Microencapsulations of konjac alkaloid and effect of biological prevention

In order to study the organism of prevention and cure effect, microencapsulated alkaloid and bio-pesticide sustained-release agent were made. The composition of particle wall, concentration of calcium chloride, time of solidification, impact of drop speed and height were studied to examine their microcapsulation effects. Konjac alkaloid was extracted and isolated as the core material and sodium alginate with konjac gum was used as the principal wall material. Then they were investigated by means of piercing method. It was found that the konjac light-flour and alcohol ratio of 1∶3, and mixing them at high speed for 48 h at room temperature could reach the best result. In the Dry Alumina Column Chromatography(DACH), we used methanol as dispersing agent. The optimum ratio of the dispersing vs. dispersed agent was determined to be 3 mL∶3 mL. The results of orthogonal experiment indicated that the optimum ratio of sodium alginate to konjac gum was 10∶1; the calcium chloride concentration was 0.25 mol/L; solidification time was 10 min; and the drop speed and height were 120～180 drop/min and 10～15 cm, respectively. The microencapsulated konjac alkaloid was applied to an insecticidal experiment to study its allurement and expellant effect.