Exploratory studies on the detoxification of karanj cake through various processing techniques

Abstract

The present study aimed at ascertaining the comparative efficacy ofdetoxification of karanj (Pongamia glabra) cake through a combination of chemical and physical processing methods. The chemical treatments involved use of organic solvents (methanol and n-hexane) and dilute acids (1-1.5% HCl and glacial acetic acid) while the physical processing methods involved refluxing, cold maceration with agitation, soaking and finally drying. The efficacies of various detoxification methods applied were evaluated on the basis of the extent to which it has reduced the toxins along with possible alterations in its nutritive potential. Among all the chemical treatments employed, cold maceration with methanol along with agitation resulted in maximum reduction of karanjin (51% reduction; 0.25% vs. 0.51% in raw karanj cake). Maximum removal of pongamol (0.095% in original to non-detectable level) was observed upon soaking the karanj cake with methanol followed by water soaking. The acid treatments with hydrochloric and glacial acetic acids significantly (P<0.05) reduced trypsin inhibitor activity; however, levels of karanjin and pongamol remained unchanged. Maximum reduction in trypsin inhibitor activity (82% reduction; 5.40 vs. 30.06TIU/ mg of protein) was observed in detoxification method involving treatment with hydrochloric acid for 12h. None of the treatment attempted could alone reduce the level of all the three major toxins to maximal reduction level. Treatment with organic solvent led to substantial removal of karanjin and pongamol, but treatment with hydrochloric and glacial acetic acid reduced trypsin inhibitor activity substantially. It was concluded that, a combination of organic solvent treatment and acid or heat treatment has the potential to remove all the three major toxins of karanj cake. © 2019 Indian journals.