Kinetics of the migration of lipids in composite chocolate measured by magnetic resonance imaging

Migration of hazelnut oil into chocolate was followed non-invasively by magnetic resonance imaging, using a spin echo pulse sequence to acquire images with a 5 ms echo time and a 2000 ms repetition time. A calibration curve was used to correlate the image intensity with the concentration of hazelnut oil. Two different degrees of chocolate temper, at three different storage temperatures (20, 23 and 28 degreesC), were monitored over a period of 80 days. The effect of thermal treatment (24 h at 30 degreesC followed by 24 h at 4 degreesC) on the speed of migration of hazelnut oil was also studied. Qualitative analysis yielded the spatial resolution of the oil migration data, whereas quantitative analysis gave the oil diffusion constants. (C) 2001 Elsevier Science Ltd. All rights reserved.