Comparative study between chemical, physical and enzymatic methods for Jatropha curcas kernel meal phorbol ester detoxification

Abstract

Detoxification of protein rich Jatropha kernel cake to eliminate the phorbol esters is a great challenge for its industrial utilization in food processing. Several methods either chemical or physical have been previously applied trying to degrade phorbol esters in Jatropha curcas seed cake, which are the main toxic compound with thermo-stable properties. The objective of this study was to compare the different methods to get rid of phorbol esters (PE) including, chemical treatments (0.1 M NaOH/90 % methanol, 85 % ethanol, 90 % methanol & 85 % ethanol (50:50) for 8 h), physical treatments (microwave, ultrasonic and microwave + ultrasonic) and enzymatic treatment by crude germinated Jatropha seed lipase (CGJS). The results showed that the elimination of phorbol esters content chemically treated either by 0.1 M NaOH/90 % methanol or ethanol 85% had effectively decreased by 98.04 % and 98.17 %, respectively compared to control. The treatment by methanol 90% and ethanol 85% (50:50) gave degradation percentage of 95.43% of phorbol esters. The enzymatic elimination of phorbol esters by crude germinated Jatropha seed (CGJS) lipase proved high efficiency of detoxification by reducing the percentage to 98.43%. On the other hand, physical detoxification of Jatropha seed kernel showed good results with microwave treatment by reducing phorbol esters content to 86.29 %. Treatment by ultrasound has detoxified the phorbol esters content by 87.60 % in Jatropha curcas seed. While, combination between microwave & ultrasound increased the percentage of phorbol esters degradation to 88.38 %. In conclusion, enzymatic degradation of phorbol esters is a safe method for degradation as it is both an un-expensive and easy way for detoxification.