The best way to preserve truffles - what is lyophilization / freeze-drying?
What is lyphilizing? What is freeze drying?
Lyphilization of truffles
Lyphilization is a technically new type of freeze-drying, which finally makes truffles long-lasting, namely for more than 24 months. The best thing about it is that the taste and unique aroma of the truffle also remain.
This preservation process was first introduced to the queen of truffles, the Alba truffle. Freshly harvested truffles can now be preserved for 2 years without any loss of quality.
This new freeze-drying technique is carried out in a vacuum container to gently remove all of the moisture from the truffle. Water is the main reason the truffles lose their taste so quickly. No preservatives or artificial flavors are required here to make the noble tubers durable!
During the dehydration process, between 80% and 90% of the moisture can be withdrawn, which means that 10g of fresh truffles result in 2g of lyphilised truffles.
The freeze drying process takes place in three phases:
The material is first frozen. Freezing has to be done very quickly to prevent large ice crystals from surrounding the cells, because the tips of the ice crystals pierce cell walls. This phenomenon is responsible for the fact that strawberries, for example, become mushy after thawing.
Then the material is put under pressure. More precisely; the air pressure is slowly decreased until the food is in a vacuum. With the help of the condenser, which is located in the freeze dryer, the water vapor remains on the cool surface and can be easily removed. In addition, the condenser protects the vacuum pump from moisture. In the second phase of the process, 95% of the water can be extracted from the truffle. At this step, slow warming is critical to the desired success.
In the third and final phase of the process, ionically bound water molecules are removed, namely by increasing the temperature, the connections between the water molecules and the cells are broken. Freeze-dried materials remain porous. After almost all of the moisture has been removed from the noble bulb, the vacuum is refilled with an inert gas and then sealed in a glass. Thanks to this modern method, the truffles can be dried to 5% to 1% residual moisture!
The freeze-drying method is clearly the best method to preserve truffles for a long time with as little loss of flavor and taste as possible.