Contrast Enhancers
When it is necessary to mark the skin of a fruit or vegetables this is often done with a laser, with marking substance used to add information. Food additives used as contrast enhancers primarily focus on modifying the visual appearance of food, making colours appear more vibrant or distinct. Indelible marking technology provides an alternative to removable adhesive paper stickers which are currently in use and limits the risks of losing, mixing up or inverting food items and therefore facilitates transportation and storage. Contrast enhancers are to be used in small quantities and only on the external part of fruit and are not expected to migrate significantly into the internal part. For that reason, the treatment of fruit of which the peels are not commonly consumed is not likely to have an effect on human health. In the EU the use of iron oxides and hydroxides (E 172) and hydroxypropyl methyl cellulose (E 464) are permitted for marking of citrus fruit, melons and pomegranates and polysorbates (E 432-436) for use in the contrast enhancer preparation.
Iron oxides and hydroxides (E172) includes Iron oxide yellow, Iron oxide red and Iron oxide black.
Iron oxides and hydroxides (E172) includes Iron oxide yellow, Iron oxide red and Iron oxide black. These are produced by the controlled oxidation of iron in the presence of water and can produce colours from yellow to black with the precise colour controlled by the manufacturing process. They provide basic yellow, red or black colours to foodstuffs and are highly stable, particularly to light. They are used in fish paste, canned goods and confectionery but can also be used to mark citrus fruits, melons and pomegranates as contrast enhancers. They are included in the EU Food colours: Group II authorised to be used quantum satis.
Hydroxypropyl methyl cellulose (E464)
Hydroxypropyl methyl cellulose (E464) also known as Hydromellose is produced from purified cellulose by treatment with methyl cellulose and propylene oxide. It is soluble in cold water as a thickener but insoluble in hot water forming gels. It is typically used in soya burgers, sausages, onion rings, formed potato products and gluten free bakery products and is permitted quantum satis in the EU.
Polysorbates (E 432-436)
Polysorbates (E 432-436) are used in contrast enhancer preparations. You can find out more about these in the section on emulsifiers.
