PRODUCTS

E 171 (TITANIUM DIOXIDE)

CAS Number: 1317-80-2
Molecular Weight: 79.87
EC Number: 215-282-2
MDL number: MFCD00011269
PubChem Substance ID: 24882842
NACRES: NA.23

APPLICATIONS

E 171 (titanium dioxide) is a general-purpose multi-purpose titanium dioxide, which is widely used in various high-grade indoor and outdoor architectural coatings, industrial coatings, powder coatings, as well as plastic masterbatches, plastic profiles, rubber, high-grade inks and papermaking.
E 171 (titanium dioxide) is used a food colour (E171) and, as with all food colours, its technological function is to make food more visually appealing, to give colour to food that would otherwise be colourless, or to restore the original appearance of food.
E 171 (titanium dioxide) is also present in cosmetics, paints, and medicines.

The main food categories contributing to dietary exposure of E 171 (titanium dioxide) are fine bakery wares, soups, broths and sauces (for infants, toddlers and adolescents); and soups, broths, sauces, salads and savoury based sandwich spreads (for children, adults and the elderly).
Processed nuts are also a main contributing food category for adults and the elderly.

Titanium dioxide (TiO2), also known as E 171 (titanium dioxide), is very commonly used as a white colourant in food, but also in paints, coatings, pharmaceuticals, cosmetics, and even in toothpaste.
E 171 (titanium dioxide) is a mix of TiO2 particles which can be defined as nanoparticles.
Because of their extremely small size, nanoparticles can squeeze through natural protective barriers of the human body and pass into the liver, lungs or the whole digestive system.

E 171 (titanium dioxide) is a food additive otherwise known as titanium dioxide.
E 171 (titanium dioxide) is widely used in food to whiten or brighten it’s colour and appearance.
It can also be found in beauty products and medications and is noted on labels as E 171 (titanium dioxide) or TiO2.

E 171 (titanium dioxide) is commonly used and found in soups, sauces, broths and savoury sandwich spreads.
Other foods that widely feature the food colouring are sweet treats like white chocolate bars, confectionary and chewing gum.
E 171 (titanium dioxide) is even found in some seemingly healthy cheeses and some skimmed milk brands too.

Known in food as the colourant E 171 (titanium dioxide), its unique whiteness and brightness, stability to heat, light and UV absorbance make titanium dioxide the most effective white colourant in food.
In fact, it’s up to five times more efficient than alternatives, so that relatively low levels of E 171 (titanium dioxide) are required to achieve the desired effect.

In decades of use as a food colourant, no verifiable link has ever been shown between a general intake of E 171 (titanium dioxide) and harm to human health.
E 171 (titanium dioxide) (TiO2) is a transition metal oxide with application as a pigment or photocatalyst.

As a white pigment, E 171 (titanium dioxide) has been added to a variety of food products, including bakery products, sauces, cheeses, edible ices and sweets.
In addition to food, E 171 (titanium dioxide) is also used in medicinal products as an excipient, and in personal care products as a pigment and thickener, and can also be used as an UV filter in mineral sunscreen products.

E 171 (titanium dioxide) is used as a food additive (E171) and can be found in sauces, icings, and chewing gums, as well as in personal care products such as toothpaste and pharmaceutical tablets.
E 171 (titanium dioxide) (TiO2) is a widely used white pigment and opacifying agent, with applications in paints, pharmaceuticals, cosmetics, and food.

E 171 (titanium dioxide) is extensively used as an opacifier and colorant in Food, Cosmetics, and Pharmaceuticals.

The most important application areas are paints and varnishes as well as paper and plastics, which account for about 80% of the world's E 171 (titanium dioxide) consumption.
Other pigment applications such as printing inks, fibers, rubber, cosmetic products, and food account for another 8%.
The rest is used in other applications, for instance the production of technical pure titanium, glass and glass ceramics, electrical ceramics, metal patinas, catalysts, electric conductors, chemical intermediates, or as a substrate for phosphonic acid adsorption.

-Pigment

First mass-produced in 1916, E 171 (titanium dioxide) is the most widely used white pigment because of its brightness and very high refractive index, in which it is surpassed only by a few other materials (see list of indices of refraction).
E 171 (titanium dioxide) crystal size is ideally around 220 nm (measured by electron microscope) to optimize the maximum reflection of visible light.
However, abnormal grain growth is often observed in E 171 (titanium dioxide), particularly in its rutile phase.

