Table 1.

Coded levels of independent variables employed in the CCD

Independent variables	Symbol	Unit	Intervals and levels
			−α	−1	0	+1	+α
Fermentation time	X1	Hour	24	48	72	96	120
Temperature	X2	°C	30	35	40	45	50
pH	X3	-	3	4	5	6	7
Moisture content	X4	% v/w	40	50	60	70	80
Casein concentration	X5	% w/w	0.5	1	1.5	2	2.5