Cover Image
close this bookFood Chain No. 17 - March 1996 (ITDG, 1996, 16 p.)
View the document(introduction...)
View the documentGreetings
View the documentJak fruit - one of nature's gifts
View the documentAbout aflatoxin
View the documentBook Lines
View the documentOpen-pan sulphitation sugar processing
View the documentWadian - A fermented Indian food
View the documentNews Lines
View the documentResearch notes
View the documentThe Pearson square - common calculations simplified
View the documentAcknowledgments


A journal about small-scale food processing


A question that frequently arises in projects that are intended to support enterprises is that of scale of operation.

At the smallest scale of processing, people, often women, process foods to earn extra income. They produce foods and sell them to neighbours or in local markets. Such enterprises should be considered as 'income-generating activities' as they are unlikely to expand and develop. This is because they are not able to supply regular orders to more formal retailers who require a guaranteed supply and a consistent quality product. Similarly, they find it difficult to compete with products from larger companies or with imports, which have more attractive packaging and more uniform quality They rarely have the capital to invest in special processing equipment and quality assurance. Therefore they are not able to operate with equipment that would give economies of scale or that would allow better control over processing conditions.

At a larger scale of operation (often called 'small' or 'cottage' scale), the problems are different. Typically these businesses, which may employ from two to five people and have an investment of up to $US 5000, are intended to provide a major part of the family income for the owner They may have a dedicated room for processing and an investment in some special equipment. At this scale the processors are often attempting to compete with imported equivalent products, with the expectation that they can be made more cheaply because of lower labour and distribution costs. In such cases the main problems are difficulties in obtaining small items of equipment or affordable packaging materials in the amounts required, lack of technical knowledge about production costing or quality assurance, and, in a few cases, lack of access to finance. At this scale, producers can be greatly assisted by appropriately designed training courses in both technical and business aspects of their production and by help in locating suppliers of equipment and packaging.

Finally, at the-largest scale of independent production commonly found in developing countries, the number of employees may be around 20 and the investment in plant and machinery may exceed $US 20,000. This type of enterprise not only provides the major source of income for the but also employs considerable numbers of skilled and unskilled people directly, and indirectly through linkages to farmers and distributors. Historically, this scale of production has been largely ignored by international development organizations because of a commonly held view that larger companies were either exploitative or could afford their own development costs. Today the picture is changing somewhat and it is recognized that such companies, when properly operated, provide desperately needed employment opportunities to a large number of people who are unable or unwilling to establish their own businesses.

The main problems faced by these enterprises are prohibitive tax regimes; competition due to the opening up of national economies to cheaper imports (structural adjustment programmes; inadequate control by standards boards over the quality of imported raw materials and packaging; and inadequate information about markets and consumer requirements in both national and export markets). Slowly it is being recognized that assistance to this scale of enterprise can have significant effects on both national economies (through reduced imports and increased exports) and unemployment levels.

However, in most developing countries there is still little support for either cottage- or larger-scale producers. In some countries, trade associations - such as the Kenyan Federation of Employers, the All India Food Preservers Association, and the Uganda Manufacturers Association - are leading the way as a voice for manufacturers, pressuring governments to improve legislation or tax regimes, and as a coordinating body to improve product standards and provide a service to members. Such organizations can do much more both to directly support smaller food processing industries, which then may grow into larger companies, and to influence the international development community that previous conceptions of 'all business is bad,' are no longer appropriate

Introducing the Asia pages

Food Chain has been published regularly for five years and we now think it is time to make stronger links with IT Sri Lanka and IT Bangladesh. They will be sending a regular feature of articles, news and items from Asia. They already have regular contact with people in Sri Lanka through a newsletter and radio programme about Madam Tasty. Through their communication unit they inform of recipes and methods, old and new, which may interest and benefit to others. They now wish to widen their network and reach more people. We are very pleased to bring you News from Asia.

