Chemical Composition, Antioxidant Activity and Nutritional Potential of Two Species of Okra: Abelmoschus caillei and Abemonchus moschatus

Abstract

This work aims to study the intervarietal variation of chemical and biochemical characterization and antioxidant capacity in fresh immature fruits of four varieties of Abelmoschus caillei and one variety on Abelmoschus moschatus. The phytochemical screening of fresh immature fruits powder was estimated using the experimental methodology of Houghton et al. [1]. Total phenolic content was determined by the method of Folin-Ciocalteu while total flavonoid and condensed tannins content were estimated using the AlCl3 method and vanillin method respectively. The antioxidant capacity in the forms of DPPH (2, 2-diphenyl-1-picrylhydrazyl) and ferric reducing/antioxidant power (FRAP) analysis was evaluated by spectrophotometric methods. Protein and sugar contents were evaluated by the method of Gornall [2] and Dubois [3]. Atomic absorption spectrophotometry was used for mineralogic analyses. The phytochemical screening revealed in fresh immature fruits of A. esculentus the presence of catechin tannins, mucilages, flavonoids, leuco-anthocyanins, reducing compounds, sterols and terpenes. Variety V61 seems to be the richest in total polyphenols (28.655 mg EAG/100mg of dry matter) and in flavonoïds (71.638 mg CQ/g of dry matter). However, condensed tannins contents are substantially low. Variety V58 of A. caillei had the highest content of condensed tannins (13.602 ± 0.220 mg EC/g of dry matter). The highest protein content is observed in the variety V61 (21.546 ± 0.017 g/100 g). The zinc and iron contents are relatively low. Varieties V58 (58 mg/kg) and V55 (36 mg/kg) showed the high contents of zinc and iron. The copper content varied from 10 mg/Kg to 12 mg/kg. At 1mg/ml, the inhibition percentage of DPPH radical scavenging activity ranged from79.81 to 99.26%. The variety V61 had the highest DPPH scavenging capacity. The highest ferric ion reduction capacity was observed with the variety V55 (57.91 mmol EAA / g). Therefore, all varieties of okra studied are a potential source of nutrients and antioxidants that can be used in pharmaceutical and food preparations.