THE POTENTIAL OF GESHO (RHAMNUS PRINOIDES L. HERIT) AS SUBSTITUTES FOR HOP (HUMULUS LUPULUS) IN BEER PRODUCTION

Abstract

Rhamnus prinoides (gesho) which is belongs to the family Rhamnaceae and order Rhamnales is a dicotyledonous angiosperm plant. In Ethiopia, the plant is utilized as a bittering agent in local alcoholic beverages. Due to its bittering substance compositions it could have the potential to be used as a raw material for alcoholic beverages. However, knowledge of its potential as a hop substitute during alcoholic beverage production is limited. The major goal of this research was to investigate the potential of R. prinoides as a raw material substitute for hops in the production of alcoholic beverages. Bittering substance of R. prinoides and physic-chemical of finished beer were done. Four beer types were identified and designated as A, B, C and D (control). The analysis of key brewing variables of the R. prinoides was as follows: total resin (15.96-16.02%), ISO-alpha acid (1.17-1.45 mg/l), alpha acid (1.44-1.92 mg/l), essential oil (3-.0-3.07 %), were obtained. Beer type C (7.4+0.01%w/w and 9.5+0.01%v/v) has been shown significantly (p<0.05) greater concentration of alcohol in comparison with other beer types. Real degree of fermentation value of beer type D (66.29+0.03%) was significantly (p<0.05) different compared with other beer types. Bitterness value (2.2 to 2.8) of the beer produced by R. prinoides was in the range of the values (0-100) of common hopped beer. The bitter substance compositions and key brewing variables of beer produced by R. prinoides are comparable with hop. This indicates that R. prinoides can serve as a substitute for hops in the breweries.