Document Type

Open Access Thesis

Embargo Period


Degree Program

Food Science

Degree Type

Master of Science (M.S.)

Year Degree Awarded


Month Degree Awarded



Lipid oxidation is a major challenge faced by the food industry since it causes loss of quality in lipid containing foods which results in a decrease of shelf life. In order to delay the oxidation in lipids, food industries make use of antioxidants such as EDTA (ethylene diamine tetraacetic acid), BHA (tbutyl-4-hydroxyanisole), BHT (t-butyl-4-hydroxytoluene), and TBHQ (tert-butyl-hydroxyquinone). However, these antioxidants are chemically synthesized and consumers desire simpler and cleaner labels without artificially synthesized antioxidants. Also, artificially synthesized antioxidants such as t-butyl-4-hydroxyanisole (BHA) can cause cancer in humans. Previous studies have shown that phospholipids such as phosphatidylethanolamine (PE) and phosphatidylcholine (PC) affect the activity of nonpolar antioxidants such as -tocopherol in bulk oils. PE when added to stripped soybean oil containing 100 M of -tocopherol was able to improve oxidative stability of the oil. However, PC decreased the activity of -tocopherol or had no effect. HPLC demonstrated that tocopherols were regenerated by PE which explains its synergism with - tocopherol. This study evaluated the effect of -tocopherol with varying levels of PE in stripped soybean oil. vi Additionally, antioxidant activity of -tocopherol has been shown to increase with increasing PE/PC ratio in lecithin. This study also examined the possibility of converting PC to PE in egg lecithin which will can be further used with -tocopherol. The enzyme phospholipase D was used for the conversion since it has been shown to have transphosphatidylation activity with phospholipids. The synergism of the modified lecithin with -tocopherol was analyzed in stripped soybean oil as well as in commercially refined oils. KEYWORDS: phospholipid, antioxidant, lipid oxidation, tocopherols, lecithin.

First Advisor

Eric Decker