EXAMINATION OF WHOLE MILK POWDER BY CONFOCAL LASER-SCANNING MICROSCOPY

Confocal laser scanning microscopy was used to examine components of w hole milk powder. Powder was dispersed in a glycerol suspension contai ning a fat-soluble fluorescent dye which was excited by laser Light to produce images of the fat at the surface of and inside the whole milk powder particle. Lactose crystals, produced in the milk prior to spra y drying, were seen to be in the diamond-like, alpha-hydrate form. The surface coverage and the stability of a wetting agent sprayed on to t he surface of whole milk powder particles were examined. The wetting a gent was shown to be located as a thin surface layer that partly migra ted into creases and folds on the particle surface during storage at 3 7 degrees C.