A 2(3)-factorial experimental design has been used to study the main, two-factor-interaction, and three-factor-interaction effects of the NaOH concentration (X-1), deacetylation time (X-2), and deacetylation temperature (X-3) on the degree of deacetylation (DD) of deacetylated products prepared from beta-chitin. Because the DD values of deacetylated products increase as X-1, X-2, or X-3 increases, the main, two-factor-interaction, and three-factor-interaction effects for these three deacetylation conditions are positive. The sequence of the main effects on the DD values of deacetylated products is X-1 < X-2 < X-3 The sequence of the two-factor-interaction effects on the DD values of deacetylated products is X-2 versus X-3 < X-1 versus X-3 < X-1 versus X-2. The prediction equation is Y = 42.4 + 13.9X(1) + 9.4X(2) + 8.4X(3), + 5.8X(1)X(2) + 4.9X(1)X(3) + 3.7X(2)X(3) + 2.6X(1)X(2)X(3) (where Y is the predicted response) (C) 2004 Wiley Periodicals, Inc.