Optimized Conditions for Flavonoid Extraction from Pomelo Peel Byproducts under Enzyme- and Ultrasound-Assisted Extraction Using Response Surface Methodology

Table 2

Box–Behnken design and observed responses.

Run	Independent variable				Response (TFC, mg RE/g db)
	X1	X2	X3	X4
	Ratio (mL/g)	Enzyme concentration (%, v/m)	Incubation time (min)	Ultrasonic time (min)
1	150	2.5	40	90	10.32
2	150	4.5	40	60	9.01
3	50	2.5	60	30	8.99
4	150	4.5	60	30	9.83
5	50	2.5	40	60	8.54
6	150	4.5	60	90	10.49
7	250	2.5	60	90	8.90
8	150	0.5	80	60	8.64
9	150	2.5	40	30	8.92
10	150	0.5	60	90	9.82
11	250	4.5	60	60	9.19
12	150	2.5	60	60	10.73
13	150	2.5	80	30	9.98
14	250	2.5	40	60	8.16
15	250	2.5	80	60	8.19
16	50	2.5	80	60	9.50
17	150	2.5	80	90	9.85
18	50	2.5	60	90	9.26
19	150	0.5	40	60	9.87
20	150	2.5	60	60	10.62
21	150	4.5	80	60	10.57
22	150	0.5	60	30	10.02
23	150	2.5	60	60	10.90
24	50	0.5	60	60	9.09
25	150	2.5	60	60	10.69
26	50	4.5	60	60	9.11
27	150	2.5	60	60	11.09
28	250	2.5	60	30	8.58
29	250	0.5	60	60	8.02