Grease Penetration and Browning Resistance of Pulpboard and Paperboard Coated with Whey Protein

Whey protein concentrate (WPC) was explored alone and in combination with sucrose (Suc) plasticizer as a grease-barrier coating for bulrush pulpboard and solid bleached sulfate paperboard used in food packaging. WPC-coated and WPC:Suc-coated pulpboards showed better oil-barrier properties compared with untreated, water-treated or Suc-coated pulpboards. Coating formulations with 10% WPC, without and with Suc, resulted in oil barriers comparable with commercial fluorinated hydrocarbon for pulpboard. When pulpboard trays containing cheesy pasta were microwave-heated, 10% WPC:20%?Suc solution-coated trays showed grease barrier property comparable with fluorinated hydrocarbon-treated trays. Caramelization and Maillard browning of WPC and WPC:Suc coatings were initiated at 300 degrees F, but microwave-heated foods do not normally reach this high temperature. Paperboard with 10%?WPC:20%Suc solution coating had oil barrier comparable with polyethylene-coated paperboards. WPC?:?Suc solution mixture at 2.5%:5% and 3.3%:7% were determined as the solution concentration minima for 4 and 24 h tests, respectively. HunterLab colorimeter L and b values indicated slight colour change of the paperboard coated with the higher WPC concentration solutions. Coating resulted in thicker paperboards but not in a linear manner. The 10%WPC:20%Suc solution-coated solid bleached sulfate paperboards on which slabs of butter sat in a refrigerator did not show any butterfat penetration, comparable with polyethylene-coated paperboards and unlike uncoated paperboards that showed poor butterfat-barrier properties. WPC:Suc coating was shown in this study to have potential to replace synthetic materials as a grease barrier. Copyright (c) 2011 John Wiley & Sons, Ltd.