Table 1.

Variables and their levels for factorial design

Variables	Levels
	Lower (-1)	Middle (0)	Upper (+1)
X1-Concentration of xanthan gum (Xa)	0.6% w/v	1 % w/v	1.4 % w/v
X2-Concentration of chitosan (CS)	0.6% w/v	1 % w/v	1.4 % w/v