Jak fruit - one of nature's gifts

Nature's gifts are wonderful and strange. The jak tree (Artocapus heterophyllus) is one such wonder. We Sri Lankans call it bath gasa (rice tree), because jak fruit could easily replace our staple food, rice. The fruit itself is a package carrying a variety of food - jak bulbs, sepals, seeds etc. Sri Lankan women's experiments carried from generation to generation proved that jak fruit is consumable at four different stages.


Sinhalese call it polos, Tamils, palamusu. Using the whole fruit, with the outer shell removed, our women prepare a curry which tastes like meat curry; the boiled fruit is mashed and used to make cutlets, replacing potatoes.


The next stage is very popular in busy urban societies. In all the markets, jak vendors are a common sight during the season. They remove the thick outer shell of the fruit which is a bit more mature than the tender jak, and cut the fruit in a masterly style, charging ten rupees a portion. The unit of measure is usually a condensed milk tin. The finely chopped jak is used for preparing a side dish (a kind of salad) to go with curries


Sinhalese call it kos; Tamils, palakkai. This is the mature stage preferred by women for preservation. During the season, Sri Lankans eat the boiled jak bulbs and seeds with scraped coconut (the white flesh or 'meat' of the coconut) and curry which is a very heavy meal; jak bulbs are also cooked with spices and served as a curry To preserve for use when out of season, Sri Lankan women Blanche and sun dry the bulbs. Seeds, as well as sepals, are sun-dried and stored.


Ripe jak is sweet fruit. People eat ripe jak bulbs as a dessert, with a pinch of salt and pepper. There is a belief that eating ripe jak without salt and pepper may cause stomach troubles. You are advised not to drink water soon after eating ripe jak.

Ripe jak is what nature offered us. Our great-grandmothers experimented with the fruit at different stages... in their tiny kitchens Was it because they had enough time to spare to experiment with food recipes or was it because they wanted to find answers to problems such as food scarcities and managing available resources more effectively ?

Food preservation methods evolved from those tiny 'laboratories' furnished with basic equipment. They were passed from generation to generation, with new methods adding on. But the findings were not recorded. No one recognized these inventions until, recently, some researchers looking for more information, and a team of communicators took the challenge of sharing women's knowledge. The exercise resulted in both women and men writing about the kitchen-based experiments carried out by women to address the basic needs, without which we cannot survive


Chanachur is also known as Bombay Mix or Cocktail Mixture and is a spicy combinations of four different mixtures. First you should prepare the 4 mixtures separately.

Mixture No. 1

Wheat flour 150g Dhal flour 300g Water 225g Salt 10g Oil to fry and a perforated steel sheet

Mix the wheat flour and dhal flour well. Add salt and water to make a dough. Add a little oil to soften the dough. Heat oil in a deep pan, and when the oil is ready, press the flour dough through the perforated sheet into to the hot oil. Deep fry until it goes golden.

Mixture No.2

Peanuts 100g
Oil to fry
Remove the shells of the peanuts and deep fry them.

Mixture No.3

Pigeon pea 100g
Oil to fry
Clean the pigeon peas and let them soak for about 3 to 4 hours. Drain the water and deep fry in the hot oil

Mixture No.4

Chick pea 100g
Oil to fry
Clean the chick peas and let them soak for about 3 to 4 hours Drain the water and deep fry in the hot oil.

To prepare the main mixture

Chanachur - first mix all the four mixtures together. Add spices and chilli powder and salt to taste. If you want to keep it for a certain period add two or three drops of citric acid and seal in a polypropylene packets.


You need a large clay pot, jak seeds (well formed and undamaged), and dry sand.

The clay pot should be well dried. Clean and dry the seeds allowing no moisture on the outer sheath. Spread a thick layer of dry sand in the bottom of the pot. Spread a layer of jak seeds (2 inches thick) over it. Over the layer of seeds put another layer of sand. Continue to spread sand and seed layers alternately, until the pot is completely filled The uppermost layer of sand should be at least 2 inches thick. When the process is completed, keep the clay pot near the hearth; away from water and moisture Jak seeds preserved this way can be kept for more than a year.

A course with a difference

Muy Ly from Cambodia writes about her experience during - and after - a six-week training course in Sri Lanka.

