What You Need to Know
Microwave energy causes dipolar rotation of water molecules, generating internal heat that vaporizes water at the reduced boiling point imposed by the vacuum (≈50–80 °C). The lowered pressure suppresses oxidative and Maillard reactions, limiting protein denaturation and preserving volatile aroma compounds. Evaporation under vacuum thus concentrates flavors and nutrients without the thermal degradation typical of conventional drying.
Steps
- 1.
Japanese katsuobushi (Japan): Preserves umami compounds while removing moisture
- 2.
French herb powders (France): Retains volatile aromatics lost in conventional drying
- 3.
Peruvian freeze-dried potato (chuño) (Andes): Modern adaptation of traditional freeze-drying
The Science
Primary Reaction
Dielectric heating‑induced water evaporation under vacuum