The occurrence of abnormal grain growth brings about a deviation of a small number of crystallites from the mean crystal size and modifies the physical behaviour of TiO2.
The optical properties of the finished pigment are highly sensitive to purity.

As little as a few parts per million (ppm) of certain metals (Cr, V, Cu, Fe, Nb) can disturb the crystal lattice so much that the effect can be detected in quality control.
Approximately 4.6 million tons of pigmentary TiO2 are used annually worldwide, and this number is expected to increase as use continues to rise.

E 171 (titanium dioxide) is also an effective opacifier in powder form, where it is employed as a pigment to provide whiteness and opacity to products such as paints, coatings, plastics, papers, inks, foods, supplements, medicines (i.e. pills and tablets), and most toothpastes; in 2019 it was present in two-thirds of toothpastes on the French market.

In food, E 171 (titanium dioxide) is commonly found in products like ice creams, chocolates, all types of candy, creamers, desserts, marshmallows, chewing gum, pastries, spreads, dressings, cakes, and many other foods.
In paint, E 171 (titanium dioxide) is often referred to offhandedly as "brilliant white", "the perfect white", "the whitest white", or other similar terms.
Opacity is improved by optimal sizing of the E 171 (titanium dioxide) particles.

-Thin films

When deposited as a thin film, its refractive index and colour make it an excellent reflective optical coating for dielectric mirrors; it is also used in generating decorative thin films such as found in "mystic fire topaz".

Some grades of modified titanium based pigments as used in sparkly paints, plastics, finishes and cosmetics – these are man-made pigments whose particles have two or more layers of various oxides – often E 171 (titanium dioxide), iron oxide or alumina – in order to have glittering, iridescent and or pearlescent effects similar to crushed mica or guanine-based products.

In addition to these effects a limited colour change is possible in certain formulations depending on how and at which angle the finished product is illuminated and the thickness of the oxide layer in the pigment particle; one or more colours appear by reflection while the other tones appear due to interference of the transparent titanium dioxide layers.
In some products, the layer of titanium dioxide is grown in conjunction with iron oxide by calcination of titanium salts (sulfates, chlorates) around 800 °C.
One example of a pearlescent pigment is Iriodin, based on mica coated with titanium dioxide or iron (III) oxide.

The iridescent effect in these titanium oxide particles is unlike the opaque effect obtained with usual ground titanium oxide pigment obtained by mining, in which case only a certain diameter of the particle is considered and the effect is due only to scattering.

-Sunscreen and UV blocking pigments

In cosmetic and skin care products, E 171 (titanium dioxide) is used as a pigment, sunscreen and a thickener.
As a sunscreen, ultrafine E 171 (titanium dioxide) is used, which is notable in that combined with ultrafine zinc oxide, it is considered to be an effective sunscreen that lowers the incidence of sun burns and minimizes the premature photoaging, photocarcinogenesis and immunosuppression associated with long term excess sun exposure.
Sometimes these UV blockers are combined with iron oxide pigments in sunscreen to increase visible light protection.

E 171 (titanium dioxide) and zinc oxide are generally considered to be less harmful to coral reefs than sunscreens that include chemicals such as oxybenzone, octocrylene and octinoxate.

Nanosized E 171 (titanium dioxide) is found in the majority of physical sunscreens because of its strong UV light absorbing capabilities and its resistance to discolouration under ultraviolet light.
This advantage enhances its stability and ability to protect the skin from ultraviolet light.
Nano-scaled (particle size of 20–40 nm) E 171 (titanium dioxide) particles are primarily used in sunscreen lotion because they scatter visible light much less than E 171 (titanium dioxide) pigments, and can give UV protection.

Sunscreens designed for infants or people with sensitive skin are often based on titanium dioxide and/or zinc oxide, as these mineral UV blockers are believed to cause less skin irritation than other UV absorbing chemicals.
Nano-TiO2 blocks both UV-A and UV-B radiation, which is used in sunscreens and other cosmetic products.
It is safe to use and it is better to environment than organic UV-absorbers.

The risk assessment of different titanium dioxide nanomaterials in sunscreen is currently evolving as nano-sized TiO2 is different from the well-known micronized form.
The rutile form is generally used in cosmetic and sunscreen products due to it not possessing any observed ability to damage the skin under normal conditions and having a higher UV absorption.