I am very privileged and proud to have participated in the Food Processing as a Small Business course held at the Intemational Centre for the Training of Rural Leaders in Embilipitiya, Sri Lanka I thought it was just another course on food technology, but found it was not. Sincerely, I have to admit that we learnt more than we expected during our stay of six weeks.

Back in Cambodia, I tried my best to share the knowledge and experiences I gathered from different cultures during the training. I found the usefulness of doing needs assessments, market feasibilities etc. before starting any kind of business. Food enterprises cannot survive if the entrepreneurial requirements are not fulfilled. Motivated by the training course, I redesigned the training programmes here, including both food technology and business development components.


Introduction to food processing; why process foods; hygiene and sanitation; principles of processing and preservation; practical sessions - nine marketable food products; evaluation of the training

I also added two new products - jujubes and chanachur - to my practical sessions, and I am thinking of expanding and diversifying future training programmes.


How to run a small business successfully; needs assessment; conducting market feasibility studies; preparing business plans; keeping accounts etc.

Usually, small business management training is conducted by small enterprise promotion officers (SEPOs) of the Association of the Cambodia Local Economic Development Agency (ACCEDA). They also do a follow-up and provide counselling for their trainees.

So far, with support from an Indian food processing specialist, I have been able to train more than 50 people starting or expanding food processing enterprises. Based on the knowledge I gathered, we also conducted training of trainers courses for extension officers, helping them to be better counsellors to small-scale food processors.

I am thinking of expanding and diversifying my food processing training programmes, after conducting feasibility studies, by adding more products that I learnt about at ICTRL.

About aflatoxin

With the recent attention given to the incidence of food poisoning organisms such as salmonella and listeria in the UK food industry, what of the problems of food poisoning in the context of developing countries? One of the chief areas of concern in this regard is the problem of aflatoxin poisoning, particularly as it can occur in a wide range of unprocessed food crops such as cereals and legumes, which constitute the staple diet of the rural poor in many developing countries. Aflatoxins are compounds highly toxic to both animals and man, and are known to cause severe liver damage and carcinomas Due to their chemical nature, aflatoxins are not destroyed by heating, boiling, or other simple means, and therefore, once present in a food crops, can be carried intact through subsequent processing and cooking stages.

The danger of aflatoxins was first noted in the 1960s following the death of 100,000 young turkeys in the UK after having been given feed containing imported peanut meal. The deaths were subsequently found to be due to a toxin produced by the moulds Aspergillus flavus and Aspergillus parasiticus. The toxic compounds produced by these moulds in peanut meal have subsequently been identified in a wide range of products including wheat, maize, millet, rice, cottonseed, sweet potato, cassava, coconut, soybean and sunflower. Subsequent stringent import regulations, including regular aflatoxin testing at ports of entry, has minimized the incidence of aflatoxin in these crops in the developed world. However, the people most at risk from aflatoxins are those who live in the developing world, and whose diet is heavily dependent on those crops most likely to carry the toxins. It should be pointed out however, that unlike the majority of food poisoning cases, aflatoxicosis occurs as a result of prolonged exposure to aflatoxic food rather than as a result of eating a single contaminated meal.

While techniques to remove aflatoxins are known and are under development, the processes involved are frequently too complex and costly to undertake in the context of a developing country; and in any case the resulting aflatoxin-free product is only suitable for animal consumption. Research has shown that the growth of Aspergillus moulds and subsequent formation of aflatoxin in food crops occurs primarily after harvesting during drying and storage, and that the most important factors affecting aflatoxin formation are moisture and temperature.

Moulds require moisture to grow, and products with moisture levels above 16 per cent are capable of supporting the growth of A. flavus. The optimum temperature for the formation of aflatoxin producing moulds is about 24-28°C Therefore aflatoxin poisoning can most effectively be controlled by taking measures to control the growth of aspergillus moulds; by ensuring the food crops are properly dried to below a moisture content of 16 per cent and through the introduction of adequate and improved storage techniques to prevent moisture pick up. Detection of aflatoxin can be problematic. In a consignment of peanuts for example only a relatively few kernels may contain toxin, and substantial differences in toxin levels can occur in individual kernels from the same toxic consignment. Care in sampling procedures and in taking a sufficiently large sample are therefore essential for an accurate determination of aflatoxin to be made.

