... agent, preservative and antistaling agent in food and beverage industry. Citric Acid is mainly used as acidulant, flavouring agent, preservative and ... ), sodium citrate (blood transfusion agent) and so on. Moreover, citric acid is also used as the acidulant in lots of medicines ... . 3. In the chemical industry, esters of citric acid can be taken as the non-toxic plasticizer to make ...