In this study, capsaicin microcapsules were prepared by the complex coacervation of gelatin, acacia, and tannins. The antimicrobial activities of these microcapsules on the common microorganisms of food preservation, Botrytis cinerea and Aspergillus niger, were investigated. The factors affecting their antimicrobial effects, including the microcapsule concentrations, PH values, and release behavior were also examined. The results showed that the optimum pH for the antimicrobial effect was about 5.0, which might be related to the strongest protein-precipitating ability of tannins at this pH value. The inhibitory activity of the system originated from the synergistic actions of both capsaicin and tannins. The release behavior of the microcapsules had an important influence on the antimicrobial effect for the long shelf-life storage of foods. The present study indicated that the capsaicin microcapsules displayed potential antimicrobial applications in the food storage. (c) 2006 Wiley Periodicals, Inc.