As a popular food, vermicelli will encounter various common problems during processing. Let us analyze the reasons and solutions below.
Reason: The sweet potato is separated and precipitated by beating, and the starch obtained is usually called hair powder. Hair powder contains impurities, phenolic substances, and many pigments.
The solution: refined starch. The method is: add 2 to 3 times of water to the hair powder, stir, add an appropriate amount of potato starch decolorizer, and filter it with a 120-mesh nylon mesh after about 20 minutes. After the filtrate is precipitated for 4-6 hours, remove the upper layer of clear water, add water and stir, and then precipitate again. Do this 3 times to achieve the purpose of decolorization and purification.
Reason: If the kneading noodles are too thin, the cooling time is too slow after the powder is extracted, and too much thickening will cause the vermicelli to stick together, resulting in more drawing and difficulty in opening.
Solution: add water when kneading noodles, and the amount of thickening should be appropriate. The total amount of water and thickening should not exceed 90 kilograms per 100 kilograms of dry starch. Use an electric fan or blower to blow at the powder outlet of the vermicelli machine to speed up the process. cool down. When kneading dough, alum and vegetable oil can be added according to 0.3%~0.4% of dry starch weight. If the production of silver powder with a diameter of less than 1 mm, an appropriate amount of vermicelli quality improver (opening agent) should be added.
Reason: The temperature is too high during gelatinization, and the vermicelli shrinks rapidly when it is cold after it comes out of the machine. It is not balanced, forming a bead shape with one big section and a small section, which is not smooth. The dough is too dry and the water is too little to exacerbate this phenomenon.
Solution: Reduce the temperature of the water flow in the interlayer of the vermicelli machine, and reduce the temperature difference before and after the vermicelli leaves the machine. The total moisture content of the dough should be between 45% and 50%.
Reason: The vermicelli is not fully cooked when the vermicelli is extracted, dried before it is completely cooled after extraction, too much alum is added, too dry in the sun, and long-term storage without packaging will cause the vermicelli to be crispy and cause losses during storage and transportation.
Solution: In addition to taking measures against the cause, sodium pyrophosphate can be added at 0.1% of the dry starch weight during dough kneading to maintain moisture; 0.1%~0.5% of salt can also be added to allow it to absorb moisture naturally.