Differences in Development of Oleic and Linoleic Acid in High- and Normal-Oleic Virginia and Runner-Type Peanuts

Abstract

A consistent, pure supply of high-oleic (HO) peanuts is important to certain segments of the food industry as it allows for the production of confections and other products with improved shelf-life characteristics. Peanut shellers have struggled with food industry demands for lots which contain greater than 95% high-oleic peanuts. Normal-oleic (NO) and HO cultivars of virginia and runner market type peanuts were grown during the 2012 and 2013 growing season respectively to investigate differences in fatty acid development between HO and NO peanuts. Fatty acid profiles of individual seeds from individual plants taken across the growing season were determined in relation to seed fresh weight. Fatty acid profiles of HO virginia-type seeds from the early sampling date of 78 days after planting (DAP) revealed oleic acid to linoleic acid ratios (O/L) of only 4.0 in the seeds of the greatest fresh weight. As the oleic acid concentration in many of the HO virginia-type peanuts reached 60 to 80% and the linoleic acid concentrations ranged from less than 1.0 to 10 % by the middle sampling date (106 DAP), the O/L ratios of most HO seeds were well above the industry accepted cut-off ratio of 9.0. A similar change in the fatty acids was seen in the HO runner cultivar. Increases in oleic acid and decreases in linoleic acid contents occurred in conjunction with the increased seed fresh weights. The data indicate that HO seed attain high-oleic status as physiological development progresses as seen in the changing seed fresh weight. However at the final sampling dates which corresponded to the harvest dates, O/L ratios of less than 9.0 were still present for the HO cultivars of both market types despite the fresh weight of some seeds being of potential marketable size. It was concluded that some of the perceived contamination of HO seed lots with NO seed could be the result of normal peanut development, especially in the virginia-type cultivar with the larger sized seeds.

Rainout Shelter-Induced Water Deficit Negatively Impacts Peanut Yield and Quality in a Sub-Humid Environment

“…Similarly, for peanut seed from dry fields, decrease of C18:1 and increase of C18:2 is expected; but this is based on rather indirect than direct effect of water stress. Drought usually reduces seed development and increases the proportion of immature seeds in the seed sample, i.e., more mediums, number 1's, and fall through than ELK (Dang et al, 2013); and under-developed and immature seeds have less C18:1 content (Andersen and Gorbet, 2002;Hinds, 1995;Klevorn et al, 2016;Sanders et al, 1982). But it is not clear if drought can affect C18:1 directly.…”

“…Finally, drought may delay peanut maturity from reduced growth rates (Reddy et al, 2003) and oleic fatty acid (C18:1) accumulation in the seeds. For example, C18:1 was low in immature peanut seed (Andersen and Gorbet, 2002;Hinds, 1995;Klevorn et al, 2016;Sanders et al, 1982). The C18:1 is an important quality characteristic for the new cultivars with high oleic oil chemistry because of positive effect of increased oil saturation levels on seed shelf life, i.e., delayed oxidative degradation, (Mozingo et al, 2004).…”

‘Walton’, a new virginia‐type peanut suitable for Virginia and northern U.S. growing regions

“…From 1 May to the end of October in Virginia, 1,800 °C d can be accumulated in some years, but long periods of spring rainfall, as in 2018 and 2019, may substantially delay planting, leaving insufficient time for pod and seed maturation. This could reduce yield, grade characteristics, and the oleic fatty acid content (Dang et al., 2013; Klevorn et al., 2016 ). One way to estimate maturity is by digging at different days from planting (DFP), for example, 130 and 145 DFP, and then comparing yield.…”

“…Irregular rainfalls with soil moisture extremes and increased temperatures, caused by global climate change, are projected to become more intense and frequent in the future (Wheeler & Broun, 2013;World Bank, 2010). This can reduce yield and delay peanut maturation with a direct effect on the C18:1 accumulation (Andersen & Gorbet, 2002;Hinds, 1995;Klevorn et al, 2016;Reddy et al, 2003;Sanders et al, 1982). To hasten the development of more drought-tolerant virginia-type peanut cultivars, identification of drought-tolerant lines is crucial.…”

Measurements of Oleic Acid among Individual Kernels Harvested from Test Plots of Purified Runner and Spanish High Oleic Seed

“…As peanuts mature, it's established that the oleic acid (%) increases while linoleic acid (%) decreases, hence the overall O/L ratio increases with maturity (Pattee et al, 1974;Klevorn et al, 2016). However, such changes are poorly understood at the single kernel resolution across populations of interest.…”