Ultrasound-assisted extraction (UAE) of antioxidant phenolics from Corchorus olitorius leaves: a response surface optimization

Chemical and Biological Technologies in Agriculture

Table 3 Analysis of variance (ANOVA) of regression equation for optimization of TFC

Source	Sum of squares	df	Mean square	F-value	p-value	Significance
Model	26.99	14	1.93	29.23	< 0.0001	***
A-Ethanol conc. (%)	4.70	1	4.70	71.26	< 0.0001	***
B-Temperature (°C)	0.4161	1	0.4161	6.31	0.0239	*
C-Time (min)	2.67	1	2.67	40.43	< 0.0001	***
D-Liquid–solid ratio (mL/g)	1.22	1	1.22	18.56	0.0006	***
AB	0.7225	1	0.7225	10.96	0.0048	**
AC	1.08	1	1.08	16.40	0.0010	***
AD	1.10	1	1.10	16.72	0.0010	***
BC	0.6561	1	0.6561	9.95	0.0066	**
BD	0.1521	1	0.1521	2.31	0.1496	Ns
CD	0.0016	1	0.0016	0.0243	0.8783	Ns
A²	9.43	1	9.43	142.94	< 0.0001	***
B²	1.36	1	1.36	20.59	0.0004	***
C²	6.59	1	6.59	99.86	< 0.0001	***
D²	0.6069	1	0.6069	9.20	0.0084	**
Residual	0.9892	15	0.0659
Lack of fit	0.7927	10	0.0793	2.02	0.2272	Not significant
Pure error	0.1966	5	0.0393
Cor total	27.98	29
Std. dev	0.2568
Mean	6.19
C.V.%	4.15
Press	4.85
R²	0.9646
Adjusted R²	0.9316
Predicted R²	0.8267
Adeq precision	17.7873

***Highly significant (P < 0.001); **quite significant (0.001 < P < 0.01); *significant (0.01 < P < 0.05)