Understanding the mechanism of saccharides type and concentration affecting texture of freeze-dried pectin-CMC cryogels through experiment and molecular dynamic simulation.

Saccharides are the dominant factor shaping the texture of freeze-dried products. This study investigated the impact of various molecular-weight saccharides at different concentrations on the physical properties and intermolecular interactions of pectin-CMC cryogels by experiment and molecular dynamic (MD) simulations. Results showed that the increased shrinkage of cryogels and enhanced molecular interactions between saccharides and pectin-CMC were mechanisms that enhanced the hardness of cryogels. Notably, the cryogel with fructose exhibited significantly higher hardness compared to cryogels with other saccharides. The cryogel containing 16 % fructose had the lowest glass transition temperature (T), leading to the highest shrinkage (70 %). Moreover, the MD results revealed that fructose had the highest intermolecular interaction energy (coulombic short range) with pectin-CMC (-5316.78 kJ/mol). This study revealed that the intermolecular interactions between the added saccharide and the pectin-CMC, in addition to the density of the cryogel, are critical determinants of the hardness and crispness of cryogels.