Integrierte Vermeidung und Verminderung der Umweltverschmutzung

2.2.3.2 Fruit juice
Chapter 2
Fruit juices are produced throughout temperate and tropical areas of the world. Orange juice
predominates in temperate climates and pineapple juice in tropical climates. The bulk of the
world fruit juice production is from citrus fruits, mostly oranges, pomes; from apple and pear
type fruits and from vine fruits. Some stone fruit juices are manufactured but in much smaller
quantities.
In a typical citrus juice process, the fruit is sorted, graded and washed to remove extraneous
matter such as sticks and leaves, adhering dirt and insects. The fruit is then passed through oil
extraction equipment where it is subjected to hundreds of small cuts of the skin to rupture the oil
sacs and release the citrus oil, which is removed by washing. Oil extraction may be carried out
after juice extraction. The fruit juice is mechanically extracted and screened to remove excess
pulp, pieces of skin and seeds. The screened juice is preserved by a number of methods such as
canning, aseptic processing, chemical inhibition, freezing, and membrane separation. It may be
concentrated before packaging to reduce transport costs. The juice may be clarified before or
after preservation.
A typical pome juice process includes similar processes but without an oil extraction step. The
fresh fruits are delivered to the processing installation and unloaded, washed, sorted and then
crushed after eventual coring or pitting, e.g. for peaches and apricots. The white fruits are
heated to avoid enzymatic browning. The crushed fruits are then strained and refined to extract
the juice. For apple juice, the juice is sometimes clarified with an enzymatic treatment and
filtration.
Orange, apple and tomato juices are often concentrated, normally by evaporation or in some
cases by RO or cryoconcentration. The juice is obtained either from fresh fruits or from
reconstituted concentrates from citrus, pineapple and other tropical fruits. It can be packed
directly, as it is the case with juices, or mixed with sugar and water, as it is the case with
nectars. The juices are then de-aerated and hot filled into bottles or cans.
Because of the low pH, filling with a HTST pasteurisation treatment is sufficient to stabilise the
product when followed by bottle sterilisation in a steam tunnel. Aseptic packaging is carried out
by pasteurising, cooling and filling, all in aseptic conditions. The filling is carried out in
cardboard bricks or preformed bricks.
2.2.3.3 Heat treated fruit
In typical canned fruit processes, the fruit is ideally used as soon as possible after delivery,
although it often has to be stored for a time under chilled conditions, e.g. apple. The fruit is first
washed, then sorted and possibly trimmed, then graded or cored before peeling. A variety of
methods are used for peeling, including abrasive, caustic, steam or mechanical peeling. Peeled
fruit may be blanched or transferred to tanks containing materials such as brine or ascorbic acid
solutions to prevent browning. If necessary, the fruit may be sliced. Products such as orange
segments are subjected to acid and caustic soaks to remove stringy fibres before canning. The
fruit is filled into containers, e.g. cans or glass jars, in syrup or a natural juice. Before sealing,
they can be gently heated to remove entrained gases, a process known as exhausting. Filling
under vacuum conditions avoids the need for exhausting. The container is then sealed, heat
processed and cooled. For fruit, a pasteurising treatment with a temperature under 100 ºC is
sufficient.
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