Exploring the interaction between Lycium barbarum polysaccharide and gelatin: Insights into gelation behaviors, water mobility, and structural changes

Gelatin-polysaccharide interactions have garnered significant attention in recent years due to their profound effects on the properties (rheology and structure) of various food products. This study investigates the interaction between Lycium barbarum polysaccharide (LBP) and gelatin, focusing on the impact of different concentrations LBP (0-2.0%, w/v) on gelation behavior, water mobility, and gelatin structure. The results show that the addition of LBP initially increases and then decreases the gel strength and hardness of the gelatin. Incorporating LBP into gelatin leads to decreased brightness, gelling temperature (Tg), gelation rate (kgel), immobile water content, and residue, while increasing the redness, yellowness, bound and free water content, and thermal stability. Fourier transform infrared spectroscopy (FTIR), x-ray diffractometer (XRD), cryogenic scanning electron microscopy (Cryo-SEM), and atomic force microscopy (AFM) analyses provide evidence for the existence of hydrogen bonds, electrostatic interactions, and ionic bond interactions between LBP and gelatin, in addition to covalent bonds formed through the Maillard reaction. Moreover, LBP induces changes in the structure of gelatin, including alterations in secondary structure, crystalline structure, and microstructure. AFM observations further indicate that LBP promotes the formation of gelatin aggregates. These findings present promising avenues for the application of LBP-gelatin composite gels as novel materials in the food industries.