Microstructure of protein bodies in marama bean species

Abstract

Marama bean is an underutilised indigenous legume from Southern Africa. The understanding of the microstructure of marama protein bodies, the organelles of protein storage, is an important step towards the characterisation and utilisation of its protein. The protein body structures of two species of marama bean (Tylosema esculentrum and Tylosema fassoglense) were determined in comparison with soya bean (Glycine max). T. fassoglense seemed to have higher protein content than soya. Marama showed clustered spherical protein bodies surrounded by lipid bodies similar to soya bean. T. esculemtum seemed to contain smaller sized (4 ± 2 µm) protein bodies per cell as compared with T. fassoglense (7 ± 4 µm), Marama protein bodies contained spherical globoid and druse crystal inclusions, which were absent in soya. P, K, Mg and Ca were the major minerals in marama, which probably originated mainly from storage protein sites. The protein body structure of marama is similar to soya in terms of spherical shape and localisation within the parenchyma cells.