Cryo-dried technology
Cryo-dried technology is a method used to preserve perishable food, by removing moisture. The process involves several key steps:
1. Freezing
The material is first frozen, typically at very low temperatures (-60° to -80°C). This solidifies the water content within the product. Rapid freezing is often employed to minimize the formation of large ice crystals, which can damage cellular structures.
2. Primary Drying: Sublimation
After freezing, the pressure around the product is reduced (vacuum is applied), and heat is gently added. This causes the ice in the frozen material to sublimate, meaning it transitions directly from a solid state to a vapor state without passing through the liquid phase. This step removes about 95% of the water content.
3. Secondary Drying: Desorption
Following primary drying, the temperature is increased further to remove any remaining moisture that is not bound to the product (that is, the water that may still be chemically or physically bound within the material). This step ensures the final product has a low moisture content, usually around 1-4%.
4. Packaging:
The cryo-dried food is then packaged in moisture-proof containers to prevent reabsorption of moisture and ensure a longer shelf life.
Main Advantages of Cryo-drying:
- Preservation of Nutritional Value: Cryo-drying retains most of the flavor, nutritional content, and color of the original material.
- Lightweight: The elimination of humidity significantly reduces its weight, making it ideal for storage, transport and consumption in complex contexts such as remote areas of the planet or space missions.
- Extended Shelf Life: Products can be stored for long periods without refrigeration at room temperature.
- Rehydration: cryo-dried products can be easily rehydrated by adding water, quickly returning to a more consumable state.
Differences between cryo-food and dehydrated food
Texture:
- Cryo-Dried Food: Retains a light and crispy texture when rehydrated, often resembling the original food closely.
- Dried Food: Generally has a chewier texture and can be tough or leathery depending on the method of drying and the food itself.
Nutritional Content:
- Cryo-Dried Food: Often retains more nutrients compared to dehydrated food because the process occurs at lower temperatures, minimizing nutrient loss.
- Dried Food: Heating during the dehydration process can lead to the loss of some vitamins and enzymes, particularly those sensitive to heat.
Flavor:
- Cryo-Dried Food: More closely preserves the original flavor of the food, making it more palatable when rehydrated.
- Dried Food: Flavor can be concentrated, but the heat can also change the taste profile, sometimes making it less appealing.
Rehydration:
- Cryo-Dried Food: Usually requires less water and time to rehydrate, returning to a state closer to its original condition.
- Dried Food: Typically requires more water and time to rehydrate fully.
Shelf Life:
- Cryo-Dried Food: Generally has a longer shelf life due to lower moisture content and better preservation of nutrients.
- Dried Food: Has a shorter shelf life depending on the type of food and storage conditions.
Learn more
Find out the competitive advantages of cryo-drying