Red 2G Research Articles

Natural clay membranes: A sustainable and affordable solution for treating dye solutions, coal mine washery waste, and aquaculture wastewater

In this study, we fabricated low-cost, sustainable inorganic membranes using a one-step dry compaction process that incorporates natural clay and edible glycerin, followed by sintering at low temperatures. Open porosity and permeability of the membranes were in the 33.6–45.2 % and 621.74–864.7 l/m2.h.bar range, respectively. Regarding molecular weight cut-off (MWCO) and mercury porosity of membranes with 33.6 % and 45.2 % porosity, the average pore size of the former was ~10 nm, while it was increased up to 10–70 nm, 0.9–3 μm, and ~ 10 μm for the latter. The membranes were subjected to filtration for dye solutions, coal mine washery waste, and aquaculture wastewater, resulting in remarkable removal efficiencies. Specifically, the membranes achieved removal rates of 99.8 % for direct blue 71, 92.44 % for disperse red 74, and 99.1 % for red 2G in dye solutions. Furthermore, they demonstrated removal efficiencies of 99.19 % for turbidity and 94.2 % for chemical oxygen demand (COD) in coal mine washery waste. The membranes removed 98.5 % of total suspended solids from the fish farm effluent. During extended periods of operation, the clay membrane exhibited remarkable stability and minimal leaching of metal ions. Superior properties, including low-cost, nontoxic, and accessible precursors, one-step uni-axial fabrication process without the need for lubricant and plasticizer, low sintering temperature compared to commercial ceramic membranes, promising long-term chemical stability in highly acidic and alkaline media, recyclability, and reproducibility, make the as-prepared membranes an affordable and sustainable solution for treating wastewater in various industries, including textile, mining, and aquaculture, thereby mitigating the environmental impact of these industries.

Average daily intake of artificially food color additives by school children in Saudi Arabia

Food safety is related to nutritional risk in children. This study is to determine the types of artificial food color additives (AFCAs) daily intake by school children aged 6 to 17 years for ten AFCAs. Sunset Yellow (E110), Tartrazine (E102), Carmoisine (E122), Brilliant Blue (E133), Allura Red (E129), Black PN (E151), Indigo Carmine (E132), and Fast Green (E143) were identified using 24 h food consumption questionnaire, including the two unapproved AFCAs, Red 2G (E128) and Erythrosine (E127) in 839 food products. These food products are distributed into nine categories, containing juices and drinks, ice cream, cakes, jelly, chocolates, candy, chips, biscuits, and chewing gum. Results showed that the artificial food colors, Carmoisine (32.3 %) and Sunset Yellow (30.1 %) were the most highly consumed AFCAs by school children, whereas Erythrosine (0.05 %) was consumed the least. Therefore, Sunset Yellow was highly consumed (30.1 %) and detected in high amounts by high performance liquid chromatography, (HPLC) 34.2 %. The average daily intake (ADI) of AFCAs decreased with age to varying degrees in both sexes. In comparison to the Food and Agriculture Organization and World Health Organization, acceptable daily intakes, most permitted colors exceeded their acceptable daily intakes (ADIs) in the 6–11 years of age groups, and most permitted colors were within the recommended ADIs in the 12–17 years of age group. The average daily intake of AFCAs by school children decreased with age. Therefore, further studies are required to gain information about the possible negative health effects of high intake of these AFCAs on the test population.

Development of ic-ELISA and colloidal cold-based immunochromatographic assay for red 2G detection in fruit drinks, red wine, and yoghurts

Red 2G (R2G), a cheap industrial colorant, cannot be added to food. An anti-R2G monoclonal antibody (mAb) was prepared by immunizing mice with the conjugate of R2G hapten and protein, which based on the 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) method. Indirect competitive enzyme-linked immunosorbent assay (ic-ELISA) and colloidal gold-based immunochromatographic assay (CG-ICA) methods were used to determine R2G in fruit drinks, red wine, and yoghurts. A standard curve of the developed ic-ELISA showed that the IC50 of the anti-R2G mAb was 1.02 ng/mL, and limit of detection value (LOD) was 0.21 ng/mL. For the CG-ICA developed, the visual limit of detection values (vLOD) were 2 ng/mL and cut-off values of 100 ng/mL in samples. The results indicated that these two methods could be used to quickly detect R2G in fruit drinks, red wine, and yoghurts.

