Development of Bioactive Opuntia ficus-indica Edible Films Containing Probiotics as a Coating for Fresh-Cut Fruit

Bioactive edible films have received more attention in recent years as a method for food preservation with value-added functions. The aim of this study was to develop a bioactive edible film containing mucilage of cactus (Opuntia ficus-indica) and incorporating the probiotic strain Enterococcus faecium FM11-2 as an active component to promote consumer health benefits. Opuntia ficus-indica is rich in nutritional and bioactive compounds and the abundance of this cactus makes it attractive for food applications. Mucilage of Opuntia ficus-indica contained 0.47 ± 0.06 mg/g total sugar, 0.33 ± 0.06 mg AGE/mL phenolic content, 0.14 mg/ mL vitamin C, and possessed 35.51 ± 1.88% DPPH scavenging activity. The edible film that was developed exhibited the following characteristics: thickness of 0.02-0.11 mm, percent moisture content 0.19-0.24%, water solubility 30.66-59.41% and water vapor permeability of 0.15-1.5 g·mm/m²·min·kpa, while the range of the variation depended on the type of plasticizer used (either sorbitol or glycerol). The addition of sorbitol in the film provided the maximum mechanical strength based on the evaluation of tensile strength, Young's modulus and elongation at break (44.71 ± 0.78 MPa, 113.22 ± 0.23 MPa and 39.47 ± 0.61%, respectively). The optimal formulation of the edible film, according to the physicochemical, physical and maintenance of fresh-cut apple slices, contained cactus mucilage, gelatin, glycerol and a probiotic. The incorporation of a probiotic into the cactus film created a bioactive edible film that could provide a health benefit. While improvement is needed to maintain the survival rate of the probiotic, this work presents an exciting method for furthering the study of food preservation with edible films.