finally, taste the saltiness, add a little salt, turn to high heat and add juice slightly.

The changes in the state of frozen tofu are as follows:

Fresh tofu contains a lot of water, put it in the freezer of the refrigerator, the water will solidify into a lot of Xiaoice crystals; The next day, at room temperature, the Xiaoice crystal will melt into water again.

Frozen tofu is a traditional soy product. It is made from fresh tofu that is porous, elastic, nutritious, and delicious. There are many delicacies that can be made with frozen tofu.

Frozen water tofu is called frozen tofu. Frozen tofu, also known as sponge tofu, that thaws and dehydrates and dried, contains less than 1% water and is easy to preserve.

Frozen tofu is an invention of the northerners, that is, the tofu is frozen before eating. After freezing, the tofu undergoes a physical change (the inside of the tofu has countless small holes, some of which are connected to each other, and some of which are closed into small "containers", which are filled with water.)

We know that water has a singular property: at 4, it is the densest and the least in volume; At 0, it formed ice, and its volume was not reduced but expanded, about 10% larger than the volume of water at room temperature. When the temperature of the tofu drops below 0 clumps, the moisture inside freezes, and the original holes are enlarged by the ice, and the whole piece of tofu is squeezed into a network shape.

When the ice melts and water runs away from the tofu, it leaves countless holes that make the tofu look like a plastic foamed with silver foam.) This kind of tofu has a very layered taste. Frozen tofu is very tasty when boiled in a meat soup because the honeycomb tissue in the frozen tofu absorbs the soup.

Frozen tofu is suitable for making hot pot or deep-frying and then freezing tofu. It's not difficult to eat it when you usually want to eat it, just put it in the refrigerator, and it will take about a day for frozen tofu to appear. Of course, the most important thing is that all soy products are more or less astringent, and boiling water before boiling can basically solve the astringency.

Frozen tofu is a traditional soy product. Frozen with fresh tofu, it is porous, elastic, nutritious and delicious. Frozen tofu can be used to make many delicious foods.

Water tofu is frozen tofu. Defrosted and dehydrated frozen tofu, also known as sponge tofu, has less than 1% moisture and is easy to preserve.

How to make frozen tofu:

Ingredients: 1 piece of tofu.

Accessories: a pinch of refined salt, 1 bowl of water.

1. Prepare a piece of fresh tofu.

2. Cut in half, soak in lightly salted water for half an hour, then drain.

3. Divide the two pieces of tofu into several small pieces.

4. Then bagged separately.

5. Put it in the refrigerator and freeze for more than 8 hours.

6. After that, take it out and you can complete it.

Why can frozen tofu be **? **You can also have a taste marinated frozen tofu.

Frozen tofu is made from frozen fresh tofu, which has many pores, good elasticity, rich nutrition, and delicious taste.

Production process: 1. Cut the old tofu into pieces, thick squares or long squares can be, as long as they are not too thin.

2. Add water to the steamer, and brush the steaming drawer with a drop of oil to prevent the tofu from sticking after steaming.

3. Open the cut tofu, cover it over high heat and steam it, change to low heat and steam it for about 20 minutes after the pot is steamed, if the cut is thick, you can steam it for a while.

4. Turn off the heat after steaming, take out the steaming drawer, let the tofu cool, and then put it in the freezer, try not to stack the tofu together, the tofu is not sticky when it is opened, and it is easy to take when you want to use it.

5. It is done in the freezer for more than one night, and the rest can be eaten at any time you want, and it is no problem to freeze for a few weeks.

Coagulation is mainly due to the change of water in tofu from liquid to solid.

In order to judge the change of state in the formation process of frozen tofu pores, we must first understand the formation process of frozen tofu pores. When tofu is frozen, the water condenses into ice, which is a coagulation phenomenon; When the frozen tofu is thawed, the frozen ice melts into water, which is a melting phenomenon, and small holes are formed in the frozen tofu in the above process, and the correct option can be judged accordingly

Solution: The small holes of frozen tofu are formed by the water in the tofu freezing when it is cold, and then melting into water, so the main changes in the state of matter are solidification and melting.

