run Experimental factors Concentration (%)
fennel or bay black pepper or nutmeg
Cnt -1 -1 0 0
2 -1 1 0 0.25
3 1 -1 2.5 0
4 1 1 2.5 2.5
5 -1 0 0 1.25
6 1 0 2.5 1.25
7 0 -1 1.25 0
8 0 1 1.25 2.5
9 0 0 1.25 1.25
10 0 0 1.25 1.25
Table 1a: Run, experimental factors and concentrations of Central Composite Design (CCD).