A continuum‐approach modeling of surface composition and ternary component distribution inside low fat milk emulsions during single droplet drying

Abstract

Surface composition of dairy powders plays an important role in determining the functionality. However, the surface composition may be different from the bulk composition because of component migration during drying. In this study, a comprehensive mathematical model has been developed to describe the phenomena. To the best of our knowledge, it is the first mathematical model which predicts the dynamics of surface composition during drying. The model consists of a set of equations of conservation of mass of water, lactose, protein, and fat as well as conservation of heat and momentum in which the effects of diffusion induced material migration and surface activity are incorporated. This model is applicable to describe the kinetics of surface composition of dairy droplets during drying. It suggests that both diffusion and protein surface activity govern the component segregation during drying. The study indicates that the model implementing the measured initial surface composition as the initial conditions generates more realistic profiles than the one using the bulk composition. The modeling confirms that the difference between the surface and bulk composition that occurs prior to drying is not primarily governed by diffusion, but the emulsion's atomization behavior seems to play an essential role in the overrepresentation of fat. © 2017 American Institute of Chemical Engineers AIChE J, 63: 2535–2545, 2017

A successful comparison between a non-invasive measurement of local profiles during drying of a highly shrinkable food material (eggplant) and the spatial reaction engineering approach

“…Nevertheless, the gradient temperature inside the eggplant samples is essentially small which is also indicated by Ch_Bi (Chen and Peng, 2005) which is found to be about 0.002. The low gradients of temperature during drying of food materials are also reported previously (Putranto and Chen, 2015 a-c ;Putranto et al, 2017).…”

“…The spatial reaction engineering approach (S-REA) is used to model the convective drying of eggplant in this study. The details of the reaction engineering approach (REA) have been published previously (Chen and Putranto, 2013;Putranto and Chen, 2015 a,b ;2016;Putranto et al, 2017). The S-REA consists of a set of equations of conservation of heat and mass transfer in which the REA is used to describe the local evaporation rate.…”

Modeling Maillard reaction kinetics in spray dryers using both lumped‐ and distributed‐parameter modeling approaches

“…However, as shown in other studies, the reaction rate decreases at lower moisture contents due to limited molecular mobility (Schmitz‐Schug et al, 2014). This difference between the predicted and actual correlation between the reaction rate constants may lead to an overestimation of the extent of the Maillard reaction in the final product by the model, even though the segregation process tends to be completed at lower moisture contents (Putranto et al, 2017).…”

An accurate account of mass loss during cheese ripening described using the reaction engineering approach (REA)‐based model

“…More recently, it has been shown that the REA is not only able to model the evaporation of water but also volatiles (organic components) (Putranto & Chen, ). In addition, the REA has been applied to model the solute segregation inside dairy droplets (Putranto et al ., )…”

“…More recently, it has been shown that the REA is not only able to model the evaporation of water but also volatiles (organic components) (Putranto & Chen, 2016). In addition, the REA has been applied to model the solute segregation inside dairy droplets (Putranto et al, 2017) Due to the applicability of the REA so far, it is worthwhile to develop the REA-based model to represent the mass loss during cheese ripening. Although the REA has been proven to model the several challenging heat and mass transfer processes as described above, it is uncertain whether the REA is applicable to model the mass loss during cheese ripening because chemical and biological reactions may significantly alter the cheese structure.…”