Kinetic modelling of cookie browning during baking

The modern food industry relies on the application of the Maillard reaction to produce many foods, e.g. coffee and bakery products that possess the colour and flavour demanded by the consumer. The aim of this study was kinetics modelling of cookie browning during 10 minutes of baking at 205 C in order to predict the cookie lightness variation during baking. Cookies were produced according to AACC Approved Method 10-50D from a commercial cookie plain white flour and wholegrain flour. Baking quality of used flours was determined using Alkaline water retention capacity (AWRC) and Solvent retention capacity (SRC) methods and by measuring width (W), thickness (T), W/T ratio (cookie spread factor) and volume of cookies. Both type of flour was used to make three types of mixing distinguished in water addition (standard-S ; dry-D and wet-W formula). The colour of samples was measured using digital image analysis, and quantified using CIEL*a*b* colour model. Several mathematical model was proposed to predict the development of browning during baking (zero-, first- and second-order kinetics model). Lightness (L*) variation were supposed to be representative of colour formation reaction. Comparing all the results of surface and bottom cookies lightness, the cookies with the plain white flour and standard addition of water had the lowest value of lightness change. The evolution of lightness appears to follow a second- order kinetic of cookies made from wholegrain flour, and evolution of lightness of cookies made from plain white flour followed zero-order kinetic. According to obtained results, all tested kinetics model can be used for modelling of cookie browning. Kinetic model is also suitable to suggest how baking profiles should be changed in order to obtain products with a different final lightness.