The Effect of Freeze Drying on the Nano and Micro Structures of Sugars

Abstract

Aims: Crystallization during freeze-drying (FD) play essential role for creating high-quality sugar products and optimizing production processes in the sugar and   pharmaceutical industry. The primary objective of this study is to examine the impact of the FD process on the nanoscopic nucleation stage of monosaccharides (glucose, galactose and fructose) and disaccharides (sucrose and lactose) during the crystallization process. Study Design: Experimental and employs software for modelling. Place and Duration of Study: Department of Food Engineering (METU) and Department of Physics Engineering (Hacettepe University), National Synchrotron Radiation Research Center, between 2022 and 2024. Methodology: The 3D nanoscopic structures of the sugars were established by SAXS-WAXS (Small and Wide-Angle X-ray scattering) methods for the first time. Attenuated Total Reflectance Fourier Transform Infrared spectroscopy (ATR-FTIR) was used to examine the molecular structural changes and behavior of water molecules surrounding of sugar molecules. Results: Crystallographic unit cells, lattices of the nano-nucleation and nano morphologies were determined. The uniform distribution and well-defined compact morphology were found for FD-lactose. Marked spectral differences in ATR-FTIR spectra between FD and control samples of glucose and sucrose were observed.  Conclusion: The findings of the study suggest that the freeze-drying process may potentially result in an enhancement of the molecular and nanoscopic stability of sugars.