Colourants turmeric

It is a feeble acid, and reddens litmus slightly it colours turmeric brown, like alkali. With bases it forms salts called borates, which are for the most part insoluble. The alkaline borates alone are soluble. All the salts of this acid are very fusible, and promote the fusion of other bodies when mixed wili them. Hence, borax is much used as a blowpipe flux, which not only promotes fusibility, but at a red-heat dissolves siliceous compounds to a clear, fusible glass. 

Sowbhagya, H.B. et ah. Stability of water-soluble turmeric colourant in an extmded food product during storage, J. Food Eng., 67, 367, 2005. 

Chatteijee, S., Padwal-Desai, S.R., and Thomas, P., Effect of y-irradiation on the colour power of turmeric Curcuma longa L.) and red chillies Capsicum annuum) during storage. Food Res. Int., 31, 625, 1998. 

The main representatives of direct dyes are turmeric, annatto, saffron, and orchil. They are directly bound to fibres. Most of the colourants present in these dyestuffs can be easily extracted by water or alcohols. 

To purify the soap 20-30 g. are dissolved in boiling water, salted out from the hot solution, and again allowed to solidify. In this way the small amount of alkali in the crude product is removed. The soap, however, remains alkaline to litmus and turmeric papers. The hydrolysis of the quite pure soap is, however, not sufficiently extensive, the concentration of OH-ions not sufficiently large, for phenolphthalein to be coloured. 

The dried and polished fingers of turmeric contain 5 to 10% fatty oils, up to 5% volatile oil, and 5 to 10% of the colouring matter, curcumin. 

Colouring Matters.—In Italy butter may be coloured, but not with certain prohibited colouring matters, such as Martius yellow, Victoria yellow and metanil yellow. As a rule annatto is used, but sometimes also saffron or turmeric, and rarely carotin coal-tar colours (aniline yellow, butter yellow) are also employed. 

The coloured materials most frequently added are gamboge, dragon s blood, turmeric, indigo, and especially artificial organic colouring matters. For some varnishes mineral colours are used, such as ferric oxide, white lead, minium, lamp black, etc. 

The former are mostly derived from plants [vegetabty colours) and may be contained in woods (e.g., campeachy, Brazil wood, sandalwood, yellow wood, fustic), barks (quercitron), roots [madder, turmeric), leaves (indigo, woad), flowers [safflower), fruit (Persian berries) and lichens [archil). Far fewer are animal colours [cochineal, kermes). 

The 3-4 Cals, here represent the heat of admixture of a mol of ammonia with water, and this is much greater than the heat of admixture of ammonia with other liquids which do not react chemically with the ammonia. There is also a possibility that ammonia hydrates. NH3.nH20, are formed, vide infra and a possibility that the ammonium hydroxide is ionized NH OH NH +OH. In agreement with the assumption that ammonium hydroxide is formed which acts as a weak base, the liquid tastes alkaline it reddens turmeric colours the juice of violets green and colours litmus, etc., the same as do soln. of the alkali hydroxides. These changes of colour disappear on exposure to air owing to the volatilization of the ammonia— the volatile alkali of the early chemists. The feeble character of ammonium hydroxide as a base is evidenced by its heat of neutralization with acids which is about 1-5 Cals, less than is the case with potassium or sodium hydroxides like other weak bases, the soln. cannot be satisfactorily titrated with phenolphthalein S. Arrhenius found that its effect on the hydrolysis of ethyl acetate is about 40 times leBS than that of sodium hydroxide and the electrical conductivity of aq. soln. of... 

Saffron and turmeric were used to add taste and colour to food. Vegetable dyes were used to make colourful textiles. Red lead was used to add colour to perfume bottles made of clay. Tribal chiefs painted their faces to show their status and to frighten the enemy. 

Curcumin, or curcuminoids concentrate, for use as a food colour, is not a regular article of commerce because the cheaper turmeric oleoresin has been found suitable for most current uses. Curcumin is included in the list of colours with a restricted use because it has been allotted a low ADI (acceptable daily intake) of 0-1 mg/kg body weight/day. Curcumin gives a bright yellow colour even at doses of 5-200 ppm. A variety of blends are available to suit the colour of the product (Henry, 1998). 

