In food additives, Citric acid mainly used for refreshing beverages and pickled products such as carbonated drinks, juice drinks, and lactic acid beverages, and its demand varies with seasonal climate changes. Citric acid accounts for about 2/3 of the total consumption of sour agents. Adding citric acid to canned fruit can maintain or improve the flavor of the fruits in the collection, improve the acidity (lower pH) of certain low acidity fruits, reduce the heat resistance of microorganisms and inhibit their growth, and prevent acidity. The canned fruit can often undergo bacterial expansion and destruction. The addition of citric acid as a sour agent to the candy is easy to coordinate with the fruity taste. The use of citric acid in gel foods such as sauces and jellies can effectively reduce the negative charge of pectin, thereby causing the pectin molecules to hydrogen bond and gel. When processing canned vegetables, some vegetables are alkaline, and citric acid is used as a pH adjuster, which not only can play a role in flavoring, but also maintain its quality. Citric acid has chelation and pH-adjusting properties, which can increase the performance of antioxidants, inhibit enzyme activity and prolong food preservation in the processing of quick-frozen foods.