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

Abstract

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® or allyl isothiocyanate (AIT) effectively suppressed the growth of Listeria monocytogenes and Salmonella cells, respectively; the co‐release of Nisaplin® and AIT played a synergistic effect on inhibition of L. monocytogenes. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

A Review of Poly(Lactic Acid)‐Based Materials for Antimicrobial Packaging

“…The potential of PLA for use in antimicrobial packaging applications has been investigated in recent years by a number of researchers (Mustapha and others ; Rhim and others ; Chen and others ; Li and others ; Jamshidian and others ; Fei and others ). There are also a number of patents worldwide on PLA‐based materials containing antimicrobial agents (Auras and others ; Buonocore and others ; Chen and others ; Liu and others ).…”

“…Other studies have focused on coating methods where the antimicrobial substance is coated onto the surface of a primary polymeric film or substrate (Jin and Gurtler ; Jin and Niemira ; Li and others ). The 2 common types of coating methods are spray gun coating and diffusion coating with each of these techniques involving the prior dissolution of the antimicrobial agent.…”

Antimicrobial Activity of Allyl Isothiocyanate Used To Coat Biodegradable Composite Films as Affected by Storage and Handling Conditions

“…In this study, the antimicrobial layer was used as a coat on pre-extruded films, which provided several advantages over the one-step method, including (i) less concern for the loss of antimicrobial activity during thermal film making; (ii) reduced amount of antimicrobial compounds used in packaging material, since only the outer layer plays an antimicrobial role; and (iii) avoidance of " filler effect" that could breech the integrity of the plastic films and cause structural changes, and minimal impact on the physical or mechanical properties of the base materials. In our previous study, PLA + AIT or chitosan + AIT coatings on the composite films only caused minor structural changes (12), while the inclusion of EDTA and nisin directly into PLA blends significantly reduced the mechanical properties of the films and caused them to become less flexible (13).…”

“…The biodegradable composite films, consisting of PLA and sugar beet pulp, were prepared as described in our previous study (12).…”

“…Our previous study (12) demonstrated that coats of nisin and allyl isothiocyanate (AIT) on biodegradable composite films consisting of polyester and sugar beet exhibited strong antimicrobial activities against foodbome pathogens such as Salmonella and Listeria monocytogenes. However, before those films are applied in the food industry, it is necessary to answer the question of what happens to the antimicrobial activity of the films on their journey from film making to final use in food packaging.…”