Development of a model food gel based on whey protein and starch for investigating thermal kinetics.

Model foods are effective tools for assessing heating patterns and
identifying hot and cold spots during microwave processing, as studying
actual food is highly complex. This study aimed to develop a whey proteinstarch-
based model food to simulate Indian flatbread. We optimized the
protein-to-starch ratio (20:30) and precursor levels (4% D-Fructose and 2%
Lysine) for chemical marker development. The prepared gel matrix
demonstrated good stability without structural breakdown during heating,
and its physicochemical parameters, such as water activity, Moisture
content, and strain, were 0.95, 54.03%, and 6.63, respectively, making it
suitable for representing medium-moisture products. The model food
formulations were treated at 70, 80, and 90°C in a water bath for validation
of chemical marker development in terms of colour. A colour map was
created based on L* values. A strong correlation was observed between L*
values and the cumulative time-temperature effects of pasteurization. It
was found that L* values of the model food follow first-order reaction
kinetics. The temperature sensitivity of colour change was determined to
evaluate its suitability as an indicator for thermal treatments. This study
introduces a new, cost-effective chemical marker method for rapidly
mapping microwave heating patterns in industrial pasteurization processes.