Prediction of thermal induced color changes of chicken breast meat during convective roasting: A combined mechanistic and kinetic modelling approach

Abstract

Consumers first assess the quality of roasted chicken meat by its appearance. However, studies that evaluate the color changes during thermal processing are lacking. The aim of this work was, therefore, to develop a mathematical model that can predict the lightness (L *) changes of chicken breast meat during convective roasting. Chicken breast meat was roasted in a convection oven and the internal as well as surface lightness was measured at different time steps. The lightness of chicken meat increases in the beginning of the process, which shows a whitening due to myoglobin denaturation. When the surface temperature is rising above 88 °C, the lightness starts to decrease again as a result of browning reactions. We developed a non-isothermal kinetic model that describes the browning (decrease of the lightness) of the surface as function of temperature, water activity and roasting time. The kinetic models for the whitening and browning were then coupled to the validated mechanistic model for chicken meat roasting. This enables the prediction of the internal as well as surface lightness development from the spatial temperature and water activity changes. The validation of the model showed a good agreement between model predictions and experimental values for different roasting conditions. Overall, the developed model allows the prediction of the spatial lightness distributions with roasting time and advances our understanding of the mechanisms of heat induced color changes. Thus, the model can be applied to control and optimize the roasting of chicken meat to ensure the quality and safety for the consumer.

Water distribution and key aroma compounds in the process of beef roasting

“…During the roasting process, the L * values of the beef significantly increased and subsequently decreased after 3 min of roasting ( Table 1 ). Similar results were also reported for the infrared heating (grilling) of fish ( 32 , 33 ), convective roasting of chicken breast meat ( 34 ) or microwave cooking of beef meat ( 35 ). Meanwhile, the a * values decreased significantly in the samples roasted for 0–3 min and then kept stable, and the b * values increased in the samples roasted for 0–9 min and then decreased at the end stage of roasting.…”

Cooking chicken at home: Common or recommended approaches to judge doneness may not assure sufficient inactivation of pathogens

“…The results from the present study and others showed that the judging techniques for doneness recommended by food safety experts are not widely used by consumers [14]. Furthermore, no single technique, neither those used or recommended, will assure the target-inactivation of pathogens of 5 log reduction, if used alone (present study, [15,50,54,55].…”

“…Surprisingly, studies on the relation between colour of chicken fillets and core temperature during cooking are almost lacking. Rabeler et al (2019), reported about colour change (increasing lightness) over time during convection cooking of chicken fillets [50]. As corresponding core temperatures were not measured, it is difficult to compare with our results.…”

Interpretation of the color due to the ubiquitous nonenzymatic browning phenomena in foods

“…Chromatic displacement of samples undergoing the browning process in ( a * , b * ), A, and ( u * , v * ) planes, B. The diagrams contours indicate the limits of the optimal colors, 18 and the color bars in the borders are provided as a reference of the corresponding hues. The maximum a *, b *, u *, and v * values achieved for all the systems, as so as the maximum values for chroma ( C * ab ) and saturation () are also indicated in the diagrams; error bars are smaller than the symbols and lay below them…”

“…In food science literature, it is sometimes analyzed just by visual assessment, 16 often by light absorbance measurements at a single wavelength, frequently 420 nm 17 . Most of the times, the lightness ( L * ) decrease is related to the increase of the browning degree 18 . The first definition of a browning index was performed by Buera et al, 19 who analyzed brown coloration originated by nonenzymatic reactions.…”