Whey protein concentrate-beeswax-sucrose suspension-coated paperboard with enhanced water vapor and oil-barrier efficiency

This study investigated the effect of whey protein concentrate (WPC):beeswax (BW): sucrose (Suc) coating on the moisture-and oil-barrier properties of paperboard. Six coating suspensions with different WPC:BW:Suc ratios (1:0:1, 1:0:2, 1:1:1, 1:1:2, 1:2:1, and 1:2:2) were prepared and coated on paperboards. Droplet size increased with higher BW and Suc concentration in the coating (p < 0.05). Higher concentrations of BW and/or Suc increased the coating suspension viscosity (p < 0.05). Scanning electron microscopy images indicated that the WPC:BW:Suc suspension-coating with higher BW concentration was thicker, more uniformly dispersed, and stable in the network structure formed. Further, Cobb test, water vapor permeability measurement, and oil penetration analysis indicated that WPC:BW:Suc coatings improved the water and oil-barrier properties of pa-perboards (p < 0.05). Therefore, paperboards with coatings containing WPC, BW, and Suc have the potential to replace pure paperboard in applications that require a moisture/oil-barrier.