how are freeze dried food prepared? how do they remain preserved for long periods
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Background
Freeze drying is a relatively recent method of preserving food. It involves freezing the food, then removing almost all the moisture in a vacuum chamber, and finally sealing the food in an airtight container. Freezedried foods can be easily transported at normal temperatures, stored for a long period of time, and consumed with a minimum of preparation. Once prepared, freeze-dried foods have much the same look and taste as the original, natural products.
Each food has different processing, storage, and rehydration requirements. Some of the variables include the sizing of the raw food products before freezing, the cooking or blanching time and temperature, the rate of freezing and final freezing temperature, the rate of application of vacuum and the final vacuum pressure during drying, the rate and method of application of heat and the final dried product temperature, the allowable residual moisture content after drying, the storage temperature and atmosphere (vacuum, nitrogen, etc) after drying, and the rehydration procedures. At large freeze-drying facilities, electronic microprocessors regulate the times, temperatures, and pressures throughout each step of the process. A central computer collects this data, analyzes it using statistical quality control methods, and stores it for later reference.
Freeze drying is a relatively recent method of preserving food. It involves freezing the food, then removing almost all the moisture in a vacuum chamber, and finally sealing the food in an airtight container. Freezedried foods can be easily transported at normal temperatures, stored for a long period of time, and consumed with a minimum of preparation. Once prepared, freeze-dried foods have much the same look and taste as the original, natural products.
Each food has different processing, storage, and rehydration requirements. Some of the variables include the sizing of the raw food products before freezing, the cooking or blanching time and temperature, the rate of freezing and final freezing temperature, the rate of application of vacuum and the final vacuum pressure during drying, the rate and method of application of heat and the final dried product temperature, the allowable residual moisture content after drying, the storage temperature and atmosphere (vacuum, nitrogen, etc) after drying, and the rehydration procedures. At large freeze-drying facilities, electronic microprocessors regulate the times, temperatures, and pressures throughout each step of the process. A central computer collects this data, analyzes it using statistical quality control methods, and stores it for later reference.
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Hey dear,
● Preparation of freeze-dried food -
- Actually, there's no special method to prepare freeze-dried food.
- It's prepared same as other foodstuffs, just packing is different.
- Free-dried food is packed with nitrogen so as keep away from oxygen/CO2.
● How does freeze-drying preserves food -
- Freeze-drying removes all moisture from the food without affecting the taste.
- It creates a special vacuum chamber around the foodstuff to avoid rancidity.
- Freeze-drying can preserve food for approximately 2 years.
Hope this helps you..
● Preparation of freeze-dried food -
- Actually, there's no special method to prepare freeze-dried food.
- It's prepared same as other foodstuffs, just packing is different.
- Free-dried food is packed with nitrogen so as keep away from oxygen/CO2.
● How does freeze-drying preserves food -
- Freeze-drying removes all moisture from the food without affecting the taste.
- It creates a special vacuum chamber around the foodstuff to avoid rancidity.
- Freeze-drying can preserve food for approximately 2 years.
Hope this helps you..
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