Determination of sorbitol crystal content and crystallization rate using TD-NMR

Abstract

Sorbitol crystallization in low moisture systems is difficult to measure using traditional methods such as differential scanning calorimetry, microscopy, and x-ray diffraction. This study developed a novel method for sorbitol crystal content determination using a time domain nuclear magnetic resonance (TD-NMR) method adapted from that commonly used to measure solid fat content and recently proven to measure sucrose crystal content (Porter and Hartel, 2013). TD-NMR was proven to accurately measure sorbitol crystal content (p < .5) and was then used to determine crystallization rate at a variety of moisture contents (0.8%, 1.7%, 4.2%, and 6.7%) and crystallization temperatures (10 °C, 25 °C, and 40 °C). Data for crystal content as a function of time was fit to a growth model, which was further used to derive crystallization rate and phase diagrams with contour plots. Importantly, this study marks the first time γ-sorbitol crystallization rate has been quantified in literature.