Automated image analysis tool for migration fat bloom evaluation of chocolate coated food products

Migration fat bloom remains a major problem in the production of coated confectionary products where a layer of chocolate is added around a filling or other fat containing substrate. Fat bloom quantification is typically done by a human panel scoring samples in time using a low resolution discrete scale. In view of developing a mechanistic model for migration fat bloom, it is important to have a higher resolution. In this paper, a new, high resolution quantitative method based on image analysis is developed. The method is able to detect both the evolution of fat bloom in terms of the disappearance of gloss and the development of “whitish” portions at the chocolate surface. It was successfully applied to distinguish the difference in fat bloom development rate between samples containing different fat concentrations (0, 3 and 6g/100g) coated on fillings containing different amounts of fat (25 and 75g/100g). In the 25g/100g filling fat case, blooming occurred at a very late stage and was caused by the disappearance of gloss. In the 75g/100g filling fat case the development of a “whitish” surface was responsible for the change in acceptability. The newly developed image analysis method is a solid alternative for the panel procedure.