Using Response Surface Methodology to Optimize Edible Coating Formulations to Delay Ripening and Preserve Postharvest Quality of Tomatoes

Table 2

Level of independent variables used for the center composite design (CCD).

Independent variable	Symbol	Level
		−α (−1.809)	Low	High	α (1.809)
CPE (kg/l)	X1	0.381	0.5	0.83	0.959
CGA (%)	X2	0.955	5	15	19.045
Time (min)	X3	1.909	10	30	38.091

CPE: concentration of pineapple peel extract in water/ethanol (1/1, v/v) solvent mixture, CGA: concentration of gum arabic.