Influence of fatty acid contents and biochemical changes during storage of groundnut varieties cultivated in Tamil Nadu, India

Groundnut varieties lose their physical and nutritional qualities during post-harvest storage, although their yield is high. In this study, we assessed the fatty acid profile and changes in their content and their influence on the seed quality of groundnut varieties (TMV 13, TMV 14, CO 6, VRI 8 and BSR 2) cultivated in Tamil Nadu, India, under normal storage conditions (with moisture content <8 %). In all varieties, the electrical conductivity (EC) of seed leachate, free fatty acids and lipid peroxidation were increased with age, accompanied by decreased levels of phytate content, germination percentage and vigor index. However, the seed weight, total oil and protein contents were not considerably altered up to 7 months in all varieties. Among the varieties, VRI 8, TMV 13 and TMV 14 had less upsurge of EC (44 - 47 % increase), an indicator of membrane integrity, after seven months, but CO 6 (88.67 % increase) and BSR 2 (86.89 %) showed high EC values. The oleate/linoleate ratio was high in VRI 8 (2:1) and low in BSR 2 (1.27:1). The varieties with high oleate, VRI 8 (50.68 %) and TMV 13 (49.28 %), can be stored (with >70 % germinability) for 5-6 months, whereas CO 6, with low oleate content (42.0 %), lost its germinability (below 65 %) and vigor within 3-4 months in ambient conditions. In addition, phytate, a suppressor of oxidative reactions, was relatively high in TMV 13 and TMV 14 and low in CO 6 after 5 months. Our study reveals that all varieties (VRI 8, TMV 13, TMV 14, BSR 2) with moisture content <8 %, except CO 6, can be stored for up to five months with minimum germination standards and without loss of oil and protein contents.