Table 1.

Experimental design for the extraction process from central composite design.

Run order	X 1 (extraction time) (min)	X 2 (extraction temperature) (°C)	X 3 (solid-to-liquid ratio) (g/ml)
1a	32.5	75	15
2a	32.5	75	15
3a	32.5	75	15
4	32.5	50	15
5a	32.5	75	15
6	32.5	75	20
7a	32.5	75	15
8	5	50	20
9	32.5	75	10
10	60	50	10
11	60	50	20
12	60	100	10
13	60	75	15
14	32.5	100	15
15	5	100	20
16	5	75	15
17	5	100	10
18	5	50	10
19	60	100	20
20a	32.5	75	15

^aCenter point.