Malic acid is a four-carbon dicarboxylic acid that was first discovered by CarlWilhelmScheele in 1785 from apple juice.
It is abundant in fruits and vegetables and is currently produced by hydration of fumaric or malic acid which results in a mixture of the D and L forms.
The present use lies in the food industry as an acidulant for beverages, candy, and other foods (Goldberg et al. 2006) and in the nonfood industry, e.g., metal cleaning, textile finishing, and pharmaceuticals, and in paints.