|El rassi, Ziad|
Submitted to: Journal of Separation Science
Publication Type: Peer reviewed journal
Publication Acceptance Date: 5/6/2008
Publication Date: 8/1/2008
Citation: Bannore, Y.C., Chenault, K.D., Melouk, H.A., El Rassi, Z. 2008. Capillary electrophoresis of some free fatty acids using partially aqueous electrolyte systems and indirect UV detection: Application to the analysis of oleic and linoleic acids in peanut breeding lines. Journal of Separation Science. 31:2667-2676. Interpretive Summary: Due to their importance in the food industry, the analysis of fatty acids in food plays a key role in controlling various parameters like product stability, quality and chemical properties of edible oils and fats. Peanuts are composed principally of oils (44-56%) and proteins (22-30%). Peanuts with normal oleic content go rancid on the shelf in about a year. High oleic acid content along with low linoleic acid content is beneficial in increasing product shelf life, product flavor, decreasing rancidity and also offers consumers health advantage by reducing the blood level of LDL cholesterol. Peanut seeds are classified as high oleic if the oleic acid content is 70% or greater while they fall under normal oleic acid category if the oleic acid content is less than 70%. In this study, peanut oil was evaluated for its fatty acids composition, e.g., oleic acid and linoleic acid contents using a technique called capillary electrophoresis which is very accurate but uses only a small amount of material and preserves seed vitality. The extraction procedure of fatty acids from peanut oil was very reproducible with a ~97% recovery from the seed. This is the first report on the use of capillary electrophoresis to determine fatty acid profiles of peanut seed. This method will allow accurate but non-destructive screening of peanut seeds for high oil content and will be extremely beneficial to peanut breeding programs.
Technical Abstract: This study has shown for the first time the suitability of CE with a partially aqueous electrolyte system for the analysis of free fatty acids (FFA's) in small portions of single peanut seeds. The partially aqueous electrolyte system consisted of 40 mM Tris, 2.5 mM adenosine-5'-monophosphate (AMP) and 7 mM alpha–cyclodextrin (alpha–CD) in NMF-dioxane-water (5:3:2, v/v) mixture, pH 8-9. While AMP served as the background UV absorber for indirect UV detection of the FFA's, the alpha–CD functioned as the selectivity modulator by affecting the relative effective electrophoretic mobilities of the various FFA's due to their differential association with alpha–CD. This CE method allowed the screening of peanut seeds for their content of oleic and linoleic acids, which is essential in breeding of peanuts of high oleic acid content. The extraction method of FFA's from peanut seeds is very reproducible with high recovery approaching quantitative yield (~ 97% recovery).