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Food additive is a compound that added to food. This compound added imadietly to food to repair taste of the food, tekstur, flavor, and storability to can saved longger. bisede that, there are some of food additive that can repair nutritional value, such as levels of vitamin, protein, and mineral

Food additive divided to two groups, natural food additive and synthesis food additive. Natural additive food won't present negative effect for human health, but it will influence or change the color of food, and taste, even the first pupose increase is do not change them.

There are an example of food additive, such as food preservative, food color (Dyes), sweetener, etc. and for this project, our team will present some information about food color (Dyes), that is INDIGOTINE. Have you eat an ice cream ? or marshmallow ? or maybe candy with sweet color ? You can find an ice cream with a lot of color, blue ice, red, and yellow. candy and marshmallow are also contain dyes. and blue color in food is originated from plant named indigo. Most natural indigo was obtained from those in the genus [|Indigofera], which are native to the [|tropics]. The primary commercial indigo species in [|Asia] was true indigo ( [|Indigofera tinctoria], also known as Indigofera sumatrana). In [|Central] and [|South America] the two species [|Indigofera suffruticosa] (Añil) and Indigofera arrecta (Natal indigo) were the most important. In temperate climates indigo can also be obtained from [|woad] (Isatis tinctoria) and [|dyer's knotweed] (Polygonum tinctoru m), although the //Indigofera// species yield more dye.In the past, people ekstracted blue color from indigo. it used to coloring jeans, and for textiles color. But the ekstraction prosses is relatively difficult and need much time.and this process was important economically because blue dyes were once rare. Nearly all indigo produced today several thousand tons each year is synthetic. So, now people find another way to get blue dyes easily. they shintesize blue dye in laboratory. this synthesis dye is also use to coloring food. even they know it doesn't receivable to coloring food. The synthetic indigo is **Indigo Carmine**.  Indigo carmine, or 5,5'-indigodisulfonic acid sodium salt, is a pH indicator with the chemical formul [|C] 16 [|H] 8 [|N] 2 [|Na] 2 [|O] 8 [|S] 2. It is registered as a food additive (colorant) and has the [|E number] E132.

USES The primary use of Indigo carmine is as a pH indicator. It is blue at pH 11.4 and yellow at 13.0. Indigo carmine is also a redox indicator, turning yellow upon reduction. Another use is as a dissolved ozone indicator. It is also used as a dye in the manufacturing of capsules. ** Chemical properties ** Indigo Indigo is a dark blue crystalline powder that sumblimes at 390–392 °C. It is insoluble in water, alcohol, or ethers but soluble in DMSO, choloroform, nitrobenzene, and concentrated sulfuric acid. The chemical formula of indigo is [|C]16[|H]10[|N]2[|O]2. The molecule absorbs light in the orange part of the spectrum (λmax = 602 nm). The compound owes its deep colour to the conjugation of the double bonds, i.e. the double bonds within the molecule are adjacent and the molecule is planar. In indigo white, the conjugation is interrupted because the molecule is nonplanar.
 * INDIGO CARMINE || pH INDICATOR ||
 * bilow pH || above pH ||
 * 11,4 || 13,0 ||
 * blue || yellow ||

** Chemical synthesis **
Given its economic importance, indigo has been prepared by many methods. The [|Baeyer-Drewson indigo synthesis] dates back to 1882 but was impractical. The first practical route is credited to Pfleger in 1901. In this process, //N//-phenylglycine is treated with a molten mixture of [|sodium hydroxide], [|potassium hydroxide], and sodamide. This highly sensitive melt produces [|indoxyl], which is subsequently oxidised in air to form indigo. Variations of this method are still in use today. An alternative and also viable route to indigo is credited to heumann in 1897. It involves heating //N//-(2-carboxyphenyl)glycine to 200 °C in an inert atmosphere with sodium hydrixide. The process is easier than the Pfleger method but the precursors are more expensive. Indoxyl-2-carboxylic acid is generated. This material readily decarboxylates to give indoxyl, which oxidises in air to form indigo. The preparation of indigo dye is practiced in college laboratory classes. Heumann's original synthesis of indigo

Pfleger's synthesis of indigo. Structure of indigo carmine
 * Indigo derivatives ** The benzene rings in indigo can be modified to give a variety of related dyestuffs. Thioindigo CAS# [522-75-8], where the two NH groups are replaced by S atoms, is deep red. Tyrian purple is a dull purple dye that is secreted by a common Mediterannean sea snail. It was highly prized in antiquity. In 1909 its structure was shown to be 6,6'-dibromoindigo. It has never been produced on a commercial basis. The related Ciba blue (5,7,5′,7′-tetrabromoindigo) (CAS# 2475-31-2) is, however, of commercial value.

Treatment with sulfuric acid converts indigo into a blue-green derivative called sulfonated indigo. It became available in the mid-18th century. Sulfonated indigo is also referred to as //Saxon blue// or indigo carmine. It is used as a colorant for food, pharmaceuticals, and cosmetic. **HOW TO INDENTIFYING INDIGO CARMINE IN FOOD PRODUCT** There are a lot of method to indentifyng Indigo dyes in food produtc. It can detemined by kualitative test by thin layer chromatography method.We use Indigo carmine standard solution, and we have to make sample solution that suspected contain of indigo dye. We can also indentifyng the discoloration of indigo carmine with increase of concentrated acid and concentrated base. We use Sulfuric acid, cloride acid, and sodium hydroxide with the different concentration. Indigo carmine will show destinctive color in those solution. << back >> next home