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:
