Effects of processing and added ingredients on oil diffusion through cocoa butter using magnetic resonance imaging

Abstract

This study investigates the diffusion of oil in different blends of cocoa butter with sugar and lecithin, processed under different crystallization conditions (0 and 250 s⁻¹ shearing rate). Magnetic resonance imaging (MRI) was used to quantify the extent of oil migration from a cream filling to the lipid blends. Oil migration was monitored using MRI and liquid oil diffusivity in the samples was evaluated using a short-time approximation to Fick's II law of diffusion. For all the formulations, sheared samples showed distinctively lower oil diffusivity values. Furthermore, the effect of shearing on oil diffusion varied based on the addition of lecithin and/or sugar to cocoa butter. Short-time liquid oil diffusivity decreased by about 91% in sheared samples containing sugar while shear crystallization reduced the migration rate by about 70% and 62% in the binary mixture of cocoa butter and lecithin, and samples containing both sugar and lecithin, respectively.