Abstract: By using orifice granulation method, microcapsules with sodium alginate and chitosan as the wall materials and gallnut extract as the core material are prepared. Scanning electron microscope and infrared test method are adopted to determine the best process for preparing the microcapsules, and the agar plate diffusion method is applied in the measurement and evaluation of the antibacterial properties of the prepared microcapsules. The test results show that the prepared microcapsules have good encapsulation effect, pelletizing properties and particle size uniformity. They also have good antibacterial properties, which can achieve ideal antibacterial effect.

Key words: sodium alginate; chitosan; gallnut extract; orifice granulation; agar plate diffusion method