The production of relatively inexpensive test kits based on imuno-assay techniques has enabled an easier detection of aflatoxin, particularly under field conditions However, the costs per individual test are too high to allow for frequent and routine monitoring of aflatoxin incidence, and therefore it is likely that agricultural marketing boards or corporations in developing countries, who act as bulk purchasers will continue to accept or reject food crops based simply on their moisture content. While crops whose moisture content is above specification (e.g. 9.5 per cent for groundouts), are rejected on the grounds that they are likely to contain aflatoxic material, in reality infected crops can be expected to be found in local markets, and it is to be hoped that the consumers, natural rejection of produce that is obviously shrivelled or mouldy will minimize the incidence of aflatoxin.

Book Lines


Peter Robbins. ISBN 0 7494-1627 0. Kogan Page Ltd. 120 Pentonville Road, London N1 9JN, UK. A hardback edition of the book is for sale priced at £40, with a soft cover version at £20 available only to overseas readers, it is an unusual book which concentrates on the markets for some 200 tropical agro-commodities. The first part examines markets and issues such as: pricing, fair trade, trends, and trading in futures. The book then briefly examines the commodities (fruits, vegetables, spices, oils, essential oils, etc.), in alphabetical order. Each commodity is described, and in most cases the quantity traded and price is given. The book finishes with a list of useful contacts, e publication of this book is an attempt by TWIN to disseminate, in a single volume, information which is often inaccessible or unpublished. It should prove extremely helpful to those seeking trade outlets for a wide range of commodities, and to agencies planning agro-based programmes.

Any other queries regarding this book may be directed to TWIN Ltd., 5-11 Worship Street, London EC2A 2BH, UK

TWIN is a trade development organization based in London. It helps organizations of producers in developing countries strengthen their capacity to export their commodities. TWIN does this by working directly with producer organizations, offering advice and training and providing timely and practical information. Assistance includes the development of management administration and marketing skills, and providing advice on planning, market research and trade development. TWIN's programmes involve the transfer of technology and know-how to the South and the familiarization of producers with Northern trading and business practice.

Memina Sanongo, GRET, Rue La Fayette 75010, Paris

The average mother in every country naturally wishes to provide the best nutrition for her child. In developing countries most are faced with two choices; use traditional methods in which the child essentially receives the same as an adult (which usually tends to be low in protein and high in starch) or purchase very expensive imported weaning foods.

This small book explains that small-scale weaning food manufacture is possible using simple, cheap equipment. The products, if formulated with expert advice, are of good nutritional quality, safe and, above all, affordable.

Case studies from Burkino Faso, Congo, Togo, Burundi and Benin are included together with a useful bibliography and contacts list One concern is with the availability of equipment illustrated and how isolated field workers could obtain detailed drawings to allow local fabrication.

A very useful, practical book that with excellent illustrations and simple language. It could warrant translation into English for wider dissemination.

Open-pan sulphitation sugar processing

Open-pan sulphitation (OPS) is a smallscale sugar processing technology developed in India in the 1950s for the production of whim crystal sugar. The technology is ideally suited to processing between 100 and 500 tonnes of sugar cane per day yielding 50 to 80kg of sugar per tonne of cane.

Unlike large-scale sugar factories (processing over 1000 tonnes of cane per day) OPS plants do not usually have their own estates to supply cane but rely instead on contractual agreements with local growers. This level of technology can be beneficial to rural communities by creating employment opportunities at the factory, and providing income for cane growers in the area.

Since the introduction of the technology, large numbers of OPS sugar plants have been built throughout India, with estimates of several thousand still in use by the late 1980s. Dissemination of the technology outside India has been limited to one successful OPS sugar factory in western Kenya. However, the potential for OPS is considerable in countries that pro duce non-crystalline sugars (jaggery, gur, panela, muscovado etc) as they already have some of the necessary expertise.


