Précédente - Suivante
Table des matières
- Précédente - Suivante
- Samu - Negus H. Mariam
INTRODUCTION
Dehydration by sun-drying of various products, notably chillies, on a village or domestic level' is traditional in Ethiopia. The benefits to be derived from improving and extending this ancient method of food preservation were recognised by IAR and following adaptive research' the publication, "Sun-Drying of Fruit and Vegetables in Ethiopia" appeared in 1977. A report on simple methods of storing dehydrated products, followed later.
In spite of the manifest advantages which could secure from sun drying surplus produce from rain fed crops for consumption during the long dry season, these proposals were not taken up and developed by any of the agencies working in rural development, even though the inputs required are very small.
Recently, a new proposal' as yet unpublished, has been made by HDD; "Appropriate Technology for Dehydration of Vegetables and Fruits". If implemented, this proposal could have a national impact on improving food supplies and there would also be the possibility of developing exports of certain products.
PROPOSED DEVELOPMENT AND WORK PLAN
Briefly, the proposal envisages intergration of two levels of technology in order to combine the best features of both, each being appropriate and complementary.
Many parts of Ethiopia have a prevailing dry atmosphere which is very suitable for open tray sun drying, without the use of solar drying structures. Suitable crops for sun-drying would be grown and sun dried by small farmers. Vegetables can be reduced to a moisture content of 10% by sun drying, at which stage they can be stored at medium temperatures for about 18 months. Such products could be stored for home use by the producers or could be sold locally.
However, in order to convert the farmer's sun dried produce into products of a standard suitable for national distribution or even for export, some finishing operations are necessary. For this purpose, farmer/sun driers would have the option of soiling their products to a central finishing plant, which could be developed by installation of quite simple equipment at one of the existing agro-industrial processing plants.
The finishing process would consist of drying to a final moisture content of 5-6% for vegetables; grading to produce a standard product' packaging in consumer size packs or bulk; distribution and marketing of the products.
The advantages of this integration of technologies will be readily apparent. Major costs in conventional industrial dehydration are : high capital costs of dehydration equipment and buildings; high transport costs for transporting fresh produce with an average moisture content of 85-90% and average waste of 15%, from field to factory; high running costs for staff and for evaporating about 90% of the moisture in the raw material with non-renewable energy; high cost of discontinuous operation due to shortages of raw material.
By adopting the economical methods of production which are recommended' it should be possible to produce finished products at a low enough price to make them available to a large section of the population as well as to provide highly competitive products for export.
IMPLEMENTATION
It is proposed to confine production initially to only one product, dehydrated onion. Onion has a universal appeal in the Ethiopian diet and it is known from previous work carried out by Institute of Agricultural of Research (IAR), that dehydrated onion is well accepted by consumers. The technique for sun drying onion is a simple one and the dry product has good storage life. There is a good export market for dehydrated onion.
FIELD PRODUCTION OF ONIONS AND SUN-DRYING
It is proposed that in the first season' 100 farmers should each grow 0.25 ha of onion under irrigation and sun dry the crop. Ma, serial inputs for growing the crop and sun-drying it would be provided by the project. Seasonal inputs would be repayable at the end of the season and capital inputs over 3 seasons. Inputs are detailed in Appendix 1.
Sun dried produce which is purchased by the finishing plant should be priced according to the formula:
Agreed contract farm gate price x 10 plus 0.75 Birr/kg (labour of sundrying)
Thus, if the farm gate price is 0.20 Birr/kg, the price paid to the farmer for sun dried onion would be 2.75 Birr/kg. (U.S. $ 1.00 . 2.07 Birr).
It is estimated that with good husbandry' the yield from 0.25 ha would be 4,000 kg. After sun-drying, gross return to the farmer would be 1,100 Birr from 1/4 of a hectare.
One suitably trained field agent would be required to supervise the production of onions and sun-drying of the crop.
In the second season, production should be extended to 200 growers and double the production of sun dried onion.
THE FINISHING PLANT
It is proposed that production and sun-drying should be undertaken within transport range of the merti Processing Plant so that finishing could be undertaken as a subsidiary operation there. A flow sheet of the finishing operation is shown in Appendix 1.
The plant is design d for 180 day operation so that maximum advantage can be taken of solar energy for bin drier operation during the dry period of the year. Solar heat is utilised by passing the intake sir of the bin drier through the double akin roof of the building and forged draught is provided by electric fan. The bin drier can be built locally of sheet metal and timber. It should have an initial capacity of 50 kg input/12 hours, divided into 2 sections of 25 kg each.
The flow sheet B for local market grade dehydrated onion, packed in plastic pouches of 100 g, is vary much simpler than the flow sheet recommend d for export grade. This should result in an attractive price to the consumer.
PRIORITY AND DURATION
The priority of this project has to be discussed. It is a long term project but continuation must depend on assessment of the first season's results.
ACKNOLEDGEMENT
Thanks of acknowledgement goes to Mr. T.H. Jackson, Export in the Horticulture Development Department for the original idea.
Appendix 1
