• Apr 3, 2026 Malic Acid Isomers rarely encountered in nature. Key Takeaways Malic acid exists in multiple isomeric forms, primarily as L-malic acid and D-malic acid, which are enantiomers (mirror images). L-malic acid is the naturally occurring form, contributing significantly to the sour taste of fruits. The differen BY Buck Tillman-D'Amore