Submitted to: Peanut Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/18/1996
Publication Date: N/A
Interpretive Summary: Changes in quality of many agricultural commodities have been made through classical plant breeding. Identification of plant material with useful characteristics is critical to those breeding efforts. The "hairy" peanut (plant parts have tiny hairs) was identified in Mexico as having very good flavor and was collected for evaluation. This study examined oil, oil stability, sugar and amino acid composition of six lines of the hairy peanut. Oil and oil stability characteristics were generally not as good when compared to two standard U.S. grown cultivars; however, two of the "hairy" lines contained less than 37 percent oil compared to common values of ca. 49 percent. This finding may have application in breeding for low oil content cultivars considering the current trend in consumer preferences for low fat products. The "hairy" peanuts contained more sugar than the two standard cultivars and this may be important in breeding for increased sweet taste in peanut products. The results of this study indicated that some useful characteristics are found in this plant material but further evaluation of quality variability associated with environment and use in breeding programs will determine final usefulness.
Technical Abstract: The biochemical composition of peanut seed collected from six landrace accessions of Arachis hypogaea var. hirsuta cultivated in Mexico was investigated. Florida-grown runner- (Florunner) and virginia-type (NC 7) seed were used as comparative controls. Free amino acids, free sugars, and tocopherols were analyzed by high-performance liquid chromatography. Fatty acid methyl esters were prepared from hexane-extracted oil and analyzed by gas-liquid chromatography with flame ionization detection. Oil stability was determined using oxidative stability instrumentation which measures the rate of accumulation of volatile lipid decomposition products. In general, var. hirsuta peanuts contained more free sugars (141.2-178.5 æmoles/g defatted meal) and free amino acids (18.5-37.2 æmoles/g defatted meal) than Florunner (126.6 and 20.1 æmoles/g defatted meal free sugars and free amino acids, resp.) or NC 7 (121.5 and 20.3 æmoles/g defatted meal). Tocopherol levels (in oil) ranged from 295 to 377 ppm, which was lower than Florunner (425 ppm) but roughly equal to the level found in NC 7 (303 ppm). Total oil content ranged from 34%-45% for var. hirsuta seed compared to 46% and 45% for Florunner and NC 7, respectively. Oleic acid/linoleic acid ratios ranged from 0.76-0.95 for the var. hirsuta peanuts compared to runner (2.1) and virginia (3.1) controls. These oil quality characteristics were reflected in the much shorter lipid decomposition times for var. hirsuta seed (7.5-8.0 h) compared to Florunner (11.2 h) or NC 7 (14.7 h)