The technology is based on an upgrade of khandsari production (a non-crystalline powdery sugar) in India, using a mix of traditional and scaled-down versions of modern sugar technologies. The production process can be divided into six stages:

Extraction of juice from the cane
Clarification of the juice
Boiling of the juice
Drying and packaging


Juice is extracted from the cane by a crushing unit, consisting of two or three power roller mills of three rolls each. These crushers are similar to those found in large-scale factories. Improved extraction can be achieved by hydraulically loading the pressure roller and by slicing the cane along its length before crushing.


Chemical clarification, based on modern cold lima, sulphitation, is carried out to remove impurities which inhibit the formation a' the crystals and can discolour the final product. Lime also reduces the natural acidity of the cane juice.

Batches of juice are treated simultaneously with line (as a milky solution) and sulphur dioxide (by air forced through a sulphur furnace), after which the juice is transferred to an open boiling pan and quickly heated to 90°C or above. The lime and heat treatment form a heavy precipitant that flocculates, carrying with it most of the suspended impurities in the juice. The juice is then filtered and allowed to settle, the clear juice is decanted and transferred to the boiling furnaces.


The boiling operation is required to evaporate water and reduce the juice to a concentrated form usually called massecuit. The equipment used is based on traditional Indian technology for the production of khandsari and jaggery. A series of four or five open pans, each boiling a successive concentration of juice at progressively higher temperatures, is located above a furnace (see figure opposite). The massecuit is removed from the final boiling pan at about 84° Brix at a temperature of around 112°C. The term 'degrees Brix' (or more usually °Brix) is the sugar technologists measure of the concentration of dissolved solids in solution.

The heat required for boiling is provided by bagasse (the cane fibre remaining after juice extraction) and, depending on the design of furnace, is often supplemented by other fuels. The hot flue gases pass directly under the pans, heating the juice, before being exhausted to the atmosphere.

The transfer of juice from one pan to the next is controlled by valves through overflow pipes, or the juice can be ladled manually. The massecuit from the final pan is usually too viscous to flow easily so it is ladled into buckets and transferred to the crystallizers.


The massecuit is placed in U-shaped vessels where it is slowly rotated and allowed to cool for up to 48 hours. This technique is often referred to as crystallization in motion. Rotation promotes even cooling of the massecuit which helps to achieve uniform crystal growth. Seeding can also he carried out: that is, granulated massecuit from a crystallizer in which grains have already been developed are placed into the crystallizer before it is filled with fresh massecuit. This helps to promote uniform crystal growth

The massecuit, now consisting of crystals suspended in molasses, is transferred to the centrifuge.


The centrifuge, a scaled-down version of those used in large-scale factories, consists of a perforated inner drum located inside a larger drum. The perforated drum is rotated rapidly, forcing the molasses to separate from the crystals. Water is sprayed into the spinning drum to assist in the removal of the molasses.

The crystals of sugar are then removed from the centrifuge and transferred for drying. The molasses is collected and can be reboiled, crystallized and re-centrifuged to produce a second, lower quality, crystal sugar known as number two or B-sugar.


The crystals can be dried in a number of ways: by placing them in the sun, by using simple solar driers, or by using rotary or hopper driers which require fuel to provide drying heal. The dried product can then be packed into suitable containers or bags for distribution.



Although OPS is a low-cost option compared to large-scale production plants, it still requires substantial investment. A feasibility study, undertaken by ITDG in the late 1980s, for a 100 tonnes of cane per day (tpd) OPS factory in Kenya, estimated that it would cost US$0.5 million for the complete factory including buildings, tractors and imported sugar-processing equipment. The cost of a small 100tpd conventional vacuum pan plant is approximately $US3-5 million


Using forced draught shell furnaces it is possible to obtain a fuel balance for the (first sugar) boiling operation using only the bagasse. Therefore, operating the crushers crystallizers, centrifuge and other powered equipment will require an additional energy source (electricity, diesel etc.) all of which increase costs.


