WHY FREEZE DRYING
There are several important advantages of freeze drying over other types of drying such as oven-drying.
- Freeze drying guarantees the best quality since drying occurs at sub-zero temperatures; this means that texture, flavor and nutrients remain completely intact.
- Other types of drying require high temperatures, which could damage nutrients such as proteins and vitamins.
- Our freeze-dried products have a shelf life of up to 18 months.
WHAT IS FREEZE DRYING
So what exactly is freeze drying? Freeze-drying is a dehydration process used to dry products, which are heat sensitive. Freeze-drying works by freezing the substance and then subliming the ice or other frozen solvent in a high vacuum. Conventionally dried insects are dried by heated air or by direct warmth radiation. This relatively cheap process has many downsides. An insect is surrounded by a solid, usually water tight, chitin armature. When dried by force, the insect will relatively slowly lose its moisture due to this armature. The result of this is that during the process of drying through force a change takes place, causing the internal structure, the proteins and vitamins to disintegrate. The insect’s color will turn brown - black. For a large part they will lose their original color, smell, taste, vitamins and nutritional value. Most of these dried insects are practically hollow and often consist of a less easy digestible chitin-covering.
Freeze-drying is a complex and relatively expensive process, where the internal structure, smell, color, taste and nutritional value are kept intact. In general, living insects can easily be replaced by freeze-dried insects. The high quality of this new product truly justifies its higher cost price. Provided that it is packaged well and stored in a dry place, these insects have an excellent storage life. Kreca Ento-Food BV’s produces well fed insects for drying. Directly from production the insects are cooled and due to the cold the insects stiffen in a rather natural way. Thanks to accelerated cooling they will keep their inner- and outer structure and most importantly their nutritional value.
The process of freeze-drying starts at a temperature of -20 °C. At these low temperatures water evaporates extremely slow. To accelerate this process, the insects are placed in a vacuous space, where the evaporated water precipitates on to a much cooler condensation sheet. When dried at temperatures this low, the outer cell structure will stay intact. Because of the high vacuum, existing proteins, fat and carbohydrates, but also vitamins, color, aroma and flavorings will hardly change due to the lack of a combination of water and oxygen. After freeze-drying, the insects’ essential nutrients remain entirely present, provided that they are stored in a dry, well-sealed place.
The body of an insect contains approximately 2/3 of water. While drying more than 98% of this water is extracted from the existing structures. A very fine, sponge-like structure with micro linking canals arises inside the insect. This causes aroma and flavorings to be easily released and digestive juices to work quicker and more effectively then when using non dried insects. Freeze-dried insects are therefore lighter and better digestible.