Chemical Composition, antioxidant activity, functional properties and inhibitory action of unripe plantain (M. Paradisiacae) flour
In this study, an evaluation of the chemical composition, antioxidant activity, functional properties and inhibitory action of the extract of unripe plantain flour on 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical was carried out. Chemical analysis of the flour showed that it contained significant quantities of dry matter (48.00 ± 3.96%) and starch (31.10 ± 0.44%) but was low in phenol (1.42 ± 0.03%), protein (3.15 ± 0.042%), ash (5.50 ± 0.42%) and total soluble sugar (0.64 ± 0.001%) (p < 0.05). The antioxidant activity of the extract as determined by the quantities of peroxidase (52 ± 0.00%) and reducing power tests indicated that the flour had a strong antioxidant activity while the inhibitory capacities of the extract and quercetin on DPPH radical were 78.57% and 5.32ug/ml respectively. Analysis of the phytochemical compositions of the using the Association of Official Analytical Chemists (AOAC) and the gravimetric method of Harbone showed that it contained 1.58 ± 0.04% tannin, 1.82 ± 0.05% saponin, 1.37 ± 0.05% alkaloid and 0.98 ± 0.00% flavonoid. The unripe plantain flour was found to have good functional properties in addition as indicated by the values obtained for water solubility index (3.38 ± 0.007%), water absorption capacity (1.25 ± 0.35g/g) and bulk density (0.94 ± 0.014gml-1).These findings suggest that unripe plantain could serve as a good source of natural antioxidants with free radical scavenging activity. In addition, it could have a wider utility in alcohol production, food and sugar industries and as a drug binder and disintegrant in pharmaceuticals.
Key words: Antioxidant Activity, Chemical Composition, Functional Properties, Plantain flour, Reducing power, Percentage inhibition.