Introduction: Citric acid, also known as citric acid, English: Citric Acid, is a natural preservative naturally produced in citrus fruits, and can also prevent the fruit from being damaged by pests to a certain extent (like sour taste at will). It can reach 8% in dried lemons and limes, and the content in lemon juice is about 47g/L, which is why we call it citric acid.
1. Properties: Citric acid in additive state is a white crystalline powder that looks very similar to white sugar.
"Citric acid crystallizes from hot water to form an unhydrate; crystallization in cold water forms a monohydrate. When heated to 78 °C, monohydrate decomposes to produce a hydrate-free. At 15 degrees Celsius, citric acid can also be dissolved in absolute ethanol. Structurally, citric acid is a tricarboxylic acid compound and therefore has similar physical and chemical properties to other carboxylic acids. When heated to 175 °C it breaks down to produce carbon dioxide and water, leaving some white crystals. ”
Edible citric acid sold in the U.S. market
2. Production methods and their history: Although citric acid is high in citrus fruits, it is still very uneconomical to extract pure citric acid directly from fruits. However, in 1917, an American food chemist James Currie discovered that certain species of Aspergillus niger can efficiently produce citric acid. So two years later, the famous pharmaceutical giant "Pfizer" obtained this method and began large-scale industrial production. (Pfizer's main product after the American Civil War turned out to be citric acid, until the discovery of penicillin in 1928, Pfizer "abandoned the dark and bright" and returned to the right way of the pharmaceutical industry)
Pfizer
Aspergillus niger head SEM microscope photo
3. The role of citric acid in food:
3.1 Sour taste regulator: According to statistics, 50% of the world's citric acid is used in beverages. After adding citric acid, it will make the originally too sweet drink slightly sour, and there is a fresh feeling (but not the freshness of the Green Arrow).
All kinds of drinks can not lack the "taste" of citric acid
3.2 pH regulator: Citric acid can also adjust the pH of the drink (pH will be reduced), help inhibit the growth of bacteria, in addition to the drink meat sausage ham, as well as jam will also use citric acid to preserve. In addition, some foods need to maintain a certain pH to be formed when making, which is between 3.0-3.8 (depending on the variety) if the jelly and fruit cakes are needed, so that the pectin in it can complete the coagulation.
3.3 Emulsifier: Citric acid can also be added to ice cream as an emulsifier to prevent fat stratification, and can also prevent sucrose crystallization in caramel.
4. So does it add safety to food: of course it's safe! Citric acid belongs to China's national food safety standards. And in principle, it can be absorbed by the human body, and can also be converted into energy (247 kcal/100 g.) by the body's citric acid cycle, which inhibits the growth of harmful bacteria during food preservation and ensures the safety and reliability of food during the shelf life. Therefore, citric acid can be said to be "beneficial and harmless" in food.
In the future, we will share more knowledge about food additives and food nutrition, and hope that everyone will pay attention to or correct the wrong places! Thank you