The difference between DL-malic acid and L-malic acid

L-malic acid is an important organic acid, widely distributed in plant, animal and microbial cells, and its taste is close to the sour taste of apples. In 1967, the U.S. Food and Drug Administration registered L-malic acid as a safe, non-toxic, harmless, edible organic acid.

Malic acid, also known as 2-hydroxysuccinic acid, has two stereoisomers due to an asymmetric carbon atom in the molecule. In nature, it exists in three forms, namely D-malic acid, L-malic acid and DL-malic acid. DL-malic acid is a mixture of D-malic acid and L-malic acid. The naturally occurring malic acid is L-malic acid and is present in almost all fruits, with the most in pome fruits. L-malic acid is generally considered to have important physiological functions, and the D-form of DL-malic acid is physiologically ineffective.

The use of L-malic acid:
L-malic acid is an important component of fruit juice. Compared with citric acid, it has a higher acidity (20% stronger acidity than citric acid), but has a soft taste (with a higher buffer index). It has a special fragrance, and does not damage the mouth and teeth. Metabolism is beneficial to the absorption of amino acids and does not accumulate fat. It is a new generation of food acidulant.

L-malic acid in various tablets and syrups can present fruity flavor, and is conducive to absorption and diffusion in the body. It is often mixed into compound amino acid injection to improve the utilization rate of amino acids. L-zinc malate is used in toothpaste as an antibacterial agent and an anti-calculus agent, and a synthetic fragrance formulation.

L-malic acid can be used as one of the synthetic raw materials of descaling agent and fluorescent whitening agent. Added to shellac varnish or other varnishes to prevent skinning of paint surfaces, polyester resins and alkyd resins produced with this acid are special-purpose plastics.