Oil, frying and quality control
Most oils used for frying are of vegetable origin but there is no reason why animal fats cannot
be used. The oil used has a great impact on the taste, texture and keeping quality of the final
product. For example, palm oil gives products a red colour. Mustard seed oil gives fried
foods a distinctive sulphur-like flavour. Fats and oils are subject to a type of deterioration
known as rancidity. This produces disagreeable odours and flavours and makes the fried
foods unpalatable. Some oils are more prone to rancidity than others and this is important
when considering which oil to use. In many countries, however, there is only one type of oil
widely available at the lowest cost and processors will use this, despite rancidity problems, if
it gives a flavour that is acceptable.
The amount of oil required for frying will vary according to whether the product is to be
shallow fried or deep fried. The temperature to which the oil is heated is not limited by a
boiling point as with water. Heated oil does however reach a stage at which it breaks down to
fumes, which is known as the smoke point. It is important that oils do not reach the smoke
point when used for frying as this will cause the oil to deteriorate more rapidly and increase
the danger of it catching fire. Suitable temperatures for frying are between 180 and 200°C.
Frying can take place using a simple pan heated by an open fire or other heat source.
Alternatively, for deep frying, an electrically powered fryer fitted with a thermostatic control
gives more control over heating for larger quantities of food.
At the end of the frying operation, the oil should be left to cool and then filtered to remove all
particles of food that have accumulated in the bottom of the pan or fryer. These burnt pieces
of food will cause the oil to spoil more rapidly.
The cost of oil is one of the major factors to calculate when considering starting to produce
fried chips. The quality of the finished product is highly dependent on having good quality,
Sun-dried banana chips
Sun-dried banana chips are a popular snack food. They are made by drying the banana pieces on
trays under the sun. A solar dryer or cabinet dryer can be used if available – both these
interventions will produce higher quality banana chips. See the Practical Action technical briefs
on drying for further information on the practicalities of drying at the small scale.
Knives or small fruit slicer
Plastic buckets or bowls for soaking fruit
Plastic sieve for draining the soak water
Drying trays (solar drying)
Drying cabinet (for assisted drying)
Selection and preparation of raw material
The selection and preparation of raw material is the same as for fried bananas above.
After soaking the banana slices in honey, syrup or fruit juice dip, drain the pieces well and place
on the drying tray. If you do not want to soak the pieces prior to drying, it is possible to paint
with a honey solution once the slices are laid on the drying trays.
Place the pieces as close together as possible on the drying trays to ensure the maximum drying
capacity. The pieces must not be touching or overlapping each other. If drying outside in the
sun, cover the tray with a piece of muslin cloth to protect from insects and dust. Place in the
drying position or into the solar dryer. If you are using a cabinet dryer, dry the pieces at 60°C.