Study of antioxidant activities of vernonia amygdalina aiming at using it as a hop substitute in the production of Rwandan traditional beers

Abstract

The study explores the potential of Vernonia amygdalina as a substitute for hops in the production of traditional Rwandan beers, with a focus on its antioxidant properties. Vernonia amygdalina, commonly known for its bitter taste and medicinal properties, was analyzed for its antioxidant activities using the ORAC (Oxygen Radical Absorbance Capacity) method. The study assessed extracts from different parts of the plant (leaves, flowers, and bark) and explored various extraction methods, including acetone/water/acetic acid, water, and ethanol-acetic acid solvents. The antioxidant capacities of the plant parts were evaluated, with the bark exhibiting the highest antioxidant activity (1514 μmol Trolox eq/g) which surpassed those of industrial Citra T90 hops (614 μmol Trolox eq/g). Further, the total polyphenol and flavonoid contents were determined, indicating the plant’s significant antioxidant potential, particularly in the leaves and bark. The results suggest that V. amygdalina could serve as an effective hop substitute, offering both antioxidant and bittering properties that could improve the quality, stability, and shelf life of traditional beers. These findings contribute to the growing body of knowledge on functional ingredients in brewing and offer a promising way for the development of healthier, locally sourced beer alternatives