ARS | Publication request: Biodegradable composites from polyester and sugar beet pulp with antimicrobial coating for food packaging

Submitted to: Journal of Applied Polymer Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 27, 2012
Publication Date: April 16, 2012
Citation: Li, W., Coffin, D.R., Jin, Z.T., Latona, N.P., Liu, C., Liu, B., Zhang, J., Liu, L.S. 2012. Biodegradable composites from polyester and sugar beet pulp with antimicrobial coating for food packaging. Journal of Applied Polymer Science. 126:E361-E372.

Interpretive Summary: Food packaging industry requires new materials and technologies. The ideal material should be environmentally friendly, price competitive to petroleum-derived thermoplastics, and can extend the shelve-life of packaged foods. In the present research, we introduce double-layered composite sheets for food packaging. The sheets were prepared from 50% biodegradable thermoplastic and 50% low-priced agricultural byproduct, sugar beet pulp, thus they are totally biodegradable and price-affordable. The sheets possess an antimicrobial layer on one side that can actively suppressed the growth of the Grant positive bacterial, L. monocytogenes and Grant-negative bacterial, Salmonella. The mechanical properties of the sheets match that of conventional thermoplastics and much higher than Styrofoam, and can be used for the manufacture of containers for quick-food, fresh-cut-food, yogurt, and other minimally processed food. Food industry and fruit processer will benefit from this research.

Technical Abstract: Totally biodegradable, double-layered antimicrobial composite Sheets 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 L. monocytogenes and Salmonella cells, respectively; the co-release of Nisaplin® and AIT played a synergistic effect on inhibition of L. monocytogenes.