Ponceau 4R is a synthetic colourant that may be used as a food colouring. It is denoted by E Number E124 Its chemical name is 1-(4-sulpho-1-napthylazo)- 2-napthol- 6,8-disulphonic acid, trisodium salt. Ponceau (French for "poppy-colored") is the generic name for a family of azo dyes.
Ponceau 4R and health
Because it is an azo dye, it may elicit intolerance in people allergic to salicylates (aspirin). Additionally, it is a histamine liberator, and may intensify symptoms of asthma.
Ponceau 4R is considered carcinogenic in some countries, including the USA, Norway, and Finland, and it is currently listed as a banned substance by the U.S. Food and Drug Administration (FDA) .Since 2000, the FDA has seized Chinese-produced haw flakes (a fruit candy) on numerous occasions for containing Ponceau 4R.
EFSA has decided on 2009-09-23 to lower the Acceptable Daily Intake (ADI) for Ponceau 4R from 4 mg/kg to 0.7 mg/kg bodyweight per day. The substance causes increased migration of nuclear DNA in glandular stomach, bladder (≥ 100 mg/kg) and colon tissue (≥ 10 mg/kg). Clastogenic activity was seen in bone marrow at dosages equivalent to an intake ≥ 80 mg/kg, but no carcinogenic effects were noted. The production process may result in unsulphonated aromatic amines to be present in concentrations of up to 100 mg/kg which may be linked to cancer. Also the EFSA panel noted that the JECFA limit for lead is ≤ 2 mg/kg whereas the EC specification is ≤ 10 mg/kg. The colour additive can also increase the intake of aluminium beyond the tolerable weekly intake (TWI) of 1 mg/kg/week. Therefore the limit for aluminum may become adjusted to accommodate for this.
In 1995, it was reported that exposing a thin film of azo-polymer to a light intensity (or polarization) gradient leads to spontaneous surface patterns. In essence, the polymer material will reversibly deform so as to minimize the amount of material exposed to the light. This phenomenon is not laser ablation, since it readily occurs at low power and the transformation is reversible. The mechanism of this surface holography seems related to a new photomechanical effect, involving azobenzene isomerization.
Side Effects of Ponceau 4r
Ponceau 4R and health
Because it is an azo dye, it may elicit intolerance in people allergic to salicylates (aspirin). Additionally, it is a histamine liberator, and may intensify symptoms of asthma.
Ponceau 4R is considered carcinogenic in some countries, including the USA, Norway, and Finland, and it is currently listed as a banned substance by the U.S. Food and Drug Administration (FDA) .Since 2000, the FDA has seized Chinese-produced haw flakes (a fruit candy) on numerous occasions for containing Ponceau 4R.EFSA has decided on 2009-09-23 to lower the Acceptable Daily Intake (ADI) for Ponceau 4R from 4 mg/kg to 0.7 mg/kg bodyweight per day. The substance causes increased migration of nuclear DNA in glandular stomach, bladder (≥ 100 mg/kg) and colon tissue (≥ 10 mg/kg). Clastogenic activity was seen in bone marrow at dosages equivalent to an intake ≥ 80 mg/kg, but no carcinogenic effects were noted. The production process may result in unsulphonated aromatic amines to be present in concentrations of up to 100 mg/kg which may be linked to cancer. Also the EFSA panel noted that the JECFA limit for lead is ≤ 2 mg/kg whereas the EC specification is ≤ 10 mg/kg. The colour additive can also increase the intake of aluminium beyond the tolerable weekly intake (TWI) of 1 mg/kg/week. Therefore the limit for aluminum may become adjusted to accommodate for this.
Azobenzene
Azobenzene is a chemical compound composed of two phenyl rings linked by a N=N double bond. It is the best known example of an azo compound. The term 'azobenzene' or simply 'azo' is often used to refer to a wide class of molecules that share the core azobenzene structure, with different chemical functional groups extending from the phenyl rings. These azo compounds are considered as derivatives of diazene (diimide), and are sometimes referred to as 'diazenes'. The diazenes absorb light strongly and are used as dyes in a variety of industries.
