Fruit Juice Preservation and Packaging

1. Pasteurisation: This requires raising the temperature of the juices to 80 – 95degC for 1-10 minutes prior to filling hot. At the simplest level, this may be carried out in a stainless steel, enamelled or aluminium saucepan over a gas flame, but this can result in localised overheating at the base of the pan, with consequent flavour changes. To avoid the use of large expensive, stainless steel pans, a large aluminium pan can be used to boil sugar syrup. A given amount of the syrup is then mixed with fruit juice in a small stainless steel pan and this increases the temperature to 60 – 70degC. The juice/syrup mixture is then quickly heated to pasteurising temperature.

2. Preservation under CO₂ pressure may be done at a concentration of 1.5% CO₂ under a pressure of 7 kg/cm2. At the distribution step, proceed at CO₂decompression and the juice is then submitted to a sterilising filtration and aseptic filling in receptacles.

Filling and bottling

Note: Care is needed when producing pineapple juice due to a heat resistant enzyme in the juice. The enzyme damages skin after prolonged contact and workers should therefore wear gloves to protect their hands. The juice must be heated to a higher temperature for a longer time to destroy the enzyme (eg boiling for 20 minutes).

Quality control 

• Pay particular attention to the quality of re-usable bottles, check for cracks, chips etc and wash thoroughly before using. If bottles are not able to be sterilized with hot water as in the case of plastic bottles, they can be sterilised in cold water using the sterilising agent Calcium Hypochlorite.
• The concentration of preservative should be carefully controlled for correct preservation of squashes and cordials, and may be subject to local laws. Check first and use accurate scales to measure the preservative.
• The temperature and time of heating are critical for achieving both the correct shelf life of the drink and retaining a good colour and flavour. A thermometer and clock are therefore needed.
• Standardisation of products is a must therefore the correct weight should be filled into the bottles each time