Freeze-drying—technically known as lyophilization, lyophilization, or cryodesiccation—is a dehydration process typically used to preserve a perishable material or make the material more convenient for various applications. Freeze-drying works by freezing the material and then reducing the surrounding pressure to allow the frozen water in the material to sublimate directly from the solid phase to the gas phase. Since 98% of the moisture is removed from the product, the product becomes very light in weight hence there are a lot of advantages associated with Freeze Dried products and has found a variety of applications.
With time various innovative applications are created and successfully being used extensively. Some of the perishable products like Milk are converted in to dry powder. Storage of Milk requires low temperature (Refrigeration) which also has the limited shelf life. We produce Dry Powder out of the fresh milk which has a very long shelf life and can be easily converted to Milk be dissolving in water to produce Fresh Milk. We produce Camel Milk Powder, Goat Milk Powder, A2 Cow Milk Powder, Lactose-Free Milk Powder etc.
History: The process of freeze-drying was invented in 1906 by Arsène d’Arsonval and his assistant Frédéric Bordas at the laboratory of the biophysics of Collège de France in Paris. In 1911 Downey Harris and Shackle developed the freeze-drying method of preserving live rabies virus which eventually led to the development of the first anti-rabies vaccine.
Modern freeze-drying was developed during World War II. Blood serum is sent to Europe from the US for medical treatment of the wounded required refrigeration, but because of the lack of simultaneous refrigeration and transport, many serum supplies were spoiling before reaching their intended recipients. The freeze-drying process was developed as a commercial technique that enabled serum to be rendered chemically stable and viable without having to be refrigerated. Shortly thereafter, the freeze drying process was applied to penicillin and bone, and lyophilization became recognized as an important technique for preservation of biologicals. Since that time, freeze-drying has been used as a preservation or processing technique for a wide variety of products. These applications include the following but are not limited to: the processing of food, pharmaceuticals, and diagnostic kits; the restoration of water-damaged documents; the preparation of river-bottom sludge for hydrocarbon analysis; the manufacturing of ceramics used in the semiconductor industry; the production of synthetic skin; the manufacture of sulfur-coated vials; and the restoration of historic/reclaimed boat hulls.
Freeze Drying in Food and Agriculture Industry:
Although freeze-drying is used to preserve food, its earliest use in agriculturally based industries was in the processing of crops such as peanuts/groundnuts and tobacco in the early 1970s. Because heat, commonly used in crop and food processing, invariably alters the structure and chemistry of the product, the main objective of freeze-drying is to avoid heat and thus preserve the structural and chemical integrity/composition with little or no alteration. Therefore, freeze-dried crops and foods are closest to the natural composition with respect to structure and chemistry. The process came to wide public attention when it was used to create freeze-dried ice cream, an example of astronaut food. It is also widely used to produce essences or flavorings to add to food.
Because of its light weight per volume of reconstituted food, freeze-dried products are popular and convenient for hikers. More dried food can be carried per the same weight of wet food and remains in good condition for longer than wet food, which tends to spoil quickly. Hikers reconstitute the food with water available at point of use.
Culinary herbs, vegetables (such as vitamin-rich spinach and watercress), the temperature sensitive baker`s yeast suspension and the nutrient-rich pre-boiled rice can also be freeze-dried. During three hours of drying the spinach and watercress has lost over 98% of its water content, followed by the yeast suspension with 96% and the pre-boiled rice by 75%. The air-dried herbs are far more common and less expensive. Freeze dried tofu is a popular foodstuff in Japan (“Koya-dofu” or “shimi-dofu” in Japanese).
We also Freeze Dry Cheese in Flakes (grated) or powder form. This is very useful for Hotels and restaurants. The biggest advantage is that all these products can be stored at room temperature and does not require refrigeration.
- Light Weight hence ideal for a Camping food for hikers, cyclists, mountaineers etc. They can carry more food and can easily rehydrate them or eat it as a snack. It is an ideal food product for Military, Air Lines, Astronauts and people who wish to travel with lightweight. It is ideal for Sight Seeing tour operators who carry the entire kitchen with them to offer local food to their clients.
- Because of its long shelf life, the seasonal fruits and vegetables can be Freeze Dried and kept at normal room temperature for years together. Can be rehydrated as and when it is required. This is very handy for cooking.
- Ideal for emergency supplies. During a shortage, natural calamities like floods etc, Freeze Dried foods can be an asset for helping calamity struck people.
- Saves on electricity. Freeze Dried Foods are not required to be stored in Refrigerator and can be stored at Room temperature.
- As such we consume a lot of Dried Stuff like fruits etc. Unlike Dried food which is either Sun Dried or Air Dried, Freeze Dried foods are very rich in vitamins and minerals whereas during Sun drying or Hot Air Drying important minerals and vitamins are lost.
- Freeze Dried Spices are ideal for Housewives because everything is so handy and ready to use. For example spices like Spinach, Coriander, Lemon Grass, Ginger, Fenugreek, Tomato, etc are available off the shelf in the kitchen. No need to keep the fresh material in the Freeze and then when we want to use them, they are required to be washed, cut and then mix it. Freeze Dried spices are ready to use the material. They are highly concentrated hence very little quantity is required.
- Freeze Dried Pulses like Sweet Corn, Green Peas, etc are ideal as a food intermediate. For making soup or some vegetables, just open the pack and take the required quantity.
- Freeze Dried Fruits and Vegetables available throughout the year and do not have to wait for the season. For example fruits like Mango, SapodilLa, Jackfruit etc are available only during the season. Freeze Dried fruits can be used to make Milk Shakes or any such items which require Fresh Fruits.
- Freeze Dried Herbs are extremely useful as per Ayurveda and Unani way of medicine. Pharma or Nutraceutical Industries use Freeze Dried products as intermediates for their ultimate products. Herbs like Ashwagandha, Jamun Seed Powder, Ginger, Bitter Gourd etc are very much in demand.
- All other processes of preserving food for a longer shelf life requires the use of Preservatives, additives etc. This use of preservatives or any other additives is not desirable substances in our human body. Freeze Dried food are 100% pure and full of Vitamins, minerals, etc AND NO PRESERVATIVES AND NO ADDITIVES.
- Some of the products like Orange peels etc are used for skin treatment.