As it is one of the stronger edible acids, the dominant use of citric acid is as a flavoring and preservative in food and beverages, especially soft drinks. Citric acid is a naturally occurring preservative used in many applications including canning, flavoring, cleaning, and even photography development. Acid flavoring agents are a large class of food additives that can give food a sour taste, divided into organic acid flavoring agents and inorganic acid flavoring agents. Organic acidity agents commonly used in food production are citric acid, malic acid, tartaric acid, lactic acid, gluconic acid, etc.; commonly used inorganic acidity agents are phosphoric acid, etc. The acidity of the acid flavoring agent is the sensation produced by the hydrogen ions dissociated in the solution stimulating the taste nerve. Acid sensation has a lot to do with the characteristics of acidic groups, pH, titration acidity, buffering effect, and the presence or absence of other compounds. For example, at the same pH, organic acids are more acidic than inorganic acids. In food production, acid flavoring agents can not only present a sour taste but also have a variety of roles such as taste adjustment, antiseptic and antibacterial, antioxidant, anti-discoloration, etc. The following are the details of the role of acid flavoring agents in food production. Various acid flavoring agents due to the different chemical structures will produce different acidity, acidity acuity, and taste speed, and give the food a different acidity style. Citric acid produces a pleasant and refreshing acidity, but the taste disappears quickly; malic acid produces a slightly bitter acidity, and its acidity is slower to produce and disappear than citric acid; tartaric acid has a weak astringency and a strong fruit flavor, especially in grape products can produce a "natural acidity" feeling; phosphoric acid has a weak astringency and a strong fruit flavor. Phosphoric acid has a weak astringent taste, especially in cola-type beverage products that can provide a unique sour taste.
