In the process of industrialized production of natto, appropriate automatic cleaning, soaking, cooking, constant temperature fermentation and low temperature drying are selected according to the output.
1. Raw material treatment:
The raw soybeans harvested from all over the country, after grade inspection, qualified as raw soybeans, and then refined treatment, removal of inclusions and uniform grain shape, and then put into 30 KG paper bags for storage, storage requirements temperature control at 15 degrees, humidity control at about 60% of the low-temperature warehouse, otherwise soybeans are liable to deterioration and cause losses, from the low-temperature warehouse to pick up the original for about a week. Material to the processing plant.
2. Bean washing and dipping:
The selected soybeans are cleaned with a bean washer to remove the sand, dust and organic substances attached to the surface. The purpose of impregnation is to make the water absorbed into the seeds of raw soybeans, soften the tissue and make it easy to cook, so that natto bacteria can easily use the soybean ingredients. Moderate impregnation needs to be calculated by weight ratio. When the weight reaches 2.3-2.4 times, cutting off the soybean can see that the two seeds expand to almost no void. The impregnation time varies according to the soybean variety and size, but the most influential factor is the water temperature, which needs to be impregnated 23-24 hours at 10 degrees, 17-18 hours at 15 degrees and 13-14 hours at 20 degrees. It takes 7-8 hours to impregnate at 25 degrees water temperature. In summer, special attention should be paid not to impregnate excessively. When the soaking water temperature is high, the miscellaneous bacteria can easily reproduce up to 104 g soybean. Although the following cooking process can kill the miscellaneous bacteria, its residual metabolites will affect the growth of natto bacteria, and when severe, it can completely inhibit the growth of natto bacteria. Therefore, it is necessary to take low temperature to inhibit the growth of miscellaneous bacteria as far as possible. The ideal condition is to use the water temperature below 10 degrees for soaking, while a small amount of production can be in the refrigerator. The temperature is controlled to 5 degrees for dipping and cooking in about 24 hours. Soaking time can be judged according to the size, tissue condition and water absorption of soybean seeds. To determine the length of soaking time, 100 g soybean raw materials can be put into small bags for soaking, taken out at a certain time, and weighed after removing water as far as possible. The time when the weight of soybean is 2.3-2.4 times that of the original can not be boiled into soft when the soaking is insufficient can be found. Soft can't provide enough nutrients for natto bacteria.
The function of cooking is to kill soil microorganisms on soybean surface, soften most tissues, and immerse soluble components of seeds into the surface of soybean skin. Therefore, after inoculation, natto bacteria can easily absorb nutrients, while in vitro enzymes of natto bacteria can easily soak in and decompose soybean components. Firstly, the pressure of the pressure cooker is raised to about 5 kg. Then, the impregnated soybeans with two sandbags are put into the cooking tank. The top cover is opened to lock the door bolt, the drainage valve and the exhaust valve are opened. Then the steam of the boiler is introduced into the cooking tank through the steam pipes. Once the drainage pipe of the cooking tank is opened, the incoming steam first discharges the condensate water and the boiling juice produced by the soybean cooking. When the water vapor is discharged, close the drain valve, then close the exhaust valve. After 10-20 minutes, the steam pressure will rise to 1.0-2.0 kg, keep 30-40 minutes, then turn off the steam valve. After 10-15 minutes, the cooking will be completed. After cooking, the water distribution pipe and exhaust valve will be opened slowly, and the internal and external pressure will be equal after the steam is discharged, and then the cover will be opened.
4. Inoculate natto bacteria:
The temperature of operation is between 70-90 degrees, and the spores of natto bacteria are evenly attached to the surface of boiled soybean. This operation is called inoculation. 5cc soybean bacteria liquid can be inoculated into a soybean sandbag. Soybean bacteria liquid is the suspension of natto spores. There are about 100 million to 200 million spores in 1cc. According to the calculation of 100 million, there are about 400 spores attached to 1g boiled soybean, and about 1300 spores attached to 1 g boiled soybean. On the surface of grain soybean, 5cc raw bacteria should be evenly distributed on a sand bag. It is necessary to add the sterilized water increments in advance, to cool the boiled drinking water to about 50 degrees. Spray two sandbags and spray them to 2kg, and when the kettle is spread, it needs 2.5kg solution.
The 6P drying and dehumidification machine is equipped with 5.5 m long, 3 m wide, 2.2 m high and 10 cm polyurethane thermal insulation drying room. There are six material trucks built in. The material size is 1.2 m long, 1 m wide and 1.7 m high. The truck is divided into 12 layers of grid pallets. Each truck is loaded 300 kg. One batch of 1200 kg is loaded. The temperature range is set to 50-60 degrees, and the time is set for 20 hours until the water content reaches 12%, and the drying process is over.
The bean air drying equipment of Xi'an Sunda Environmental Protection Equipment Co., Ltd. can be applied to the drying process of most soybean products, such as dried beans, soybean oil skin, natto, Yuzhu and so on. Santa can tailor-made all kinds of drying equipment you need according to the needs of customers. The company is equipped with experimental machines. Welcome to visit and discuss cooperation.