Iron Oxides

Identifiers

INS No. 172(i); Iron oxide, black
INS No. 172(ii); Iron oxide, red
INS No. 172(iii); Iron oxide, yellow
Synthetic iron oxide
E 172; Iron oxides and hydroxides

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Physical Description

Synthetic iron oxide consists of any one or any combination of synthetically prepared iron oxides, including the hydrated forms. Iron oxides are produced from ferrous sulfate by heat soaking, removal of water, decomposition, washing, filtration, drying, and grinding. They are produced in either anhydrous or hydrated forms. The range of hues for synthetic iron oxide includes yellows, reds, browns and blacks.

Common Uses

Typical applications include cosmetics, and pharmaceuticals, and foods, including confectionery, cereals, edible ices, sausage casings, dietary supplements, flavored milk and water based drinks, soups and broths, and fruit preparations.

Specifications

JECFA
US FDA
Commission Regulation (EU) No 231/

Codex GSFA Provisions

Iron oxides (INS Nos. 172(i-iii)) are added to foods and beverages at concentrations up to maximum permitted levels (MPLs) as established by the Codex Alimentarius Commission and adopted in the General Standard of Food Additives (GSFA). The 32 provisions are defined at the additive group level, and thus apply to the total content of the additives participating in this group: Iron oxide, black (172(i)); Iron oxide, red (172(ii)); and Iron oxide, yellow (172 (iii)).

Regulatory Approvals

JECFA: ADI of 0-0.5 mg/kg body weight (

: ADI of 0-0.5 mg/kg body weight ( 23rd meeting,

USA: Synthetic iron oxide is exempt from certification and may be safely used in sausage casings intended for human consumption in an amount not exceeding 0.10% by weight of the finished food; in hard and soft candy, mints and chewing gum at levels consistent with GMP; in dietary supplement tablets and capsules, including coatings and printing inks, such that the total amount of elemental iron per day for labeled dosages does not exceed 5 mgs; for the coloring of dog and cat foods in an amount not exceeding 0.25% by weight of the finished food (

: Synthetic iron oxide is exempt from certification and may be safely used in sausage casings intended for human consumption in an amount not exceeding 0.10% by weight of the finished food; in hard and soft candy, mints and chewing gum at levels consistent with GMP; in dietary supplement tablets and capsules, including coatings and printing inks, such that the total amount of elemental iron per day for labeled dosages does not exceed 5 mgs; for the coloring of dog and cat foods in an amount not exceeding 0.25% by weight of the finished food ( 21 CFR 73.200 ), to color ingested or topically applied drugs generally, with the amount of elemental iron for ingested drugs not to exceed 5 mg per day ( 21 CFR 73. ) and iron oxides are safe for use in coloring cosmetics generally, including cosmetics applied to the area of the eye, in amounts consistent with GMP ( 21 CFR 73. ).

EC: No ADI allocated (

: No ADI allocated ( EFSA, ). Maximum levels of iron oxides and hydroxides have been defined in Annex II to Regulation (EC) No / on food additives, as amended. Currently, iron oxides and hydroxides are authorized food additives and permitted to be used in specified foodstuffs at quantum satis.

 

Safety Reviews

Evaluation of certain food additives (23rd Report of the Joint FAO/WHO Expert Committee on Food Additives) WHO Technical Report Series No 648, . Available online

Listing of Color Additives Exempt from Certification; Synthetic Iron Oxide, 83 FR (Nov 1, ). Available online

Listing of Color Additives Exempt from Certification; Synthetic Iron Oxide, 80 FR (Mar 20, ). Available online

ANS Panel (EFSA Panel on Food Additives and Nutrient Sources added to Food), . Scientific Opinion on the re-evaluation of iron oxides and hydroxides (E 172) as food additives. EFSA Journal ;13(12):, 57 pp. Available online

 

Reddish pigment

"Indian red" redirects here. For the song, see Indian Red

Iron oxide pigments in jars: yellow, red, brown

Iron oxide red is a generic name of a ferric oxide pigment of reddish colors. Multiple shades based on both anhydrous Fe
2O
3 and its hydrates were known to painters since prehistory. The pigments were originally obtained from natural sources, since the 20th century they are mostly synthetic. These substances form one of the most commercially important groups of pigments, and their names sometimes reflect the location of a natural source, later transferred to the synthetic analog. Well-known examples include the Persian Gulf Oxide with 75% Fe
2O
3 and 25% silica, Spanish red with 85% of oxide, Tuscan red.

Properties

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The anhydrous pigment has a dark purple-red or maroon color, hydrates' colors vary from dull yellow (yellow ochre) to warm red.

The iron oxide red is extremely stable: it is not affected by light and most chemicals (soluble in hot concentrated acids); heat only affects the hydrated variants (the water is removed, and the color darkens).

Indian red

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Indian red is a pigment, a variety of ocher, which gets its colour from ferric oxide, used to be sourced in India,[2] now made artificially. Other shades of iron oxides include Venetian Red, English Red, and Kobe, all shown below.

Chestnut is a colour similar to but separate and distinct from Indian red.

Etymology

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The name Indian red derives from the red laterite soil found in India, which is composed of naturally occurring iron oxides.[citation needed] The first recorded use of Indian red as a color term in English was in .[4]

Deep Indian red

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Deep Indian red is the colour originally called Indian red from its formulation in until , but now called chestnut, in Crayola crayons. This colour was also produced in a special limited edition in which it was called Vermont maple syrup.

At the request of educators worried that children (mistakenly; see Etymology) believed the name represented the skin color of Native Americans, Crayola changed the name of their crayon color Indian Red to Chestnut in .[5]

Indian red in culture

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Railroads/Railways

• The Talyllyn Railway painted their locomotives Talyllyn and Dolgoch Indian Red in honour of the 150th anniversary of the line in .

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  If you are looking for more details, kindly visit Iron Oxide Colors for Roofing.

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  Furness Railway Nº20, as restored today

Venetian red

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At right is displayed the colour Venetian red.

Venetian red is a light and warm (somewhat unsaturated) pigment that is a darker shade of scarlet, derived from nearly pure ferric oxide (Fe2O3) of the hematite type. Modern versions are frequently made with synthetic red iron oxide.

The first recorded use of Venetian red as a colour name in English was in .[7]

English red

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At right is displayed the colour English red.

This red is a tone of Indian red, made like Indian red with pigment made from iron oxide.

The first recorded use of English red as a color name in English was in the s (exact year uncertain).[8] In the Encyclopédie of Denis Diderot in , alternate names for Indian red included "what one also calls, however improperly, English Red."[9]

Kobe

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At right is displayed color kobe.

The color kobe is a dark tone of Indian red, made like Indian red from iron oxide pigment.

The first recorded use of Kobe as a colour name in English was in .[10]

The normalized colour coordinates for Kobe are identical to sienna, first recorded as a color name in English in .[11]

See also

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References

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Sources

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• Gettens, R. J.; Stout, G. L. (a). "Indian Red". Painting Materials: A Short Encyclopedia. Courier Corporation. p. 119. ISBN 978-0-486--5. OCLC .

• Gettens, R. J.; Stout, G. L. (b). "Iron Oxide Red". Painting Materials: A Short Encyclopedia. Courier Corporation. p. 122. ISBN 978-0-486--5. OCLC .