A COMPARISON OF SOME CHEMICAL PROPERTIES OF GARCINIA KOLA AND HOPS FOR ASSESSMENT OF GARCINIA BREWING VALUE

摘要

Some chemical properties of a species of tropical seed, Garcinia kola, were assessed and compared with those of hops. Methanol and chloroform extracts of both materials were positive to the lead acetate test. Paper and thin-layer chromatographic analyses suggested the presence of similar active ingredients in samples of both hops and the Garcinia kola species, as they exhibited similar solvent fronts and had the same R_f values. Spectrophotometric analyses of both samples showed functional-group bond stretches appearing at similar wavelengths in the infrared, while maximum UV absorbance was at 325 nm for the fresh extracts of both materials. The UV absorbance of both hops and Garcinia kola shifted from 325 to 355 nm after storage of the extracts for 60 days, while the α-acids present in the fresh extracts of both materials were lost after 60 days of storage and β-acids accumulated after this period, probably due to isomerization.