The 23 factorial experiments were chosen to examine
the optimum condition of corn powder hydrolyzed
by alpha-amylase and glucoamylase (Table 1). The
three factors were alpha-amylase dosage (A), glucoamylase
dosage (B), and reaction time (C). Levels
were 0.005 g (−), 0.010 g (+) for A; 0.100 g (−),
0.200 g (+) for B and 1 h (−), 2 h (+) for C.
Buffer solution was prepared with 0.2N of dipotassium
hydrogen phosphate (103.00 mL) and 0.1N of
citric acid (97.00 mL). Accurately 5.000 g corn powder,
10.00mL buffer solution and distilled water
were mixed, and the corn powder was hydrolyzed
by alpha-amylase and glucoamylase at 60 ◦C and
pH 6.0.