Verghese, J. and Joy, M.T. (1 989) Isolation of the colouring matter from dried turmeric (Curcuma longa L.) with ethyl acetate. Flavour and Fragrance journal 4, 31-32. 

The colour pigment of turmeric is curcumin. Curcumin is relatively polar and almost unsoluble in C02 at extraction pressures below 400 bar. At pressures higher than 500 bar a yellow mixture of oil and cristalline curcumin can be obtained. The extraction yield varies between 5 and 12% depending on raw material. 

Dietary compounds are represented in a number of highly successful drugs such as lovastatin 31 and salicylic acid, the archetypal statin and non-steroid anti-inflammatory drugs, respectively. Lovastatin occurs in the red yeast of rice Monascus ruber),91 an ingredient of Eastern cuisine used to give a red colour to the Pekinese duck, while salicylic acid is ubiquitous in plants.92 Other important dietary drug candidates are curcumin 32 from turmeric and capsaicin from hot pepper 33,93 while traces of pharmaceutical benzodiazepines (including diazepam) occur in common edible plants such as potatoes and cherries.5... 

This may be identified (a) by its odour (cautiously smell the vapour after removing the test-tube or small beaker from the flame) (b) by the formation of white fumes of ammonium chloride when a glass rod moistened with concentrated hydrochloric acid is held in the vapour (c) by its turning moistened red litmus paper blue or turmeric paper brown (d) by its ability to turn filter paper moistened with mercury(I) nitrate solution black (this is a very trustworthy test ) and (e) filter paper moistened with a solution of manganese(II) chloride and hydrogen peroxide gives a brown colour, due to the oxidation of manganese by the alkaline solution thus formed. 

Acidify a portion of the sample with dilute hydrochloric acid, and apply die solution to turmeric paper. A brown-red colour, which intensifies when the paper is dried indicates the presence of borate. 

Cosmetics and personal care Natural colours (paprika and turmeric) Defatting cereal and nuts Vegetable oils Ginger (for toothpaste)... 

This slightly acid colouring-matter is contained in turmeric, the underground stem of Curcuma longa and C. viridiflora. 

Curcumin is extensively used in dyeing, although not fast to light. Its principal application is in modifying red shades on cotton, for example safiranine. Curcumin dyes cotton without mordant. The powdered root is generally used suspended in water. The cotton is boiled in a mixture, and the curcumin becomes fixed as it dissolves. An alcoholic extract is sometimes used, and is mixed with water to an emulsion. Turmeric is also used for colouring butter, wax, and fatty oils. 

The compound of this gas and ammonia was a perfect neutral salt, neither chan g the colour of turmeric or litmus it had no perceptible odotu, but a pungent saline taste it was deliquescent, and of course very soluble in water it was decomposed by the sulphuric, nitric, and phosphoric acids, and also by liquid muriatic acid but it sublimed unaltered in the muriatic, carbonic, and sulphureous acid gasses, and dissolved without effervescing in acetic acid. The products of its decomposition collected over mercury were found to be the carbonic and muriatic acid gasses and in the experiment with concentrated sulphuric acid Mien accurate results could be obtained, these two gasses were in such proportions, that the volume of the latter was double that of the former. 

The system of classification used by Dalzell (1997) includes two other groups of natural food colorants the phenalones (e.g., circumin and turmeric) (Fig. 7.8) anthraquinone (Fig. 7.9) (cochineal carmine). Other naturally occurring coloured... 

The turmeric plant. Curcuma longa, is cultivated in maty tropical countries, with the primary conunercial production taking place in India. It has been used as a spice for thousands of years and is one of the principal ingredients in curry. The main colouring pigment is curcumin. The turmeric roots are harvested around February, ground to a powder and subsequently extracted with solvent. The resulting turmeric oleoresin has a curcumin content of 37 to 55% and the same relative proportion of flavour compounds and colour as in the spice. 

Processing parameters are also essential to consider, the most critical one normally being heating. Not all natural colours are equally heat stable. Colours like carmine and turmeric are generally considered to have excellent heat stability and can be used in, for example, UHT products. Red beet shows poor heat stability and tends to turn brownish during heating. The actual food matrix may also influence the heat stability. 

---