Utilization of bitter vegetable leaves (Gongronema latifolium, Vernonia amygdalina) and Garcinia kola extracts as substitutes for hops in sorghum beer production

Abstract

Sorghum beer was brewed using extracts of ‘utasi’ leaf (Gongronema latifolium), bitter leaf (Vernonia amygdalina) and bitter kola (Garcinia kola) to impact bitter taste and flavour as substitutes for hops used for beer production. The physicochemical and sensory characteristics of the beer samples were evaluated. The results showed that ‘utasi’ leaf, bitter leaf and bitter kola flavoured beer samples had alcohol values in the range of (12.50 - 12.55%), pH (3.37 - 4.44), specific gravity (1.0140 - 1.0400), titratable acidity (0.107 - 0.328%), volatile acidity (0.003 - 0.103%), soluble solids (0.12 - 0.97%), moisture content (95.71 - 98.37%), protein (0.17 - 0.85%), ash (0.20 - 0.29%) and fat (1.25 - 2.95%). Sensory evaluation of the beer by trained panelists (connoisseurs) showed that the utasi flavoured beer was preferred to the other beer samples and compared favourably with hopped beer in terms of flavour and taste.

Keywords: Beer production, ‘utasi’ leaf, bitter kola, bitter leaf, hops substitutes