Impact of storage on peanut seeds: Part A – long-term storage and oxidation product accumulation

Authors: Tonnis, Brandon; Wang, Mei; Wang, Ming; CHITTIBOYINA, AMAR - University Of Mississippi; ZHAO, JIANPING - University Of Mississippi; Benke, Ryan; Li, Xianran; Mobley, Mylee; Tallury, Shyamalrau

Submitted to: ACS Food Science and Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/13/2026
Publication Date: 2/20/2026
Citation: Tonnis, B.D., Wang, M., Wang, M.L., Chittiboyina, A., Zhao, J., Benke, R.L., Li, X., Mobley, M.B., Tallury, S.P. 2026. Impact of storage on peanut seeds: Part A – long-term storage and oxidation product accumulation. Journal of Agricultural and Food Chemistry. 6(3):844-852. https://doi.org/10.1021/acsfoodscitech.6c00140.
DOI: https://doi.org/10.1021/acsfoodscitech.6c00140

Interpretive Summary: Peanut seeds have about 50% oil on average. This makes them a high calorie food as well as a good source of oil for cooking and frying. However, the high oil content also makes peanuts prone to a process called oxidation over time during storage. Oils and fats are made up of different fatty acids, and certain fatty acids are more likely than others to be oxidized due to their specific chemical structure. Oxidation causes the oil to go rancid resulting in bad tasting peanuts and reduced shelf life of the oil. It also reduces the viability of the seeds over time, an important factor to consider in preserving stored oilseed collections. We compared stored peanut seeds from the USDA collection with freshly grown seeds to study the effects of storage on the oil. We identified three chemical compounds that were present in higher amounts in the stored seeds. We also found a corresponding decrease in one fatty acid that is more susceptible to oxidation. Through a series of chemical analyses, we were able to positively identify the three compounds and show that they are the products of fatty acid oxidation in stored seeds. Finally, we discussed strategies for preserving the seeds and maintaining their viability while in storage.

Technical Abstract: Peanut seeds contain approximately 50% oil, presenting a significant challenge for both short- and long-term storage due to their susceptibility to lipid peroxidation. This oxidative process can deteriorate the nutritional quality of peanut products and reduce seed viability and germination rates, posing risks for germplasm conservation, breeding programs, and the peanut industry. In an evaluation of fatty acid profiles from long-term stored seeds representing more than 8400 peanut germplasm accessions, we identified one unique (1) and two similar (2a and 2b) peaks in the GC analysis as potential chemical markers of peroxidation formed during transesterification. Subsequent analysis of 168 peanut accessions demonstrated that peaks 1 and 2b accumulated at significantly higher levels in stored seeds compared with freshly harvested seeds (0.66% vs 0.09% and 1.15% vs 0.14%, respectively). A concurrent reduction in linoleate acid content was also observed in stored seeds (29.61% vs 32.56%). Structural elucidation using NMR and GC-MS, in conjunction with comparison to authentic standards, identified peak 1 as methyl epoxystearate, derived from the epoxidation of methyl oleate, and peaks 2a and 2b as methyl coronarate and methyl vernolate, formed through epoxidation of methyl linoleate at the 9,10- and 12,13-epoxide positions, respectively. This study provides the first evidence of epoxidation products arising from oleic and linoleic acids in stored peanut seeds and establishes their potential as biochemical indicators of oxidative deterioration. In addition, we outline strategies for developing peanut cultivars with improved nutritional profiles and greater resistance to storage-related degradation. Together, these findings offer new insights into the chemical pathways underlying seed quality decline and highlight opportunities to develop peanut cultivars with enhanced nutritional stability and improved storage resilience.