Why do traditional vermicelli machines add alum?

Vermicelli is a strip made of starch as raw material and processed through different processes. The common ones on the market are sweet potato vermicelli, potato vermicelli, etc. Vermicelli is a traditional folk food. At present, large-scale manufacturers have realized mechanized processing. The vermicelli has the ability to absorb soup, and it can be combined with a variety of ingredients to make delicious dishes, so it is loved by consumers.
 However, the traditional vermicelli machine needs to add alum when making vermicelli. The scientific name of alum is "aluminum potassium sulfate dodecahydrate", which presents a colorless and transparent bulk crystal or crystalline powder. Alum has a wide range of uses and is often used in daily life. However, alum contains aluminum ions, which are harmful to human body if eaten in large quantities, so the dosage should be strictly controlled. Why does the traditional vermicelli machine need to add alum to produce it? Is there any vermicelli processing equipment that can be made without adding alum?
1。the production process reasons
  Many people think that hand-made food tastes better and is more reassuring than mechanically produced food, but it is not. Most of the traditional vermicelli machine adopts extrusion or leaking scoop process. Due to the limitation of production conditions, alum needs to be added in order to increase the precipitation speed of starch, otherwise the vermicelli made will easily sink to the bottom and not easily float. ; At the same time, the color of the vermicelli is dim, and it is easy to break.
2. Prevent vermicelli from being drawn together
  Adding alum to handmade vermicelli can increase the transparency of the vermicelli and make the vermicelli stick faster and easier to divide. The vermicelli with added alum is not easy to stick when boiled at high temperature, the roots are distinct, and the appearance is better.
3. Increase the taste of vermicelli
  The vermicelli made from sweet potato starch has a smaller gluten, and after adding alum, the vermicelli has stronger toughness, and is not easy to be broken and broken during the process of drying and transportation.
  In fact, the modern vermicelli processing equipment has realized the process of no alum. The vermicelli machine adopts the steaming process of slurrying. After beating the starch, it is steamed with high temperature steam. Different types of cutting knives can produce vermicelli of different widths. Although no alum is added, it can still make the vermicelli firmer, the rehydration speed of the vermicelli is fast, and the taste is good. The pulp-spreading vermicelli machine is produced indoors and can be operated throughout the year, which improves the production efficiency.