Table 5.

Predicted levels of extraction condition for the maximum response of extraction conditions by the ridge analysis in Zea mays L.

Response variables	Optimum extraction conditionsa				Maximum	Morphology
	X1	X2	X3	X4
Total polyphenol content (mg GAE/g)	29.02	8.99	33.67	10.25	7.89	Saddle point
Total anthocyanin content (mg C3GE/100 g)	45.22	7.85	34.14	22.97	82.44	Saddle point
Extraction yield (%)	58.87	7.53	32.31	17.65	10.33	Saddle point

^aX₁, extraction temperature (°C); X_2, extraction time (hour); X_3, solid-liquid ratio (%); X₄, solvent volume (1:X)