_Sesamé Oil_, _Gingeli_, _Gingili_ or _Jinjili Oil_, _Til_ or _Teel
Oil_, _Benné Oil_; F. _Huile de Sésame_; G. _Sesamöl_.
=Botanical Origin=—_Sesamum indicum_ DC., an erect, pubescent annual
herb, 2 to 4 feet high,[1729] indigenous to India, but propagated by
cultivation throughout the warmer regions of the globe, and not now
found anywhere in the wild state. In Europe, _Sesamum_ is only grown in
some districts of Turkey and Greece, and on a small scale in Sicily and
in the islands of Malta and Gozo. It does not succeed well even in the
South of France.
[1728] Paolino da San Bartolomeo, _Voyage to the East Indies_
(1776-1789), translated from the German, Lond. 1800; pp. 14. 409.
[1729] Fig. in Bentley and Trimen’s _Med. Plants_, part 23 (1877).
=History=—Sesamé is a plant which we find on the authority of the most
ancient documents of Egyptian, Hebrew,[1730] Sanskrit, Greek, and Roman
literature, has been used by mankind for the sake of its oily seeds
from the earliest times. The Egyptian name _Semsemt_ already occurring
in the Papyrus Ebers, is still existing in the Coptic _Semsem_, the
Arabic _Simsim_, and the modern _Sesamum_. The Indian languages have
their own terms for it, the Hindustani _Til_, from the Sanskrit _Tila_,
being one of the best known.[1731] _Tila_ already occurs in the Vedic
literature. In the days of Pliny the oil was an export from Sind to
Europe by way of the Red Sea, precisely as the seeds are at the present
day.
During the middle ages the plant, then known as _Suseman_ or _Sempsen_,
was cultivated in Cyprus, Egypt and Sicily; the oil was an article of
import from Alexandria to Venice. Joachim Camerarius gave a good figure
of the plant in his “Hortus medicus et philosophicus” 1588 (tab. 44).
In modern times sesame oil gave way to that of olives, yet at present
it is an article which, if not so renowned, is at least of far greater
consumption.
=Production=—The plant comes to perfection within 3 or 4 months; its
capsule contains numerous flat seeds, which are about ²/₁₀10 of an
inch long by ¹/₂₀ thick, and weigh on an average ¹/₁₆ of a grain. To
collect them, the plant when mature is cut down, and stacked in heaps
for a few days, after which it is exposed to the sun during the day,
but collected again into heaps at night. By this process the capsules
gradually ripen and burst, and the seeds fall out.[1732]
The plant is found in several varieties affording respectively white,
yellowish, reddish, brown or black seeds. The dark seeds may be
deprived of a part of their colouring matter by washing, which is
sometimes done with a view to obtain a paler oil.[1733]
We obtained from yellowish seeds 56 per cent. of oil; on a large scale,
the yield varies with the variety of seed employed and the process of
pressing, from 45 to 50 per cent.
=Description=—The best kinds of sesamé oil have a mild agreeable taste,
a light yellowish colour, and scarcely any odour; but in these respects
the oil is liable to vary with the circumstances already mentioned. The
white seeds produced in Sind are reputed to yield the finest oil.
We prepared some oil by means of ether, and found it to have a sp. gr.
of 0·919 at 23° C.; it solidified at 5° C., becoming rather turbid at
some degrees above this temperature. Yet sesame oil is more fluid at
ordinary temperatures than ground-nut oil, and is less prone to change
by the influence of the air. It is in fact, when of fine quality, one
of the less alterable oils.
[1730] Isaiah xxviii. 27.
[1731] The word _Gingeli_ (or _Gergelim_), which Roxburgh remarks was
(as it is now) in common use among Europeans, derives from the Arabic
_chulchulân_, denoting sesame seed in its husks before being reaped
(Dr. Rice). The word _Benné_ is, we believe, of West African origin,
and has no connection with _Ben_, the name of _Moringa_.
[1732] For further particulars see Buchanan, _Journey from Madras
through Mysore, etc._ i. (1807) 95. and ii. 224.
