Malic acid is a naturally occurring organic compound found in various fruits, particularly in apples, which is why it is often associated with their tart flavor. It plays a crucial role in the Krebs cycle, a key metabolic pathway that helps produce energy in living organisms. In addition to its role in metabolism, malic acid is commonly used as a food additive to enhance flavor and preserve freshness. It is also found in some skincare products due to its exfoliating properties, helping to improve skin texture and appearance.