Improvement of extraction method of coagulation active components from Moringa oleifera seed

A new method for the extraction of the active coagulation component from Mo ringa oleifera seeds was developed and compared with the ordinary wafer ext raction method (MOC-DW). In the new method, 1.0 mol l(-1) solution of sodiu m chloride (MOC-SC) and other sails were used for extraction of the active coagulation component. Batch coagulation experiments were conducted using 5 00 mi of low turbid water (50 NTU). Coagulation efficiencies were evaluated based on the dosage required to remove kaolinite turbidity in water. MOC-S C showed better coagulation activity-with dosages 7.4 times lower than that using MOC-DW for the removal of kaolinite turbidity. MOC-SC could effectiv ely coagulate more than 95% of the 50 NTU initial kaolin turbidity using on ly 4 ml l(-1), while 32 ml l(-1) of MOC-DW could only remove about 78% of t he same kaolin turbidity. The improvement of coagulation efficiency by NaCl is apparently due to the salting-in mechanism in proteins wherein a salt i ncreases protein-protein dissociations, leading to increasing protein solub ility as the salt ionic strength increases. There was no difference in the coagulation efficiency observed for extracts using any of four 1:1 salts (N aCl, KNO3, KCl and NaNO3) in our study. Purification and isolation of the a ctive component confirmed that the active component of MOC-SC was mainly pr otein. (C) 1999 Elsevier Science Ltd. All rights reserved.