TABLE 3.

Experimental design and results of the CCD design.

Trial	Variable level			Response value (V0)
	A	B	C	Actual value (mM/h)	Predicted value (mM/h)
1	1	1	1	7.72	7.64
2	−1	1	−1	5.10	5.12
3	1	−1	−1	3.21	3.14
4	0	0	0	6.91	6.88
5	0	−1.682	0	4.70	4.68
6	1	1	−1	5.11	5.14
7	−1	−1	1	6.51	6.53
8	0	0	1.682	8.01	7.94
9	0	1.682	0	7.22	7.22
10	0	0	0	7.03	6.94
11	0	0	0	7.04	6.94
12	0	0	−1.682	3.01	2.95
13	0	0	0	7.01	6.93
14	−1	1	1	7.51	7.58
15	0	0	0	6.99	6.85
16	1	−1	1	6.40	6.42
17	0	0	0	6.91	6.93
18	1.682	0	0	5.44	5.52
19	−1	−1	−1	3.21	3.22
20	−1.682	0	0	5.71	5.62

Reaction conditions: 0.04 mmol arbutin, 2 mL THF-isopropyl et her (20%, v/v), 200 r/min.