Abstract: Rinsing with sodium hypochlorite and hydrolysis with hydrochloric acid are two key procedures for the preparation of microcrystalline cellulose from apple pomace. In the present study, based on single factor experiments, by which hydrolysis time of 50 min and temperature of 100 ℃ were determined, the pairwise interactive effects of material/liquid ratio, hydrochloric acid concentration and the amount of sodium hypochlorite addition on microcrystalline cellulose yield were discussed by central composite design (CCD) in combination with response surface analysis. The significance of the above three factors affecting microcrystalline cellulose yield decreased in the following order: hydrochloric acid concentration ＞ material/liquid ratio ＞ the amount of added sodium hypochlorite. Analysis based on response surface and contour plots showed that all the pairwise interactions significantly affected microcrystalline cellulose yield. The regression equation based on the results from CCD design was resolved, and the results indicated that the optimal amount of added sodium hypochlorite for rinsing apple cellulose was 2.5 mL/100 mL, and that the optimal hydrolysis effect was achieved by the use of 6% hydrochloric acid to hydrolyze the substrate diluted 25-fold by volume. Under these conditions, a microcrystalline cellulose yield of 69.5% was obtained. 

Key words: microcrystalline cellulose, yield, response surface analysis