Influence of the temperature and granulometry on the hygroscopic behavior of tapioca flour

Abstract

The morphological difference between two types of tapioca flour motivated this research, which aims to evaluate the hygroscopic behavior of these products via moisture sorption isotherms (MSI). The MSI of the products were obtained at 25°C, 35°C, 45°C, and 55°C and the experimental data were fitted at seven mathematic models that concern the effect of temperature. MSI had type-II behavior and hysteresis were observed between the moisture adsorption and desorption isotherms, whose magnitudes decreased with higher temperatures. According to adsorption, the two flour are microbiologically stable if they have moisture below 11% and they are less susceptible to becoming moist if they are stored at relative humidity below 70%. The MSI indicated that the tapioca flour more expanded is more hygroscopic and with higher moisture decreases as temperature increases, suggesting distinct storage conditions for the two flour. The modified Oswin model had a good fit to the sorption data.

Keywords

• manihot esculenta
• starch
• hygroscopicity
• mathematical modeling