Oil migration in a chocolate confectionery system evaluated by magnetic resonance imaging

Oil migration is a common problem in composite chocolate confectionery products resulting in softening of chocolate and hardening of the filling. Spatial and temporal changes in the liquid oil content of a 2-layer peanut butter and chocolate model system were evaluated using a magnetic resonance imaging (MRI) technique. The experimental factors were chocolate particle size, milk fat content, emulsifier concentration, degree of temper, and storage temperature. The responses were migration rate and overall change in signal intensity (amount of migration). Based on analysis of variance (ANOVA), particle size, milk fat content, and storage temperature were significant factors for oil migration rates. Milk fat content and temperature were significant factors for overall change in signal intensity.