Photocatalytic degradation of Red 2G on the suspended TiO2-hollow glass sphere

Photocatalytic degradation of Red 2G on the suspended TiO2-hollow glass sphere

Development and validation of spectrophotometric method for quantitative determination of carvedilol in tablets

INTRODUCTION: Carvedilol is in a class of medications called beta blockers. It works by relaxing blood vessels and slowing heart rate to improve blood flow and decrease blood pressure. AIM: The aim of this article is to develop a spectrophotometric method for the quantitative determination of carvedilol with diazonium salts, establish optimal conditions for the quantitative determination of carvedilol in drugs, and validate the developed methodology. MATERIALS AND METHODS: All studies were conducted on the basis of the experimental pharmaceutical research department of the scientific medical laboratory center (NMLC) of the Zaporozhye State Medical University. Reagents and solvents: 6.25 mg carvedilol tablets (PRANAPHARMJSC, Samara, series 20717), 12.5 mg Carvedilol Canon tablets (Canonpharma Production CJSC, Russia, series 060517), 25 mg Talliton tablets (EGIS Pharmaceuticals PLC, Hungary, series 473D0617), 25 mg Carvedilol-KV tablets (OJSC Kyiv Vitamin Plant, Kyiv, Ukraine, series EF 411017), diazol red 2G (NVF Sinbias), acetone, methanol, ethanol, isopropanol, water. Analytical equipment: SPECORD-200spectrophotometer (Analytic Jena AG, Germany), ULAB S131UV spectrophotometer, RADWAG XA 210.4Y electronic laboratory scales, Sonorex Digitec DT100H ultrasonic bath. RESULTS: The technique of spectrophotometric determination of the quantitative content of carvedilol based on its reaction with red diazole in water-methanol medium has been developed. The 1:1 stoichiometric ratios of the reactive components were obtained by the methods of continuous changes and the saturation method. CONCLUSION: A spectrophotometric method of analysis for the quantitative determination of carvedilol in tablets has been developed. The method is simple, fast, accurate, and reliable. This has been proven by verification characteristics (linearity, precision, correctness and sustainability). The developed methodology is correct and can be used in the chemical and pharmaceutical industries.

Extraction and determination of synthetic food dyes using tetraalkylammonium based liquid-liquid extraction

Tetraalkylammonium based liquid-liquid biphasic systems (employing room-temperature ionic liquids tetraoctylammonium N-lauroylsarcosinate, TOALS, and tetrahexylammonium dihexylsulfosuccinate, THADHSS, as well as tetrahexylammonium bromide, THABr) were used for liquid-liquid extraction of synthetic food dyes followed by spectrophotometric determination. Dyes studied are Allura Red AC, Red 2G, Azorubine, and Fast Green FCF (all anionic). Both extraction to pre-synthesized ILs and to ILs formed in situ was studied. The effects of pH, ionic liquid volume, dye concentration, time of extraction/centrifugation and other factors were investigated and optimum conditions were established. Dispersive liquid-liquid microextraction (DLLME) in situ is based on a metathesis between two salts which are suppliers of cations and anions of IL. It was found that efficiency of in situ DLLME with the studied ILs strongly depends on the ratio between cation and anion suppliers (THABr and NaDHSS/ NaLS, resp.) and drops sharply if an excess of anion supplier is used. Liquid-liquid extraction system using THABr was found to be superior for preconcentration and spectrophotometric determination of Allura Red AC and Azorubine in food samples. Under optimal conditions, recovery of all analytes was nearly 100%. Linear calibration curves in the range of 0.05–4.95 mg L−1 for Allura Red AC and 0.05–2.00 mg L−1 for Azorubine were obtained. Detection limits based on 3Sb were 0.004 and 0.006 mg L−1 for Allura Red and Azorubine, respectively. The proposed method was applied to determination of Allura Red and Azorubine in beverage and Easter egg coloring set.

Dietary intake of artificial food color additives containing food products by school-going children.