In 2016 Scientific Committee on Consumer Safety (SCCS) tests concluded that the use of nano Titanium Dioxide (95%-100% rutile, ≦5% anatase) as a UV filter can be considered to not pose any risk of adverse effects in humans post-application on healthy skin, except in the case the application method would lead to substantial risk of inhalation (ie; powder or spray formulations).
This safety opinion applied to nano TiO2 in concentrations of up to 25%.

Initial studies indicated that nano-TiO2 particles could penetrate the skin causing concern over the use of nano-TiO2.
These studies were later refuted, when it was discovered that the testing methodology couldn't differentiate between penetrated particles and particles simply trapped in hair follicles and that having a diseased or physically damaged dermis could be the true cause of insufficient barrier protection.

SCCS research found that when nanoparticles had certain photostable coatings (eg. alumina, silica, cetyl phosphate, triethoxycaprylylsilane, manganese dioxide) the photocatalytic activity was attenuated and no notable skin penetration was observed; the sunscreen in this research was applied at amounts of 10 mg/cm2 for exposure periods of 24 hours.
Coating E 171 (titanium dioxide) with alumina, silica, zircon or various polymers can minimizing avobenzone degradation and enhance UV absorption by adding an additional light diffraction mechanism.

E 171 (titanium dioxide) is used extensively in plastics and other applications as a white pigment or an opacifier and for its UV resistant properties where the powder disperses light – unlike organic UV absorbers – and reduces UV damage, due mostly to the particle's high refractive index.

-Other uses of E 171 (titanium dioxide)

In ceramic glazes, E 171 (titanium dioxide) acts as an opacifier and seeds crystal formation.

E 171 (titanium dioxide) is used as a tattoo pigment and in styptic pencils.
Additionally, E 171 (titanium dioxide) is produced in varying particle sizes which are both oil and water dispersible, and in certain grades for the cosmetic industry.
E 171 (titanium dioxide) is also a common ingredient in toothpaste.

The exterior of the Saturn V rocket was painted with titanium dioxide; this later allowed astronomers to determine that J002E3 was the S-IVB stage from Apollo 12 and not an asteroid.

DESCRIPTION

The present opinion deals with an updated safety assessment of the food additive E 171 (titanium dioxide) based on new relevant scientific evidence considered by the Panel to be reliable, including data obtained with TiO2 nanoparticles (NPs) and data from an extended one‐generation reproductive toxicity (EOGRT) study.
Less than 50% of constituent particles by number in E 171 (titanium dioxide) have a minimum external dimension < 100 nm.
In addition, the Panel noted that constituent particles < 30 nm amounted to less than 1% of particles by number.

The Panel therefore considered that studies with TiO2 NPs < 30 nm were of limited relevance to the safety assessment of E 171 (titanium dioxide).
The Panel concluded that although gastrointestinal absorption of TiO2 particles is low, they may accumulate in the body.
Studies on general and organ toxicity did not indicate adverse effects with either E 171 (titanium dioxide) up to a dose of 1,000 mg/kg body weight (bw) per day or with TiO2 NPs (> 30 nm) up to the highest dose tested of 100 mg/kg bw per day.

No effects on reproductive and developmental toxicity were observed up to a dose of 1,000 mg E 171/kg bw per day, the highest dose tested in the EOGRT study. However, observations of potential immunotoxicity and inflammation with E 171 (titanium dioxide) and potential neurotoxicity with TiO2 NPs, together with the potential induction of aberrant crypt foci with E 171 (titanium dioxide), may indicate adverse effects.
With respect to genotoxicity, the Panel concluded that TiO2 particles have the potential to induce DNA strand breaks and chromosomal damage, but not gene mutations.

No clear correlation was observed between the physico‐chemical properties of TiO2 particles and the outcome of either in vitro or in vivo genotoxicity assays.
A concern for genotoxicity of TiO2 particles that may be present in E 171 (titanium dioxide) could therefore not be ruled out.
Several modes of action for the genotoxicity may operate in parallel and the relative contributions of different molecular mechanisms elicited by TiO2 particles are not known.

