THE USE OF A REACTION CELL TO MODEL THE DEVELOPMENT AND CONTROL OF COLOR IN EXTRUSION-COOKED FOODS

A reaction cell was designed to allow rapid, small-scale examination o f colour development which occurred in an extrusion cooker. It simulat ed the temperature, time, rapid heating and pressure experienced durin g extrusion cooking, but not the mechanical shear. A starch-glucose-ly sine mixture was both extrusion cooked and heated in the reaction cell , and the colour of the samples was analysed. Of all the ranges of par ameters examined, pH had the most significant effect on colour develop ment but temperature, moisture and residence time were also significan t. Reaction cell results were used to successfully predict L and a* v alues of samples extruded at a predetermined pH.