Science around you | food coloring

In ancient China, there was a record of using red yeast pigment to make red wine. In 1856, when the British people Parkin synthesized the first artificial pigment, aniline violet, they had chemical synthetic pigments. There are many natural and synthetic food colorings available today.

Walking into the food store, you will find that almost all foods will attract your eye, which is the role of pigments. Some are natural, such as the caramel color of most colas is formed by heating the sugar; some are azo compounds synthesized by petroleum processing, such as red 40 (FD&C Red No. 40).

No matter where it is obtained, the pigment additives in any food are strictly controlled by the relevant government departments, such as the Food and Drug Administration of China and the Food and Drug Administration (FDA) of the United States. Use and have a clear mark on the package. In fact, pigments may be the most rigorous food additive ingredient. The FDA controls the final application of pigments, including food, pharmaceuticals, cosmetics and medical supplies. Food coloring is broadly divided into two categories: certified and exempt from certification. The pigments to be certified include synthetic products that are completely different from the natural pigment structure. The FDA-tested and approved pigments can be marked with “FD&C”, indicating that they can be used in food, medicine or cosmetics.

Depending on the solubility, these pigments may be dyes or lakes (a pigment precipitated from an organic pigment material and a metal inorganic substrate or carrier). The definition of the dye is soluble, while the lake is such that the soluble dye becomes insoluble, typically the dye is adsorbed onto the substrate of the aqueous alumina. Lakes are usually added to products with low moisture content to ensure that they do not absorb pigment dyes or that they do not spread in foods, including some icing-coated, oil-based products such as chewable vitamins on food surfaces. And candy with a coat (such as chocolate beans, rainbow candy).

The pigments processed by natural or natural raw materials are derived from the pigments of plants, fungi, and even some insects. They can also be obtained by chemical synthesis of biological materials. The beta-carotene in carrots commonly found in food stores is synthesized in the laboratory. Chemicals.

Natural pigments can be untested, but the processing of bio-pigments must be strictly controlled and the purity standards are very high. For example, the Italian wine Campari contains a non-certified pigment, carminic acid, which is derived from dry, ground, female scests (sc a leinsects). This pigment is also known as cochineal. The Inca and Maya have used the parasites of these cacti as pigment sources for centuries and entered the Western market in the 16th century. Today, most of the cochineal magenta is derived from cactus plantations in Peru and the Canary Islands, processed according to the requirements of food processing technology.

The dried cochineal magenta contains 17% to 24% carminic acid (an antimony compound). Most insect predators are not interested in it. The modern processing method is to extract carminic acid from the cochineal magenta with an alcohol solution. Directly as a dye or precipitated on an alumina substrate as a magenta lake.

Blue pigments seem to be less popular and can not cause appetite. In fact, the anthocyanins in blueberries are not really blue. The red color on the surface of the fruit is relatively stable, while the interior of the fruit, the pigment is generally combined with other compounds, such as flavonoids, proteins, tannic acid and other polyphenolic compounds, which can produce blue. Natural green pigments are not approved for food in the United States, and even the most common green pigment, chlorophyll, can only be used in medicines and cosmetics, and the content should not exceed 0.1%.

The extraction of natural pigments is generally carried out by chemical processes unless it is completely pressed, but some pigments are not available by pressing, and even if they are, the yield is not high. In the chemical extraction process, chemical solvents are used, which inevitably introduces chemical impurities and contaminates the pigment.

Studies have shown that synthetic pigments do not have any nutritional value for humans, but they are harmful, including general toxicity, diarrhea, tumorigenesis and carcinogenesis. Therefore, the restrictions on food coloring in countries are becoming more and more strict. In particular, artificial synthetic pigments must have strict inspection procedures. At present, it is necessary to prove that they are harmless to humans, and they are allowed to use, and the amount limit is also specified. According to reports, there are 11 kinds of pigments that can be used in Japan, 7 kinds in the United States, all of which are water-soluble. The certified blue and green pigments are FD&C Blue No. 1 (bright blue), BlueNo. 2 ( Indigo, indigotine) and GreenNo. 3 (solid green, fast green). Both Blue No. 1 and Green No. 3 are triphenylmethane derivatives petroleum products with three aromatic rings attached to one carbon atom. Blue No. 2 is a sulfonic acid disodium salt of the natural compound indigo. Indigo is a synthesis of N-phenylglycine in a molten mixture of sodium amide, potassium hydroxide, and sodium hydroxide. 17 synthetic pigments have been approved in Europe, but some countries in Europe have completely banned chemical synthetic pigments, some have banned azo pigments, or are prohibited from meat, fish and processed products, fruits and their products, condiments, baby food, A synthetic coloring matter is added to foods such as cakes.

At present, there are six kinds of edible synthetic pigments approved for use in China, namely amaranth, carmine, lemon yellow, sunset yellow, indigo and bright blue. Except in cold foods such as sodas, confectionery, blended wines and juices, which can be used in small amounts (not more than one in ten thousand), synthetic foods cannot be used in other foods.

Regarding natural pigments, the regulations vary from country to country, and the total amount is more than that of synthetic pigments. There are 48 kinds in China, mainly including caramel color, red yeast red pigment, capsanthin, curcumin, sorghum red pigment, chlorophyll copper sodium salt, roselle pigment, etc. The total output is over 10,000 tons, and it is also exported abroad. Some countries in Europe and the United States also have strict control over natural pigments, and they have to undergo long-term tests to ensure that they are safe for humans.

Strictly speaking, the substances that are not in the human body are toxins. Synthetic pigments are not suitable for eating. Especially for children, their liver detoxification function is still immature, and they are attracted by colorful foods and eat too much. Growth and development are harmful.