Optimization of Vacuum Microwave-Mediated Extraction of Syringoside and Oleuropein from Twigs of Syringa oblata
Table 2
Estimated regression coefficients for the quadratic polynomial model and ANOVA for the experimental results in the optimization of syringoside and oleuropein extractionsa.
Regression coefficients
Sum of squares
Degree of freedom
Mean square
F value
Probability >F
Yoleuropeinb
Ysyringoside
Yoleuropein
Ysyringoside
Yoleuropein
Ysyringoside
Yoleuropein
Ysyringoside
Model
10.331
3.873
9
1.148
0.430
66.57
40.48
<0.0001
<0.0001
b
3.125
0.083
1
3.125
0.083
181.24
7.79
<0.0001
0.0269
0.085
0.034
1
0.085
0.034
4.95
3.18
0.0614
0.1178
1.835
1.514
1
1.835
1.514
106.43
142.38
<0.0001
<0.0001
0.045
0.028
1
0.045
0.028
2.62
2.67
0.1494
0.1465
0.777
1.009
1
0.777
1.009
45.05
94.89
0.0003
<0.0001
0.005
0.018
1
0.005
0.018
0.30
1.66
0.6036
0.2383
2.569
0.359
1
2.569
0.359
148.96
33.75
<0.0001
0.0007
0.525
0.001
1
0.525
0.001
30.47
0.05
0.0009
0.8336
0.956
0.760
1
0.956
0.760
55.45
71.48
0.0001
<0.0001
Lack of fit
0.056
0.044
3
0.019
0.015
1.17
1.92
0.4263
0.2684
Credibility analysis of the regression equations
Index mark
Standard deviation
Mean
CV %
Press
R2
Adjust R2
Predicted R2
Adequacy precision
Yoleuropein
0.13
4.82
2.73
1.00
0.9885
0.9736
0.9042
21.92
Ysyringoside
0.10
3.43
3.00
0.75
0.9811
0.9569
0.8100
23.70
aThe results were obtained with Design Expert 8.0.6 software; b is microwave irradiation time (min); is liquid-solid ratio (mL/g); is microwave irradiation power (W); Yoleuropein and Ysyringoside are the yield of oleuropein and syringoside (mg/g); , significant; , highly significant;, extremely significant.
