As shown in the literature, chitosan (Ch) can react easily with acetaldehydes to form Schiff bases with high yields at room temperature. Therefore, in this work, we report an innovative idea to prepare nanocomposites (NCs) of Ch-capped gold NPs (NPs) for effectively catalytic decomposition of acetaldehyde in spirits. Ch of NCs can easily catch acetaldehydes in spirits. Thus the caught acetaldehydes were therefore concentrated on NCs. Subsequently, the concentrated acetaldehydes were catalytically decomposed on catalysts of Au NPs in Ch/Au NCs. Experimental results indicate that the acetaldehyde was significantly decomposed by ca. 40 % in 120 ppm acetaldehyde-containing white spirits by adding 0.05 ppm Ch-capped Au NPs after three days. This efficiency for catalytic decomposition of acetaldehyde is a marked increase by ca. 200 % of magnitude, as compared with that based on commercial Au NPs with similar sizes at the same Au concentration. (c) 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013