Mathematical Models for Prediction of Water Evaporation and Thermal Degradation Kinetics of Potato Starch Nanoparticles Obtained by Nanoprecipitation

Abstract

The aim of this research is to study the thermal degradation kinetics and some physicochemical properties of starch nanoparticles (SNPs) produced from potato starch (PS) by nanoprecipitation. Native PS is used as a control. The powder samples are analyzed by means of light and transmission electron microscopies, X-ray diffraction, Fourier transform infrared, and thermogravimetric analysis. PS shows oval and spherical granular shaped with a diameter between 6 and 18 µm, whereas SNPs display spherical and elliptical shapes with particle sizes between 50 and 150 nm. The relative crystallinity is 25.4% to PS, and it decreases to approximately 23.5% for SNPs. Activation energy (E) associated to the water evaporation and thermal degradation is calculated using the Newton model as well Ozawa-Flynn-Wall (OFW) and Kissinger-Akahira-Sunose (KAS) models, respectively. The E values using the Newton model increase from 43.7 kJ mol−1 (PS) to 84.1 kJ mol−1 (SNPs). The E values using the OFW and KAS models vary between 165 and 227 kJ mol−1 for PS, and between 180 and 400 kJ mol−1 for SNPs. Modifications in E values are associated with the increase in surface area in SNPs. This research reports new information of the thermal properties of SNPs.