Citric acid occurs in a variety of fruits and vegetables, most notably citrus fruits. Lemons and limes have particularly high concentrations of the acid; it can constitute as much as 8% of the dry weight of these fruits (about 47 g/L in the juices). The concentrations of citric acid in citrus fruits range from 0.005 mol/L for oranges and grapefruits to 0.30 mol/L in lemons and limes; these values vary within species depending upon the cultivar and the circumstances under which the fruit was grown.Citric acid is a versatile organic acid with a wide range of uses, including adding a tangy flavor and acting as a preservative in foods and drinks, cleaning and descaling household appliances like kettles and microwaves, and gently exfoliating and rejuvenating the skin in cosmetics. It also serves important functions in industry, where it acts as a complexing agent, a component in detergents, and in some pharmaceutical formulations. Food and Beverages Flavoring and Acidulant: Citric acid gives foods and drinks their tartness and is used in soft drinks, candies, and other products to enhance flavor. Preservative: Its antibacterial properties help extend the shelf life of certain products, such as canned fruits and vegetables. Emulsifier: It can help keep ingredients mixed together in food products. Cleaning and Household Uses Descaling:It's effective at removing limescale from appliances like kettles, coffee machines, and dishwashers. General Cleaning:Citric acid can be used to clean ovens, microwaves, and other surfaces by helping to break down dirt and grime. Metal Cleaning:It can remove tarnish and dirt from copper and other metal surfaces, leaving them shiny. Skincare and Personal Care Exfoliation:As an alpha-hydroxy acid (AHA), it gently removes dead skin cells, promoting cell renewal and a healthy glow. Skin Tone and Hydration:It can help even out skin tone and provide hydration, making it a common ingredient in cleansers, toners, and face creams. Acne Treatment:By unclogging pores, it can help prevent acne breakouts and skin inflammation. Other Applications Health Benefits:It's used in some medications to prevent kidney stones and to mask the taste of medicines. Industrial Applications:In industry, it functions as a chelating agent, a water softener in detergents, and a component in some biodegradable polymers.