Oil migration in chocolate and almond butter confectionery systems

Oil migration from high oil content almond confections into adjacent chocolate causes changes in product quality. The objective of this study was to quantify the oil migration from almond butter and cream products to dark chocolate. Magnetic resonance imaging (MRI) was used to monitor spatial and temporal changes of liquid lipid content. A multi-slice spin echo pulse sequence was used to acquire images with a 7.8 ms echo time and a 1000 ms repetition time using a 1.03T Aspect AI MRI spectrometer. Samples were prepared as a 2-layer model system of chocolate and almond confection. Four different almond products and one type of dark chocolate were used. Samples were stored at 30C over a time frame of one month. Rates of migration were quantified by a kinetic expression based on the linear dependence of oil uptake and the square root of the time. Samples showed distinctly different rates of oil migration, as evidenced by quantitative differences in the kinetic rate constants and equilibrium uptake for the different sample types. This work will be helpful to design formulations, processing conditions and storage environments for almond use in confections.