Development and Characterization of a Novel Edible film Based on Xanthoceras sorbifolia Seed Kernel Protein Isolate: Effects of Plasticizers and pH Value

Biopolymer ingredients have received extensive attention as raw materials for film production due to their low cost, nontoxicity, and compatibility. Xanthoceras sorbifolia seed kernel protein isolate (SKPI), which is prepared from defatted kernel meal, can serve as a valuable source for edible film production. Herein, the performance of SKPI-based films was characterized and evaluated under the influence of pH values (8, 9, and 10) and glycerol concentrations (3.5%, 4.0%, and 4.5% W/V) of the film-forming solutions. The water vapor permeability, color, light transmission, mechanical properties, and microstructural changes of the films were investigated. When the pH value increased from 8 to 10, the tensile strength of glycerol plasticized film increased, while the elongation at break decreased. On the contrary, regardless of the alkalization of SKPI, the flexibility of the films was notably improved with increasing glycerol concentration. In addition, all obtained films exhibited excellent UV-blocking properties. The overall results showed that glycerol concentrations and pH values can be combined to produce SKPI films for multiple packaging requirements in the food industry. Graphical Abstract