Freeze-drying is one of the most advanced yet gentle methods of food preservation. Its principle is based on the removal of water from the product at low temperature and under reduced oxygen availability, without passing through the liquid phase. As a result, the structure of the raw material and its natural nutrients remain largely intact.
Mechanism of concentration – why do values increase?
To reliably assess how this process affects nutritional value, we conducted comparative studies on our own products. The same batches of fruits and vegetables were analyzed first in frozen form and then after freeze-drying carried out in our facility. This approach allowed us to clearly determine which changes result solely from the technology itself.
Fruits and vegetables typically contain 80–90% water. Freeze-drying removes this water but does not remove vitamins and minerals.
As a result:
– the product mass is significantly reduced,
– while the concentration of vitamins and minerals per 100 g of product increases markedly
Vitamin C – the most illustrative example of concentration
Vitamin C is particularly sensitive to oxygen and long-term storage, making it a good indicator of process quality.
BERRY FRUITS
Raspberry
– frozen: 7 mg / 100 g
– freeze-dried: 107 mg / 100 g
Strawberry
– frozen: 6 mg / 100 g
– freeze-dried: 35 mg / 100 g
Blackcurrant
– frozen: 52 mg / 100 g
– freeze-dried: 143 mg / 100 g
Redcurrant
– frozen: 14 mg / 100 g
– freeze-dried: 153 mg / 100 g
In all cases, the same pattern is observed: after freeze-drying, vitamin C is present at a significantly higher concentration. From a physiological perspective, vitamin C supports immune function, collagen synthesis, iron absorption, and protection of cells against oxidative stress
Folates (vitamin B9) – a nutrient that “emerges” after freeze-drying
Folates play a key role in nervous system function, blood formation, and energy metabolism.
Strawberry
– frozen: <50 µg / 100 g (below the limit of quantification)
– freeze-dried: 251 µg / 100 g
Kiwi
– frozen: <50 µg / 100 g (below the limit of quantification)
– freeze-dried: 591 µg / 100 g
Mango
– frozen: <50 µg / 100 g (below the limit of quantification)
– freeze-dried: 373 µg / 100 g
These results demonstrate that after freeze-drying, folates are not only preserved but clearly concentrated, which is particularly relevant in diets focused on energy and cognitive performance.
Minerals – natural concentration without quality loss
Minerals do not degrade during freeze-drying, therefore their concentration increases proportionally as water is removed.
EXOTIC FRUITS
Banana
– frozen: 3733 mg/kg
– freeze-dried: 14111 mg/kg
Mango
– frozen: 1565 mg/kg
– freeze-dried: 7599 mg/kg
Pineapple
– frozen: 884 mg/kg
– freeze-dried: 5533 mg/kg
Potassium supports proper muscle function, heart activity, and nervous system performance.
Vegetables – the highest concentration of mineral components
BROCCOLI
Vitamin K1
– frozen: 23.1 µg/100 g
– freeze-dried: 1070 µg/100 g
Calcium
– frozen: 394 mg/kg
– freeze-dried: 4858 mg/kg
SPINACH
Vitamin K1
– frozen: 164 µg/100 g
– freeze-dried: 3600 µg/100 g
Calcium
– frozen: 1923 mg/kg
– freeze-dried: 25,655 mg/kg
Vitamin K1 supports bone health and proper blood clotting, while calcium is essential for the skeletal system and muscle function.
Conclusions from the study
The analysis of several fruits and vegetables, examined in the same form before and after freeze-drying, presents a very consistent picture. The freeze-drying process does not alter the nature of the raw material or its intrinsic composition. Its sole function is the removal of water, without destructive effects on vitamins and mineral components. As a result, the same nutrients become concentrated in a smaller product mass, leading to a significantly higher density of vitamins and minerals in freeze-dried products compared to frozen ones.
Studies conducted on our products under real production conditions confirm that freeze-drying is one of the most effective food preservation methods in terms of preserving and concentrating nutritional value.