The Effect of Traditional Primary Processing of the Shea Fruit on the Kernel Butter Yield and Quality
The influence of three traditional unit operations (fruit storage, par-boiling duration and nut drying method) in the primary processing of the shea fruit in Ghana for the marketable kernel was assessed. Mouldiness in kernels Butter Yield (BY) and Free Fatty Acid (FFA) were evaluated as standard quality parameters. All kernels irrespective of the duration of par-boiling attained the desired 7-7.5% moisture content in 7 days when solar dried while the mat and floor took 11 and 14 days to dry, respectively. Parboiled kernels longitudinally cut, indicated very mouldy kernels from the floor dried kernels resulting in significantly higher levels of FFA in the butter compared to those from mat and solar dried kernels. The moulds isolated and identified from the parboiled kernels were Aspergillus tamari, Aspergillus wentii, Aspergillus terreus, Aspergillus versicolor, Aspergillus flavus, Fusarium avenaceum, Rhizopus stolonifer, Rhizoctonia and Penicillium species. Non parboiled kernels, irrespective of the drying method had no mouldy nuts but high FFA (19.10-19.99%). Both parboiling duration and drying method significantly affected BY and FFA levels. Fruit storage before depulping negatively affected the quality of the resulting butter. Drying method had a significant effect on the shea kernel and butter quality. Solar and mat drying could therefore be adopted as part of the first step in the primary processing for good quality shea butter. Storage of fruits beyond three days before depulping adversely affected kernel and butter quality.