Citric acid

**Natural Occurrence and Industrial Production**:
– Citric acid is naturally found in high concentrations in lemons, oranges, limes, and other citrus fruits.
– It was first isolated in 1784 by Carl Wilhelm Scheele from lemon juice.
– Industrial-scale production started in 1890 using Italian citrus fruit treated with hydrated lime.
– Concentrations vary within species and cultivars.

**Chemical Characteristics and Biochemistry**:
– Citric acid can be obtained in anhydrous or monohydrate forms and acts as a tribasic acid with specific pK values.
– It plays a crucial role in the citric acid cycle as an intermediate.
– The citric acid cycle is a central metabolic pathway for animals, plants, and bacteria.
– Citrate synthase catalyzes the formation of citrate in the cycle.

**Industrial Applications and Health Impact**:
– Over two million tons of citric acid are produced annually.
– China contributes over 50% of the global volume.
– Citric acid is widely used in beverages, food, detergents, cosmetics, pharmaceuticals, and the chemical industry.
– It is generally recognized as safe for consumption but can be corrosive in high concentrations.

**Applications in Various Industries**:
– Citric acid is extensively used as a flavoring and preservative in food and beverages.
– It is a common ingredient in ice cream, caramel, and effervescent formulas.
– Citric acid is utilized in cleaning products as a chelating agent and in bathroom and kitchen cleaning solutions.
– It is also found in cosmetics, pharmaceuticals, dietary supplements, and as a passivation treatment for stainless steel.

**Research, Studies, and Safety**:
– Studies focus on citric acid quantification in fruit juices, its role in biological systems, and its applications in various fields.
– Citric acid is researched for its effects on urine composition and calcium stone formation.
– Safety aspects include erosion behavior on tooth enamel and guidelines from organizations like NIOSH and pharmacopoeial standards.https://en.wikipedia.org/wiki/Citric_acid