Nutritional risk in children is associated with food safety. This is the first study to identify the food type consumed by 6–17-year-old school-going children in Saudi Arabia. Eight permitted artificial food color additives, including Tartrazine (E102), Sunset Yellow (E110), Carmoisine (E122), Allura Red (E129), Indigo Carmine (E132), Brilliant Blue (E133), Fast Green (E143), and Black PN (E151), and two non-permitted ones, Erythrosine (E127) and Red 2G (E128), were determined using 24-h dietary recall questionnaires. Artificial color additives in 839 food products were divided into nine categories, including biscuits, cakes, chocolates, chips, ice cream, juices and drinks, candy, jelly, and chewing gum, are determined using high performance liquid chromatography and diode array detector. The results indicated a high intake of juices and drinks, ice cream, and cakes, but low consumption of chewing gum among school-going children. Among the permitted artificial food color additives, Brilliant Blue (E133) (54.1%) and Tartrazine (E102) (42.3%) were the most commonly used. Sunset Yellow (E110) in one chocolate sample, Tartrazine (E102) and Sunset Yellow (E110) in one and two juice and drink samples, respectively, and Brilliant Blue (E133) in two candy samples exceeded the permitted level. Therefore, further investigations are needed to provide insights into the possible adverse health effects of high intake of these additives in artificial food coloring on the test population are warranted.

Fast separation of red colorants in beverages using cyano monolithic column in Sequential Injection Chromatography

Flexible medium-pressure Sequential Injection Chromatography (SIC) flow manifold was used for development of a fast green chromatography method. The article presents novel use of a cyano monolithic column (Merck Chromolith 50mm×4.6mm) for a separation of three water soluble colorants (carmoisine, Ponceau 4R and red 2G), aiming the extension of the SIC separation capabilities for polar analytes. The separation was performed in a gradient elution mode with changing concentration (0.05–0.005% v/v) of ammonium phosphate at pH6.0 as a mobile phase. No organic modifier was used in mobile phase, thus the green chromatography rules were fulfilled. The vis spectrophotometric detection was set at 500nm. High performance of the separation with the cyano monolithic column was described and discussed (peak capacities 6.67–10.94, peak symmetries 1.11–1.50, resolutions ≥2.78 and time for one analysis 3.15min). The method was represented by analytical parameters - LODs of 0.45mgL−1, a LOQs of 1.5mgL−1 and calibration range of 1.5–60.0mgL−1 (r>0.997) for all analytes, and a method repeatability at 10mgL−1 of RSD≤2.69% (n=5) and system precision of RSD<1.55% (n=6). The developed method was used for determination of carmoisine and Ponceau 4R in red coloured beverages with red 2G as an internal standard. The results confirmed benefits of extended chromatographic selectivity of cyano monolithic column in the SIC.

Simultaneous determination of synthetic dyes in foodstuffs and beverages by high-performance liquid chromatography coupled with diode-array detector

Abstract Synthetic dyes are added to food and drinks to restore their original appearance when color is affected by processing, storage, packaging and distribution. Furthermore colors are used to make food more visually attractive to consumers. The EU Directive 1994/36/CE lists the permitted substances that can be used in foodstuffs. In order to investigate the content of some permitted and non-permitted dyes in food and drinks, a sensitive and helpful method has been developed to determine simultaneously seventeen synthetic colorants by high-performance liquid chromatography coupled with a diode-array detector in solid food matrices and beverages. Substances involved were azorubine (E122), amaranth (E123), cochineal red A (E124), red 2G (E128), allura red (E129), azocarmine B (AZO B), azocarmine G (AZO G), ponceau 2R (P2R), ponceau 6R (P6R), tartrazine (E102), sunset yellow (E110), quinoline yellow (E104), orange II (OR II), metanil yellow (MY), patent blue V (E131), indigo carmine (E132) and brilliant blue FCF (E133). Solid food matrices were extracted by a water–alcohol mixture, cleaned up on a polyamide SPE cartridge and eluted with basic methanol solution. Otherwise a simple dilution and filtration of samples were used for drinks. The method has been validated according to Regulation (2004/882/CE) and could be applied to a concentration range between 5 and 300 mg kg−1 (5–100 mg l−1 for drinks) depending on the dye. The accuracy (precision and trueness) and specificity were assessed. During years 2009–2011 many food samples for the detection of synthetic colorants were analyzed. Most of them were fresh fishery products in which the use of food colorant is banned.

