Concentrated fruit juice is processed to remove a defined proportion of the natural water content found in the fruit and produces a product that is approximately 3 to 7 times more concentrated and therefore smaller in volume. Some concentrates are able to be stored for longer and at more convenient temperatures than not from concentrate fruit juice. This can greatly reduce the costs required for transportation of equivalent volumes of concentrate, which can then be returned to its single-strength state by reconstituting with water once it reaches the final processing destination.
|Citrus Fruit Juice||Apple Juice|
Although citrus fruit processing methods may vary between each processing plant and from fruit to fruit, typically the processing begins with the washing and sorting of the citrus fruit to ensure the raw produce is cleaned and graded for use. The fruit is then placed in an extractor to separate out the juice by applying physical pressure to the fruit.
The juice is then spun in a centrifuge at a high speed to filter out fragments of pulp. This is achieved as the refined juice is pushed out of the front of the machine through the inner basket whilst the larger pulp fragments stays inside the machine. If clear juice concentrate is required, the extracted juice is then put through an ultrafiltration system that removes the suspended fine particles of pulp that give juice its cloudy appearance.
The fruit juice then passes through an evaporator, which typically concentrates the product in a series of smaller steps. This helps minimise the heat that must be applied to the juice, protecting the colour and flavour of the fruit. Evaporators operate at low pressure, allowing the water component to be evaporated more readily at lower temperatures, again to minimise the effects of the processing on the quality of the juice. In some cases the concentrated product is then pasteurised, but this is not necessary for all packaging formats as the evaporator stage applies sufficient heat to control microbiological activity in the product. As the concentrate is a raw material, it is generally pasteurised when it is reconstituted with water ready to be packed into a consumer format.
Although processing methods vary between each processing plant, in general the processing begins with the washing and sorting of the fruit to ensure it is cleaned and graded for use. Once this has taken place the apples are then milled to a pulp before undergoing an enzyme treatment to break down pectin in the fruit, increasing the juice yield from the apples when pressed and preventing the product setting and becoming jam-like as the water is removed during concentration. The pulp is then conveyed to a press that extracts the juice by applying physical pressure, leaving just the fibrous insoluble parts of the apple behind.
The juice is then heated to a specific temperature and flash-cooled immediately to pasteurize the product and inhibit any microbiological growth. This also removes some water content and is the first stage of the evaporation process.
Both the added and naturally occurring enzymes are then deactivated and the extracted juice is put through an ultrafiltration system to clarify the juice by removing any remaining suspended pulp before being passed through an evaporator to concentrate the juice. As with the Citrus products, this is undertaken at low pressure to reduce the impact of the thermal processing on the quality of the juice. Where required the concentrate may be pasteurised or, as it is now a clear juice with virtually no suspended solid matter, may be sterilised through filtration, but as with most concentrates the evaporation process provides sufficient microbiological control to allow the material to be stored and handled ready for processing by a final packer.
Technical Manager's note:
The details above are provided as an indicative guide to processing techniques for Apple and Orange Juice Concentrates. Please note that this does vary between different products and sites, and as such this information should not be interpreted as a formal process description or part of a HACCP plan or related food safety system. For specific details regarding individual products, please contact the Cobell technical team who will be happy to assist.