Milk products are based mostly on casein micelles, fat globules, and whey proteins. The former two constituents are corpuscular and whey proteins become corpuscular when coagulated. Structural changes in these basic constituents during processing have been studied by electron microscopy. This review discusses the structures of yoghurt, curd, cheeses (hard cheeses, mould-ripened cheeses, cream cheeses, and process cheese), cream, milk powders, and nontraditional dairy products. Defects and deviations from traditional structures of these products are explained where the causes are known. Examples of such causes are foaming of milk, presence of unusual ingredients (bacterial polysaccharides, whey protein concentrates), and alterations in manufacturing procedures (temperature regimens, ultrafiltration, or microparticulation).
The review emphasizes the importance of electron microscopy alone and also in conjunction with X-ray microanalysis and image analysis. Data obtained by structural studies facilitate understanding of sensory properties of the products and help to develop new foods with desired properties. The review is illustrated with 29 micrographs and supported by 165 references.
"Practical Aspects of Electron Microscopy in Dairy Research,"
1, Article 11.
Available at: http://digitalcommons.usu.edu/foodmicrostructure/vol12/iss1/11