Citric acid (CA) is an important organic acid, also known as citric acid, with a molecular formula of C ₆ H ₈ O ₇, colorless crystals, often containing one molecule of crystalline water, odorless, with a strong sour taste, and easily soluble in water. Its calcium salt is more soluble in cold water than in hot water, and this property is often used to identify and separate citric acid. Controlling the appropriate temperature during crystallization can obtain anhydrous citric acid. It has a wide range of applications in industries such as food and cosmetics.

Eating danger

Citric acid is an edible acid that can enhance normal metabolism in the body, and an appropriate dose is harmless to the human body. Adding citric acid to certain foods can improve taste and stimulate appetite. In China, citric acid is allowed to be used in jams, beverages, canned goods, and candies. Although citric acid has no direct harm to the human body, it can promote the excretion and deposition of calcium in the body. Long term consumption of foods containing citric acid may lead to hypocalcemia and increase the risk of developing duodenal cancer [7].  [8] 

Based on the influence of citric acid on calcium metabolism, people who often eat cans, drinks, jam, sour candy, especially children, should pay attention to calcium supplementation, drink more milk, fish head, fish bone soup, eat some shrimp skin, etc., so as to avoid causing insufficient blood calcium and affecting health. Patients with gastric ulcer, excessive stomach acid, dental caries, and diabetes should not often eat citric acid. Citric acid should not be added to pure milk, otherwise it will cause the milk to coagulate. The dairy industry often mixes citric acid into a solution of about 10% and adds it to low concentration milk solutions, stirring quickly when adding.  [8] 

Storage conditions

Citric acid monohydrate loses its crystalline water in dry air or when heated to about 40 degrees Celsius. It undergoes slight deliquescence in humid air, and dilute citric acid aqueous solution can ferment when left to stand. So solid monohydrate compounds or anhydrous substances should be stored in airtight containers and kept in a cool and dry place.