Reduced-Pressure Boiling Extraction of Oleuropein Coupled with Ultrasonication from Olive Leaves (Olea europaea L.)

Table 2

Design and results of the RSM.

Number	Extraction temperature	Ultrasonic power	Ethanol concentration	Ratio of solid to liquid	Yield/%
1	−1	−1	0	0	6.71
2	1	−1	0	0	6.77
3	−1	1	0	0	6.64
4	1	1	0	0	6.79
5	0	0	−1	−1	6.03
6	0	0	1	−1	5.95
7	0	0	−1	1	6.46
8	0	0	1	1	5.93
9	−1	0	0	−1	6.29
10	1	0	0	−1	6.39
11	−1	0	0	1	6.55
12	1	0	0	1	6.68
13	0	−1	−1	0	6.65
14	0	1	−1	0	6.81
15	0	−1	1	0	6.59
16	0	1	1	0	6.63
17	−1	0	−1	0	6.61
18	1	0	−1	0	6.59
19	−1	0	1	0	6.88
20	1	0	1	0	6.93
21	0	−1	0	−1	6.01
22	0	1	0	−1	5.91
23	0	−1	0	1	6.59
24	0	1	0	1	6.39
25	0	0	0	0	7.09
26	0	0	0	0	7.13
27	0	0	0	0	7.22
28	0	0	0	0	6.99
29	0	0	0	0	7.08