Processing
Snack foods are made from a wide range of raw materials and the preparation differs from product to product. Frying, however, is the main process by which many are made and this is considered in detail here. (It should also be noted that concentrated milk solids or fruit pulps are also used for snacks in some countries.)
Principles of frying
Frying alters the eating quality of food. It also provides a preservative effect as the heat treatment destroys microorganisms and enzymes, and there is a reduction in moisture at the surface of the food.
Choice of oil
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.
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.
Raw material preparation
Cutting
Cutting into slices or cubes is often the only preparation needed for many snack foods. An ordinary kitchen knife can be used, or one of the many gadgets on the market (both manual and powered), make this stage easier and faster.