Effect of detoxification methods on anti-nutritional factors and proximate composition of defatted Jatropha curcas kernel meal.

Abstract

A study was conducted to evaluate the effect of chemical treatment and solid state fermentation on the anti-nutritional factors (ANFs) and proximate composition of defatted Jatropha kernel meal (DJKM). The DJKM samples were treated with alkaline methanol (90% methanol containing 0.2M NaOH; CT- 1), alkaline ethanol (80% ethanol containing 0.1M NaOH; CT-2), highly alkaline methanol (90% methanol and 3% NaOH; CT-3), modified ethanol (4-times extraction using 80% ethanol; CT-4) and modified methanol (4-times extraction using 90% methanol; CT-5), in combination with moist heat treatment in all cases. Another sample was treated by solid state fermentation (SSF) using Aspergillus niger fungus (FT). The untreated sample was considered as control (J0). In comparison to control and the chemical treated samples (CT-1, CT-2, CT-3, CT-4 and CT-5), SSF treated sample contained significantly (P<0.05) lower levels of moisture and crude fibre, and higher levels of ether extract and total ash. However, these parameters did not vary (P>0.05) among the control and chemically treated samples. Though the CP content of FT sample was significantly higher than the control, it was found comparable to all the chemically treated samples. The moisture and ether extract contents of control and treated samples exhibited a reverse trend. Significantly lower and higer GE values were observed in CT-2 and CT-3, respectively; however, it was not affected much due to other treatments. Results indicated that any of the chemical treatments could not result in significant (P>0.05) removal of phytic acid and tannin, whereas FT was able to significantly (P<0.05) remove 100% phytic acid and 65.79% tannin from DJKM. However, all the treatments were equally effective in removal (100%) of trypsin inhibitor from DJKM. It is concluded that among the different treatment methods used, solid state fermentation was found to be the most effective method for removal of ANFs from DJKM.