Optimized Extraction of Resveratrol from Arachis repens Handro by Ultrasound and Microwave: A Correlation Study with the Antioxidant Properties and Phenol Contents
Table 3
Real and coded values (+ level, 0 intermediate, − lower level) for the independent variables, 24–1 experimental factorial design and results of CCRD for resveratrol extraction by the microwave-assisted technique.
Entry
Variable levels
t-resveratrol (mg/g extract)
Stirring (rpm)
Temperature (°C)
Solvent conc. (MeOH aq.) (%)
Solvent : mass proportion (g/mL)
1
−1 (975)
−1 (37.5)
−1 (75)
−1 (1 : 30)
0.149
2
1 (1125)
−1 (37.5)
−1 (75)
−1 (1 : 30)
0.062
3
−1 (975)
1 (52.5)
−1 (75)
−1 (1 : 30)
0.064
4
1 (1125)
1 (52.5)
−1 (75)
−1 (1 : 30)
0.343
5
−1 (975)
−1 (37.5)
1 (85)
−1 (1 : 30)
0.065
6
1 (1125)
−1 (37.5)
1 (85)
−1 (1 : 30)
0.071
7
−1 (975)
1 (52.5)
1 (85)
−1 (1 : 30)
0.302
8
1 (1125)
1 (52.5)
1 (85)
−1 (1 : 30)
0.809
9
−1 (975)
−1 (37.5)
−1 (75)
1 (1 : 20)
0.527
10
1 (1125)
−1 (37.5)
−1 (75)
1 (1 : 20)
0.090
11
−1 (975)
1 (52.5)
−1 (75)
1 (1 : 20)
0.120
12
1 (1125)
1 (52.5)
−1 (75)
1 (1 : 20)
0.070
13
−1 (975)
−1 (37.5)
1 (85)
1 (1 : 20)
0.058
14
1 (1125)
−1 (37.5)
1 (85)
1 (1 : 20)
0.048
15
−1 (975)
1 (52.5)
1 (85)
1 (1 : 20)
0.087
16
1 (1125)
1 (52.5)
1 (85)
1 (1 : 20)
0.133
17
−2 (1200)
0 (45)
0 (80)
0 (1 : 25)
0.092
18
−2 (1200)
0 (45)
0 (80)
0 (1 : 25)
0.067
19
0 (1050)
−2 (30)
0 (80)
0 (1 : 25)
0.076
20
0 (1050)
−2 (30)
0 (80)
0 (1 : 25)
0.280
21
0 (1050)
0 (45)
−2 (90)
0 (1 : 25)
0.124
22
0 (1050)
0 (45)
−2 (90)
0 (1 : 25)
0.256
23
0 (1050)
0 (45)
0 (80)
−2 (1 : 35)
0.195
24
0 (1050)
0 (45)
0 (80)
−2 (1 : 35)
0.058
25
0 (1050)
0 (45)
0 (80)
0 (1 : 25)
0.074
26
0 (1050)
0 (45)
0 (80)
0 (1 : 25)
0.070
27
0 (1050)
0 (45)
0 (80)
0 (1 : 25)
0.076
Measured by HPLC-DAD based on a calibration curve of trans-resveratrol in five different levels.
