What is the production process of freeze-dried strawberries? How to retain nutrients and improve the taste?

1. Raw material selection
First, select fresh, moderately mature, and pest-free strawberries as raw materials. These strawberries should have bright colors, plump grains, and good taste and flavor.

2. Cleaning and pretreatment
Cleaning: Put the strawberries in clean water and wash them thoroughly to remove dirt and pesticide residues on the surface.
Stem removal and slicing: Remove the stems of the cleaned strawberries and cut them into small pieces of 2~3 mm. This step helps to remove moisture and improve freeze-drying efficiency in the subsequent process.

3. Pre-freezing
Put the cut strawberry slices in the freezer for pre-freezing and frosting. The purpose of this step is to remove moisture more effectively in the subsequent freeze-drying process and retain the vitamins and dietary fiber in the fruit. The temperature and time of pre-freezing will vary depending on the equipment, but it usually needs to reach a certain low temperature and be maintained for a period of time.

4. Low-temperature vacuum freeze-drying
Vacuum environment: Put the pre-frozen strawberry slices into a vacuum freeze dryer. The vacuum environment helps to lower the boiling point of water, thereby achieving sublimation of water at a lower temperature.
Low-temperature freeze-drying: In a vacuum environment, a special low-temperature vacuum freeze-drying technology is used to convert most of the water in the strawberry from a solid state directly into a gas state (i.e., the sublimation process). This process takes a certain amount of time, usually about 2 to 3 days, to ensure that the water in the strawberry is fully removed.

5. Packaging and storage
Packaging: After drying, quickly package the freeze-dried strawberries to prevent re-absorption of moisture. The packaging material should have good sealing and moisture barrier properties to maintain the crisp taste of the freeze-dried strawberries and extend the shelf life.
Storage: Freeze-dried strawberries should be stored in a low-temperature, dry, light-proof environment to maintain their best taste and quality. Because the moisture content of freeze-dried strawberries is extremely low, they have a long shelf life, usually about 18 months.

The freeze-dried strawberries produced through the above steps not only retain the various nutrients in fresh strawberries (such as vitamin C, antioxidants and dietary fiber, etc.), but also make the strawberries taste crisper and more refreshing, and have a richer and sweeter taste during the freeze-drying process. In addition, freeze-dried strawberries are easier to store and eat than fresh strawberries, making them convenient to carry and enjoy at any time.