Biodegradable composites from polyester and sugar beet pulp with antimicrobial coating for food packaging

Totally biodegradable, double-layered antimicrobial composite films were introduced for food packaging. The substrate layers of the sheets were prepared from poly(lactic acid) (PLA) and sugar beet pulp (SBP) or poly (butylene adipate-co-terephthalate (PBAT) and SBP by a twin-screw extruder. The active layer consisting of antimicrobial in either PLA or chitosan was formed on the surfaces of the substrates by solution coating followed by solvent evaporation. Air-coupled ultrasonic evaluation and microscopic examination showed a homogeneous structure for the composite sheets. Mechanical analysis and acoustic emission demonstrated the double-layered composites possessing appropriate tensile strength and fracture characteristics for the use as light weight-bearing materials. The release of Nisaplin (R) or allyl isothiocyanate (AIT) effectively suppressed the growth of Listeria monocytogenes and Salmonella cells, respectively; the co-release of Nisaplin (R) and AIT played a synergistic effect on inhibition of L. monocytogenes. (c) 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012