Citric acid is a naturally occurring weak organic acid with the chemical formula C6H8O7. It is found in citrus fruits such as lemons, limes, oranges, and grapefruits and is known for its sour taste. Citric acid is widely used as a food additive to enhance flavor, acidity, and as a preservative. It is also used in the pharmaceutical industry for its antioxidant properties and in the biomedical field for its ability to chelate metal ions.
In the food industry, citric acid serves various functions, including acidity regulation, preservation, antioxidant properties, emulsification, flavor and aroma enhancement, buffering, and antibacterial activity. It is used in soft drinks, canned foods, jams, jellies, and other processed foods to give them a tart, acidic taste and to help prevent spoilage by inhibiting the growth of bacteria and fungi.
Citric acid is also used in the pharmaceutical industry for its antioxidant properties, particularly in oil production and in limiting the oxidation of lipids in meat processing. It inhibits lipid oxidation by forming bonds between pro-oxidative metal ions and the carboxyl or hydroxyl groups of the acid.
In the biomedical field, citric acid is used in the synthesis of various organic compounds and in the treatment of certain types of wastewater. It is also used in the textile industry for dyeing and printing processes.
Regarding safety, citric acid is generally recognized as safe (GRAS) by the FAO/WHO Expert Committee on Food Additives. However, excessive intake can lead to health issues such as tooth enamel erosion. It is important to handle citric acid with care and to follow safety guidelines and regulations.
For storage, citric acid should be kept in a cool, dry place to prevent degradation. It is generally stable under normal conditions, but exposure to high humidity can cause it to clump. Proper handling and storage are essential to maintain its quality and effectiveness for various applications.