Modeling of the effect of freezer conditions on the hardness of ice cream using response surface methodology

Contour plots of the effect of overrun and drawing temperature on depth of penetration predicted by 3 models: a) DP-15, b) DP-10, and c) DP-5, where DP-15, DP-10, and DP-5=depth of penetration at –15°C, –10°C, and –5°C. The other process parameters were set at their center values: mix flow rate of 75 L/h, cylinder pressure of 300 kPa, and dasher speed of 222rpm.

Microstructure of harder and softer ice cream: a) harder ice cream in DP-15 (sample 2); b) softer ice cream in DP-15 (sample 1), where DP-15=depth of penetration at –15°C. A=air bubble; I=ice crystal. Bar=50.0 μm.