Table 1.

RSM experimental (2² design) and results obtained for response variable: TPC. Experimental and predicted values by the mathematical model are shown

Run	Ethanol content (%)	Output amplitude (%)	TPC (mg GAE/g)		Confidence interval, 95%
			Experimental value	Predicted value
1	45	90	31.3	28.9	19.4–38.5
2	21	75	12.4	13.8	4.3–23.4
3	35	96	19.4	24.3	14.8–33.9
4	25	60	16.8	19.4	9.8–28.9
5	35	54	29.9	24.8	15.3–34.4
6	49	75	29.4	27.8	18.3–37.4
7	25	90	20.6	16.1	6.5–25.7
8	45	60	21.7	26.4	16.8–35.9
9	35	75	27.1	27.2	20.3–34.2
10	35	75	26.1	27.2	20.3–34.2
11	35	75	28.5	27.2	20.3–34.2

TPC, total phenolic compounds.