Simultaneous determination of 11 restricted dyes in cosmetics by ultra high-performance liquid chromatography/tandem mass spectrometry

A simple, fast, and sensitive method was developed for the simultaneous determination of 11 restricted water-soluble colorants (including Tartrazine, Amaranth, Ponceau 4RC, Sunset Yellow, Allura Red AC, Acid Red 2G, Ponceau SX, Brilliant Blue FCF, Orange I, Acid Black 1, and Acid Orange 7) in eye shadow, lipstick, lip gloss, and other cosmetics by using ultra-high performance liquid chromatography/tandem mass spectrometry (UPLC–MS/MS). The conditions of sample preparation and separation were optimized. The UPLC separation was performed on a UPLC HSS T3 column with acetonitrile-water as the mobile phase. The results showed that the 11 investigated dyes displayed good peak shape within 4 min. The linear ranges were between 0.1 and 50 μg L−1, and the linear correlation coefficients were high (≥0.9942). The limits of quantification were in the range of 4.1–100 μg kg−1. Dyes that spiked in eye shadow, lipstick, and lip gloss in the range of 0.005–2.0 mg kg−1 were tested in terms of sensitivity, repeatability, and recovery. Recoveries obtained for the dyes ranged from 81.6% to 118.2%. Intraday and interday precisions (relative standard deviations) were less than 8%. The results confirmed that UPLC–MS/MS method could be a fast and quantitative technique for the simultaneous determination of restricted dyes in cosmetics.

Dye Concentration Calculations Using Derivative Ratio Method in an Online and &lt;i&gt;In Situ&lt;/i&gt; Optical Fibre Dyeing Sensing System

The objective of this work was to discuss a calculation method of dye concentration in mixed dye bath, to develop an optical fibre sensing system for in-situ monitoring of dye concentrations in a dye bath and control the rate of exhaustion to ensure that the dyeing process yields the desired product. A designed optical fibre sensing system was proved to be practicable to measure the single dye concentration accurately, it is important to chance right calculation method in measuring mixed dye bath concentration. The experiment prepared known concentration mixture with reactive red 2G and yellow 4G. Based on measured absorption spectra, dyes concentrations were calculated by derivative ratio method. The calculated results were compared with the prepared concentrations. The accuracy was discussed. The results show that calculated dyes concentration by derivative ratio method well matched the prepared value at the certain concentration range.

Re-evaluation of synthetic colours: State of the art

Food colours are used in foodstuffs such as soft drinks, bakeryproducts, desserts, sauces and confectionery to make them visually appealing to consumers. The most common synthetic food colours are mono-, di- and tri-azo dyes; triarylmethyl, quinoline, xanthene and indigoid structures are also used. Safety assessmentsof food colours date back many years, and consequently the 45 currently permitted food colours are undergoing re-evaluation by the European Food Safety Authority's (EFSA) Scientific Panel on Additives and Nutrient Sources in Food (ANS). This talk describes the re-evaluation of the synthetic food colours. The results to date have indicated some gaps in the toxicological data, particularly in relation to reproductive toxicity. EFSA has lowered the Acceptable Daily Intake (ADI) for several of these colours, and the authorisation for the colour Red 2G was withdrawn because of concerns regarding genotoxicity and carcinogenicity. The re-evaluation of six of the synthetic colours, Tartrazine (E102), Quinoline Yellow (E104), Sunset Yellow FCF (E110), Azorubine/Carmoisine (E122), Ponceau 4R (E124)and Allura Red AC (E129) was prioritised after a study published in 2008 by Southampton University linked consumption of these colours with hyperactivity in children. The ANS Panel concluded that the study provided limited evidence that certain mixtures of these food colours could have a small effect on some children's activity and attention, but overall the study did not justify changing the ADIs for the individual colours involved. However the Panel considered that the ADIs for Ponceau 4R, Quinoline Yellow and Sunset Yellow should be lowered, on different toxicological grounds.

Consideration of fluorescence properties for the direct determination of erythrosine in saffron in the presence of other synthetic dyes

Direct selective detection of erythrosine in saffron in the presence of other synthetic dyes considers its fluorescence at 532 nm excitation/548 nm emission. Saffron pre-treatment was according to the ISO 3632-2 trade standard test methods. On account of calculated quantum yield values, none of the yellow dyes is expected to interfere. Among red ones, reservations about allura red AC, azorubine and red 2G were not verified by experimentation, signifying excellent method specificity. Detection and quantification limits (0.56 and 1.70 nM) were of the same magnitude as those reported in the literature after chromatographic separation of erythrosine. The percentage recovery from spiked saffron samples ranging from 63 to 141 was acceptable for residue levels in foods. The matrix effect from crocins (saffron pigments) was evidenced only at a lower spiking level (0.02 mg kg−1). The minimum required performance limit (MRPL) was 0.04 mg kg−1, indicating that the method is appropriate for determining traces of erythrosine in saffron. The approach offers improved sensitivity (by three orders of magnitude) and specificity than the direct spectrophotometric detection of certain synthetic dyes in saffron and deserves attention by the ISO Technical Committee for ‘Herbs, culinary spices and condiments’.

