Bio-microcapsules production for a controlled release of natural antimicrobials from packaging materials

In this work, bio-microcapsules of chitosan have been developed by a membrane process using both polymeric and ceramic membranes. This technique permitted the formation of monodispersed bio-polymer droplets which were then cross linked with a natural additive adapted for this polymer structure that enhanced the water resistance of chitosan. Furthermore, two different types of natural antimicrobial were included in the capsules making the loading both during their production and after the droplet formation. The most effective entrapping method was then selected considering the amount of natural antimicrobial incorporated. The antimicrobial activity of the microcapsules was assayed by turbidimetric methods against bacteria and yeasts selected as dangerous and common microorganisms, which may be present in fresh food. Results are reported about the relationship between the amount of natural active substances released by microcapsules and the different degree of crosslinking, as well as the effects of the technological variables investigated on the kinetics of antimicrobial release