Freeze drying consists of two stages: first, the product is frozen until completely solidified, then dried in a high vacuum. Removal of water from the frozen product is carried out by the sublimation method; those. water (ice) passes from the solid phase to the gaseous phase, bypassing the liquid. Thus, only evaporating water (steam) moves in the product, while the movement of substances dissolved in water, such as sugar, salt, etc. does not occur in the product. This leads to the main advantages of freeze drying food products compared to the traditional method, which are as follows:

• - Retention of taste and smell
• - Maintain shape, color and texture
• - Slight reduction in volume
• - Excellent hydration capacity
• - Longer shelf life
• - Less losses
• - Complete preservation of proteins and vitamins
• - Reduced risk of spoilage