What You Need to Know
Vacuum drying involves removing moisture from food using a vacuum pump at temperatures between 30°C to 50°C and pressures below atmospheric pressure. Freeze-drying, also known as lyophilization, involves freezing food and then reducing the surrounding pressure to allow the frozen water to sublimate directly into a gas, typically at temperatures around -30°C to -50°C.
Steps
- 1.
Astronaut ice cream (United States): creates shelf-stable dairy product
- 2.
Katsuobushi (Japan): intensifies umami through multiple drying cycles
- 3.
Chuño (Andes): preserves potatoes through freeze-thaw cycles
The Science
Primary Reaction
sublimation