Fixation Staining Methods for Examining Microstructure in Whipped Cream by Electron Microscopy

Abstract

ABSTRACTWhipped dairy cream (WDC) specimens were prepared for examination by transmission electron mircoscopy (TEM) and scanning electron microscopy (SEM) by one of three alternative post‐mordant procedures, i.e., imidazole‐buffered osmium tetroxide (IBO), ferri‐cyanide osmium tetroxide and tricomplex osmium tetroxide. These procedures utilized a tannic acid‐guanidine‐HCI mordant, thiocarboh‐ydrazide as a bridging Iigand, and a p‐phenylenediamine en bloc stain treatment to improve specimen fixation and staining. TEM and SEM specjmens prepared by all three procedures provided good contrast and resolution of the microstructure of WDC. The IBO method provided more uniform staining and more complete fixation and retention of lipids in milkfat globules than either of the other two methods.