; Email: simi.poulose@tuni.fi Mikael S. Hedenqvist-; ? orcid.org/; Email: mikaelhe@kth.se

The potential of using potato fruit juice (PFJ), a byproduct from the potato starch industry, was investigated as a barrier paper-coating material. The paperboard was initially hand-coated with PFJ (with and without glycerol as plasticizer) and then extrusioncoated with poly(lactic acid) (PLA) or a blend of PLA and poly(butylene adipate terephthalate) (PBAT). The multilayer coated paperboard was homogeneous in appearance with a glossy finish. The coated paperboard showed, at the most, a ca. 95% reduction in specific water vapor transmission rate compared to the uncoated paperboard. In the presence of the PFJ layer, the extrusion-coated paperboard experienced, at the most, a 98% reduction in oxygen permeability. The grease resistance of the paperboard was also improved significantly with this multilayer coating. PLA- and PFJ-coated samples showed better barrier properties, whereas PFJ with PLA/PBAT layers exhibited better adhesion and heat-sealing properties. The peel strength of the coated samples was moderately good for paper converting applications. The developed coated paperboard also exhibited good creasing properties which is yet again an advantage for packaging applications. The presented barrier properties make the developed multilayer coatings on paperboards a sustainable competitive alternative to several of today's coatings. KEYWORDS: paper coating, barrier coating, bio-based coating, potato fruit juice, poly(lactic acid), poly(butylene adipate terephthalate), barrier properties, peel strength, heat sealing