Titanium dioxide occurs in nature as the well-known minerals rutile, anatase and brookite, and additionally as two high pressure forms, a monoclinic baddeleyite-like form and an orthorhombic α-PbO2 -like form, both found recently at the Ries crater in Bavaria. It is used in food colouring. Used as a whitener.
Foodstuffs in developed countries contain increasing quantities of microscopic particles such as titanium dioxide. Titanium dioxide is used by the millions of tons as a whitening or brightening pigment to make white-colored paint, but also as an additive to make white-colored food. It’s added to food so much so that people eating conventional diets may be ingesting a trillion particles of titanium dioxide every day! Titanium dioxide, also known as titanium(IV) oxide or titania, is the naturally occurring oxide of titanium, chemical formula TiO 2. When used as a pigment, it is called titanium white, Pigment White 6 (PW6) , or CI 77891. Generally it is sourced from ilmenite, rutile and anatase. It has a wide range of applications, from paint to sunscreen to food colouring. Titanium dioxide is chemically processed to remove these impurities, leaving the pure, white pigment available for use. Titanium dioxide has a variety of uses, as it is odorless and absorbent. This mineral can be found in many products, ranging from paint to food to cosmetics. In cosmetics, it serves several purposes. It is a white pigment, an opacifier and a sunscreen. References: Titanium dioxide is the subject of new controversy, yet it is a substance as old as the earth itself. It is one of the top fifty chemicals produced worldwide. It is a white, opaque and naturally-occurring mineral found in two main forms: rutile and anatase. Foodstuffs in developed countries contain increasing quantities of microparticles such as titanium dioxide. Titanium dioxide is used by the millions of tons as a whitening or brightening pigment to make white-colored paint, but also as an additive to make white-colored food. It s added to food so much so that people eating conventional diets may be ingesting a trillion particles of titanium dioxide every day. Two potential risk factors are animal protein and nanoparticles, such as titanium dioxide. Of all dietary factors, animal protein from meat and fish is most associated with a higher risk of inflammatory bowel disease. Usually referred to as Food Grade titanium dioxide, or additive E171 in Europe, the white powder is typically made up of particles a few hundred nanometers in diameter – a particle size that reflects visible light extremely well.  About TITANIUM DIOXIDE: Titanium dioxide is an inorganic compound used in a range of body care products such as sunscreens and makeup. It appears to have low skin penetration but inhalation is a concern. Function(s): Colorant; Opacifying Agent; Sunscreen Agent; Ultraviolet Light Absorber.  The Food and Drug Administration (FDA) lists Titanium Dioxide as a color additive exempt from certification. Titanium Dioxide is safe for use in coloring products, including cosmetics and personal care products applied to the lips, and the area of the eye, provided it meets certain specifications. Titanium Dioxide is used in a wide range of cosmetics and personal care products including makeup, nail products, bath soaps and foot powders. Titanium Dioxide is also used in Over-the-Counter (OTC) sunscreen drug products. Titanium dioxide occurs in nature as the well-known minerals rutile, anatase and brookite, and additionally as two high pressure forms, a monoclinic baddeleyite-like form and an orthorhombic α-PbO2 -like form, both found recently at the Ries crater in Bavaria. It is mainly sourced from ilmenite ore. When used as a pigment, it is called titanium white, Pigment White 6 (PW6) , or CI 77891. Generally it is sourced from ilmenite, rutile and anatase. It has a wide range of applications, from paint to sunscreen to food colouring. Food grade titanium dioxide is really common and not so nano. The titanium dioxide used by Dunkin' Brands and many other food producers is not a new material, and it's not really a nanomaterial either. Nanoparticles are typically smaller than 100 nanometers in diameter. Yet most of the particles in food grade titanium dioxide are larger than this. Titanium dioxide (which isn't the same thing as the metal titanium) is an inert, insoluble material that's used as a whitener in everything from paper and paint to plastics. Titanium dioxide is the most widely used white pigment in products such as paints, coatings, plastics, paper, inks, fibres, and food and cosmetics because of its brightness and high refractive index (2.4), which determines the degree of opacity that a material confers to the host matrix. 
http://nutritionfacts.org/2013/08/13/is-titanium-dioxide-in-food-harmful/ https://en.wikipedia.org/wiki/Titanium_dioxide http://www.organicmakeup.ca/CA/titaniumdioxide.asp http://www.care2.com/greenliving/is-titanium-dioxide-in-food-harmful.html http://2020science.org/2014/06/07/lost-nano-translation-titanium-dioxide-food-products/ http://www.ewg.org/skindeep/ingredient/706561/TITANIUM_DIOXIDE/ http://www.cosmeticsinfo.org/ingredient/titanium-dioxide https://en.wikipedia.org/wiki/Titanium_dioxide http://phys.org/news/2015-03-dunkin-donuts-ditches-titanium-dioxide.html http://www.fao.org/fileadmin/templates/agns/pdf/jecfa/cta/67/cta_tio2.pdf
what is titanium dioxide in food