Modelling fat and water migration in multi-phase systems using Raman confocal microscopy

Overview

This research program develops a predictive model to describe fat and water migration in multi-phase systems, such as oleogel-based emulsions and sugar/fat mixtures. Fat and water migration is a common cause of quality loss in food products, leading to texture changes, fat bloom, or moisture redistribution. The proposed model combines computational fluid dynamics with population balance equations to describe both transport phenomena and the evolution of solid crystal populations, including number, shape, and size.

To generate the experimental data needed to build and validate the model, the program uses Raman confocal microscopy, a non-destructive analytical technique that provides spatially resolved chemical information. A 1064 nm laser suppresses fluorescence, making the technique suitable for highly fluorescent materials such as cocoa powder.

Technical specifications

Raman confocal microscopy platform:

• Equipped with four lasers, including a 1064 nm laser for highly fluorescent samples
• Polarized lens enables visualization of liquid crystals
• Mechanical stage supports fast 3D imaging with spatial resolution down to 200 nm
• Raman spectral maps reveal the spatial distribution of fat and water, their physical state (liquid vs solid), and distinguish between different polymorphs

Modelling approach:

• Computational fluid dynamics describes water and liquid-fat transport
• Population balance equations describe the temporal evolution of solid crystal populations
• Chemometric tools extract migration fronts, local phase distributions, and crystal descriptors from spectral maps

Validation methodology:

• Sample formulations designed using Design of Experiments principles
• Initial characterisation of water activity, rheology, solid-fat content, polymorphic form, porosity, and texture
• Storage under controlled temperature and relative humidity, including thermal cycling
• Complementary validation via differential scanning calorimetry, X-ray scattering (SAXS/WAXS), and mass balances

Technology readiness level

The technology is at an early research stage. The modelling framework and experimental protocol have been defined, and validation experiments are planned on industrially relevant multi-phase systems. Samples will be produced across varied compositions and monitored over time under controlled storage conditions to generate the dataset needed to refine and validate the predictive model. The program is designed for collaboration with an industrial partner to select target systems and ensure industrial relevance.