Total Phenolics and Antioxidant Capacity of Some Nigerian Beverages

Abstract

The aqueous extract of Nigerian beverages namely: fortified cocoa powder (Samples; FCA , FCB ,FCC ,FCD) Pure cocoa powder (PCA, PCB), coffee (C), ginger (G) and Tea samples (Green, TA, TB) were assayed for total phenols, flavonoids, Vitamin C and radical scavenging abilities using four different in vitro antioxidant assay methods. Coffee contains the highest amount of total phenols (135.71±0.92mg/g) and Vitamin C. (62.90± 2.97mg/g). The highest amounts of flavonoids were found in all the tea samples (10.0± 0.00mg/g). Green tea and coffee had the highest 2, 2-diphenyl-1-picrylhydrazyl
radical [DPPH] radical scavenging ability. Green tea also had the highest radical scavenging ability as measured by the 2, 2-azino-di-[3-ethylbenzothialozine-sulphonic acid] [ABTS] radical scavenging ability and ferric reducing antioxidant property [FRAP]. (1.04± 0.037mg/g and 1235.88 ± 22.67mmol/g
respectively). Cocoa powder (PCA) had the highest iron II chelating ability (38.46 ± 2.72mg/g). The total phenolic content of the beverages had good correlation with total flavonoids, DPPH, ABTS and FRAP radical scavenging abilities with r values higher than 0.7. Vitamin C assay correlated well with DPPH
free radical scavenging ability assay (r = 0.73) while iron (II) chelation ability correlated fairly with vitamin C (r = 0.43). The results suggest that the beverages possess significant radical scavenging ability that may be due to the presence of the antioxidant.