On Lipid Migration from Particle-based Compacted Consumer Foods into Paper Packaging

Many particle-based consumer foods are in compacted or tableted form and contain lipids such as fats, oils and greases for nutritional, organoleptic, and technical functionalities. Driven by sustainability goals, consumer goods manufacturers aim to implement flexible paper-based packaging which however is more susceptible to lipid absorption due to its porous structure. Seasoning tablets or bouillon cubes are popular culinary condiments composed of compacted powders and lipids, wrapped individually in increasingly paper-based wrappers and often produce undesired lipid stains on the packaging. Research in lipid migration from foods has so far focused on chocolate. For the first time, a holistic approach is now taken to understand, characterise, and mitigate oil and fat migration from seasoning tablets into paper packaging. A literature review revisits fundamental mass transfer phenomena of lipid migration in particle-based food systems focusing on measurement, modelling and control approaches. The method of Raman chemical imaging and magnetic resonance imaging are further developed and applied for the first time to effectively quantify lipid mobility in seasoning food structures. As a migration mitigation strategy, interstitial pore size restructuration was performed by particle size variation of the salt fraction in the seasoning formulations. Capillary flow and diffusion modelling and experimental validation were performed. It was found that lipid migration out of the seasoning tablet into paper packaging was reduced in tablets with smaller pore microstructures, achieved with finer salt fractions. Lipid migration behaviour was explained by thermodynamic driving force being the relative difference of capillary suction between the food and paper matrices, and by kinetic resistance due to flow channel size in the food and paper porous media. This work for the first time investigated lipid migration from seasoning tablets into paper packaging, reviewing literature, developing advanced characterisation methodologies, and fundamentally describing and applying innovative migration mitigation strategies based on food microstructuration.