Level | Factor | |||
X1: additive amount of enzyme/% | X2: pH | X3: enzymolysis temperature/˚C | X4: enzymolysis time/h | |
−1 | 1.5 | 8.5 | 50 | 2 |
0 | 2 | 9 | 55 | 2.5 |
1 | 2.5 | 9.5 | 60 | 3 |