Legal and illegal colours

Food additives are evaluated by the European Food Safety Authority's (EFSA) Scientific Panel on Food Additives, Flavourings, Processing Aids and Materials in Contact with Food (the AFC Panel). The AFC Panel is supported by its standing working group on food additives (WG ADD), which prepares draft opinions on food additives, including colours, and on the bioavailability and safety of nutrient sources. The WG ADD consists of several members from the AFC Panel together with selected external experts. The draft opinions go forward to the AFC Panel for discussion and final adoption. The adopted opinions are published on the EFSA web site. During its first 5 years of existence the AFC Panel has experienced the highest workload of all EFSA Panels, of which evaluations of food additives have been a substantial part. Although the AFC Panel has issued many opinions on food additives, some of which have been widely debated, such as opinions on aspartame [EFSA. (2006). Opinion of the Scientific Panel on Food Additives, Flavourings, Processing Aids and Materials in Contact with Food (AFC) related to a new long-term carcinogenicity study on aspartame. Opinion expressed on 03/05/2006. Available at http://www.efsa.europa.eu/EFSA/efsa_locale-1178620753812_1178620765743.htm . Accessed 12.05.08.] and parabens [EFSA. (2004). Opinion of the Scientific Panel on Food Additives, Flavourings, Processing Aids and Materials in Contact with Food (AFC) related to para hydroxybenzoates (214e219). Opinion expressed on 13/07/2004. Available at http://www.efsa.europa.eu/EFSA/efsa_locale-1178620753812_1178620761956.htm . Accessed 12.05.08.] this paper only deals with some of the major issues that the Panel has faced in relation to the use of food colours. The three topics to be dealt with are (1) evaluation of illegal colours in food in the EU (EFSA, 2005), (2) re-evaluation of the authorised food colours in the EU (ongoing, but one opinion on Red 2G has been published; EFSA, 2007), and (3) evaluation of “the Southampton study” on hyperactivity in children after intake of food colours (and sodium benzoate) (ongoing at the time of this presentation, but an opinion has now been published; EFSA, 2008).

Rapid analysis of azo‐dyes in food by microchip electrophoresis with electrochemical detection

A method based on microchip electrophoresis with electrochemical (EC) detection has been developed for the simultaneous determination of Yellow AB, Red 2G, Sunset Yellow, New Coccine, and Amaranth which are azo-dyes frequently added to foodstuffs. Factors affecting both separation and detection processes were examined and optimized, with best performance achieved by using a 10 mM phosphate buffer (pH 11) as BGE solution and applying a voltage of 2500 V both in the separation and in the electrokinetic injection (duration 4 s). Under these optimal conditions, the target dye analytes could be separated and detected within 300 s by applying a detection potential of -1.0 V (vs. Ag/AgCl) to the glassy carbon (GC) working electrode. The recorded peaks were characterized by a good repeatability (RSD=1.8-3.2%), high sensitivity, and a wide linear range. Detection limits of 3.8, 3.4, 3.6, 9.1, 15.1 microM were obtained for Yellow AB, Red 2G, Sunset Yellow, New Coccine, and Amaranth, respectively. Fast, sensitive, and selective response makes the new microchip protocol very attractive for the quantitative analysis of commercial soft drinks and candies.

Opinion of the Scientific Panel on food additives, flavourings, processing aids and materials in contact with food (AFC) on the food colour Red 2G (E128) based on a request from the Commission related to the re-evaluation of all permitted food additives

Opinion of the Scientific Panel on food additives, flavourings, processing aids and materials in contact with food (AFC) on the food colour Red 2G (E128) based on a request from the Commission related to the re-evaluation of all permitted food additives

Sensitive determination of erythrosine and other red food colorants using capillary electrophoresis with laser-induced fluorescence detection

