A solution to the Clayton ring problem (continued)


Continuing my endeavours to find “a solution to the Clayton ring problem” (see Results of Winter 2005/2006 and of Winter 2006/07 expeditions) I recently approached the BioCem agrar GmbH laboratory, D-04827 Gerichshain, Germany, to investigate and possibly to carry out biological and chemical analysis on the samples derived from my “Clayton roasting processes” in Eastern Sudan. (see Results of Winter 2006/07, chapters 2.24 – 2.26) I was kindly informed by one of the company´s chemists, Hartmut Thomas, that although the amount of bitter or poisonous substances that may be present in the samples (mainly cucurbitacins which constitute a group of triterpenoid substances which are well-known  for their bitterness and toxicity) could be determined by high-pressure liquid chromatography-mass spectrometry, the process was however time-consuming and costly because colocynth seeds contain quite an amount of oil (17 – 19%). Moreover, there was no guarantee that the tests on the roasted samples would produce any useful results as there is no previous seed testing benchmark data to provide a basis for making comparisons between roasted and unroasted seeds and the testing data available in existing publications deals only with the substance analysis of the colocynth´s pulp, leaves and roots.


H. Thomas further explained that his research of the relevant literature raised doubts as to whether the natural seeds contain any amounts of cucurbitacins at all. However, contrary to this scepticism three references found in the scientific literature attest to the fact that the bitter substances either attached to or contained in natural colocynth seeds are removed by mere roasting thus converting the seeds into safely digestible food for desert nomads. Therefore, it would seem that costly tests to verify already known information also attested to by the routine practise of nomads (as conjectured for the distant past in my reports mentioned above) is not required. 


The literature research produced inter alia, the following:


1.) Freedman, R.: Famine foods, February 26, 1998, www.hort.purdue.edu/newcrop/faminefoods/ff­­_indices/ff_family_cd.html


“Citrullus Colocynthis (L) Schrad.(syn. Colocynthis vulgaris, Schrad) India (Rajasthan): the seeds of this plant are gathered , washed with salt water many times to remove the bitter principles (mostly contained in the attached pulp), or are buried with common salt in small dugouts in the sand, kept covered there for a few weeks, washed, dried, ground into flour and made into Sogra, a rather hard-baked bread… seeds eaten raw, fried and roasted.”


2.) Lloyd, J. U.: Citrullus Colocynthis. In: The Western Druggist (reprint), Chicago 1898, pp. 4,5,8,9,10. 


“Colocynth… is distinctly a desert plant… natural requirements being merely a sandy soil, warm climate and little moisture…. Bergius (Bergius, P.J.: Materia Medica. Stockholmiae 1778, vol II)... explicitly states that the pulp is the sole carrier of the bitterness, and that the traces found in the seed may be removed by washing in tepid water… Proof of the innocuousness of the seeds is established by the fact that they afford an important food material to African tribes of the desert.


In this connection we quote from Flueckiger´s report of an interesting account given of the mode of preparation of colocynth seeds as observed by the celebrated German Sahara traveller, Doctor Nachtigal, who visited the poor tribe of the Tibboo Resade in 1870. This is one of the tribes inhabiting the mountainous country of Tibesti in the central part of Sahara. They settle the upper valleys of the rivers where the land is somewhat fertile. Their sole food resources are milk of goats and a few miserable products from vegetable life, chief among which, strangely enough, are seeds of colocynth, called “aber”, which they collect on special nomadic expeditions. The scantiness of their resources compels these people to be very economical in searching out and preparing this strange food. After the bulk of the pulp is removed the seeds are enclosed in strong sacks and tramped upon in order to facilitate the removal of the last traces of the bitter pulp. The seeds remain whole and are cleaned by winnowing. They are then mixed with ashes from camel´s dung, placed upon a smooth stone and rubbed with a rounded stone, which has the effect of crushing the testa. The kernels are then sifted and are thus obtained rather pure. Other Tiboo tribes  (Duveyrier) attain the same end by roasting the seeds. Doctor Nachtigal further relates that the seeds are then boiled in water for a short time, the fresh leaves of the ethel bush(?) being added. The last trace of bitterness is afterwards removed by cold water. The seeds are then dried in the sun, powdered, and mixed with dried and powdered dates, and the food thus laboriously obtained, is said to be exceedingly palatable and nutritive. … Too high a tribute cannot be bestowed upon these half-civilized people whose necessities and instincts led to the preparation of such an exceedingly rational nourishing food by extricating it from its poisonous enclosure.”


