Table 1.

Central composite design, independent variables' levels and experimental and predicted values of response variables.

Sample No.	Powder weight(g)	pH	Foam height (cm)	Antioxidant activity (%)	Colour (% a.u.)	Turbidity (% a.u.)
1	20	6.5	3.6	90.5	0.708	0.111
2	15	9	4	87	0.488	0.061
3	15	4	3.6	90.6	0.611	0.128
4	11.46	8.2	3.7	*	0.564	0.115
5	10	6.5	3	89.7	0.583	0.106
6	15	6.5	3	89.7	0.463	0.119
7	18.53	4.7	2.7	90.2	0.787	0.129
8	11.46	4.7	3.6	90.3	0.509	0.117
9	15	6.5	2.8	90.1	0.609	0.106
10	18.53	8.2	*	88.8	0.681	0.143
11	15	6.5	2.3	*	0.690	0.119
12	15	6.5	2.7	89.9	0.587	0.141
13	15	6.5	2.7	89.9	0.587	0.141

* Out of range.