POSSIBILITY OF COLOURING VANASPATI WITH RATANJOT TO PREVENT
ITS USE AS AN ADULTERANT IN GHEE
By NOSHIR N. DASTUR, A. KANNAN AND ZAL R. KOTHAVALLA, Imperial Dairy Research Institute,
Bangalore
(Received for publication on 20 November 1946)
H YDROGENATED vegetable oils, or what are popularly known as vanaspati, are used now a
days in large quantities as cooking media. They provide a cheap substitute for ghee for this
purpose and for this reason are normally made to resemble ghee, as closely as possible, in appearance.
The two being visually very similar there is always the temptation to vendors to mix the cheaper
product (vanaspati) with ghee and to pass the mixture off as genuine ghee. The detection of the
admixture of these two is further made difficult by the fact that there is great variation in the chemi-
cal composition of ghee and it is not always possible to distinguish between genuine ghee and adultera-
ed products, even by routine chemical methods.
The ordinary purchaser must rely on his sight to distinguish between the two products and in
order to enable him to do this it has been strongly urged that all vanaspati manufactured in India
should be given such a distinct colour that it may not be mistaken for ghee even by a casual pur-
chaser. Deep yellow (turmeric) and orange colour (like the one given by annatto) are obviously
not suitable. Next to these two, red is the most agreeable colour. It was therefore, decided to
carry out trials to determine the most suitable variation in red to colour vanaspati and 'rose red'
or the tint commonly known as 'Gulabi' was finally decided upon. The selection of this tint no
doubt was rather arbitrary, considering the fact that the accepted colour of natural fats is yellow
but that made the selection of a tint other than yellow all the more necessary, as long as it was not
repulsive to the consumer and fulfilled all the requirements of a cooking medium; for, after all vanas-
pati is used for this purpose only.
The dye to be used for colouring edible products like vanaspati must fulfil certain essential re-
quirements such as, (a) it must be easily available, (b) it should be non-toxic in raw state or even
after heating to the frying temperature of vanaspati, (c) it should not in any way affect the quality
of vanaspati by lowering its keeping quality or imparting a foreign flavour to it and (d) the coloured
vanaspati must be stable to light and heat to a reasonable extent so that the colour may not be des-
troyed during storage. Preliminary examination of several natural and synthetic dyes showed that
the red dye obtained from the ratanjot roots, Onosma echides, fulfilled all the above conditions. Ratan-
jot plants grow in abundance in colder regions of India. The roots form the main source of the dye.
EXPERIMENTAL
Isolation of the Dye. The colouring principles of ratanjot are insoluble in water but freely soluble
in fats and common organic solvents. The dye was usually concentrated by extraction with ether.
Before extracting the roots with ether, they were steeped in ten parts of water for about 24 hours.
The roots were dried at room temperature and fibres and other impurities were removed. The loss
in weight during the steeping was of the order of 6 per cent. The percentage of impurities, including
fibres, etc., varied from 13 to 18 per cent. Thus on the whole the quantity of extractable roots was
about 80 per cent of the original roots taken. Steeping was also done in 5 per cent salt solution.
This however, did not give any better results. The concentration obtained was to the extent of
6 per cent calculated on the basis of the weight of cleaned roots. The constitution of the colouring
principles of the ratanjot roots has not been studied in detail but presumably it is closely
related to that of the alkanet roots, Anchusa tinctoria, lam. [Perkin and Everest, 1918.] Nargund
[1942] suggested the formula C 30 H 28 O 8 for the colouring matter. It melts at 220ºC., with previous
softening at about 190ºC.
Ratanjot roots are commonly sold in the bazar. The roots on storing do not seem to loose their
colour imparting property. The colour concentrate, extracted with ether, when stored at 37ºC.,
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