Actual levels of factors
  Ingredients (% fwb) Process conditions
Coded levels Egg albumin (%) Milk powder (%) Temperature (ºC) Time (min)
-2.0 0.00 0.00 190 20
-1.0 2.50 2.50 200 25
0.0 5.00 5.00 210 30
1.0 7.50 7.50 220 35
2.0 10.0 10.0 230 40
Table 1: Coded and actual levels of the factors in the central composite design of the RSM.