FrizOvet

Freeze Dryer:

Lyophilization or Freeze Drying is a process in which water is removed from a product after it is frozen and placed under a vacuum, allowing the ice to change directly from solid to vapour without passing through a liquid phase. The process consist of three separate, unique and inter dependent processes: Freezing, Primary Drying (Sublimation) & Secondary Drying (Desorption)
– As per Food & Drug Administration

Home Model Freeze Dryer

Industry Model Freeze Dryer

Lab Model Freeze Dryer

Stages In Freeze Drying

The material is fill in the tray and frozen between -20 and 45 degrees Celsius in a blast freezer, Material must be frozen below eutectic temperature to avoid liquid phase.

  • Freezing Frothing when vacuum is applied.
  • Freezing Shrinkage (retention of form)
  • Freezing Concentration of solids

Primary Drying

During primary drying phase, pressure is lowered and enough heat is supplied to substance by radiation for ice to sublimate, moreover vapour absorb in to ice condenser, that re-solidify on coil and formation of ice. that play important role to prevent water vapour reaching in to the vacuum pump, which degraded vacuum pump performance. condenser temperature below -40°C.

Secondary Drying

Aim to remove all ice by sublimation, bound moisture still present in the product In this phase, the temperature is raised higher than primary drying phase, to break any physic-chemical interactions that have formed between the water molecules and the frozen material, pressure is also lowered in this stage to encourage desorption.

Packaging

After drying, food is sealed/store in an airtight container that is impermeable to oxygen and prevent them from moisture absorbing.

Rehydrated

Simply add lukewarm water, it will regain its original fresh taste, aroma, and appearance

Technical Explanation:

  • Lyophilization involves the removal of water or other solvents from a given product by a process called sublimation.
  • This occurs when the ice of a frozen product converts directly to the Gaseous state without passing through the liquid phase.
  • This enables the preparation of a stable product that is easy to use and store at ambient temperatures.
  • A low pressure environment is pre-requisite to allow this process to take place. In order to start the removal of water, the pressure inside the freeze dryer must be below the “triple point value” for the product, whilst also maintaining the temperature of the sample below its freeze point in the lyophilization process.