The purpose of the present study was to clarify the browning behavior of calcium maltobionate (CaMb). CaMb samples with varying water content (0-50 %) and water activity (0-0.98) were prepared. Absorbance due to the browning of CaMb-water samples increased linearly with an increase in holding time, and the browning rate was evaluated as a pseudo-zero-order reaction at each temperature (353-413 K). The effect of temperature on the browning rate of CaMb samples was analyzed using the Arrhenius formula, and the pre-exponential factor and activation energy were determined. In addition, the browning rate at 298 K (typical ambient condition) was determined according to the Arrhenius behavior. The browning rate at 298 K slightly decreased, markedly increased, and then decreased with an increase in water content and water activity. This behavior can be explained by the monolayer effect, plasticizing effect, and dilution effect of water molecules. There was a linear relationship between the natural logarithm of the pre-exponential factor and activation energy according to the thermodynamic compensation rule. The effect of water content on the activation energy was fitted using the cubic function. From these results, an approach for prediction of the browning of CaMB during thermal condensation was established.
Keywords: TG-DTA; activation energy; browning; calcium maltobionate; water activity.
2023 by The Japanese Society of Applied Glycoscience.