The majority of fruits and vegetables grow in short seasons and one main reason for processing is therefore to secure a supply of these foods when they are not available in a fresh state. This is both because some (tomatoes, onions, spices etc.) are used in daily cooking in different societies and because regular consumption of fruits and vegetables is necessary to maintain health.
In different societies throughout the world, the consumption of fruits and vegetables has different levels of significance in the diet. In some areas, such as the cold, infertile conditions of Central Asian steppes, mountainous regions of Latin America and arid deserts of Africa and Asia, fruit and vegetable cultivation is difficult and has a short annual growing season. These products do not therefore play an important role in local diets and there is greater reliance on animal products. However, the requirement to eat fruit and vegetable products to maintain health means that in almost all of these societies, small amounts of leafy vegetables and collected fruits are preserved for winter or dry seasons and as a result of their shortage, they have a high value.
By contrast, in almost every country of the humid tropics and sub-tropical regions, the soils and climate are suitable for fruit and vegetable cultivation and there is an historic reliance on these products as an important part of the normal daily diet. Indeed in some areas this may be reinforced by religious beliefs, such as Hinduism, which requires followers to be vegetarians. In many communities throughout the world, vegetables are eaten daily as an accompaniment to a main cereal or root crop meal, with or without meat and fish. Fruits are eaten fresh when in season as appetisers, snacks, juices and desserts.
There are a large number of traditional processed fruit and vegetable products that are traditionally made in the home. Examples from Asia include fruit 'leathers' (dried sheets of fruit paste that have an appearance of thin leather), fruit pastes, pickles and chutneys. In Africa and Latin America, a wide range of dried chips, dried and powdered leaves, fruit beers and other fermented fruit and vegetable products are traditionally produced. Each of these products is stored for future use and is often not intended for sale, although no clear distinction is possible. Some products that are processed for home consumption may also be sold to neighbours or at village markets when additional income is needed. Problems that may be found when developing this type of income generating activity are described at the end of this Section.
In general terms because of low incomes, home processing requires simple, cheap equipment and will usually be done without specialised machines, using existing kitchen utensils and simple pieces that can be made from local materials at almost no cost. Processing methods are also inexpensive but in some cases are complex and sophisticated, involving a sequence of process stages that require considerable experience and expertise to perform correctly.
Some of the main reasons for home processing are to maintain a secure supply of food for seasons of shortage (to provide food security) and to maintain health through an adequate supply of nutrients in the diet. These aspects are described in more detail below.