Solid state fermentation of Jatropha curcas kernel cake: Proximate composition and antinutritional components

Abstract

Five fungi ( Aspergillus niger, Penicillium chrysogenum, Rhizopus oligosporus, Rhizopus nigricans and Trichoderma longibrachitum) were used in the fermentation of Jatropha curcas kernel cake for a 7 days period in a completely randomized design model. The results revealed significant increase in the crude protein content of all the fungi treated samples with Aspergillus niger and T. longbrachitum treated cake recorded higher value compared to other treated samples. There was no significant difference in the crude fiber content among all the samples. With the exception of ether extract content of sample treated with Rhizopus nigricans which was similar to that of the control (untreated sample) other samples showed lower significant values than the untreated (control) sample. Contrarily, the ash content was significantly lower in the control sample compared to other fungi treated samples. The content of the trypsin inhibitor was highest (18.6 mg/kg) in the control but reduced significantly in the fungi treated samples (6.50 - 8.23). The lectin, saponins, phytate and phorbolester contents followed similar trend. It could be concluded from this study that solid state fermentation of Jatropha kernel cake detoxified and inactivate almost 100% of the antinutrient contents expect phorbolester to a tolerable level in the A. niger treated sample.