1, soy sauce is sour and neutralized with baking soda. 10 kg put one or two baking soda and mix well. Leave it overnight and stir again. Look at the acidity. If it's still sour, you can put it in half a second or one or two. It is best to buy PH precision test paper 3 to 7 to measure the pH value. About PH5 will do. The acidity is adjusted, salt is added to make it salty and light, and maltose is added to increase the sweetness.

2. After the cultivation and manufacturing of soybean seeds, raw material treatment, large-scale production and fermentation, soybean becomes cooked sauce after fermentation, and it also has to be sterilized at high temperature, ground and preserved, which not only removes harmful components, but also makes the structure of soybean protein change from dense to loose, and protein decomposing enzyme easily enters the molecule to improve the digestibility. The protein digestibility of whole soybean is about 65%, and it is 92% to 96% after processed into sauce products.