Cane supply

To ensure that enough cane is produced it is necessary for the OPS factory to enter into contracts with cane growers which will guarantee the supply of cane to the factory and income for the growers. Therefore the success of an OPS plant is more closely related to the design and administration of this contract than any other single factor. To transport the cane to the factory it is usual for the factory to supply the tractors and trailers and the farmer the labour.

Operation and management

Sugar production even at the small scale is a complex business so skilled people will be required to manage and supervise the production from the collection of cane to the delivery of the sugar to the market place. If these skills are not available locally then they will have to be brought in to set up the business and to train staff which will increase the cost of the project.


Kaplinsky R., et al, Cane Sugar - The small-scale processing option, IT Publications, London, 1989.

Kaplinsky R., Sugar Processtng - The development of a third-world technology, IT Publications, London, 1985

Garg, M.K., 'A case study on the development and extension of improved khandsari technology on open-pan sulphitation process', All India Improved Khandsari Sugar Manufacturers Association, India, uncrated.

Wadian - A fermented Indian food

This article, written by G.K. Sharma, A.D. Semwal, S.S. Arya tells of their research on wadian - a traditional food in many areas of the world.

Wadian, a traditional savoury food is usually made from legumes such as blackgram lentils (Phaseolus mungo), bengal-gram lentils (Cicer arietinum), and green-gram lentil (Paseolus aureus). In addition to legume-based wadian, other types are made from arrowroot starch (Phul Wadian) and wheat flour. They may be eaten either deep fat fried or unfried.

Legume-based wadians are more popular in northern India, while starch-based types are more popular in south India They are prepared from a thick, spiced batter which is formed into balls of varying sizes (15-40g) and then dried. After drying, the wadian may be fried and eaten as a savoury snack, or may be added to other Indian dishes of rice, vegetables arid pulses. When making wadian, the raw material is soaked and then wet milled, after which salt and spices are beaten in to form a soft dough. This is made into small balls and sun dried. The recipe varies from region to region but typically consists of 1kg legume flour paste (45 parts legume &l, 55 parts water), 5-10g dried fenugreek leaves, 3-5g coriander powder, 1 - 3g cumin seed powder, 1 - 3g chili powder, 1 - 2g black pepper, 0.5 - 1g asafoetida, 2-3g ginger and 5-8g salt. The paste and spices powder must be whisked thoroughly to incorporate air into the batter which, after sun drying has a porous texture and shiny appearance After drying the final moisture content is 9-12 per cent. The approximate composition is shown in Table 1.

During production, the batter is left to stand, which results in fermentation. This enhances both the digestibility and keeping quality of wadian. The fermentation also results in a significant increase in water-soluble B-vitamins including thiamin (B1), riboflavin (B2) and cyanocobalamine (B12), (though drying then reduces these). Proteinase activity increases significantly, as does the level of citric acid which rises to about 1.7 per cent in the final product and helps to extend the shelf life. As can be seen, legume wadian is very good source of protein.

Fermentation is carried out by natural microflora in the raw materials and the local environment. The particular microorganisms associated with fermentation vary during the seasons; with summer more favourable for bacteria (i.e. Leuconostoc mesenteroides, Lactobacillius fermentum) and winter being more favourable for yeasts (i.e. Saccharomyces cerevisiae) which give a more raised or leavened product. (Soni & Sandhu, 1990).

Legume-based, wadians take rather long time to cook (20-25 minutes) which is a disadvantage. The shelf life is 6-10 months depending upon the packaging used.

A standard recipe and process has been developed for making instant spiced vegetable wadian based on pre-gelatinized legume flour, cooked vegetables and spices This product, made from bengalgram flour, cooked carrots, bottlegourd, potatoes, spices and salts, will reconstitute in three minutes when boiled.


