Potato fruit juice - Poly(3-hydroxybutyrate) multi-layer coated paperboards for bio-based packaging

In this work, the use of potato fruit juice (PFJ) in combination with poly(3-hydroxybutyrate) (PHB) was explored as a biobased barrier coating on paperboard. A two-layer and three-layer solution were explored. In the two-layer structure, the PFJ layer was rod-coated on pigment-coated paperboard, followed by extrusion coating of PHB on top. In the three-layered coating, paperboard without pigment coating was extrusion-coated with PHB, followed by rod coating of PFJ, and finally, extrusion-coated with PHB. The specific water vapour transmission rate was reduced by approximately 95 % and 90 % for the two- and three-layer coatings, respectively, relative to the uncoated paperboard. Besides contributing to barrier properties, the PFJ increased the bonding strength between the PHB and the paperboard. Although the three-layer coated paperboards showed better oxygen barrier properties than the two-layered coatings, the oxygen permeability was still high. Three-layer coatings exhibited moderate peeling strength, and better creasing and grease barrier properties compared to two-layered coated paperboards.