Effect of temperature on sucrose penetration and browning reactions in longan aril during osmotic dehydration

Abstract

Sucrose penetration and browning reactions in longan aril during osmotic dehydration at various temperatures were examined by measurement of total soluble solid and colour parameter (b*) of longan aril. Mathematical modelling and Arrhenius equation were used to express the changes during the process and the effect of temperature respectively. Parabola models (Y = a0 + a1X + a2X2) were fitted to the set of total soluble solid data where a0 is the initial total soluble solid and X is the soaking time, because the rate of increase in total soluble solid of longan aril during osmotic dehydration was high in the initial period and gradually decreased until the system reached equilibrium. Linear models (Y = a0 + a1X) were fitted to the set of b* values where a0 is the initial value and X is the soaking time. Mathematical equations were created for predicting response values at any temperature ranging from 30 to 90 C, but the predicted values were slightly lower than the experimental ones.

Keywords

• longan
• sucrose penetration
• browning reactions
• osmotic dehydration
• mathematical modelling
• Arrhenius equation