Functions of malic acid include:

1. Antioxidant: Malic acid acts as an antioxidant, helping to protect food products from oxidative damage. By inhibiting oxidation, malic acid helps maintain the quality and shelf life of various products.
2. pH control agent:It can be used to adjust and regulate the acidity or alkalinity (pH level) of food and beverage products.
3. Acidulant:As an acidulant, malic acid imparts a tart or sour taste to food and beverages. It is often used to enhance the overall flavor profile of various products.
4. Preservative: Malic acid has preservative properties, making it useful for extending the shelf life of certain food items. It inhibits the growth of yeasts and some bacteria, helping to maintain product freshness and quality over time.
5. Flavor enhancer:. It works synergistically with other flavor compounds to create a more robust and satisfying taste experience.
6. Flavor modifier:It can balance sweetness, enhance fruitiness, or provide a sharper, more distinct flavor profile, depending on the specific application.

On the preservation function side of things, this acid is a powerful inhibitor of the growth of yeasts and some bacteria. It is more effective than acetic acid and lactic acid in inhibiting  thermophilic bacteria but is not as effective as lactic acid in suppressing the growth of Listeria monocytogenes.