Blueberries are popular fruit in worldwide, dehydrate blueberry with freeze drying technology no ruin its nutrient elements. Great improve its storability and convenience of transport. Freeze dried machine, is the equipment to freeze dry blueberry. Although the freeze drying process of blueberry is similar with other fruits, but due to its exclusive features, some additional steps need to do and points need pay attention to.
1, Completely Freeze Blueberry Before Freeze Drying
As mentioned, product complete freezing is the first step also is the guarantee of a success freeze drying. So pre-freezing is very important. The freezing point of blueberry is quite low, research shows the temperature is around -33C. Which means your freezer temperature have to be lower than this value, and then can start the freeze drying steps.
If you are using a Vikumer food freeze drying machine, you don’t need worry about this, all our freeze dryers can reach -35C or lower in pre-freezing stage.
2, Damage Blueberry Skin
The blueberries have very thick skins, which will prevent the vapors go out during the freeze drying. Later, the blueberries start melting. As a result, the blueberries popped, because of the huge pressure difference between the fruit internal and drying chamber. Freeze drying fails.
The most feasible solution to avoid this phenomenon is to damage the blueberry skin. Due to commercial production, large volume strawberries need to process, so an automatic hole puncher is very high efficiency to do this. The machine has a roller full of needles, blueberries pass through and are pierced. These small holes will be the vapor sublimate channels during freeze drying.
Strawberry poped during freeze drying
Strawberry poped during freeze drying
3, Raise the Shelf Temperature Slowly
Unlike other fruits like strawberry or sliced apple, the entire surface can be the vapor sublimate channels, which result rapid freeze drying. The blueberries after hole puncher, only 8~12 holes, less sublimate channels means longer drying time. So the energy supply cannot be so fast. Keep in mind that blueberry need up to 40hrs to dry, the same volume apple only needs a half.
Freeze dried strawberries
Blueberries Freeze Drying Machine
A fruit freeze dryer is ok for blueberries freeze drying, here Vikumer offer 2 solutions:
- If you only use the freeze dryer for fruit freeze drying, then FDRS or FDR Food freeze dryer is ok.
- If your production also involves heat sensitive products freeze drying, like yogurt, dairy, probiotics, we suggest you use our FDL Tray freeze dryer.
The main difference between FDR and FDL is the temperature control. FDL can precise control the chamber temperature, also a lower temperature for condenser and shelves.