Furthermore, conveying his horror to the reader when he learned that his cook tried to serve him boiled colocynth seeds as a side dish for dinner in Murzuq (Nachtigal, G.: Afrika und Sudan, vol. 1, Graz 1967(reprint), p. 106, 107) Nachtigal writes: Eine “... Verwechselung, die leicht drastische Folgen hätte haben können. Eine Schüssel mit kleinen ovalen, platten Kernen von gelblich grauer Farbe sollte mein Mahl verherrlichen, und wenn auch Guiseppe seine Verwunderung darüber aussprach, dass dieselben nicht gar hätten werden wollen, so setzte ich mich doch nieder mit dem festen Entschluss, diese erste Nachgiebigkeit des eigensinnigen Mannes durch einen lebhaften Appetit meinerseits zu belohnen. Entsetzt fuhr ich freilich zurück, als ich entdeckte, dass er mich mit Coloquintenkernen zu beglücken die Absicht gehabt hatte, und versuchte auch nicht wieder, seinen Sinn auf eine Vervielfältigung meiner Gemüsegenüsse zu lenken.“ Does Nachtigal´s fright point to the explorer´s firm expectation that, due to swallowing the boiled colocynth seeds he would be severely poisoned?


3.) Dane, F.; Liu, J.; Zhang, C.: Phylogeography of the bitter apple, Citrullus colocythis. Genetic Resources and Crop Evolution (2007) 54, pp. 327-336


“Citrullus colocynthis is a desert plant with a rich history as an important medical plant and as a source of valuable oil. Its small seeds appear in several early Egyptian, Libyan and Near Eastern sites from about 4000 BC… The seeds are edible and when ground provide a rough bread for the desert Bedouins… C. colocynthis is a drought tolerant species, which can survive arid environments by maintaining its water content without any wilting of the leaves or desiccation even under severe stress conditions.”


4.) Schafferman, D.; Beharav, A.; Shabelsky, E.; Yaniv, Z.: Evaluation of Citrullus clocynthis, a desert plant native in Israel, as a potential source of edible oil. Journal of Arid Environments (1998)40, pp. 431-439


“Citrulus colocynthis (wild gourd) is a desert plant of the Cucurbitaceae, naturally adapted to arid environments… (It) occurs … in sandy soils and in wadis.”


5.) www.aluka.org - a digital library of scholarly resources from and about Africa. Entry for Citrullus colocynthis (Linn.) Schrad. (family Cucurbitaceae)


“The plant is distributed across the Sahara… It favours drier conditions… The vegetative parts are browsed by donkeys and goats… and are said to be taken by wild game, but the fruit only by donkeys, gazelles and ostriches… A bitter black extract prepared from the rind is sometimes smeared on water-bags by the Arabs to keep camels, etc. away from them… Though the fruit is poisonous, the seeds are sometimes eaten. In the Hoggar area the Tebbou boil them for a whole day with a change of water. The seeds are then dried and eaten. The Tuareg of the same area steam the seeds to drive off a black oil after which the seeds can be eaten or dried for storage. In Sudan the seed is eaten as an emergency food.”


6.) Madaus, G.: Lehrbuch der biologischen Heilmittel, Abteilung 1: Heilpflanzen. Bd 1, Leipzig 1935.


„Die gerösteten oder gekochten (Koloquinten)Samen bilden ein Nahrungsmittel der eingeborenen Bevölkerung von Nordafrika. (Roasted or boiled colocynth seeds provide an aliment for the indigenous population of North Africa.) Ein merkwürdiger Gebrauch von dem aus den Früchten gewonnenen Teer ist bei den Berbern üblich. Die Frucht  wird in einem irdenen Gefäß, dessen Boden ein Loch hat, erhitzt, so dass der Teer in ein anderes Gefäß tropfen kann. Er wird zum Einschmieren der Wassersäcke verwendet... Die getrockneten Früchte der Koloquinte sind ein uraltes Abführmittel... Der vorwiegend wirksame Bestandteil ist der glykosidische Bitterstoff Colocynthin.... Nach Korbert enthalten die Samen weniger Colocynthin als das Fruchtfleisch.“




To be continued


Sehlis 1/29/2009