A Low-Temperature Scanning Electron Microscopy Study of Ice Cream. I Techniques and General Microstructure

The objective of this study was to investigate techniques suitable for viewing the microstructure of ice cream in the frozen and fully hydrated state using low temperature scanning electron microscopy (L T-SEM), and to examine the microstructure of the frozen product. lee cream bad four distinct structural phases: ice crystals, air bubbles, fat globules and serum. Air bubbles, 10 to 60 ~-tm in diameter, were lined with fat globules, 0.5 to 2.5 J.tnl in diameter. Ice cry stals with a mean di ameter of 40 J.Lffi showed a characteri stic reticulat e structure after sublimation. The appearance of the ice cream micrographs was greatly influenced by the degree of sublimation. Optimum sublimation time prov ided a clearly defined ice crystal socket with network structure remaining. Sublimation was influenced by composition, sample size, specimen holder, and temperature. Although sublimation can be achieved in both the preparation chamber and in the electron microscope, best results were obtained when the sublimation process was observed in the electron microscope