Products go through freeze drying process, will have great advantages compare other drying method even its original type, Think about freeze dried products packages no need refrigeration, only 3% to 10% weight but nutritional or ingredients contain same with original, shelf life up to 20 years, could quick rehydration by add water or solvent if need. So whether in pharmaceutical, food, chemical, fruit, milk, pet food area, freeze drying machines are popular.
1, Structure, Texture, Appearance
The freezing stage form and decide dried products shape.
Frozen products drying in low temperature, water inside (solid phase) removed by sublimation/vapor(ice absorb energy and turn to gas, skip water phase), raw material drying from surface layer till to bottom layer.By this, will not damage their physical structure, texture, no shrink.
Its very different with other drying method principle of water boiling which drying from bottom part to surface part, that dried products will bulge light or heavy as per temperature set, dried products have shrink and taste like leather.
2, Nutrition, taste, color
Freeze dried products tend to retain most of their nutritional quality, taste etc. this is also because the low temperature drying avoid damage to heat sensitive products such as enzymes, flavours, proteins and vitamins.
We could understand the differences between freeze dried products and original form is water.
3, Drying Pre-treatment
Except high sugar or high fat products need special treatment (for example: honey). Most freeze drying process or raw material no need special treatment, because freezing drying itself is a kind of concentration, no need additives to increase the taste.
4, Transport and storage
Freeze drying process could control dried products moisture to 2%,you also could adjust by drying time. Very light weight compare fresh form, easy handle and transport, After proper packing, they could transport and storage in room temperature without any critical requirement.