Its principle is to solidify the glucose in soybean milk, which can retain the nutrition of the original bean more than brine tofu and gypsum tofu.
Exercise:
1. Choose soybeans with light umbilical color, low oil content, large and thin skin, full grain weight, no wrinkles and shiny skin for soaking. Cleaning soybeans and soaking in spring and autumn at the water temperature of 10℃-20℃ for 12 hours-18 hours; In summer, the water temperature is about 30℃; Soak for 6-8 hours (change water every 24 hours); In winter, the water temperature is 5℃ and the soaking time is about 24 hours. Pure water and soft water are better for water quality. Generally speaking, the water consumption ratio of soybean water is 1: 3, and the soaked soybean is about 2.2 times the weight of raw material dried beans. Soaking beans requires douban to be full and divided into a small line. But if the soaking time is too long, it will affect the pulp yield.
2. Generally, a refiner that can automatically separate pulp residue is selected for grinding, coarse grinding and fine grinding for 2-3 times, so as to improve the extraction rate of soybean protein as much as possible. Because it is no longer necessary to press and shape tofu like using salt water and gypsum as coagulants, the amount of water added in the pulping process determines the tenderness of the finished tofu. Generally, the ratio of water to dried tofu is 3-4: 1 when making old tofu, and 6- 10: 1 when making tender tofu. The amount of water added for the first coarse grinding is 30% of the total amount of water added, and the screw of the refiner is adjusted for fine grinding for the second time, and the amount of water added for the third time is 30% and 40%, so as to wash the pulp in the bean dregs as much as possible. The ground slag should feel delicate and have no particles.
3. Boiling: put the ground slurry into a stainless steel boiling barrel, boil the slurry to 60℃-70℃ with steam, and add about 0.3% edible defoamer until the bubbles generated in the heating process are completely eliminated. Then continue to heat and boil the pulp, keep it for 3-5 minutes after boiling, and cook the pulp thoroughly.
4. Cooling The cooked pulp is cooled to below 85℃.
5. To order fat (add coagulant), first dissolve β -gluconolactone with a small amount of cold boiled water. Dosage: when making old tofu, 1 kg pulp is added with 30 g of internal fat, when making tender tofu, 1 kg pulp is added with 24 g-30 g of internal fat. Add the dissolved internal fat into the cooled soybean milk and stir slowly and evenly.
6. Forming: pour the oil-coated slurry into the forming mold and put it into the curing tank. Keeping the temperature at 80-85 DEG C for 20 minutes to obtain a finished product. The freshly formed tofu should not be shaken for a while, so let it cool for a while. If boxed tofu is produced, a filling and sealing machine is required.
Boxed lactone tofu
In traditional tofu production, gypsum and brine are often used as coagulants, which have the characteristics of complex technology, low yield, short shelf life and difficult absorption by human body. Using gluconolactone as coagulant to produce tofu can reduce the loss of protein and improve the water retention rate. The yield is greatly improved, and the tofu is white, delicate, shiny, good in taste and long in storage time. The specific manufacturing method is as follows:
1. Choose fresh soybeans with full and neat fruits, remove impurities and spoil soybeans.
2. Soak the soybeans with water 3-5 times the weight of the soybeans. Generally, the soaking time is 12- 14 hours in spring, 6-8 hours in summer and 14- 16 hours in winter. The soaking time should not be too long or too short. It is advisable to twist bean paste, with the inside parallel and a slightly concave line in the middle.
3. According to the ratio of soybean to water 1:3 ~ 1:4, the soybean should be ground evenly and finely, with more pulp and less slag, and the fineness should be suitable for passing through 100 mesh sieve. It is best to grind the pulp by drop grinding or by secondary grinding.
4. Filtration is the premise to ensure the quality of finished tofu. If the centrifuge is used for filtration, it should be coarse first and then fine, and it should be carried out in stages. Generally, the pulp filtration per kilogram of beans is controlled at 15 ~ 16 kg.
There are usually two ways to cook pulp. One is to use an open cauldron, and the other is to use a sealed boiling slurry. Boil the pot quickly and for a short time, generally no more than 15 minutes. After the pot is boiled for three times, immediately put the slurry for use. If the pulp is cooked in a sealed cooking pot, the temperature of each cooking stage can be automatically controlled, and the cooking effect is good, but it should be noted that the temperature should not be higher than 100℃, otherwise protein denaturation will occur, which will seriously affect the product quality.
6. Dispensing is an important link to ensure the yield. When the temperature of soybean milk reaches about 80℃, order soybean milk. The method is as follows: firstly, the gluconolactone is dissolved in water, then it is added to the cooled soybean milk as soon as possible, and the addition amount of gluconolactone is 0.3% ~ 0.4% of the soybean milk, and then it is stirred evenly.
7. After gluconolactone is added into the box, it can be put into the box to make boxed lactone tofu, which can be eaten or sold after stable molding. If you want to make tofu, you can narrow it and drain it according to the conventional method.