Capillary electrophoresis with laser-induced fluorescence detection (CE–LIF) was applied to separation and sensitive determination of red food colorants. Diode pumped frequency-doubled Nd:YAG laser (532 nm) was used as an excitation source in a laboratory-built CE–LIF system. For highly fluorescent erythrosine B (E127), an extrapolated limit of detection (LOD) of 0.4 ng mL −1 (S/N = 3) was achieved. Extrapolated LODs of other tested red additives, such as carmoisine, E122 (0.5 μg mL −1); amaranth, E123 (0.2 μg mL −1); ponceau 4R, E124 (0.3 μg mL −1) and red 2G, E128 (0.3 μg mL −1) were about one-order lower compared to results obtained with CE with absorbance detection in UV/vis (CE–UV/vis). The main advantages of using CE–LIF for analysis of food samples are high selectivity and minimization of matrix effect. To our knowledge, this is the first use of CE–LIF for determination of red food colorants.

Determination of 13 synthetic food colorants in water-soluble foods by reversed-phase high-performance liquid chromatography coupled with diode-array detector

A reversed-phase high performance liquid chromatographic method for the successful separation and determination of 13 synthetic food colorants (Tartrazine E 102, Quinoline Yellow E 104, Sunset Yellow E 110, Carmoisine E 122, Amaranth E 123, Ponceau 4R E 124, Erythrosine E 127, Red 2G E 128, Allura Red AC E 129, Patent Blue V E 131, Indigo Carmine E 132, Brilliant Blue FCF E 133 and Green S E 142) was developed. A C18 stationary phase was used and the mobile phase contained an acetonitrile–methanol (20:80 v/v) mixture and a 1% (m/v) ammonium acetate buffer solution at pH 7.5. Successful separation was obtained for all the compounds using an optimized gradient elution within 29 min. The diode-array detector was used to monitor the colorants between 350 and 800 nm. The method was thoroughly validated. Detection limits for all substances varied between 1.59 (E 142) and 22.1 (E 124) μg L −1. The intra-day precision (as R.S.D. r) ranged from 0.37% (E 122 in fruit flavored drink at a concentration of 100 mg L −1) to 4.8% (E 142 in icing sugar at a level of 0.9 mg kg −1). The inter-day precision (as R.S.D. R) was between 0.86% for E 122 in fruit flavored drink at 100 mg L −1 and 10% for E142 in jam at a concentration of 9 mg kg −1. Satisfactory recoveries, ranging from 94% (E 142 in jam) to 102% (E 131 in sweets), were obtained. The method was applied to the determination of colorants in various water-soluble foods, such as fruit flavoured drinks, alcoholic drinks, jams, sugar confectionery and sweets, with simple pre-treatment (dilution or water extraction).

Screening method for the detection of artificial colours in saffron using derivative UV-Vis spectrometry after precipitation of crocetin

A screening method for the detection of artificial colours (naphthol yellow, tartrazine, quinoline yellow, Sunset yellow, Allura red, amaranth, azorubine, Ponceau 4R and Red 2G) in saffron is described. The method involves removal of crocins by precipitation of crocetin (pH 0.1, 90°C) before adsorption of the artificial colours on polyamide SPE cartridges (pH 2). After washing with methanol, acetone and methanol, elution was done with a methanol:ammonia solution (95:5 v/v), and detection was performed by derivative spectrometry. Sample pretreatment changes the UV-Vis saffron extract profile in such a way that second derivative spectra can be used to identify the presence of added colours. Erythrosine, which was found to be pH dependent, could not be detected under the above conditions. The lowest detectable amount for each colour was strongly dependent on chemical structure. The recovery of carminic acid was very low possibly due to irreversible retention on the polyamide. This procedure can replace the current ISO TLC method (2003) and be used alternatively or in combination with HPLC procedures adopted in the same standard.

Assessment of the TEAC method for determining the antioxidant capacity of synthetic red food colorants

The TEAC method was used to evaluate the antioxidant capacity of six synthetic red food colorants (azorubine, amaranth, ponceau 4R, erythrosine, red 2G and allura red AC). This method assesses the ability of such compounds to scavenge the stable radical cation chromophore ABTS + , comparing it with that of Trolox, a water soluble vitamin E analogue. It is simple, fast (6 min) and, at the wavelength used for measurements (735 nm) does not interfere with the absorption maxima of the colorants. The experiments showed an antioxidant ranking of allura red AC > azorubine > amaranth > red 2G > erythrosine > ponceau 4R. Their corresponding TEAC values were 0.029, 0.026, 0.019, 0.018, 0.016 and 0.007, respectively.