The effects of moisture and fermentation periods on the physical and biochemical properties of ‘amelonado’ and ‘hybrid’ varieties of cocoa beans

Abstract

The effect of moisture content (5-24%) on some physical and compressive properties of the ‘Amelonado’ and ‘Hybrid’ varieties of cocoa beans were studied. Alongside, the effects of fermentation periods (0-8 days) on the biochemical profiles of the dried beans were studied in three morphological parts (whole bean, nib and shell). Four experiments were separately conducted as completely randomized, factorial designs. Compared to the ‘Amelonado’ variety, the axial dimensions (viz. length, width and thickness) of the ‘Hybrid’ cocoa beans were significantly higher (p < 0.05). With increasing moisture content, the bean mass, particle density, porosity, angle of repose and the coefficient of friction increased linearly in both varieties while inversely, the bulk density decreased. Increasing the moisture content decreased the rapture force with lesser deformation. As the beans were compressed, there was ca. 2 to 3-fold higher fracture resistance in the horizontal orientation compared to the vertical orientation. There were variable effects of fermentation period on phytochemicals including polyphenols, free fatty acid (FFA), titratable acidity, total soluble solids and pH in the spatial regions. Irrespective of fermentation period, the FFA content of the whole bean, nib and bean shell of both varieties remained within the acceptable range (<1.75%). The ash and carbohydrate content in the respective spatial regions of both varieties increased (P < 0.05) with fermentation duration. However, as the fermentation period increased the protein content in all the different parts of the beans decreased, irrespective of the variety.