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

The objective o f this study was to investigate techniques suitable for viewing the microstructure of ice cream in the frozen and full y hydrated state using lowtemperature 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, fa t 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 crystals with a mean di ameter of 40 J.Lffi showed a characteristic reticulate structure after sublimation. The appearance of the ice cream micrographs was greatly influenced by the degree o f sublimation. Optimum sublimation time provided 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 subl imation process was observed in the electron microscope.