Optimization of Eggshell Calcium Use for Improving the Physical Quality of Whey Protein Isolate-based Edible Films

Edible films based on biopolymers are increasingly popular as environmentally friendly and functional food packaging alternatives. One approach to improving the physical properties of edible films is by incorporating calcium derived from eggshell waste. This study aims to develop and characterize edible films made from whey protein isolate (WPI) with the addition of eggshell calcium at various concentrations. The study employed a completely randomized experimental design with four treatments: the addition of eggshell calcium at 0.25%, 0.50%, 0.75%, and without eggshell calcium (w/v) of the total volume of the film-forming solution, with five replicates per treatment. Characterization included measurements of thickness, water solubility, opacity, swelling rate, moisture content, and color parameters (L, a*, b*). ANOVA results showed that the addition of eggshell calcium had a highly significant effect (p<0.01) on solubility, opacity, swelling rate, a* and b* values in the edible film. Apart from that, it had a significant effect (p<0.05) on the thickness and L value, and had no effect (p>0.05) on the moisture content of the edible film. The addition of eggshell calcium significantly increased film thickness with increasing concentration. Film solubility decreased dramatically with calcium addition, indicating increased water resistance. Film transparency decreased at higher calcium concentrations. The degree of swelling and water content of the film also decreased with calcium addition, indicating a reduced affinity of the film for water. The film color changed: L values, a* values, and b* values tended to decrease compared to the control. The research results indicate that eggshell calcium can be utilized as a functional additive to improve the physical properties of WPI-based edible films, while also adding value to agroindustrial waste.