Chinese discover new blue natural food dye - from soil bacteria

The colour of food is critical to it's enjoyment. There are few processed foods available that do not have some colourant added.

Color additives are probably the most highly regulated food ingredient, the US Food and Drug Administration (FDA) lists only seven approved colors for general food use.

They fall into 2 categories ; 1. Certifiable 2 . Exempt from certification

Certifiable or FD&C colors can be dyes or lakes, depending on their solubility. To work, dyes have to dissolve but lakes are a form of insoluble dye made usually by adsorption on an alum
or aluminium hydrate base where the product isn't moist enough to to absorb the dye , oil-based products such as cake frosting, or dry direct compression items such as chewable
vitamins, and coated sweets such as M&Ms or Smarties. tamins, and coated sweets such as M&Ms or Smarties. (See M&M's - Masterfoods / Mars website section on Allergens)

Colours exempt from certification are invariably derived from or based on natural sources and
don't require FDA batch testing - they may be sourced from living matter or industrially
produced versions , such as carotene one of the commonest yellow food dyes.


Carminic acid , that gives Campari it's distinctive colour and taste is produced from the dried,
crushed bodies of pregnant female scale insects called cochineal (Coccus cacti L.) which is abeetle that feeds on the prickly pear (Opuntia species) and was used by the Incas and Mayas as a dye source, and introduced to Europe by stout Cortez.Today, most cochineal is harvested from managed cactus plantations in Peru and the Canary Islands and is processed in food-grade facilities.

Carminic acid, is an anthraquinone that is unpalatable to the beetles natural predators and is readily extracted using an aqueous or alcoholic extract also adds to the mildly biiter and astringent taste of Campari.

The FDA has not approved a natural source of blue food dye. Anthocyanins, the compounds
that give blueberries their namesake shade, are not really blue. The chemical exists in
pigmented bodies called chromphores and is red and combines with other compounds such as
flavonoids (yellow pigments) , proteins, tannins, and other polyphenols to produce the distinctive blue. The most commonly known green pigment, chlorophyll, is allowed only in drugs or cosmetics--and then only at levels below 0.1% - it is commonly known that potatoes left in the light which have turned green can be mildly poisonous if eaten.

In the US any food with a blue or green colouring component uses the certifiable colors FD&C
Blue No. 1 (Brilliant Blue), Blue No. 2 (Indigotine), or Green No. 3 (Fast Green). Blue No. 1 and
Green No. 3 are both petroleum-derived triphenylmethanes--that is, they have three aromatic
rings attached to a central carbon atom. Blue No. 2 is a disodium sulfonate of a naturally
occurring compound indigo. However, the indigo used to create Blue No. 2 is synthesized by
fusing N-phenylglycine in a molten mix of sodamide and sodium and potassium hydroxides...
and is also used for dying jeans.

In the European Union there are 41 permitted food colourings each provided with an E number
(details here) although their acceptance varies enormoulsy. Warning ! Just because they have an E number does not mean that they are permitted in use in every country. For example E 160d Lycopene is a natural product found in tomatoes, but is not currently used and is only banned for use in Australia.

In Norway because of associated behavioural problems all food dyes from coal tars and
associated products are banned - Tartrazine -E 102 Patent Blue V - E 131 some colours Brown K - E 154 which is used for colouring kippers (see "Vac Pac Kipper from Grimsby) is banned throughout the EU (except in the UK where its use is still permitted!) it is also prohibited in Australia, Austria, Canada, Finland, Ireland, Japan, Norway, Sweden and the United States.

Brilliant Blue FCF, FD&C Blue 1 - E 133 is another coal tar based dye used in tinned peas and is banned Austria, Belgium, Denmark, France, Germany, Greece, Italy, Norway, Spain, Sweden and Switzerland.

Sunset yellow (E110) is a dye which in combination with other common additives was linked to behavioural problems in a landmark 2004 Isle of Wight study. see FSA According to Lizzie Vann, author of Carrots or Chemistry?, an investigation into snacking and child health, ponceau 4R (E124 or cochineal Red A), also implicated in the Isle of Wight study, and indigo carmine (E132) appear to cause allergic reactions in vulnerable people, such as asthmatics. Green S (E142), has been linked with similar health problems and is banned in Canada, the US, Finland, Norway, Japan and Sweden. In 2004 research for the Journal of Developmental and Behavioural Paediatrics found that eliminating artificial colourings such as these from hyperactive children's diets results in a third of the benefit than you would expect to see from ADHD medications like Ritalin.
20 August 2006 - The Observer - The additive-packed children's tea

However it is an observable fact that many food colourings do affect childen's behaviour and
results in hyperactivity, although this is a highly contentious subject. See Food and bahaviour Research website for information on this subject

Help may be at hand because Chinese scientists have isolated a blue pigment ( 3 gms per litre) from cultured and much studied soil bacteria Streptomyces coelicolor that could offer a natural colouring with an excellent stability and toxicology profile for food.

Hechun Zhang and his colleagues have published (Food Chemistry Volume 95, Pages 186-192)how they isolated a natural blue pigment extract which they discover which is a mixture of at least ten distinct compounds. which are collectively named actinorhodin.

The solubility of the pigment was tested under acidic and alkaline conditions, and its stability was assessed on exposure to light and heat, and in the presence of oxidants and reducers at
low pH (acidic) and to reducers at higher pH (alkaline).

The pigment was stable to light and heat, and resistant to oxidants and reducers under acidic conditions and to reducers under alkaline conditions and also did not react with comon food additives such as as vitamin C and sodium benzoate.

An acute toxicity trial, carried out according to Evaluation Regulation of Food Safety in China
(GB15193), confirmed that the pigment was non-toxic (LD[50] > 15,000 mg/kg) . The scientists evaluated the half-life lethal dose (LD50) using mice models and, during a 14-day trial with 70 mice receiving dose from zero to 15,000 mg/kg, no mice died.

This means that the pigment could be classified as a non-toxic substance according to the general toxicological tets.

The Chinese are of course not inventive, produce few patents and do nothing orginal.