Over 17 million metric tons of Citric acid is produced each year because of its many applications in numerous commercial areas. Of the manufactured citric acid, about 70% is used in the food industry as an additive to enhance the sour or tart taste in foods or drinks, 20% is used for detergent applications and the remaining 10% is for non-food related applications such as cosmetics, pharma, and in the chemical industry.
Naturally, citric acid exists in relatively large quantities in a variety of fruits and vegetables, most notably in citrus fruits. Lemons and limes have a particularly high concentration of citric acid; it may even constitute up to 8% of the dry weight of these fruits. Because citric acid is a naturally occurring preservative, it is used as a food additive for flavor enhancement and preservation purposes. However, in the food industry, citric acid is primarily used to complement flavors of soft drinks and beverages, jams and jellies, candy, sherbets and wine.
Apart from improving the taste of candies and drinks, citric acid is also necessary for maintaining regular bodily functions. There is a series of enzyme-catalyzed chemical reactions involved in the Krebs cycle in all living organisms that consumes oxygen. Citric acid is one of the important intermediates and the Krebs cycle would come to a halt without it, rendering low energy in the body. Thus, the intake of citric acid is also required to allow a healthy body to function properly. Because of its low toxicity, citric acid is also used to control pH (acidity) of general household cleaners and pharmaceuticals. Citric acid’s ability to bind to minerals and metals make it very effective in soap, laundry detergents and even shampoos to help wash out the wax and gel from the hair. In pharmaceuticals, citric acid is commonly used to adjust acidity in tablets; it is also combined with sodium bicarbonate in a wide range of effervescent formulae to help ingestion.
References: (1) http://en.wikipedia.org/wiki/Citric_acid (2) http://www.answers.com/topic/citric-acid
