Impact of solute molecular mass and molality, and solution viscosity on mass transfer during immersion of meat in a complex solution

Dehydration of meat by soaking in a concentrated solution of water, salt and corn syrup (DE21) generally results in a high water loss and moderate salt and sugar gains. This study was undertaken to better understand the role of corn syrup in the transfer of water and solutes, and particularly its limiting effect on salt impregnation. Corn syrup is composed of saccharides of molecular mass varying from 180 Da (glucose) to more than 1500 Da (oligo- and poly-saccharides), in variable proportion. In an attempt to clarify the role of these different saccharides on mass transfer, immersion trials in concentrated solutions of salt (constant molality = 3.0) and polyethylene glycol (PEG, used a model solute) of varying molecular mass and molality were carried out. The influence of solution viscosity was also studied through the addition of agar agar as a viscosity agent. Results showed that water loss increased while salt and PEG gains decreased with increasing molecular mass of PEG in the range of 200-600 Da. In addition, an increasing molality of PEG from 0.6 to 1.6 mol/kg water led to increases in water loss and PEG gain but a decrease in salt gain. Under the prevailing experimental conditions, no significant influence of solution viscosity on mass transfer was found. Moreover, immersion trials were carried out to compare corn syrup with three different combinations of PEG with molecular mass distributions similar to that of corn syrup. The mixtures closely reproduced corn syrup behaviour with respect to salt gain. However, their impact on water loss and PEG gain (as compared to sugar gain) was significantly different from that of corn syrup. Information gathered in this study was used to propose a schematic representation of the mechanisms involved in the transfer of water and solutes during the immersion of meat in a ternary solution. The model is based on the development of a barrier layer of solutes at the periphery of the product, this barrier playing a key role in the control of subsequent mass transfer.