Characterization of the Enzymatic Degradation of Arabinoxylans in Grist Containing Wheat Malt Using Response Surface Methodology

Response surface methodology was employed to study the effects of endoxylanase concentration, wort pH, and Ca2+ concentration on the degradation of arabinoxylans in mashing with grist containing wheat malt. The effects of the enzymatic degradation variables were described using a three-level Box-Behnken factorial design giving a mathematical model that showed the influence of each variable and their interactions. On the basis of the objective of degradation of polymeric arabinoxylans in mashing, the degradation variables were optimized at an endoxylanase concentration of 38 U/g, pH of 5.5, and Ca2+ concentration of 114 mg/L. Under this condition, polymeric arabinoxylans content in BM60WM40 (60% barley malt + 40% wheat malt) wort was decreased from 645 mg/L (no enzyme added) to 220 mg/L, a decrease of 66%.