Long-term storage stability of type A and type B gelatin gels: The effect of Bloom strength and co-solutes

For gelatin-based confectionery, nutraceutical, and pharmaceutical products, storage stability is important for maintaining textural properties during transportation and throughout the shelf life of the final product. Exposure to elevated temperatures causes degradation of the gelatin molecule, which results in a reduction in the average molecular weight, further impacting its mechanical properties. In this study, the long-term stability of gelatin systems prepared with different gelatins (type B from bovine, type A from pig skin, or type A from fish skin) stored below and above the sol-gel transition temperature was compared. The effect of storage temperature, Bloom strength, and the inclusion of co-solutes (sugar alcohols or gum arabic) on storage stability was evaluated. The long-term stability was investigated using small amplitude oscillatory shear measurements and molecular weight analyses via size-exclusion chromatography coupled with online multiangle laser light scattering. The storage modulus of the gels and the average molecular weight of the gelatin indicated that incubation above or close to the equilibrium sol-gel transition temperature resulted in an increased degradation rate of gelatin. Type A gelatin gels exhibited better storage stability than type B gelatin gels. In addition, gels prepared with high Bloom strength gelatins exhibited improved storage stability compared to low Bloom strength gelatins. The addition of sugar alcohols increased stability, whereas gum arabic did not have a large impact on the long-term stability of the type B gelatin gel.