Machine-coated starch-based dispersion coatings prevent mineral oil migration from paperboard

• Hydroxypropylated starch-based dispersion barrier coatings for paperboard were developed for application in an industrial coating process.
• The aim was to enhance the safety of fiber-based food packaging containing printing ink that originates from recycled fibers or surface print.
• The migration of a mineral oil simulant (heptane) and actual liquid mineral oil used in offset printing through coated paperboards was studied.
• Starch-based composite dispersion coatings acted as mineral oil barriers and demonstrated good grease barrier properties.
• Environmentally friendly biopolymer-based dispersion coatings could contribute to improving the barrier properties and safety of fiber-based primary food packaging.

Mineral oil migration through paperboard presents a safety risk in modern food packaging. This study aimed to enhance the safety of fiber-based packaging by utilizing a bio-based composite barrier layer to protect against mineral oil. Starch-clay composite coatings on paperboard were created via dispersion coating. Thermal analysis of the coating components and field emission scanning electron microscopy imaging were performed to ascertain the physicochemical properties and morphology of the coatings. Coating functionality was evaluated using contact angles and transmission rate (water and oxygen) measurements. The packaging safety focus was implemented by measuring the gas phase migration of heptane and analyzing the migration of liquid mineral oil through the coated paperboards with FTIR. The functional properties of the coated paperboards were maintained or improved. The studied coatings were effective barriers against the migration of mineral oil and could hence improve the barrier properties and safety of fiber-based primary food packaging.