Antioxidant properties of beverages from graded mixture of green/roasted coffee and hibiscus sabdariffa calyx flours

Abstract

In an attempt to develop functional beverage that is health promoting, this study was carried out to investigate the antioxidant potential of beverages (powders) developed from green/roasted coffee and Hibiscus sabdariffa calyx. Green coffee beans were roasted; graded blends of green or roasted coffee beans were blended with graded amount of Hibiscus sabdariffa calyx and assessed for total phenolics, flavonoids, antioxidant properties, sensory qualities and proximate composition in the laboratory. The results showed that all the beverages exhibited good antioxidant properties with total phenolic ranging between 36.26–351.35 mg GAE/g, total flavonoids 13.74–104.05 mg QE/g, FRAP 30.30–175.89 mg GAE/g, ABTS 14.45–42.65%, DPPH 92.23–95.39%. The proximate composition, moisture content 4.62–11.55, total ash 4.74–8.00, crude fat 11.88–14.31, crude fiber 8.25–10.64, crude protein 4.32–9.51, 53.62–57.66. The sample made from 70% Hibiscus sabdariffa calyx and 30% green coffee powder showed the highest antioxidant properties comparable with standard antioxidant agent having total phenol of 351.351 mg GAE/g, total flavonoids 104.05 mg QE/g, FRAP 175.89 mg GAE/g, ABTS 42.65%, DPPH 95.39%. These findings showed that the blends have the potential to serve as a source of natural antioxidant and can stabilize free radicals. Hence can serve as a functional beverage.