2.7.1 Black Mustard
Synonym Brown Mustard.
Biological Sources These
are dried ripe seeds of Brassica nigra Linn., Koch or Brassica juncea
Linn, Czern & Coss, belonging to family Cruciferae.
Geographical Sources B.
nigra is extensively cultivated in various parts of Europe and United States.
B. juncea is widely grown in different parts of India and the CIS-countries
(i.e., Russia).
Preparation The thioglycoside
sinigrin is obtained from the defatted black- mustard seed by employing
standard methods. It is usually present in the seeds to the extent of 4%.
Black mustard seeds are
powdered and defatted with petroleum ether. The defatted meal is boiled with
ethanol to destroy the enzyme. The resulting marc is squeezed while hot, dried
at 100°C
and maceraed in cold water for
3-4 hours with constant stirring, since sinigrin is fairly soluble in cold
water. The liquid content is decanted and maceration is repeated a number of
times to ensure complete extraction of the thioglycoside. The combined
aqueous extract is collected and treated with mild alkalies, such as : BaCO3,
so as to neutralize any free acidity. The liquid is now concentrated under
vaccum to a syrupy consistency. The resulting syrup is boiled with ethanol (95%
w/v) for about 2-3 hours to allow sinigrin to dissolve and at the same time to
precipitate the mucilageous components. The alcholoic extracts are filtered and
allowed to cool slowly when sinigrin crystallizes out (approximately
4%).
Description
Colour : Black, dark
brown or reddish brown
Odour : Whole seed-none;
Crushed seed-pungent characteristic odour.
Taste : Bitter
Size : Approx. 0.9-1.0
mm in diameter
Shape : Mostly spherical
in shape
Special Features Seeds
are normally covered with a brittle testa and the kernel is oily and greenish yellow
in colour. The approx. weight of 100 seeds ranges between 150 to 170 mg.
Chemical Constituents The
black mustard seed contains a thioglycoside i.e., a β-glucopyranoside
termed as sinigrin. It is also known as myronate potassium or allyl
glucosinolate as shown under:
Source: Pharmacognosy And Pharmacobiotechnology By Ashutosh Kar
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