There was uncertainty as to whether a threshold mode of action could be assumed.
In addition, a cut‐off value for TiO2 particle size with respect to genotoxicity could not be identified.
No appropriately designed study was available to investigate the potential carcinogenic effects of TiO2 NPs.
Based on all the evidence available, a concern for genotoxicity could not be ruled out, and given the many uncertainties, the Panel concluded that E 171 (titanium dioxide) can no longer be considered as safe when used as a food additive.

E 171 (titanium dioxide) is found in over 900 of our everyday foods.
Like many processed foods which include artificial sweeteners, colourings and large amounts of hidden sugar, E 171 (titanium dioxide) is added to foods to make them look more appealing.

Environmental contamination with TiO2 and the use of TiO2 as a food additive (E 171 (titanium dioxide)) or in cosmetics result in human exposure to TiO2 via inhalation, ingestion, and through skin contact.
When inhaled, most TiO2 particles are cleared via the mucociliary escalator and are then swallowed.
Together with the ingestion of E 171 (titanium dioxide), this process results in a significant exposure of the human gastro-intestinal tract to TiO2.

One of the functions of the intestine is to protect the body from external aggression, via the so-called intestinal barrier function.
The aim of this study was to determine whether, and through which mechanisms, TiO2 affects this function.
Caco-2 and HT29-MTX cells were co-cultured to reconstitute an in vitro mucus-secreting intestinal epithelium.
This epithelium was exposed to TiO2-NPs, either pure anatase or mixed anatase/rutile, or to E 171 (titanium dioxide).

Two exposure scenarii were used: acute exposure for 6 h or 48 h after cell differentiation (21 days post-seeding), or repeated exposure during the course of cell differentiation, i.e., twice a week for 21 days post-seeding.

Epithelial cells repeatedly exposed to TiO2 developed an inflammatory profile, together with increased mucus secretion.
Epithelial integrity was unaltered, but the content of ATP-binding cassette (ABC) family xenobiotic efflux pumps was modified.
Taken together, these data show that TiO2 moderately but significantly dysregulates several features that contribute to the protective function of the intestine.

E 171 (titanium dioxide) is a technological substance that is used as a food colour (E171) mainly in sauces, and confectionery, pastry, and bakery products.
The last safety assessment made by the EFSA (European Food Safety Authority) concluded that E 171 (titanium dioxide) could no longer be considered safe and, therefore, the European Commission and Member Estates have drawn up a new regulation to ensure consumers’ health protection.

E 171 (titanium dioxide) is an important inorganic chemical product, it mainly contains white pigment.
Generally there are two types of E 171 (titanium dioxide): Rutile R and Anatase A.
Widely E 171 (titanium dioxide) is used in ceramic, paints, inks, coatings, paper-making, plastics, fiber industries, etc.

E 171 (titanium dioxide) is of outstanding importance as a white pigment because of its scattering properties (which are superior to those of all other white pigments) and its chemical stability, non-toxicity.
E 171 (titanium dioxide), also known as titanium (IV) oxide or titania, is the inorganic compound with the chemical formula TiO2.

When used as a pigment, E 171 (titanium dioxide) is called titanium white, Pigment White 6 (PW6), or CI 77891.
E 171 (titanium dioxide) is a white, water-insoluble solid, although mineral forms can appear black.
As a pigment, E 171 (titanium dioxide) has a wide range of applications, including paint, sunscreen, and food coloring.
When used as a food coloring, E 171 (titanium dioxide) has E number E171.

PROPERTIES

Chemical formula: TiO2
Molar mass: 79.866 g/mol
Appearance: White solid
Odor: Odorless
Density: 4.23 g/cm3 (rutile) ; 3.78 g/cm3 (anatase)
Melting point: 1,843 °C (3,349 °F; 2,116 K)
Boiling point: 2,972 °C (5,382 °F; 3,245 K)
Solubility in water: Insoluble
Band gap: 3.05 eV (rutile)
Magnetic susceptibility (χ): +5.9·10−6 cm3/mol
Refractive index (nD): 2.488 (anatase) ; 2.583 (brookite) ; 2.609 (rutile)

STRUCTURE

In all three of its main dioxides, titanium exhibits octahedral geometry, being bonded to six oxide anions.
The oxides in turn are bonded to three Ti centers.
The overall crystal structure of rutile is tetragonal in symmetry whereas anatase and brookite are orthorhombic.

