Fruit Juice Preparation
Fruit juices are made from pure filtered fruit juice with nothing added. Sodium benzoate can be added as a preservative to extend the shelf life, but this is not essential. Properly pasteurized juice has a shelf life of several months. Most fruits can be used to make juice. The most popular ones are pineapple, orange, mango, grapefruit and passion fruit.
The pulp is the stringy content of the fruit’s endocarp. The pulp contains the juice of the fruit. The pulp is usually removed from fruit juice by filtering it out.The color of the pulp can change, depending on the species and the ripening stage. Usually, it has the color of the fruit’s peel. The juiciness of the pulp depends on the species, variety, season, and even the tree on which it grew.
The edible part of the whole fruit, if appropriate less the peel, skin, seeds, pips, etc., which may have been sliced or crushed but which has not been reduced to a puree.
Method to Prepare Fruit Pulp:
Use fully ripe fruit. Wash and peel the mangoes and cut into slices with a stainless steel knife. Extract the pulp using a hand-driven or electrical juice extractor. Add boiling water, sugar and lemon juice to the pulp so that the mixture contains 12% total soluble solids (as measured by a refractometer) and has a pH of 3.5-3.8. Fill the juice into clean sterilized bottles and seal with caps. Pasteurize the juice by immersing batches of the bottles in a hot water bath at 75°C. Leave in the water until the temperature of the juice reaches 68°C.
Chemical Food Preservatives (fao)
|Agent||Acceptable Daily intake (mg/Kg body weight)||Commonly used levels (%)|
|Lactic acid||No limit||No limit|
|Citric acid||No limit||No limit|
|Acetic acid||No limit||No limit|
|Sulfites||50 mg/kg as residual SO2 in the end product, except when made with sulfated fruit when a maximum level of 100 mg/kg is permitted in the end product|
In the European Union all food additives are identified by an E number. Food additives are always included in the ingredient lists of foods in which they are used. Product labels must identify both the function of the additive in the finished food (e.g. color, preservative) and the specific substance used either by referring to the appropriate E number or its name (e.g. E 415 or Xanthan gum). The most common additives to appear on food labels are antioxidants (to prevent deterioration caused by oxidation), colors, emulsifiers, stabilizers, gelling agents and thickeners, preservatives and sweeteners.
Working Principle of Pulper:
The whole fruit can be fed directly to a paddle or screw pulper fitted with a 0.5 to 10 mm screen to pulp and separate the puree from the cap, leaves and larger seeds; a few small seeds are acceptable in many puree uses. A second pulper with a less than 0.5mm screen effectively removes remaining seeds and produces a smooth, is then filled into 20 to 200 litre containers and frozen at -18ºC. Actually, the puree should be deaerated prior to freezing and frozen in less than 25 litre portion at less than 25ºC for optimum quality retention but this is rarely done. It takes many hours for the centre of a 200 litre barrel of puree or frozen fruit to freeze, ample time for quality deteriorations to commence.
Types of pulper:
- Paddle Course Pulper
- Paddle Brushes Pulper
- Paddle Pulper Screw Pulper
(CODEX STAN 296-2009)