Mix legume flour (200g) with water (800ml) and vegetable oil (20g) and cook for ten minutes to obtain a smooth paste. The cooked legume paste is then mixed with grated cooked carrot (600g), bottlegourd (600g) mashed potatoes (600g), salt (10g), garlic powder (2g), chilly powder (5g), turmeric powder (2g) and ginger powder (2g). (A variation of this recipe includes an unspiced variety). The ingredients should be mixed thoroughly and the fluffy dough made into 15-20g balls which should be dried at 60°C for 2 hours and subsequently at 80°C for 6 hours in an air drying cabinet to give a final moisture content below 5 per cent. (Sharma et al, unpublished).

Table 1 Composition of wadian (%)

Blackgram Greengram





















Instant vegetable wadian (unspiced) contains 14.4 per cent protein, 6.65 per cent fat, 4.72 per cent total ash, 0.54 per cent acid insoluble ash and 3.42 per cent moisture; while spiced vegetable wadi (blended with spices and deep fried) contains 10.73 per cent protein, 23.94 per cent fat, 5.85 per cent total ash, and 3.24 per cent moisture. It has a shelf life of up to 12 months at ambient temperatures, depending on the packaging used.

We believe the product will find a market among the increasing range of convenience foods and it is also of interest in the high remote areas of India which are snowbound and without fresh vegetables for part of the year.

News Lines


13-17 november 1996, Rome, Italy

For the majority of the world's poor, lack of food security remains their most serious constraint and leads to a level of suffering and lost potential that no family or nation can afford to tolerate. The World Food Summit being organized by the Food and Agriculture Organization (FAO) from 13-17 November 1996 in Rome, will provide a forum to assess progress since the World Food Conference in 1974 and to consider future action.

The aim is to raise public awareness and to promote political commitment at the highest level for a global campaign to eradicate hunger and under-nutrition and provide food security for all. A recurring message will be that food insecurity is not just a problem for developing countries but threatens the peace and stability of the world as a whole. There is still a long way to go to complete the mission set forth in FAO's constitution of 'ensuring humanity's freedom from hunger'. Malnutrition and food surpluses, poverty and affluence still coexist. Famines are still not a thing of the past. The World Food Summit will not call for the creation of new structures or financing mechanisms. Heads of state and government will consider and adopt a policy document on food security and a plan for its implementation. Participating countries and their leaders will seek ways of fulfilling their commitment to their respective possibilities

A series of technical background papers is being presented on topics such as global developments since the World Food Conference; the critical role of water in food production and food security; investment in agriculture; lessons from the green revolution; marketing, processing, and distribution; problems of food security and ethics, and the overall socio-political and economic environment for food security, at national, regional and global levels.

A World Food Summit secretariat at FAO headquarters is co-ordinating organization of the meeting and preparations for it Comments and contributions are being actively sought from governmental and non-governmental organizations and others with a demonstrated interest in food security issues.

For information on the World Food Summit please contact either: Ms Kay Killingsworth, Secretary-General World Food Summit Secretariat, FAO, Viale delle Terme di Caracalla 00100 Rome, Italy, Tel: +39 6 52252932 Fax: +39 6 52255249, Email:, or B Riordan, 19 Sandymount Avenue, Dublin 4, Tel: +353 1 4668 8188

Research notes



Turmeric (Curcuma. sp) is common in many tropical countries and is used as both a spice and colourant. The colour of turmeric is due to its content of pigments known as curcumins, and its spicy flavour to its essential oil. In order to make an acceptable food colourant from turmeric the flavour components have to be removed.

Workers at the University of Matunga in India have been examining ways to prepare natural food colourings extracted from turmeric as a replacement for the yellow synthetic food colour tartrazine, which it is claimed can cause hyperactivity in children.

The methods used require considerable technical knowledge but initial economic calculations indicate that turmeric colouring would be considerably cheaper than tartrazine in India.

The production involves the extraction of turmeric powder by alcohol followed by removal of the solvent under vacuum. This results in turmeric oleo-resin (a mixture of colour and essential oils). The oleo-resin next has to be de-flavoured, this being carried out by extraction with petroleum ether. The ether dissolves the flavouring essential oils but not the colour. The next step is to add water to the remaining alcoholic extract at which point the curcumin precipitates. This is then sprayed onto a carrier such as sugar or starch. The carrier is then dried to provide a flavourless yellow food colour that finds use in a wide range of manufactured foods.

