Freeze-dried Food: The Better Solution
Freeze drying is an excellent method for preserving materials which are unstable in solution. In addition, freeze drying can be used to separate and recover volatile substances and to purify materials.
The fundamental process steps are:
- Freezing: the product is frozen. This provides a necessary condition for low temperature drying.
- Vacuum: after freezing, the product is placed under vacuum. This enables the frozen solvent in the product to vaporize without passing through the liquid phase, a process known as sublimation.
- Heat: heat is applied to the frozen product to accelerate sublimation.
- Condensation: low-temperature condenser plates remove the vaporized solvent from the vacuum chamber by converting it back to a solid. This completes the separation process.
Key benefits of freeze drying include:
- Retention of morphological, biochemical, and immunological properties
- High viability/activity levels
- Lower temperature, oxygen, and shear conditions versus other drying methods
- High recovery of volatiles
- Retention of structure, surface area, and stoichiometric ratios
- High yield
- Long shelf life
- Reduced weight for storage, shipping, and handling