Author
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Warner, Kathleen |
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Submitted to: Journal of Food Lipids
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 3/1/2009 Publication Date: 5/1/2009 Citation: Warner, K.A. 2009. Oxidative and Flavor Stability of Tortilla Chips Fried in Expeller Pressed Low Linolenic Acid Soybean Oil. Journal of Food Lipids. 16:133-147. Interpretive Summary: Polyunsaturated vegetable oils such as soybean and sunflower are usually unsuitable for commercial frying because they are not resistant to deterioration that occurs during this process. In the past, oils were hydrogenated and contained additives to produce oil stable enough for frying and for longer shelf life of foods to solve this problem. Now, food manufacturers are looking for alternatives to hydrogenated oils because they contain trans fatty acids. To improve oil stability, soybean and sunflower oils have been modified by traditional plant breeding to change the fatty acid compositions. In addition, expeller pressing, an alternative method to extract oil from the oilseeds, has been shown to improve frying stability of oil. In this study, we combined oil with modified fatty acid compositions with expeller pressing to create an expeller pressed soybean oil with low amounts of linolenic acid, a fatty acid known to cause deterioration problems in frying oils. Results showed that the new oil had similar frying stability to hydrogenated soybean oil, but with better flavor. This new knowledge will help the oil industry find oils that have natural stability but without the need for either chemical antioxidants or chemical hydrogenation which produces undesirable trans fatty acids. These expeller pressed oils are stable oils that are healthful and produce good quality foods. Technical Abstract: Continuous pilot plant frying studies were conducted for potato chips using five oils: expeller pressed soybean oil (SBO); low linolenic acid expeller pressed SBO (EPLLSBO); high oleic sunflower oil (HOSUN); corn oil and hydrogenated SBO (HSBO) for 9 h of frying. The chips were aged at 25 deg C. A trained, experienced sensory panel evaluated flavor quality of fresh and aged tortilla chips. Oxidative stability was determined by hexanal analyses and oil fry life was measured by total polar compounds. During the 9 hr of continuous frying, the amounts of total polar compounds did not increase much over frying time because the frying oil was kept at equilibrium with the addition of fresh makeup oil. Potato chips fried in HOSUN or HSBO had the lowest amounts of hexanal formation. A companion study was conducted using intermittent batch frying of tortilla chips using the same oils; however, regular SBO was also included. The analyses were the same as for the potato chips. The stability of tortilla chips fried in EPLLSBO was significantly better than chips fried in SBO or EPSBO as judged by rancid flavor. Tortilla chips fried in EPLLSBO had significantly lower amounts of hexanal after aging at 25 deg C for 4 months than chips fried in SBO or EPSBO. |
