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 |