Production of cloudy and clear natural Apple juice
Processed apples have an 11% sugar content. When we process apples we obtain:
- Cloudy juice. This is apple juice which contains particles in suspension which will not precipítate out. The image is of a natural
and healthy product.
- Concentrated juice
From the technological point of view, processing apples involves 3 processes which are detailed below.
1. Mass transfer
The process starts with the maceration of the whole product. It continues with depeptinisation and hydrolisation. The product is
then concentrated and finally aseptically packaged.
2. Heat Transfer
The thermal treatment used depends on whether the product is a cloudy juice or a clear juice.
- Cloudy juice
We start with the product at 10ºC which we raise to 25ºC in order to carry out an extraction of product. Then it is heated to 55ºC
in order to carry out the enzymatic treatment. Afterwards it is raised to 105ºC to sterilise the juice and it is finally cooled
to 3ºC for storage.
- Clarified juice
This is firstly raised to 55ºC in order to carry out the enzymatic treatment. Following this we start the pre-concentration phase
and raise the temperature to 120ºC. Lastly the concentration process is carried out and we arrive finally at a temperature of 20ºC
for aseptic packaging.
3. Separation of the apple residues
Separation of the various parts of the apples is carried out with decanters and clarifiers which are used during various stages
of the process.
In order to achieve a good result we have to use treatments which are not in any way aggressive to the product and which also guarantee
that there will not be any contamination from outside sources.
Another factor to take into account is that the apple contains starches which will produce fouling during the thermal treatments.
This fact alone makes corrugated tube heat exchangers more appropriate than plate heat exchangers for this application, given that
with Shell and tube units there are fewer stoppages for cleaning than with plates.