Dry Heat

Content

Destructions of Microorganisms
  Physical Antimicrobial Agents
    Moist and Dry Heat
      Moist Heat
      Dry Heat
      Incineration
      The Autoclave

In this experiment, egg white (the protein, albumin) is used to simulate microbial enzyme protein. The speed of the damaging reaction (coagulation) of moist and dry heat on protein will be observed.

Purpose To compare the effects of moist and dry heat
Materials Tubed distilled water (0.5-ml aliquots)
Sterile 1.0-ml pipettes
Clean tubes
Dry-heat oven
Egg white (albumin, a protein)

Procedures
  1. Set up a beaker water bath and heat to boiling.
  2. Set the dry-heat oven for 100°C.
  3. Using a pipette, measure 0.5 ml of egg white into 0.5 ml of distilled water.
  4. Place the tube into the boiling water bath and immediately begin timing. Observe until the egg white has coagulated, then record the elapsed time.
  5. Using a pipette, measure 1.0 ml of egg white into a clean tube.
  6. Place the tube into the dry-heat oven and immediately begin timing. Observe until the egg white has coagulated, then record the elapsed time.

Results
  1. Elapsed time for protein coagulation in moist heat (boiling): ____________________
    Elapsed time for protein coagulation in dry heat (baking): ____________________
  2. State your interpretation of the effect of moisture on protein denaturation: ____________________