Production of Cloudy and Clear Natural Apple Juice
Processed apples have around 11% sugar content. When we process apples we obtain:
- Cloudy juice. This is apple juice which contains particles in suspension which will not precipitate out.
- Concentrated juice
Processing apples for juice production typically involves the following three technological processes:
- Mass transfer
The process starts with the maceration of whole apples. It continues with depectinisation and hydrolisation. The product is then concentrated before being aseptically packaged.
- Heat Transfer
The thermal treatment used depends on whether the product is a cloudy juice or a clear juice.
- Cloudy juice – Starting with the product at 10°C, the temperature is raised to 25°C in order to extract the product. This is then further heated to 55°C to carry out the enzymatic treatment. Afterwards it is raised to 105°C to sterilise the juice and it is finally cooled to 3°C for storage.
- Clarified (clear) juice – The temperature is first raised to 55°C for the enzymatic treatment. Following pre-concentration starts by raising the temperature to 120°C. Finally the concentration process is carried out and we arrive finally at a temperature of 20°C for aseptic packaging.
- 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 produce a high-quality product, it is necessary that the treatment processes described above are non-aggressive and do not affect the product in a negative way. Such treatments also guarantee that there is no contamination from external sources.
Another factor to consider is that apples contain starches which will foul surfaces during thermal treatment. This makes corrugated tube heat exchangers more appropriate than plate heat exchangers for this application as they require less cleaning and are more efficient.