Monday, April 19, 2010

Analysis of nutritional composition and detoxification of Jatropha curcas cake after solid-state fermentation

Taís da S. Rosa1, Aline M. Castro2, Alexandre G. Torres1, and Denise M. G. Freire1. (1) Departamento de Bioquímica, Instituto de Química, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil, (2) Cenpes, Petrobras, Rio de Janeiro, Brazil

Many agroindustrial residues produced in large amounts can be used as animal feed, but some of these require the elimination of toxic and anti-nutritional components as well as an improvement in its digestibility. The aim of this study was to use the residue from the oil extraction from Jatropha curcas (physic nut cake) as a substrate for solid-state fermentation by the fungus Aspergillus niger (GRAS status) for nutritional enrichment and detoxification allowing its reuse. The nutritional analysis was performed before and after fermentation. Determinations of moisture, crude protein fractions and nitrogen, urea, iron, ash and ether extract, total carbohydrates, phytic acid and tannic substances were carried out. Apparent reduction in the toxicity of the sample was reached with the fermentation process. There was apparent difference in the component contents (g / 100 g dry weight) of the samples before and after fermentation, respectively: the crude protein content increased from 24.18 to 25.99, with an increase in the fraction of nitrogen rich in albumins, globulins and prolamins; the urea increased from 0.19 to 0.62; the carbohydrates increased from 0.65 to 1.76; the lipid decreased from 17.20 to 6.92; the ash was reduced from 5.43 to 2.44; the iron reduced from 0.48 to 0.42; the phytic acid increased from 18.44 to 25.81 and tannic substances reduced from 13.89 to 5.27. The fermentation process allowed a significant reduction in the level of phorbol esters (toxic components) and, simultaneously, a nutritional enrichment of the cake.