Development of a new family of food packaging bioplastics from cross-linked gelatin based films

Abstract

The purpose of this work was to develop green bioplastic preparation process from gelatin by using solvent-free approach with efficient use of resources. Film plasticizing was achieved by adding polyethylene glycol (Mw=200g.mol-1). Different cross linking agents - glutaraldehyde (GTA), N-hydroxysuccinimide (NHS), Bis(succinimidyl)nona(ethylene glycol) (BS(PEG)9) and ferulic acid (FA) were tested to obtain water resistant films suitable for gas permeability characterization. Functional properties (mechanical and gas transfer properties) of gelatin-based films were determined. Gelatin films cross-linked with FA presented very good gas barrier properties (48 and 175cm3.μm/m2.day.kPa respectively for O2 and CO2), compared to synthetic polymers, equivalent to polar polymer like nylon 6 or polyethylene terephthalate and better than non-polar polymers like high density or low density polyethylene. Swelling ratio measurements in water displayed gelatin/FA films resisted to water without breaking during 4h compared to 1.5h for pure gelatin films. Films could support saturated water vapour environment at 20°C during 15 days without breaking. Gelatin/PEG200 films presented very good permselectivity towards CO2 and O2 (14.5). This value was reduced to 8 when cross-linked with FA, and to 4 after PEG200 addition, presenting still interesting level. All these results confirmed that gelatin is a promising biobased polymer to prepare food packaging films.