Controlled release of natural antioxidant and antimicrobial substances on fresh-cut fruits from a layer by layer device

The high demand for convenience products and the potential of increasing the consumption of fresh fruits among the younger generations create a strong interest on fresh-cut fruits. These products require mild interventions for extending the shelf life which can be adequately met by active packaging systems. In this work a Layer by Layer assembly (LbL) coated onto PET sheets proved to be an effective controlled release system of natural polyphenols as antioxidants and chitosan as antimicrobial on the surface of fresh-cut fruits. The alternate layers of the polycation (chitosan) and the polyanion (alginate containing a green tea extract) has been confirmed by spectrophotometric, contact angles and AFM determinations. The modulated release of polyphenols and chitosan was monitored on a simulant of fresh-cut fruits in contact with the LbL assembly at 5°C. Finally, the antimicrobial and antioxidant effects of the LbL assembly device was tested on peach during the 7 day storage at 5°C, with the uncoated PET sheet as control.