Lyophilisation: A Revolution in Fruit Preservation
Freeze-drying, an innovative process in the field of food preservation, is increasingly used to preserve fruit while maintaining its nutritional and organoleptic qualities. Unlike traditional drying methods, freeze-drying involves a complex process of freezing and sublimation, which offers significant advantages in terms of food preservation.
Principle of freeze-drying
Freeze-drying is a multi-stage process. Firstly, the fruit is frozen at extremely low temperatures, generally around -40ºC. This freezing transforms the water in the fruit into ice. Next, the pressure is reduced in a vacuum chamber to around 0.01 mbar. Under these conditions, sublimation occurs, where the ice turns directly into water vapour, bypassing the liquid state. This vapour is then collected in a condenser. Finally, a secondary drying stage is carried out to eliminate any residual water molecules trapped on the surface of the fruit(1).
At the end of the process, the fruit contains only a tiny amount of water, generally between 1% and 5%, making it virtually moisture-free. This method preserves the fruit's shape, texture, flavour and nutrients, resulting in a high-quality product with an extended shelf life.
Advantages of freeze-drying fruit
Freeze-drying offers a number of significant advantages over traditional drying methods, particularly air drying or drying with food dehydrators.
Firstly, freeze-drying allows fruit to be preserved for longer periods, while preserving its shape and volume. Unlike traditional drying, which can lead to physical and chemical changes, as well as a loss of texture, freeze-drying maintains the structural integrity of the fruit(2).
What's more, freeze-drying effectively preserves the fruit's nutrients. The process takes place at low temperature, which means that up to 95% of the fruit's nutritional value is preserved. Essential vitamins and minerals are preserved, offering consumers a healthy, nutritious product(2).
As far as organoleptic qualities are concerned, freeze-drying maintains the taste, colour, smell and texture of the fruit. Unlike traditional drying methods, which can alter these characteristics, freeze-drying preserves the sensory aspect of the fruit, making it attractive and appetising to consumers.
Comparison with conventional drying
The main difference between freeze-drying and traditional drying lies in the way the fruit is preserved. Whereas traditional drying can lead to a significant loss of nutrients, as well as a deterioration in texture and taste, freeze-drying preserves the nutritional and organoleptic quality of the fruit(3).
Freeze-drying preserves up to 95% of the fruit's nutritional value, whereas conventional drying can remove up to 60%. What's more, conventional drying often leaves a certain amount of residual moisture, which can lead to premature deterioration of the fruit. Freeze-drying, on the other hand, effectively eliminates all the water, ensuring long-term preservation(2).
In conclusion, freeze-drying is emerging as a revolutionary preservation method for fruit, offering an effective solution for preserving their freshness, nutritional value and sensory qualities. Thanks to this innovative process, consumers can now enjoy delicious, nutritious fruit all year round, without compromising on quality.
What Holyfat products contain freeze-dried fruit?
You can find freeze-dried fruit in most of our fruit purees. As well as in our bars.
Where do our freeze-dried fruits come from?
Our supplier is located in Europe. The fruit comes from different origins (strawberries from Turkey, pineapples from Costa Rica, bananas from Ecuador, etc.).
1. Sagar Bhatta, Tatjana Stevanovic Janezic. Freeze-Drying of Plant-Based Foods. Foods, 2020 Jan; 9(1): 87
2.Xanyar Mohammadi, Yuhao Deng, Impact of Three Different Dehydration Methods on Nutritional Values and Sensory Quality of Dried Broccoli, Oranges, and Carrots. Foods, 2020 Oct; 9(10): 1464.
3. Norshahida Mohamad Shofian, Azizah Abdul Hamid. Effect of Freeze-Drying on the Antioxidant Compounds and Antioxidant Activity of Selected Tropical Fruits. Int. J. Mol. Sci. 2011, 12(7), 4678-4692