Corn phytosteryl ferulates are composed mainly of saturated phytosterols esterified to ferulic acid. In intermittent frying studies, these compounds were shown to be highly stable antioxidants which reduced oil polymerization, total polar compounds, and tocopherol loss in the soybean oil used for frying. However, these studies were conducted using purified corn phytosteryl ferulates. As a more practical application, the objective of this study was to evaluate the effect of 0.5% and 1% corn fiber oil, extracted from corn wet fiber using hexane and providing 162 to 300 ppm corn phytosteryl ferulates, on frying oil stability during three day studies using intermittent frying of tortilla chips in soybean oil with daily oil replenishment. Oil polymerization was reduced by 50% to 80% with 1% corn fiber oil, and 11% to 60% with 0.5% corn fiber oil. In comparison, 200 ppm tert-butylhydroquinone reduced polymerization by 0 to 22%. Similar effects were demonstrated for total polar compounds, color, and viscosity. In addition, the loss of tocopherols was reduced by 3-40% with 0.5% corn fiber oil, and by 17-47% with 1% corn fiber oil. On average, around 70% of the corn steryl ferulates were retained in the oil at the end of the studies. Low levels of corn fiber oil blended with commodity oils may therefore be a practical source of corn phytosteryl ferulates as frying oil antioxidants.
