There are two ways to dry strawberries: drying and freeze-drying. Drying is to evaporate the water in the material through high temperature. The drying method is relatively direct and simple compared to freeze-drying. However, strawberries dried at high temperature are prone to shrinkage, deformation, discoloration, and loss of nutrients. serious. With the application of freeze dry candy machine in strawberries and other fruits, the prepared freeze-dried strawberries and other fruit and vegetable chips can solve the above problems well.

 

As an advanced food processing technology, the mini freeze dryer machine can better maintain the original shape and color of the food, reduce the loss of food flavor and nutrients, and has a porous structure, instant solubility and rapid rehydration. easy and convenient,
Therefore, the freeze dryer is used in the processing of strawberry products. This will not only provide a basis for the production feasibility of strawberry deep-processing research, such as vitamins, amino acids and other health products in strawberries, but also provide guiding data for the development of third-generation functional food seasonings or additives, so as to make use of strawberry resources. open up broader prospects.

 

The process of making freeze-dried strawberries by food freeze dryer:

1.1 Process Flow

 
Select fresh strawberries → wash, remove the handle → drain → slice → dip in sugar → plate, weigh → FZG food freeze dryer part (binning → pre-freezing → cold trap refrigeration → vacuum exhaust → vacuum sublimation drying → out of warehouse
 

1.2 OperationPoints

Material Selection

Buy fresh strawberries that are ripe, non-spotted, and non-rotten, remove stems and leaves, wash 3-4 times with clean water, then drain, cut each strawberry into 3-4 slices, make each slice 6-8mm thick .
 

Loading

Lay the freshly cut strawberry slices flat on the food tray of the freeze dryer.
 

Pre-Frozen

Put the packed strawberries into the freeze-drying bin for freezing, the temperature is -35°C, and the freezing time is 1-2h, so that the central temperature of the strawberries is below the eutectic temperature.

Vacuum Sublimation Drying (under constant pressure)

First, pre-cool the temperature of the cold trap of the vacuum freeze dryer to -45°C. When the temperature of the cold trap drops to -45°C, turn on the vacuum pump to make the vacuum degree reach 20pa, and maintain this pressure. At this time, the shelf is heated and frozen. The strawberries begin to sublime and dry. In the sublimation drying stage, the temperature of the cold trap is kept strictly constant, while the central temperature of the strawberry is not higher than its eutectic temperature during the heating process, and the surface temperature of the strawberry is not higher than the maximum temperature allowed. When the surface temperature of the strawberry is close to the core temperature, the sublimation drying ends. Sublimation drying of strawberries generally lasts 4-5 hours.
 

Vacuum Sublimation Drying (under variable pressure conditions)

First, the temperature of the cold trap of the vacuum freeze dryer is also pre-cooled to -45°C. When the temperature of the cold trap drops to -45°C, the vacuum pump is turned on to make the vacuum degree reach 80pa, and the shelf is heated at the same time. When the temperature of the heating shelf rises to 30°C, start to adjust the pressure to reduce the pressure to 40pa and keep it for a period of time; when the temperature of the shelf rises to 45°C, adjust the pressure to reduce the pressure to 20pa and maintain it until The sublimation drying is completed, and the time is about 3-4h.​​
 

Analytical Drying

In the analysis and drying stage, the pressure is kept at 20pa, the shelf temperature is at 48℃, and the time is generally 1-2h.
When the analysis and drying are over, the heating of the shelf is stopped, and the vacuum pump, refrigerator and cooling water system are closed at the same time, and the air valve is opened to restore the pressure in the freeze-drying box to normal pressure.
 

The technological process of strawberry freeze-dried powder

 

Process Flow:

Select fresh strawberries - washing - cutting - blanching - cooling - draining - crushing and beating - rubber milling - sterilization - pre-freezing - vacuum freeze drying - ultra-fine grinding - weighing and packaging - testing - finished product.

Material Selection

First, select fresh, mature and high-quality strawberries in the pretreatment area of ​​the food freeze-drying machine, remove the stems and leaves, remove impurities, and then sterilize the surface of the strawberries simultaneously with preliminary cleaning, and then clean and drain again after sterilization.
 

Pre-Frozen

The drained strawberries are sliced, and the color is protected by a blanching process. After the color protection is completed, a pulping process is performed, and then a pasteurization process is performed. At this point, the pre-freeze-drying process ends.
 

Vacuum Freeze Drying

The processing core of strawberry freeze-dried powder is the food freeze-dried equipment area. The pre-treated strawberry liquid enters the food freeze-dried equipment to be pre-freezed and crystallized into a solid state at low temperature, and then sublimated and dried in a vacuum environment to obtain very little water content. lyophilized product.
 

Ultrafine Pulverization

After the freeze-dried products are out of the warehouse, they are transferred to the post-processing area of food freeze-drying for ultra-fine grinding.
 
The finished product made by the strawberry freeze-dried powder process basically maintains the color, aroma and nutritional components, and the rehydration is rapid. The whole set of technological process is simple, safe and stable. ZZKD complete set of food freeze dryer equipment is energy-saving, environmentally friendly, and meets the requirements of GMP certification. It has the advantages of remote monitoring and operation, automatic operation and industrial management. ZZKD food freeze dryer is widely used in food freeze dryers. processing enterprises.
 
The above is the specific operation of "how to make freeze dried strawberries" answered by zzkd for you. If you have any other questions, please contact us!The next issue will answer "how to freeze-dry candy" .