A comparison of methods used to determine the oleic/linoleic acid ratio in cultivated peanut (Arachis hypogaea L.)

Authors: Chamberlin, Kelly; Anglin, Noelle; TILLMAN, BARRY - University Of Florida; DILLWITH, JACK - Oklahoma State University; MADDEN, ROBIN - Oklahoma State University; PAYTON, MARK - Oklahoma State University; Bennett, Rebecca

Submitted to: Agricultural Sciences
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/13/2014
Publication Date: 2/18/2014
Publication URL: https://handle.nal.usda.gov/10113/58433
Citation: Chamberlin, K.D., Barkley, N.L., Tillman, B.L., Dillwith, J.W., Madden, R., Payton, M.E., Bennett, R.S. 2014. A comparison of methods used to determine the oleic/linoleic acid ratio in cultivated peanut (Arachis hypogaea L.). Agricultural Sciences. 5(3):227-237.

Interpretive Summary: Peanuts are a cheap source of protein compared to cheese and red meat and a good source of essential vitamins and minerals and are thus a common component of many oil and food products. The fatty acid composition of peanuts has become increasingly important with the realization that the onset of rancidity is dependent upon oleic acid content. One thing researchers and producers in all growing regions have in common is the growing desire to produce peanuts possessing high oleic/low linoleic acid content. Most peanut breeding programs screen breeding lines in early stages of development for the high oleic trait. The objective of this study was to compare four methods, capillary electrophoresis (CE), gas chromatography (GC), near-infrared reflectance spectroscopy (NIRS), and real-time polymerase chain reaction (RT-PCR), with regards to accuracy when determining the oleic acid content of a single peanut seed. Three hundred ninety (390) seed, spanning twenty-three (23) genotypes and all four peanut market-types, were individually tested by each method. Percent accuracy levels for rating individual seed as H ranged from 97.4% (NIRS) to 99.5% (CE) using GC ratings as the standard. All of the methods examined in this study carry only a minor risk for miss-classification (loss of material) and are suitable for use by peanut breeding programs in early generation breeding line screening.

Technical Abstract: Peanuts are a cheap source of protein compared to cheese and red meat and a good source of essential vitamins and minerals and are thus a common component of many oil and food products. The fatty acid composition of peanuts has become increasingly important with the realization that the onset of rancidity is dependent upon oleic acid content. A high oleic/low linoleic acid peanut has an increased shelf life of up to 10 fold that of a normal peanut. These facts have resulted in the peanut industry's increasing desire for high oleic peanuts and the incorporation of the high oleate trait into newly released varieties. Early generation screening of breeding lines for high oleic acid content greatly increases the efficiency of developing new peanut varieties. The objective of this study was to compare four methods, capillary electrophoresis (CE), gas chromatography (GC), near-infrared reflectance spectroscopy (NIRS), and real-time polymerase chain reaction (RT-PCR), with regards to accuracy when determining the oleic acid content of a single peanut seed. Three hundred ninety (390) seed, spanning twenty-three (23) genotypes and all four peanut market-types, were individually tested by each method. Percent accuracy levels for rating individual seed as H ranged from 97.4% (NIRS) to 99.5% (CE) using GC ratings as the standard. All of the methods examined in this study carry only a minor risk for miss-classification (loss of material) and are suitable for use by peanut breeding programs in early generation breeding line screening.