Influence of processing parameters on the texture and microstructure of imitation cheese

In this study the impact of cooker design and/or blade/auger speed on the functional properties of imitation cheese was investigated. Cheeses with similar compositions (48% moisture) were manufactured using water, rennet casein, rapeseed and hydrogenated palm oil and emulsifying salts in a twin-screw (Blentech) or a single-blade cooker (Stephan). The cookers were operated at auger speeds of 750, 1,125 or 1,500 (Stephan) or 100 or 200 rpm (Blentech). Increasing the blade speed of the Stephan increased (P < 0.001) the hardness and decreased the meltability of imitation cheese from 112 to 66 mm respectively. Hardness and meltability values of cheeses made in the Blentech cooker were only slightly affected by auger speed. The cheese made in the Stephan at 1,500 rpm had the highest G' and G'' values at 25 °C of all the cheeses. This study shows that imitation cheese with acceptable functional properties can be successfully manufactured in a single-blade cooker operated at moderate speeds.