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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
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View the documentOpen-pan sulphitation sugar processing
View the documentWadian - A fermented Indian food
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View the documentResearch notes
View the documentThe Pearson square - common calculations simplified
View the documentAcknowledgments

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.