Determination of Curcuma longa L. (Turmeric) Leaf Extraction Conditions Using Response Surface Methodology to Optimize Extraction Yield and Antioxidant Content

Table 2

Analysis of variance for the response surface model of extraction yield (%).

	DF	Adj. SS	Adj. MS	F value	value
Regression	5	9.65475	1.93095	87.21	0.001
Linear	2	6.66667	3.33333	150.55	0.001
Temperature (°C)	1	4.50667	4.50667	203.55	0.001
Time (min)	1	2.16000	2.16000	97.56	0.001
Square	2	0.73809	0.36904	16.67	0.006
Temperature (°C)  temperature (°C)	1	0.06412	0.00063	0.03	0.872
Time (min)  time (min)	1	0.67396	0.67396	30.44	0.003
Interaction	1	2.25000	2.25000	106.62	0.001
Temperature (°C)  time (min)	1	2.25000	2.25000	106.62	0.001
Residual error	5	0.11070	0.02214
Lack of fit	3	0.08404	0.02801	2.10	0.339
Pure error	2	0.02667	0.01333
Total	10	9.76545