In the food industry, it is used as a sour agent, a color-retaining agent, a preservative, an emulsion stabilizer for egg yolk, etc., and is also used in pharmaceuticals. It is generally believed that L-malic acid has important physiological functions, but half of the D-form in dl-malic acid is physiologically ineffective.
In the chemical industry, it can be used as one of the synthetic raw materials of descaling agent and fluorescent whitening agent. When added to shellac varnish or other varnishes, it prevents fouling of paint surfaces. Polyester resins and alkyd resins produced with this acid are special-purpose plastics.
