SCANNING ELECTRON MICROSCOPY OF THE Theobroma cacao SEED

ABSTRACT Scanning electron microscopy (SEM) of raw, roasted, unfermented and fermented cocoa beans (Theobroma cacao L.) revealed differences in morphology as a result of treatment. A 6‐day microbial fermentation caused the testa to change from a leathery and continuous, closely adhering skin to a friable, more easily removable shell. Changes in the cotyledons were less obvious. When beans were roasted at 150°C for 20 min, the testa and endosperm became porous and brittle, and cellular contents of the germ and cotyledon became thermally coagulated. Also noted in the roasted shell were dissolution of the cutin layer accompanied by hairline fissures in the surface. Both these developments, as well as the increase in porosity, undoubtedly contribute to shell brittleness, and facilitate shell removal. Observations by SEM of the cocoa bean during various treatments may be considered useful in future quality control evaluations.