Assessment of vernonia amygdalina as a substitute for hop brewing.

Babalola, G.O. and Okoh, A.I.

Abstract
The effects of a methanol extract of Vernonia amygdalina (also known as bitter leaf), a tropical African plant used in Nigeria as a food vegetable and an ingredient in traditional medicines, on brewers' yeast and on a range of bacteria and fungi isolated from sorghum (the principal brewing cereal in Nigeria) were studied as part of an investigation into the suitability of bitter leaf extract for use as a hop substitute in brewing. Bitter leaf extract was found to retard the growth of the fungal isolates (two species of the genus Aspergillus) and to inhibit the growth of the bacteria (Bacillus circulans, Aerococcus viridans, Clostridium perfringens, an unidentified species of the genus Micrococcus and two types of which neither the species nor genera could be identified), but had no adverse effects on brewers' yeast. Indeed, once the yeast had adapted to the bitter leaf extract, its growth rate and alcohol production were actually slightly better than in the controls.
Keywords : bacteria brewers' yeast contamination fermentation fungi growth hop substitute inhibition performance properties