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Title: High-Temperature Natural Antioxidant Improves Soy Oil for Frying

Author
item Warner, Kathleen

Submitted to: Journal of Food Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/1/2009
Publication Date: 7/3/2009
Citation: Warner, K.A. 2009. High-Temperature Natural Antioxidant Improves Soy Oil for Frying. Journal of Food Science. 74(6):500-505.

Interpretive Summary: In this research, we found that a new antioxidant extended the frying life of regular soybean oil as well as increasing the shelf life of food fried in the oil containing the additive. As a result of limits on the use of trans fat-containing hydrogenated oils for frying in some areas of the U.S., a number of frying operations have opted to use regular soybean oil. Although regular soybean oil is excellent for salads and home use cooking, it is not usually used for frying in restaurants or by fried food manufacturers because it breaks down easily at the high temperatures used for frying. Therefore, methods are needed to help improve regular soybean oil so it does not deteriorate in quality during commercial frying. We found that a new citric-acid based antioxidant increased the frying life of regular soybean oil when compared to the same oil without the antioxidant. In addition, the antioxidant also extended the shelf life of tortilla chips fried in the oil in comparison to chips fried in regular soybean oil. This new antioxidant helps to improve the quality of regular soybean oil used for commercial frying and results in better tasting, more healthful fried food.

Technical Abstract: The objectives of this study were to determine the frying stability of soybean oil (SBO) treated with a natural citric acid-based antioxidant, EPT-OILShield able to withstand high temperatures and to establish the oxidative stability of food fried in the treated oil. Soybean oil with 0.05% and 0.5% EPT-OILShield and an untreated control SBO were used for intermittent batch frying of tortilla chips at 180 deg C for up to 65 h. Oil frying stability was measured by free fatty acids (FFA) and total polar compounds (TPC). Chips were aged for up to 4 months at 25 deg C and evaluated for rancid flavor by a 15-member, trained, experienced analytical sensory panel and for hexanal content as an indicator of oxidation. Oil with 0.05% EPT-OILShield had significantly less FFA and TPC than the control. The effect of EPT-OILShield was apparently retained in aged chips because hexanal levels were significantly lower in chips fried in oil with 0.05% EPT-OILShield than in chips fried in the control. Tortilla chips fried in the control were rancid after 2 months at 25 deg C at sampling times evaluated from 25 to 65 h; however, chips fried in oil with 0.05% EPT-OILShield and used for 65 h were described as only slightly rancid after 4 months. Gamma tocopherol levels were significantly higher in the chips fried in the oil with 0.05% EPT-OILShield than in the control, helping to inhibit oxidation in the tortilla chips during storage.