Freeze-drying, or lyophilization, is a dehydrating process used to dry food. It is used for foodstuffs that are difficult to store or transport due to the loss of their value. Thanks to lyophilization, foodstuffs retain their properties, and their shelf life is extended. Therefore, it is successfully applied to royal jelly.
Freeze-drying is used for both food processing and archival purposes
A process called lyophilization or freeze-drying is used to dry food, but also to save archival materials, to manufacture cosmetics and medicines. Freeze-drying is based on sublimation of frozen water at low pressure and temperature. The important advantage of this method is that there is no direct transition from the liquid to the gaseous state, but freeze-dried food or documents are transferred from the liquid state to the solid state by freezing, which results in no damage to the archives and preservation of valuable substances in foodstuffs. In case of classic drying, due to the high temperature, many valuable substances and archival materials would be damaged, so freeze-drying is a very gentle method. Lyophilized foodstuffs have logically a lower weight, fully preserved nutritional value, and the shelf life of foodstuffs with a very short storage life is prolonged.
Lyophilization for long-term gentle preservation of (not only) fruit
Freeze-drying is used in the food industry mainly to preserve important vitamins and minerals, but also the shape, colour, and taste of foodstuffs. Freeze-dried foods retain the same total nutrient content as fresh foods. For example, vitamins A and C degrade very quickly during traditional drying, but freeze-drying preserves them in food practically without loss, similar to fibre or antioxidants. This is why freeze drying is used, for example, for cranberries, strawberries, or raspberries, which you can find in breakfast mixes or individual packages.
In addition, lyophilization processing makes it possible to harvest, for example, fruit at the time of its true ripeness and thus nutritionally richer. Thanks to this method of treatment, it is not necessary to use sulphites, which can often be found in dried fruit. Other advantages of lyophilization are the low weight of lyophilized foods and a substantial extension of shelf life, thus facilitating and making storage, transportation and, consequently, reducing wastage.
Storage has a key effect on the properties of royal jelly
Due to its properties, royal jelly ranks among highly valued and rare products, but due to its volatility and difficulty in storage and preservation, it becomes a very sensitive material. Its storage has a key effect on the effectiveness of royal jelly and the preservation of all valuable substances. When royal jelly is stored inappropriately, its biological properties deteriorate - its components are damaged, especially due to the influence of light, heat, and oxygen in the air.
How quickly does royal jelly lose its properties?
Fresh royal jelly in a queen cell
Royal jelly might have been exposed to negative influences already during its acquisition or at the time of first storage, which you as a consumer have practically zero chance to influence.
At a temperature of up to 5 °C, while the temperature must not fall below the freezing point, the stored royal jelly will last a maximum of 6 months, while at a temperature above 5 °C, it will lose its properties in 4 to 6 hours. It should therefore be cooled immediately after collection, as glucose oxidizes the enzymes contained in royal jelly.
Therefore, gentle lyophilization is the solution to the instability of royal jelly. Freeze-dried royal jelly stays in perfect condition with all active ingredients for 12 months. The freeze-drying process therefore enables easier handling of the royal jelly and safer delivery to the end customer.
How long does royal jelly last?
Freeze-dried royal jelly or royal jelly in honey
12 months at ambient temperature
Fresh royal jelly
up to 6 months in the refrigerator at 3 - 5 °C
2 years in the freezer at -15 to -20 °C
How does the royal jelly lyophilization process work?
Lyophilization of royal jelly in progress
Royal jelly must be collected with utmost care and any contamination must be avoided. The process of the subsequent lyophilization:
Royal jelly is transferred in thin layers (approx. 0.5 cm) to glass plates, where it is frozen at a temperature of -18 °C.
Next comes drying, during which the air pressure is reduced, and then enough heat is supplied to allow the water to sublimate. Drying removes most of water from royal jelly. It takes place at a temperature of -50 °C for 3 days.
Immediately after the end of the process, the royal jelly is stored in airtight packages.
Benefits of lyophilized royal jelly
Freeze-dried royal jelly is not as sensitive to temperature and can be stored at room temperature. A fundamental advantage for customers is that it can be transported over greater distances without losing valuable substances.
Freeze-dried and fresh royal jelly have been compared in many studies, let us take the example of the study by the research team of Y. Kayashima. They confirmed that fresh and freeze-dried royal jelly have the same properties and that the freeze-drying process does not significantly affect the quality of royal jelly or its functionality.1
Lyophilized royal jelly
Freeze-dried royal jelly is also widely used in the food and pharmaceutical industry, because it is very easy to work with thanks to this modification and can easily become a component of various products.
Lyophilized royal jelly does not lose any properties compared to fresh royal jelly and poses a very reasonable option for handling and transport.
The valuable substances in fresh royal jelly last only a few months after collection, but it is often difficult to reach the end customer so quickly. While you have to consume fresh royal jelly very quickly, you don't have to rush with freeze-dried royal jelly because freeze-drying has extended its shelf life.
1 Yasunari KAYASHIMA, Keiko YAMANASHI, Ayaka SATO, Shigenori KUMAZAWA & Kimiko YAMAKAWA-KOBAYASHI (2012): Freeze-dried royal jelly maintains its developmental and physiological bioactivity in Drosophila melanogaster; Bioscience, Biotechnology, and Biochemistry, 76:11, 2107-2111 Back