Spatial mapping of solid and liquid lipid in confectionery products using a 1D centric SPRITE MRI technique

Oil migration is responsible for the poor keeping qualities of composite confectionery products. Quality defects arising from oil migration include softening of the coating, hardening of the filling, deterioration in sensory quality and a greater tendency toward fat bloom formation. For this reason, oil migration has been extensively studied, and yet a clear understanding of the oil migration mechanisms still remains a challenge. Traditional MRI techniques are unable to acquire images from the solid lipid in chocolate. In this paper we employ a newly developed one-dimensional, centric-scan MRI technique to acquire images from the short lived signal components from the solid lipid, as well as the longer timescale components of the liquid lipid in a chocolate sample. We present one-dimensional images of a dynamic hazelnut oil absorption experiment, and one-dimensional solid and liquid distribution maps in a 5 mm thick chocolate sample in which oil migration occurs.