A Preliminary Study on Active Chitosan-Based Edible Films Enriched With Microencapsulated Probiotics for Set-Type...

This study investigated the production, characterization, and application of active chitosan-based edible films enriched with microencapsulated Bifidobacterium animalis ssp. lactis B94, Lacticaseibacillus rhamnosus GG, and their combination for the preservation of set-type yogurt. The incorporation of microencapsulated probiotics significantly affected the physicochemical, mechanical, barrier, and antimicrobial properties of the films. Film thickness increased from 0.105 to 0.157 mm, moisture content ranged from 16.53% to 18.75%, and swelling index values varied between 20.63% and 32.78%. The addition of probiotics increased water vapor permeability and reduced film transparency and tensile strength. Following the drying process, probiotic survival rates ranged between 86.26% and 90.94%. The probiotic-enriched films exhibited antimicrobial activity against Escherichia coli and Staphylococcus aureus. The developed films were applied to set-type yogurt, and their effects on physicochemical and microbiological quality parameters were evaluated during 21 days of refrigerated storage. Yogurt samples coated with active films showed pH values between 4.02 and 5.34, titratable acidity values between 0.553% and 0.828% lactic acid, and reduced serum separation compared with control samples. Microbiological analyses of yogurt samples during storage revealed total mesophilic aerobic bacteria counts of 6.06-7.13 log CFU/g, lactic acid bacteria counts of 5.07-7.33 log CFU/g, Lactococcus spp. counts of 4.97-6.30 log CFU/g, and yeast-mold counts of 0-3.28 log CFU/g. These preliminary findings suggest that active chitosan-based edible films enriched with microencapsulated probiotics may have potential as biologically active surface films for set-type yogurt; however, confirmation using independent production batches is required.