Ultrasound-Assisted Extraction of Phenolic Compounds from Moroccan Lavandula stoechas L.: Optimization Using Response Surface Methodology

Table 1

The selected factors and their levels in the Box–Behnken design.

Factors	Unity	Symbol	Factor level
			−1	0	1
Extraction time	Min	X1	20	30	40
Solvent-to-material ratio	ml/g	X2	20	25	30
Ethanol	%	X3	40	60	80