Dear, read a lot of books, combined with practice, Qibao Elite is happy while learning, professional one-on-one.

I think it includes the evaporation of water and the solidification of water.

Water tofu cut into cubes (one knife horizontally, one knife horizontally, two knives vertically and vertically) about two centimeters square, then separated by a certain distance and put in the refrigerator for a day.

When serving, take out the frozen tofu and boil it in cold water, about 1 to 2 hours, until there is no ice heart, and use your hands to remove the water.

And then cook according to your own ideas, because the way of eating is different in different regions, I won't write the method, the above is the way Northeast people make frozen tofu, we generally put it outdoors, and it will be frozen overnight.

Cut the purchased tofu into the size and shape you need, put the cut tofu in the refrigerator freezer, and after 6-7 hours, the tofu will be frozen.

Frozen tofu, as the name suggests, is frozen tofu. In the beginning, in the Tohoku, fresh tofu was cut into small cubes and placed outside the house, and it was quickly frozen into ice cubes, so that it could be stored for a long time, and when it was eaten, it was directly placed in the stew or melted and eaten in the hot pot. Because frozen tofu is quickly frozen, the water in the tofu expands in volume after freezing, and the fresh tofu becomes a sponge-like with a lot of holes in the middle, and it tastes different and has a unique taste, so it spreads.

You can use the refrigerator to make frozen tofu at home, although it is not as authentic as the frozen tofu naturally formed at more than ten or twenty degrees below zero in the Northeast, but it is more convenient, hehe.

A name in the north, it is made of soybeans grinding, after being prepared with brine or gypsum, it forms a soft block, and then it is dried by freezing water to become a block with many small holes, which is mostly used to eat hot pot!

Supplement: Eat more frozen tofu to lower cholesterol, which is most suitable for the elderly. Stewed silver carp with frozen tofu Ingredients:

Frozen tofu, silver carp head Accessories: dried bamboo shoots, barley, green onions, ginger Seasoning: salt, sugar, pepper, cooking wine Cooking method:

1. Cut the frozen tofu into pieces, cut the green onion into sections, slice the ginger, wash the fish head, put a little oil in the pot, stir the green onion and ginger to bring out the fragrance, then put in the fish head and fry it until golden on both sides, cook a little cooking wine, add dried bamboo shoots and barley; 2. Add an appropriate amount of boiling water to the pot, put in the tofu, simmer for 20-30 minutes on high heat, add salt, pepper and sugar to taste, and sprinkle chopped green onions out of the pot. Features: Frozen tofu is soft and flexible, elastic, the soup is fresh and clear, appetizing and refreshing.

Frozen tofu is to put the tofu in the refrigerator and freeze it there, but it has to be cut into small pieces first, and it will freeze for about two days.

Specific method: 1. Fresh tofu, rinse with water, and soak in salt water for half an hour.

2. Scoop it up in the water and ice the tofu in the refrigerator with a crisper or the like.

3. After a day or two, the tofu is completely frozen, take it out and soak it in water until it is completely thawed, and there are no hard lumps in the tofu at all. You will see that the texture of the tofu will be obvious.

4. Put the tofu on the cutting board, use the whole palm of your hand to squeeze out the water with feminine force, and avoid being rude. Squeeze as much as possible until no moisture. (Be careful not to suck the squeezed water back in), leaving only the fiber of the tofu.

5. (If there is a time problem, the following steps can be omitted) Absorb the fresh water of the "dried tofu" again, put it back in the crisper box, and put it in the refrigerator. Take it out again every day or two and repeat step 4 2-3 times. Anyway, the more times you do, the more chewy the fiber will be, and the closer it will be to the "meaty" taste.

6. Cut the "dried tofu" into cubes, pay attention to one-size-fits-all. Drain and set aside.

Why can frozen tofu be **? **You can also have a taste marinated frozen tofu.

Put it in the freezer compartment of the refrigerator and freeze it for a few hours.