went? Unripe fruits often taste sour due to the  high concentration of organic acids present in  

them. One of the primary acids is called malic  acid, which contributes to the sour taste. As  

the fruit ripens, the amount of acid decreases  and the amount of sugar increases. The fruit's  

enzymes convert these acids into sugars or other  compounds, which makes the fruit sweeter. Also,  

the ripening process involves complex changes  in the fruit's metabolism, causing a shift in  

the balance of these chemicals, leading to an  overall change in taste from sour to sweet.