Agar, also known as agar Gelatin products made from algae, such as Gracilaria and Gracilaria, are the most commonly used curing agents for microbial culture media, and are also used in canned meat, fish and poultry, cosmetics, medicines and dental care. It is used as clarifier in brewing and wine industry, thickener in making ice cream, cake and salad seasoning, and lubricant in drawing. Agar made of seaweed is translucent amorphous powder, flake or particle. The main producing areas are Japan, New Zealand, the United States and Russia. Agar is insoluble in cold water and can absorb 20 times its own volume. Diluent is dissolved in boiling water, and remains liquid at 42℃( 108 ℉), but condenses into a tight gel at 37℃. Agar is a component of cell wall, which contains complex carbohydrates, calcium and sulfate. Agar, also known as carrageenan, is made from a rare and precious tropical marine red algae-Eucheuma by scientific methods. It belongs to lactose sulfate, contains about 75% carbohydrates, and also contains inorganic substances indispensable to human body-calcium, iodine, iron, sodium and so on. Agar is an alginate extracted from red algae plants such as agar, which has a history of more than 300 years in China and Japan. Because of its special gel properties, it is widely used in food, medicine, chemical industry, textile, national defense, scientific research and other fields, and is called "new products in East Asia" internationally. Agar carrageenan is not only widely used in food, but also has the functions of clearing away heat and cooling lung, stimulating appetite, strengthening spleen and stimulating appetite, and can prevent constipation and treat hypertension. Because of the gelation and gel stability of agar and carrageenan solution, agar is widely used in food industry and can be used as food stabilizer. The food made of agar and carrageenan tastes much better than other gums. Agar can not only be used as a stabilizer, but also prevent packaging adhesion. When the concentration of agar reaches 0.5% to 1.0%, it can be used as a stabilizer for transparent icing of oil cake, and at the same time, it can improve viscosity and surface adhesion, solidify quickly, increase food flexibility and reduce surface defects and cracks. When the melting temperature of gel increases, the tendency of food to absorb liquid and soften decreases. In the application of food industry, agar is often mixed with other plant gums. Because agar can be used as filler and leavening agent, it can replace starch to make batter, starch-free bread and dessert. When the concentration of agar reaches 0. 1% to 1.0%, it can be used as a preservative. For example, fat is a popular food additive in many chewing gum and special sugar foods. Agar is used to make sherbet and ice crumble. Agar can reduce the separation of dairy products and improve the consistency of cheese. Agar is used in beverage products, and its function is suspension force, so that the solids in the beverage are suspended evenly and do not sink. It is characterized by long suspension time and long shelf life, which is irreplaceable by other suspending agents. Good transparency, good fluidity, smooth taste and no peculiar smell. The reference dose is between 0.09-0. 12%. The characteristics of high-quality agar are: dry body, white and bright color, high cleanliness and transparency, great elasticity, tenacity and strong fastness. Characteristics of inferior agar: yellow and dark, opaque, weak elasticity, hard and brittle, not tough. False agar is characterized by white and dull appearance, high impurity content and poor transparency (note: a large number of insoluble substances can be found in water after L% concentration aqueous solution is dissolved). If you soak it in cold water or warm water for about 30 minutes, it will quickly absorb water, swell and recover, but the real agar does not have this phenomenon.