the chemical changes during heat and mass transfer processes are incorporated in the relative activation energy (Putranto and Chen, 2015a, b). Hence, this study indicates that the composite reaction engineering approach is not only accurate to describe drying of a mixture of sugars solution (Patel et al., 2009) but also to a mixture of protein and sugar solution in which more complicated chemical changes may occur. The development of the reaction engineering approach to model drying of multiple solutes dissolved in multiple solvents (aqueous and/or non-aqueous) systems is currently underway.