Table 2.

Fractional factorial design (FFD) model totalizing 11 experiments aiming at the optimization of trans-resveratrol extraction in mg/g extract, by the microwave-assisted technique.

Entry	St (rpm)	T (°C)	Solvent concentration (MeOH aq.) (%)	Mass : solvent proportion (g/mL)	Content of t-resveratrol (mg/g extract)a
1	−1 (600)	−1 (30)	−1 (60)	−1 (1 : 60)	0.235
2	1 (1200)	−1 (30)	−1 (60)	1 (1 : 20)	0.786
3	−1 (600)	1 (70)	−1 (60)	1 (1 : 20)	0.075
4	1 (1200)	1 (70)	−1 (60)	−1 (1 : 60)	0.456
5	−1 (600)	−1 (30)	1 (100)	1 (1 : 20)	0.231
6	1 (1200)	−1 (30)	1 (100)	−1 (1 : 60)	0.085
7	−1 (600)	1 (70)	1 (100)	−1 (1 : 60)	0.103
8	1 (1200)	1 (70)	1 (100)	1 (1 : 20)	0.289
9	0 (900)	0 (50)	0 (80)	0 (1 : 40)	0.143
10	0 (900)	0 (50)	0 (80)	0 (1 : 40)	0.117
11	0 (900)	0 (50)	0 (80)	0 (1 : 40)	0.124

^aMeasured by HPLC-DAD.