[1733] This curious process is described in the _Reports of Juries_,
_Madras Exhibition_, 1856, p. 31.—That the colouring matter of
the seeds is actually soluble in water is confirmed by Lépine of
Pondicherry as we have learnt from his manuscript notes presented to
the Musée des Produits des Colonies de France at Paris. The seeds may
even be used as a dye.
=Chemical Composition=—The oil is a mixture of olein, stearin and other
compounds of glycerin with acids of the fatty series. We prepared with
it in the usual way a lead plaster, and treated the latter with ether
in order to remove the oleate of lead. The solution was then decomposed
by sulphuretted hydrogen, evaporated and exposed to hyponitric vapours.
By this process we obtained 72·6 per cent. of _Elaïdic Acid_. The
specimen of sesamé oil prepared by ourselves consequently contained
76·0 per cent. of olein, inasmuch as it must be supposed to be present
in the form of triolein. In commercial oils the amount of olein is
certainly not constant.
As to the solid part of the oil, we succeeded in removing fatty acids,
freely melting, after repeated crystallizations, at 67° C., which may
consist of stearic acid mixed with one or more of the allied homologous
acids, as palmitic and myristic. By precipitating with acetate of
magnesium, as proposed by Heintz, we finally isolated acids melting at
52·5 to 53°, 62 to 63°, and 69·2° C., which correspond to myristic,
palmitic and stearic acids.
The small proportion of solid matter which separates from the oil on
congelation cannot be removed by pressure, for even at many degrees
below the freezing point it remains as a soft magma. In this respect
sesamé oil differs from that of olive.
Sesamé oil contains an extremely small quantity of a substance, perhaps
resinoid, which has not yet been isolated. It may be obtained in
solution by repeatedly shaking 5 volumes of the oil with one of glacial
acetic acid. If a cold mixture of equal weights of sulphuric and
nitric acids is added in like volume, the acetic solution acquires a
greenish yellow hue. The same experiment being made with spirit of wine
substituted for acetic acid, the mixture assumes a blue colour, quickly
changing to greenish yellow. The oil itself being gently shaken with
sulphuric and nitric acids, takes a fine green hue, as shown in 1852 by
Behrens, who at the same time pointed out that no other oil exhibits
this reaction. It takes place even with the bleached and perfectly
colourless oil. Sesamé oil added to other oils, if to a larger extent
than 10 per cent., may be recognised by this test. The reaction ought
to be observed with small quantities, say 1 gramme of the oil and 1
gramme of the acid mixture, previously cooled.
=Commerce=—The commercial importance of Sesamé may be at once
illustrated by the fact that France imported in 1870, 83 millions; in
1871, 57½ millions; and 1872, 50 millions of kilogrammes (984,693 cwt.)
of the seed.[1734]
The quantity shipped from British India in the year 1871-72 was 565,854
cwt., of which France took no less than 495,414 cwt.[1735] The imports
of the seed into the United Kingdom in 1870 were to the value of only
about £13,000.
Sesamé is extensively produced in Corea and in the Chinese island of
Formosa, which in 1869 exported the exceptionally large quantity of
46,000 peculs[1736] (1 pecul = 133 lb.). Zanzibar and Mozambique also
furnish considerable quantities of sesamé, whilst on the West Coast of
Africa the staple oil-seed is Ground-nut (_Arachis hypogæa_ L. p. 186).
The chief place for the manufacture of sesamé oil is Marseilles.
[1734] _Documents Statistiques réunis par l’Administration des Douanes
sur le commerce de la France_, année 1872.
[1735] _Statement of the Trade and Navigation of British India with
Foreign Countries_, Calcutta, 1872. 62.
[1736] _Reports on Trade at the Treaty Ports in China for 1870_,
Shanghai, 1871. 81.
=Uses=—Good sesamé oil might be employed without disadvantage for all
the purposes for which olive oil is used.[1737] As its congealing point
is some degrees below that of olive oil, it is even more fitted for
cool climates. Sesamé seeds are largely consumed as food both in India
and Tropical Africa. The foliage of the plant abounds in mucilage, and
in the United States is sometimes used in the form of poultice.