Investigating the composition of fatty acid, tocopherol, and sterol contents and antioxidant capacity of oils from the seeds of Abelmoschus esculentus L. growing in Algeria.

Abstract

Background/aim: Vegetable oils are considered a vital source of energy when glucose cannot be utilized. Therefore, research on new sources of oil that demonstrate nutritional value is necessary. Okra (Abelmoschus esculentus), a member of the Malvaceae family, is a remarkable botanical specimen due to its various uses; its roots, stem, leaves, fruits, and seeds are all valued for their nutritional, therapeutic, and industrial value. This study aims to demonstrate okra's fatty acid (FA) composition, tocopherol content, and sterol content and evaluate the antioxidant activity of the oils extracted from okra using three solvents.

Materials and methods: The initial part of this study involved oil extraction using the Soxhlet apparatus with various solvents, followed by the conversion of FAs into methyl esters for analysis via gas chromatography. The second part focused on quantifying tocopherols and sterols using the Emmerie-Engel and Liebermann-Burchard methods, respectively. In the final part, the antioxidant activity of okra oils was measured using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical test.

Results: According to the findings, palmitic acid (28.43%-39.83%) was the primary saturated FA, whereas linoleic acid (19.58%-44.07%) and oleic acid (21.60%-23.59%) were the primary unsaturated FAs. Additionally, the results indicate that the oil extracts from okra seeds contain a substantial amount of tocopherols and a significant quantity of sterols. The results of the DPPH assay show that, while the antioxidant capacity is lower than that of vitamin E, it exceeds that of other vegetable oils.

Conclusion: Our research findings have allowed us to classify this oil as an edible vegetable oil.