Table 6. Optimal conditions of ACE inhibitory activity and pH

Dependent		Independent variables	Critical value (uncoded)	Predicted value	Stationary point
Y1		X1	10.0	90.0000	Target
		X2	37.0
		X3	17.8304
		X4	0.200
Y2		X1	6.0000	4.6	Target
		X2	32.0017
		X3	14.1670
		X4	0.200
Multiple response optimization	Y1, Y2	X1	13.4931	-	-
		X2	33.4057
		X3	21.5013
		X4	0.0578

Y₁, ACE inhibitory activity (%); Y₂, pH; ACE, angiotensin converting enzyme.