The oxygen substructures are all slight distortions of close packing: in rutile, the oxide anions are arranged in distorted hexagonal close-packing, whereas they are close to cubic close-packing in anatase and to "double hexagonal close-packing" for brookite.
The rutile structure is widespread for other metal dioxides and difluorides, e.g. RuO2 and ZnF2.

Molten titanium dioxide has a local structure in which each Ti is coordinated to, on average, about 5 oxygen atoms.
This is distinct from the crystalline forms in which Ti coordinates to 6 oxygen atoms.

PRODUCTION AND OCCURRENCE

Synthetic E 171 (titanium dioxide) is mainly produced from the mineral ilmenite.
Rutile, and anatase, naturally occurring E 171 (titanium dioxide), occur widely also, e.g. rutile as a 'heavy mineral' in beach sand.
Leucoxene, fine-grained anatase formed by natural alteration of ilmenite, is yet another ore.
Star sapphires and rubies get their asterism from oriented inclusions of rutile needles.

Mineralogy and uncommon polymorphs

E 171 (titanium dioxide) occurs in nature as the minerals rutile and anatase.
Additionally two high-pressure forms are known minerals: a monoclinic baddeleyite-like form known as akaogiite, and the other has a slight monoclinic distortion of the orthorhombic α-PbO2 structure and is known as riesite.
Both of which can be found at the Ries crater in Bavaria.

It is mainly sourced from ilmenite, which is the most widespread titanium dioxide-bearing ore around the world.
Rutile is the next most abundant and contains around 98% titanium dioxide in the ore.
The metastable anatase and brookite phases convert irreversibly to the equilibrium rutile phase upon heating above temperatures in the range 600–800 °C (1,110–1,470 °F).

SYNONYMS

Titania
Rutile
Anatase
Brookite
Titanium dioxide
Titanium(IV) oxide
titanium white
Pigment White 6 (PW6
biossido di titanio; [in polvere contenente ≥ 1 % di particelle con diametro aerodinamico ≤ 10 μm] (it)
diossidu tat-titanju;[f’forma ta’ trab li fiha 1 %jew aktar ta’ partiċelli b’dijametruajrudinamiku ta’ ≤10 μm] (mt)
dioxid de titan [sub formă de pulbere care conține 1 % sau mai mult particule cu un diametru aerodinamic ≤ 10 μm] (ro)
dioxyde de titane; [sous la forme d’une poudre contenant 1 % ou plus de particules d’un diamètre ≤ 10 μm] (fr)
ditlenek tytanu; [w postaci proszku o zawartości 1 % lub więcej cząstek o średnicy aerodynamicznej ≤ 10 μm] (pl)
Dióxido de titanio; [en forma de polvo que contenga el 1 % o más de partículas con un diámetro aerodinámico ≤ 10 μm] (es)
dióxido de titânio; [em pó, contendo 1% ou mais de partículas com diâmetro aerodinâmico ≤ 10 μm] (pt)
oxid titaničitý; [ve formě prášku obsahujícího 1 % nebo více částic o aerodynamickém průměru ≤ 10 μm] (cs)
oxid titaničitý; [vo forme prášku, ktorý obsahuje 1 % alebo vyšší podiel častíc s aerodynamickým priemerom ≤ 10 μm] (sk)
titaandioksiid; [pulbrina, mis sisaldab vähemalt 1 % ulatuses osakesi, mille aerodünaamiline läbimõõt on ≤ 10 μm] (et)
Biossido di Titanio
calcium carbonate
diooxotitanium
Dioxotitanium
dioxotitanium
dioxyde de titane
dioxyde-de-titane
Dwutlenek tytanu, ditlenek tytanu
Oxid titaničitý
oxid titaničitý
R-2629R-2617R-2654R-127R-158R-2176
R_JS_Dossier_Titanium_Dioxide
Rutile (TiO2)
Tiitanium Dioxide
TiO2
TiO2 anatase
Titan(IV)-oxid
titan(iV)dioxide
TITANDIOXID
Titandioxid
titandioxid
Titandioxid (in the form of Rutile Sand) 13463-67-7
Titane dioxide
titania in 1-methoxy-2-propanol
TITANIO BIOSSIDO
titanium (IV) oxide
titanium (IV) oxide / dioxotitanium
Titanium (IV)Dioxide