Freeze-dried, also known as sublimation drying, the material is frozen below the freezing point of water and placed in a high vacuum (10 ~ 40Pa) container, by heating the moisture in the material directly from sublimation of solid ice to water vapor of a drying method .
1. To maximize the preservation of food color, smell and taste, such as vegetables, natural pigments remain unchanged, the loss of various aromatic substances can be reduced to a minimum; freeze-dried process is better than ordinary cryopreservation process to preserve protein-containing foods.
2. Particularly suitable for heat-sensitive substances, heat-sensitive materials can be made to retain the heat-sensitive ingredients dry; to preserve food at all levels of nutrients, especially for vitamin C, can save more than 90%.
3. Dehydration thoroughly, dry products, light weight, small size, storage area less time, easy transportation; a variety of freeze-dried vegetables by pressing, weight loss significantly. As a result of the reduction in volume, the corresponding packaging costs are much lower.
4. Since there is very little oxygen to operate under vacuum, some easily oxidizable substances such as oils and fats are protected.
5. Freeze-dried method can exclude 95% to 99% of the water, the product can be long-term preservation without deterioration.