About Carboxylic Acids and Esters

A Citric acid is responsible for the sour taste of Umes and other citrus fruits. Question Can you think of other fruits that might contain citric acid  

Esters are best known for their sweet smells. For example, ethyl butanoate is responsible for the smell and taste of pineapples, and methyl butanoate is responsible for the smell and taste of apples. 

Esters are formed from the reaction of a carboxylic acid and an alcohol  

An important example of this reaction is the formation of acetylsalicylic acid (aspirin) from acetic acid and salicylic acid (originally obtained from the bark of the willow tree). 

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