Characterisation of Milk Proteins in Confectionery Products

The proteins from milk play an important part in the structural properties of confectionery products. These properties will in turn influence texture and flavour. Electron microscopy techniques have been used to examine milk chocolate, caramel and fudge and to locate and characterise the milk proteins within their structures. Following scanning electron microscopy examination of the products at low temperature, thin sectioning and freeze-fracture were used to resolve the fine ultrastructure of casein and whey proteins. A chocolate prepared from milk crumb could be distinguished from one made with a dry milk powder on the basis of a more even distribution of protein and a high level of association between milk protein and other ingredients. Caramel was seen to be composed of an amorphous sugar support matrix containing numerous fat globules. Milk protein was found frequently associated with fat although the level of association depended on whether casein or whey protein was present. The development of crystal line sugar in fudge caused the milk protein to concentrate within the remaining amorphous sugar regions. Fat/protein associations were not as obvious as those observed in caramel