Determining the Oleic/linoleic Acid Ratio in a Single Peanut Seed: a Comparison of Two Methods

ABSTRACT Peanut varieties with high oleic/linoleic acid ratios have become preferred by the peanut industry due to their increased shelf life and improved health benefits. Many peanut breeding programs are trying to incorporate the high oleic trait into new and improved varieties and are in need of diagnostic tools to track its inheritance early in development and at the single seed level. Traditionally, gas chromatography has been used to accurately determine the properties of peanut oil. Recently a method was developed to carry out this analysis by capillary elecrophoresis providing researchers with an alternative analytical platform. In this study, the use of capillary electrophoresis and gas chromatography for analysis of oleic/linoleic acid ratios are compared. Oil was extracted from approximately 0.10 g of peanut seed tissue taken from the distal end, leaving the embryonic end of the seed intact for subsequent germination. Over 100 samples inclusive of runner, Spanish and Virginia market types were processed. Oil extracts were analyzed for oleic/linoleic acid ratio using (1) capillary electrophoresis (CE) and (2) gas chromatography (GC). Results showed that the two methods are 100% in agreement in determining whether a peanut seed is “high-oleic” or “normal oleic” in oil content. Furthermore, the two methods are highly correlated (r  =  0.96; p < 0.0001) with respect to determining the exact oleic/linoleic acid ratio from each sample. Results from this study validate the use of CE as a diagnostic tool for breeding programs to identify individual high oleic peanut seed for further testing and development.