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< prev - next > Food processing Snack foods KnO 100232_Fruit leathers (Printable PDF)
FRUIT LEATHERS
Introduction
Fruit leathers are made by drying a very thin layer of fruit puree to produce a product with a texture
similar to soft leather. Fruit leathers are eaten as a snack and are often targeted at health food
markets, using marketing images such as “pure”, “sun dried” and “rich in vitamins”. Such claims
are not unreasonable given that low temperature drying is a gentle process that results in less loss of
nutrients than, for example, canning in which up to 65% of minor nutrients can be destroyed.
Losses of vitamin A and C are, however high, if the fruit is dried in direct sunlight. Fruit leathers can
be made from one type of fruit or blends of different fruits. They may be sweetened, by adding sugar
or flavoured with chopped nuts, coconut or spices.
The preservation of fruit leathers depends on their low moisture content, typically 15 to 25%, the
natural acidity of the fruit used and high sugar contents. The products have a shelf life of up to 9
months provided they have been sufficiently dried and properly packaged.
Production of fruit leathers
This technical brief describes the production of fruit leathers at three scales; from a very small simple
home based system, through cottage industry to small industrial production. The following basic
steps are involved at all levels of production:
selection and preparation of the fruit including intermediate preservation to allow production to
continue out of season.
preparation of the puree
batch preparation
drying
packing and storage.
Selection, preparation and intermediate storage
A high quality product can only be made from good quality raw materials and production should not,
as too often happens, be based on second grade fruit that is not suitable for the fresh market. Fruit
that has been rejected for being too large, too small or because of surface blemishes is, however,
usually acceptable.
Fully ripe soft fruits are very susceptible to bruising when handled and bruised areas will quickly
begin to rot. It is thus better to purchase semi-ripe fruit (which is usually cheaper) and allow it to
fully ripen in the processing area. This also has the advantage of allowing the daily selection of fruits
of equal ripeness.
Incoming fruit should be selected and any unsuitable material removed from the processing area and
properly disposed of; not simply put in an open bin outside. Selected fruits are then washed in
chlorinated water (one teaspoon of bleach per gallon of water) and then peeled, de-stoned etc,
depending on the type being used. Only stainless steel knives should be used as mild steel will
corrode and stain the flesh. Some fruits require special attention. Banana has a very low level of
acidity and is also subject to what is known as enzymatic browning which results in rapid
discoloration after peeling and cutting. After peeling, bananas should be quickly immersed in a
water containing a small quantity of a chemical, sodium metabisulphite, which controls such
browning. The solution should have a concentration of 400 parts per million of sulphur dioxide.
[See box for more details on the use of sulphur dioxide]
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