While this process requires considerable technical skill and knowledge, as it involves highly flammable solvents, the capital costs of equipment are reasonable It may offer opportunities for considerable local value addition to turmeric and provide an alternative to imported yellow colours.

From time to time we receive papers from researches and others about their work. In general, these are not suitable for direct publication in Food Chain as they are too long, too long, too technical and not directly applicable to our typical reader. Many, however, are interesting and the editors have decided to publish summaries of research papers so that interested readers can make direct contact with the authors.


Many foods are packed in pouches using form, fill, seal machines (FFSM). In these packaging machines, a sheet of plastic film is drawn into a cylinder around a filling tube, at the same time a vertical heat sealer head seals the sheet into a cylindrical shape. The cylinder of film is then pulled downwards and, after the required pouch length is reached, an impulse heat sealer makes a seal across the film to make the base of the bag, after which the bag is filled with food. A second seal is then made above the food to make the top seal of the bag, simultaneously forming the bottom seal of the next bag. This is followed by a cutting operation to separate the bags. Fillers of this type are suitable for both solid and liquid foods.

Commercial FFSMs are complex and expensive. As far as we know no low cost, simple FFSMs are commercially available (if any Food Chain readers know of one please write to the editor). There could be considerable demand for an affordable, low-speed, simple (electromechanical rather than electronic or computer controlled) FFSM.

Workers from the North Eastern Regional Institute of Science and Technology in India have developed a prototype machine that seems very simple. Detailed drawings may be available from the authors, and a competent engineer should have little trouble in building a prototype It is claimed that the machine can pro duce 140 half litre packs of milk per hour. The authors also claim that aseptic filling is possible using hydrogen peroxide to sterilize the film prior to filing.

The Pearson square - common calculations simplified

Many small-scale food manufacturers find difficulty with the calculations involved in mixing two raw materials together to give a final product of known composition (fat content, alcohol content, sugar content etc). The use of the Pearson square makes this type of calculation very simple. The Pearson square was developed many years ago and found particular application in the dairy industry for standardizing milk and blending milks to give a final product with a standard fat content.

Before looking at some examples of the use of this tool it is very important to understand that it can only be used in a two component system for example blending two wines (to give a known alcohol level), or two milks (to give a standard fat content). If more than two components such as protein level and fat level are involved, then more complex 'mass balance' calculations are required.


Producing a 10 par cent butter fat cream

In this example homogenized milk with a fat content of 3.5 per cent is to be mixed with a 20 per cent fat cream to give a light cream containing 10 per cent. In what proportions should they be mixed?

First draw a rectangle and label the two horizontal lines with the names of the two products used as shown here.


Now enter the composition of each ingredient as shown below putting the required final product fat content in the centre of the box.


Mix the two components by crossing diagonally through the centre figure; subtracting each from the larger figure. The square now appears as shown here.


Read the results; these show that we need 10 parts milk (shown by the top line) to be mixed with 6.5 pans of cream (bottom line).


In this example pure orange juice with a sugar content of 10 per cent is to be mixed with a 60 per cent sugar syrup to give a final sweetened juice containing 15 per cent sugar. Drawing the square as described above it should look like this.


Subtracting diagonally shows that 45 parts (litres) of orange juice needs to be mixed with 5 parts (litres) of sugar syrup to produce a final 15 per cent sugar sweetened juice.


In this example fruit pulp containing 10 per cent natural sugar is to be mixed with pure cane sugar to give a jam containing 70 per cent sugar.

Draw the square as before, enter the numbers and subtract diagonally.

The square should look like this.


This indicates that 30 mixed with 60 parts (kg) a 70 per cent sugar jam. pasts (kg) of fruit of sugar will, give.



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Food Chain is funded by the UK Overseas Development Administration and the States of Jersey, and is edited and produced by members of Intermediate Technology's Agro-Processing Project. Typeset by My World and printed by Neil Terry Printing on environmentally friendly paper.

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