ITDG 
Interdev Agroalimentaire  

Production of pineapple juice

	Type de fiche	Techniques/Technologies
	Mise en œuvre	ITDG(Royaume Uni)
	
	Zone géographique	Global; 
	Mots clés	JUS; PASTEURISATION; FILTRE; FRUIT; PULPE; ANANAS

	Echelle d’action	Groupe

Contexte
Pineapple is one of the most fragrant tropical fruits with a characteristic flavour.  It makes a very popular fruit juice or fruit nectar.  Pineapple juice can be mixed with other juices, notable passion fruit juice, which has a sharper taste and stronger colour, to produce a mixed fruit juice.

Pineapple is produced in many developing countries.  Quite frequently it is exported as fresh fruit or canned to make pineapple rings in syrup.  There are strict size specifications for pineapples that are exported, therefore several do not make the grade.  These fruit can be used to produce pineapple juice.

Fruit juices rely on a combination of acidity, pasteurisation and packaging in sealed containers for their preservation. They have to be drunk immediately after opening. If care is taken over the packaging, pasteurised juices can be stored in a cool dark place for up to a year.  It is normal for some sediment to form at the bottom of the bottle as it is left to stand, but if this is excessive, a finer filter can be used.

Problématique / Objectifs
Pineapple juice has a pH of 3.4-4.1 and gives a juice yield of about 30%. If the pH of the juice tends to be neutral, it can be lowered by adding citric acid or blending with clarified lemon juice.  

The Mauritius variety has the best flavoured juice, but the Kewpine variety gives better yields.  Pineapple contains the enzyme bromelin, which breaks down protein and is therefore harmful to the skin.  Care should be taken by all processors who handle pineapple.  Gloves should be worn during processing and washed each day.

Pineapple juice is highly susceptible to both microbial spoilage and enzymic degradation, therefore it must be heat treated for preservation.  To ensure that the delicate taste is not lost during processing, heat processing must be of a high temperature for a short time.

The processing unit should have sufficient space for incoming fresh fruits, particularly during the peak season. The room should be well ventilated to allow for uniform ripening. Pineapples should be handled carefully to avoid bruising.  Fruits that are free from bruising can be kept for 2-3 weeks at room temperature (about 25 C).

Description/Mise en oeuvre
Production method

1. Sort the pineapples and discard any bad fruits. Fully mature firm fruits are most suitable for high yield and quality fruit juice.  A regular supply of clean and potable water is required to wash the fruits.

2. Remove the stalks and tops from the pineapple fruit, cut off the outer cortex and pick out the eyes.  Wash the fruit and cut into small pieces, discarding any bad pieces.  A stainless steel knife should be used to cut the fruit to avoid staining the flesh.

3. Pulp the pineapple by liquidising or passing through a large sieve or a stainless steel screw-type press. Separate the juice from the pulp by squeezing through a muslin cloth that has been sterilised by boiling in water.

4. Sugar, lemon juice (or citric acid) and drinking water are added to the juice to make a ready-to-drink beverage.  Sugar and acid are added to retain and improve the characteristic sweet and sour taste of the freshly extracted juice.  The amount of sugar added depends largely on local taste.  In Uganda, sugar is added at 40% of the weight of extracted juice.  The sweetened juice is them mixed with drinking water in a ratio of 1:3 (juice:water). Lemon juice or citric acid may be added according to the acid content and to local taste.  In general, an average of 0.8% citric acid is recommended for a ready-to-drink juice.

5. Particles in the juice may separate out onstanding and can give the fruit juice a cloudy appearance.  To prevent this happening, the juice can properly strained to remove most of the large insoluble particles.  Pectin can be added to the juice (at a rate of 0.2-0.5%) to help stabilise it.  This is an optrional step, but it improves the appearance and quality of the juice.

6. The juice is pasteurised to destroy micro-organisms and de-activate any enzymes. The juice is placed in large stainless steel saucepans and heated to 62-65 C for 30 minutes.  Care must be taken to avoid localised burning.  It is better if a double jacket burner is used where the pan is heated inside a second pan of boiling water.

7. Cool the juice to 50 C and hot-fill into hot, clean, sterile glass bottles.  The bottles should be heated to avoid them cracking when the hot juice is poured in.  The bottles should be filled as quickly as possible so that the remaining juice does not have to be held at this high temperature for a prolonged period and to avoid contamination as it cools down.  Bottles should be filled, leaving a space of approximately one tenth of the height of the bottle. Wipe the lip of the bottle with clean tissue paper to ensure it is clean before the cap is placed on.  Lay the bottles on their side for 15 minutes to cool.  This is important to avoid contamination while the cap fits firmly onto the glass as the vacuum forms.

Résultats/Eléments chiffrés
Ingredients required to make pineapple juice

Pineapple juice			
Sugar				40% of the weight of juice
Water				sufficient to dilute the sweetened juice 1:3
Citric acid			0.8% of the volume of diluted juice

The yield of fruit juice varies from 30-40% depending on the maturity of the fruit and the efficiency of pressing. In general, larger fruits yield more juice as the ratio of skin to flesh is lower.

Manual extraction of pineapple juice is a labour intensive process that is dependent on availability of manpower. Continuous mechanical juice extractors (known as pulper-finishers) with in-built strainers are available, but tend to be uneconomical for small-scale production.

The shelf-life of pasteurised pineapple juice stored at room temperature (23-35 C) is between 1 and 3 months. At refrigeration temperatures (4-10 C), shelf life is extended to 3 to 5 months and when frozen, the juice will last beyond 6 months.

The following equipment is required;
  Bottles, crown corks and labels
  Crown corking machine
  Cooking facilities
  Stainless steel saucepan
  Thermometer
  Stainless steel cutting knife
  Wooden spoon for stirring
  Cutting board
  Scales 
  Measuring cylinder
  Funnel 
  Liquidiser 
  Muslin cloth

Enseignements
  Only fresh, fully ripe fruit should be used; mouldy or insect damaged fruit should be thrown away.  All unwanted parts (dirt, skins, stones etc) should be removed.
  All equipment, surfaces and floors should be thoroughly cleaned after each day's production.
  Water quality is critical, if in doubt use boiled water or add one tablespoon of bleach to each gallon of water to sterilise it.  If water is cloudy, a water filter should be used.
  Pay particular attention to the quality of re-usable bottles, check for cracks, chips etc and wash thoroughly before using.  Always use new caps or lids.
  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.
  Chemical preservatives cannot be used to cover up for poor hygiene or in-sanitary conditions.  It is imperative that all equipment is thoroughly cleaned before and after use and the juices are filled into sterile containers.  Chemical preservatives are only meant to add extra protection after the products are opened when the juice may become contaminated.
  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.
  The correct weight should be filled into the bottles each time.
  Before producing pineapple juice, a market survey should be carried out to determine local demand, tastes and requirements.  It is not sufficient to base the production of pineapple juice on a seasonal glut of the fruit.

Auteur : Sue Azam Ali
Saisie le : 05/12/2001
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