ABSTRACT

This dissertation showed the actualization of the concept of a multi-speed prototype dehuller for African breadfruit (Treculia africana) seeds. Results proved that parboiling time, holding time and dehulling speed had various effects on the dehulling efficiency of the machine and qualities of African breadfruit seeds. The linear effects of the parboiling time, holding time and dehulling speed as well as their interaction significantly (P < 0.05) affected the dehulling efficiency of the machine. Optimization of the process indicated that up to 97% dehulling efficiency and segregation could be achieved with the combination of the process variables investigated. The linear and quadratic effect of the process variables and their interaction did not cause adverse reduction/impact on the proximate composition, mineral and amino acid profile of the breadfruit samples. Optimization of the process revealed significant (P < 0.05) nutrient retention and reduction of antinutrients concentration. The functional and pasting properties of the seed flour were significantly (P < 0.05) enhanced which suggest their suitability in both domestic and industrial scale food formulation. The microbial load of the samples did not exceed the safe limit (7 x 10⁶cfu) and sensory assessment showed no objectionable impact on the attributes of the seeds. Generally, the design, fabrication and application of the dehuller proved effective in reduction and elimination of the challenges surrounding the processing of Treculia africana. This further strengthens potential national and international scale processing of African breadfruit for direct consumption or as raw material for other food production. The coefficient of determination for machine performance, proximate composition, amino acid profile, mineral composition, pasting properties, physicochemical properties, antinutrient composition, sensory attributes, microbial qualities and functional properties of the breadfruit ranges between 0.8692 to 0.9999, 0.0000 to 0.9639, 0.9692 to 0.9997, 0.0000 to 0.9999, 0.9951 to 1.0000, 0.9938 to 1.0000, 0.9670 to 0.9997, 0.9956 to 0.9998, 0.9995 to 0.9997 and 0.9715 to 0.9995 respectively. These values imply a strong relationship between the responses and the independent variables (parboiling time, holding time, and dehulling speed) except for fat (0.0000), fibre (0.1984) and calcium (0.0000) which show little or no relationship. This research work was faced with challenges of inadequate funding and the incessant erratic power supply to power the high capacity machine used for the construction. Sequel to the observations made from this dissertation, the following recommendations would be helpful; the dehulling sections and separation units should be increased, combination of more process varriables to assess the performance of the machine and effects on the breadfruit samples, use of the machine in dehulling or processing of other seeds (legumes, cereals, etc.) in order to check its performance and the test for toxicity may be carried out despite the fact that stainless steel was used at all food contact surfaces.