Physicochemical and microbiological characterization of pectin-based gelled emulsions coating applied on pre-cut carrots

Two antimicrobial formulations composed of Biosecur F440D (citrus extract) and a mixture of four essential oils (EOs) entrapped in pectin-based matrix were characterized by Fourier-transform infrared spectroscopy (FTIR). The effect of pectin-based matrix on active compounds' release and their stability during storage time were also evaluated. Furthermore, shelf-life of pre-cut carrots coated with gelled emulsions and its antimicrobial activity against Listeria monocytogenes and Penicillium chrysogenum were assessed. Based on FTIR analysis, entrapment of Biosecur F440D in pectin matrix was obtained especially by hydrogen bonding and CH stretching. A strong asymmetric -CH3 stretching in alkyl groups were also observed for the entrapment of mixture of EOs in pectin matrix. The entrapment of bioactive ingredients in pectin matrix slowed down the release behavior for both formulations and gave a better stability of total phenols content and color especially in Biosecur F440D based emulsion. Application of gelled emulsion on pre-cut carrots improved the shelf-life by 1 day as compared to untreated carrot for Biosecur-based gelled emulsion containing EOs and by 2 days for EOs-based gelled emulsion containing Biosecur F440D. An improvement in antimicrobial activity against L. monocytogenes and P. chrysogenum was also observed for both emulsions and their respective gelled emulsions.