Mechanism of off-color formation in potato chips fried in oil systems containing ascorbic acid as a stabilizer

The use of alternative, green antioxidant (AOX) systems is demanded by consumers. Natural AOX systems pose significant challenges. For example, in frying applications, these AOX can negatively alter potato chip color, one of the most important traits in consumer selection. We evaluated the role of natural AOX systems containing ascorbic acid, tocopherols, and other antioxidants in amino acid-related undesirable color formation in fried potato chips. Results indicated that both oil phase AOX and potato factors are critical to generation of off-color formation in fried potato chips through Maillard type reactions. Ascorbic acid solubilization in oil and migration to the chip surface play key roles in observed off-color formation. However, multiple complex reactions may be responsible for color development, which may involve food matrix components. Contributions of AOX other than ascorbic acid appear minimal. Nevertheless, some browning can occur regardless of the presence of ascorbic acid. Color formation through glutamine occurred in the absence of ascorbic acid, but its presence greatly exacerbates color generation, while color generation via asparagine is barely modulated by ascorbic acid. AOX and free amino acid concentrations, temperature, and moisture are critical factors for controlling undesirable color formation during frying with natural oil AOX systems.