ARS | Publication request: MICROSCOPY TECHNIQUES FOR STRUCTURAL ANALYSIS OF STARCH/OIL COMPOSITES

Submitted to: Fine Particle Society
Publication Type: Abstract Only
Publication Acceptance Date: April 3, 1998
Publication Date: N/A

Technical Abstract: Starch/oil composites prepared by co-jet cooking (Fantesk**TM) can exist in a variety of forms, and their physical states as well as the properties of particular ingredients restrict the choice of method for sample preparation and microscopy. Initial studies employed normal cornstarch, which retrogrades to form a cross-linked gel, and soy oil, which could be crossed-linked with osmium tetroxide. Conventional tissue fixation and embedding techniques allowed thin sectioning for light and transmission electron microscopy. However, certain continuous phases or lipophilic components cannot be processed in this way and require alternative approaches. Bright field and phase contrast light microscopy can be used for some unprocessed samples and those treated minimally by drying, oil mounting, iodine staining, or tagging with stained ingredients. Air-dried films can be fractured, the encapsulated oil extracted, and the fracture surface observed by conventional scanning electron microscopy. An effective technique for visualizing the starch component that surrounds micron-scale lipophilic droplets or particles will be described. Adaptation of various microscopy techniques can provide a basic understanding of ingredient interaction and processing effects as well as guidance for fine-tuning processing conditions for specific applications.