Final answer:
Lyophilization, or freeze-drying, is a process where substances are dried by placing them in a vacuum chamber and lowering the atmospheric pressure. This process speeds up drying by allowing water molecules to transition from a solid to a gas through sublimation without going through the liquid phase.
Step-by-step explanation:
Lyophilization, also known as freeze-drying, is the process where substances, such as foods, are dried by placing them in a vacuum chamber and lowering the atmospheric pressure around them. The lowered atmospheric pressure speeds up the drying process because it creates a pressure gradient that allows water molecules to transition from a solid (ice) to a gas (water vapor) without going through the liquid phase. This phase transition is called sublimation, and it causes the temperature of the food to drop because energy is required to break the intermolecular bonds holding the water molecules in the solid state.