Vacuum freeze dry Technology or the term called “freeze dried” (Freeze dried Technology) means drying. (dehydration) by freezing (freezing), causing the water to change to ice crystals first Then reduce the pressure to allow the ice crystals to sublimate.(sublimation) into vapor by reducing the pressure to below normal atmosphere. While keeping the temperature low (at temperatures equal to or below 0 degrees Celsius, ice sublimates at a pressure equal to 4.7 mmHg or lower)

Freeze dried process
1. Freezing involves reducing the temperature of food below the freezing point to allow ice crystal formation. The rate of freezing should be fast to crystals and the crystals form will be small Quick Freezing There are several commonly used methods such as air blast freezing, cryogenic freezing, and immersion freezing. etc.
2. Primary drying reduces the amount of water. (dehydration) by sublimating ice into vapor by reducing atmospheric pressure So that the ice crystals inside will sublimate into vapor. away from the surface of the product the level of vacuum (vacuum) should be below 132 Pa and 132 mPa, respectively, for complete sublimation of the ice crystals to occur. Sublimation of the ice layer starts from the ice layer on the surface of the product. sublimation into vapor This causes this area to become a dry layer. Then, it is the sublimation of the ice layer inside the product. sublimation through dry layer out onto the surface of the product Sublimation time depends on the size, shape and structure of each product.
3. Secondary drying when the primary drying is complete. All the ice will melt. There will be residual moisture. Therefore, it must be dried by raising the temperature. To pull out the remaining moisture to a safe humidity level, vegetables, fruits, or food that have been processed by vacuum freeze drying will be able to retain the originality of the food or fresh fruit as much as possible, and the Aviation Administration Organization and The National Space Agency (NASA) has used this “freeze drying” method for food and fruit used as food for astronauts. that has been in an outer space station