GC‐MS and antioxidant capacity analyses of cowpea seeds oils

Abstract

PurposeThe cowpea plant, being affordable and protein‐rich, is considered poor man's meat. The aim of this paper is to undertake a detailed investigation regardingin vitrototal antioxidant capacity (TAC) and chemical constituents of the vegetable oils from seeds of this plant, taking its nutritional value into consideration.Design/methodology/approachVegetable oils of different indigenous cowpea varieties were obtained using soxhelt extraction assembly and subjected to GC‐MS analyses and various antioxidant assays including 2,2′‐azinobis(3‐ethylbenzothiazoline‐6‐sulpohonic acid) (ABTS) radical cation scavenging, ferr, 2.2′‐diphenyl‐1‐picrylhydrazil (DPPH) radical scavenging, total phenolic contents (TPC), lipid peroxidation inhibition, and iron chelation activity.FindingsVarious chemical constituents including different hydrocarbons, tocopherols, ketones, fatty esters, estragole and cedrene were identified. TPCs were found to be 5.439, 5.7279, 7.6126, 6.7573 and 10.0591 mg/L gallic acid equivalent for S.A. Dandy, Elite, White Star, CP‐386 and FBD Rawan varieties, respectively. Employing ABTS radical decoloration assay a significant linear correlation (R2=0.997, 0.996, 0.997, 0.996 and 0.997 for S.A. Dandy, Elite, White Star, CP‐386 and FBD Rawan varieties, respectively) was found between the percent inhibition of ABTS radical cation and the amount of vegetable oils. The percent inhibition of the Fe(II)‐Ferrozine complex formation was found to be 29.45, 53.76, 82.91, 86.59 and 57.87 for the same varieties, respectively.Originality/valueGC‐MS and standardin vitroantioxidative capacity analyses data clearly demonstrated the potency of the cowpea as antioxidant and radical scavenger plant which may be used as a good source of natural antioxidants. The plant seeds may prove a better and cost‐effective substitute of expensive food items.