Deep-freezing blueberries is the fastest and easiest way of preserving the berries, guaranteeing that they don’t lose their flavour, aroma, bioenergy or nutritional value. Frozen blueberries keep until the next harvest and are also much easier to transport than fresh ones. Frozen blueberries can be packaged in plastic bags, boxes, buckets etc. Deep-freezing is the easiest way of preserving berries and their nutritional value. Frozen blueberries are widely used in the food and pharmaceutical industries because of their nutritional value and qualities. They are used in yoghurt, cakes, curds and more. The pharmaceutical industry uses frozen blueberries to make medicines.
Frozen blueberries have become very popular. The temperatures used to deep-freeze the berries are sufficiently low (mostly -25°C or lower), as freezing at such a temperature causes minimal damage to the plant cells. Flash-freezing is used to freeze the berries, as it creates smaller ice crystals, which cause less damage to the tissue structure. When a ‘slowly’ frozen berry thaws, the cell fluids seep out from the tissue damaged by the ice crystals and the berries end up dry or sodden. Vitamins C, B1 and B2 are well preserved in flash-frozen berries. Also, freezing does not reduce mineral or fibre content. Research has shown that the quantity of one of the most reactive vitamins in deep-frozen berries – ascorbic acid or vitamin C– forms generally 80% of initial content. Deep-frozen blueberries must be stored at the right temperature. The most suitable temperature for preserving them is -18°C – at this temperature they can be kept in a freezer for up to a year.
The best time to freeze blueberries is immediately after picking and cleaning, as the appearance and colour of the berries as well as their nutrients and therapeutic properties are then well preserved. High-quality blueberries are frozen.
Freezing blueberries is certainly the best and healthiest way of preserving and transporting the berries from an economic point of view. Scientists find that correctly frozen berries compete well with fresh berries in terms of their qualities.