Tartaric Acid
A crystalline acid that is naturally present in fruits and vegetables, especially grapes. It is used in food and beverage products as a sour flavoring agent, antioxidant, acid, emulsifier (to promote and/or maintain the mixture of unblendable liquids), sequestrant (to improve the quality and stability of a product), and synergist (an ingredient that when used in combination with another ingredient(s) has an effect greater than the sum of the individual effects). When combined with baking soda it can be used as a leavening agent.