2.7 Ice crystal size analysis: bright-field microscopy
Ice cream containers were transferred from the −25 °C walk-in freezer to a −18 °C
storage room 1 h before microscopy analysis. All mechanical devices required for
further treatment of the samples were precooled to −18 °C. A thin slice of ice cream
was cut from the core section at the center of the container using a sharp knife. This layer
was placed on a drop of iso-amyl-butanol (previously cooled to −18 °C) on a standard
glass microscope slide, and a few more drops of iso-amyl-butanol were added to the
sample. The microscope slide was covered with a coverslip and placed above liquid
nitrogen in an insulated Styrofoam container and immediately transported to the cold
stage (Linkam Scientific Instruments, Surrey, UK), which was previously programmed
to a constant temperature of −17 °C (Flores and Goff 1999a).