Montmorillonite as a reinforcement and color stabilizer of gelatin films containing acerola juice

Montmorillonite (Mt) is well known as reinforcing agent in films. Moreover, it stabilizes anthocyanin pigments. In this study, Mt has been added as both reinforcement and color stabilizer to gelatin films containing acerola juice. Films were produced with different Mt concentrations (0-63% on gelatin). Increasing Mt contents resulted in enhanced tensile strength and modulus, although the elongation has been decreased. Mt also reduced the water vapor permeability in up to 45%. Mt presented two effects on film color: first, it changed its color from yellowish to red; and second, it stabilized film color throughout storage, mainly when added at 3.9%. It has been suggested that metals from Mt (such as Fe3+ or Al3+) may have formed complexes to anthocyanins, changing and stabilizing their color.