Trans-cis isomerization
One of the most intriguing properties of azobenzene (and derivatives) is the photoisomerization of trans and cis isomers. The two isomers can be switched with particular wavelengths of light: ultraviolet light, which corresponds to the energy gap of the π-π* (S2 state) transition, for trans-to-cis conversion, and blue light, which is equivalent to that of the n-π* (S1 state) transition, for cis-to-trans isomerization. For a variety of reasons, the cis isomer is less stable than the trans (for instance, it has a distorted configuration and is less delocalized than the trans configuration). Thus, cis-azobenzene will thermally relax back to the trans via cis-to-trans isomerization. The trans isomer is more stable by approximately 50 kJ/mol, and the barrier to photo-isomerization is approximately 200 kJ/mol.
Spectroscopic classification
The wavelengths at which azobenzene isomerization occurs depends on the particular structure of each azo molecule, but they are typically grouped into three classes: the azobenzene-type molecules, the aminoazobenzenes, and the pseudo-stilbenes. These azos are yellow, orange, and red, respectively,owing to the subtle differences in their electronic absorption spectra. The compounds similar to the unsubstituted azobenzene exhibit a low-intensity n-π* absorption in the visible region, and a much higher intensity π-π* absorption in the ultraviolet. Azos that are ortho- or para-substituted with electron-donating groups (such as aminos), are classified as aminoazobenzenes, and tend to closely spaced n-π* and π-π* bands in the visible. The pseudo-stilbene class is characterized by substituting the 4 and 4' positions of the two azo rings with electron-donating and electron-withdrawing groups (that is, the two opposite ends of the aromatic system are functionalized). The addition of this push-pull configuration results in a strongly asymmetric electron distribution, which modifies a host of optical properties. In particular, it shifts the absorption spectra of the trans and the cis isomers, so that they effectively overlap.Thus, for these compounds a single wavelength of light in the visible region will induce both the forward and reverse isomerization. Under illumination, these molecules cycle between the two isomeric states.
Photoinduced motions
The photo-isomerization of azobenzene is a form of light-induced molecular motion.This isomerization can also lead to motion on larger length scales. For instance, polarized light will cause the molecules to isomerize and relax in random positions. However, those relaxed (trans) molecules that fall perpendicular to the incoming light polarization will no longer be able to absorb, and will remain fixed. Thus, there is a statistical enrichment of chromophores perpendicular to polarized light (orientational hole burning). Polarized irradiation will make an azo-material anisotropic and therefore optically birefringent and dichroic. This photo-orientation can also be used to orient other materials (especially in liquid crystal systems).For instance, it has been used to orient liquid crystal domains selectively, and to create nonlinear optical (NLO) materials. Azo isomerization can also be used to photo-switch the liquid crystal phase of a material from cholesteric to nematic or to change the pitch of a cholesteric phase.In 1995, it was reported that exposing a thin film of azo-polymer to a light intensity (or polarization) gradient leads to spontaneous surface patterns. In essence, the polymer material will reversibly deform so as to minimize the amount of material exposed to the light. This phenomenon is not laser ablation, since it readily occurs at low power and the transformation is reversible. The mechanism of this surface holography seems related to a new photomechanical effect, involving azobenzene isomerization.
Side Effects of Ponceau 4r
Ponceau 4r (e124) is a synthetic food color that is added to induce a red color in food. Its chemical name is trisodium salt of 1-(4-sulpho-1-napthylazo)- 2-napthol- 6,8-disulphonic acid. Ponceau red is a red food color, a red azo dye with its C.I. number being 16255 and C.I. name being Acid Red 18. Other popular names for ponceau 4r are Cochineal Red A, C.I. Acid Red 18, Brilliant Scarlet 3r, Brilliant Scarlet 4r, New Coccine, SX Purple and Food Red 7. But despite so many synonyms, it is popular as ponceau 4r only. The e number of the synthetic red food dye is e 124.
Ponceau food color is synthesized using coal tar. It is used to induce a red color in a variety of food products like sweets, jellies, desserts, tinned and canned fruits and foods, cakes, pastries, soups, soft drinks, canned beverages, etc.
Ponceau red is a synthetic red azo dye prepared from coal tar. Synthetic and artificial food products are notorious for causing allergic reactions and intolerances among a people consuming them, and ponceau e 124 is no different. The possible ill effects or the possible ponceau side effects can be listed as follows:
- Ponceau red 4r may elicit reactive responses in people who have an existing allergy to aspirin.
- Ponceau 4r is also infamous for aggravating an existing asthma problem.
- Ponceau 4r is considered to be a carcinogenic substance in many countries.
- Ponceau food color is also among the lot of food additives responsible for hyperactivity in young children and kids.
