Abstract:
The role of phenolics and saponins in contributing to bitterness in marama beans, an underutilized
legume, especially when roasted, was investigated. Marama beans were roasted at 150 C for 20, 25 or
30 min, then dehulled to separate cotyledons, and pastes were prepared from these. Water extracts were
prepared from full fat and defatted flours from roasted and unroasted marama cotyledons. A sensory
panel evaluated the sensory attributes of marama pastes and water extracts. Marama water extracts were
analysed for total phenolic content, phenolic composition and saponin content. Roasting of marama
beans for more than 20 min resulted in negative properties, such as bitterness. The major extractable
phenolic acids present in marama water extracts were gallic and protocatechuic acids which increased
as a function of roasting time. Saponin content of the water extracts was in the range of 55–63 mg/l.
The identified phenolic acids, saponins and other as yet unidentified compounds may contribute to the
perceived bitterness.
