Colourings caramel

Essence of Vanilla.—The substance sold under this name is, properly, a spirituous extract of the vanilla bean. Many samples, however, are little more than alcoholic solutions of artificial vanillin, coloured with caramel. Some samples, which cannot be described as adulterated, contain a little coumarin or other odorous substance, added to varj- the characteristic vanillin odour and flavour somewhat. 

Tests for Caramel.—Valuable indications of the nature of an extract are obtained in the process of determination of vanillin and coumarin. Pure extracts of vanilla beans give, with lead acetate, a bulky, more or less glutinous, brown-grey precipitate, and a yellow or straw-coloured filtrate, whereas purely artificial extracts coloured with caramel give a slight dark brown precipitate and a dark brown filtrate. If both vanilla bean extract and caramel are present the precipitate is more or less bulky and dark coloured, and the filtrate is more or less brown. The soluticm remaining after extraction of the vanillin and coumarin with ether, if dark coloured, should be tested for caramel. 

The most satisfactory test for caramel is to shake with Fuller s earth, as recommended - by Crampton and Simons. If the colour is due to caramel and a grade of I uller s earth is used, which experience has proved suitable, the solution, after filtering, is yellow or colourless. This test does not positively identify the colour, as some other brown substances may give similar reactions, but no such substance is liable to be present in vanilla extract. 

Chapell, C.I. and Howell, J.C., Characterization ans specifications of caramel colours an overview. Food Chem. Toxicol, 30, 351,1992. 

Coffey, J.S. and Castle, L., Analysis for caramel colour (Class III), Food Chem., 51, 413, 1994. 

Licht, B. et al.. Characterization of caramel colour IV, Food Chem. Toxicol., 30, 365,... 

Food colourant analysis characterisation of caramel colours and discrimination of malts from malt extracts. 

To provide data on the composition and heterogeneity of caramels Class I and IV and to provide test results on concentrated colour and flavour properties. 

To assess the use of HPLC and fluorophore assisted carbohydrate gel electrophoresis as a means of profiling caramel colour types III and IV. 

Natural colours include annatto, anthocyanins, beetroot red (betalaines), caramel, carotenoids, cochineal and lac pigments, flavanoids, chlorophylls and tumeric. There is a trend towards encapsulating natural colours for food use, but this is not yet reflected in the extraction techniques described in the published analytical methods. Lancaster and Lawrence (1996) described the extraction and... 

Numerous CE separations have been published for synthetic colours, sweeteners and preservatives (Frazier et al., 2000a Sadecka and Polonsky, 2000 Frazier et al., 2000b). A rapid CZE separation with diode array detection for six common synthetic food dyes in beverages, jellies and symps was described by Perez-Urquiza and Beltran (2000). Kuo et al. (1998) separated eight colours within 10 minutes using a pH 9.5 borax-NaOH buffer containing 5 mM /3-cyclodextrin. This latter method was suitable for separation of synthetic food colours in ice-cream bars and fmit soda drinks with very limited sample preparation. However the procedure was not validated for quantitative analysis. A review of natural colours and pigments analysis was made by Watanabe and Terabe (2000). Da Costa et al. (2000) reviewed the analysis of anthocyanin colours by CE and HPLC but concluded that the latter technique is more robust and applicable to complex sample types. Caramel type IV in soft drinks was identified and quantified by CE (Royle et al., 1998). 

There is a recent trend towards simultaneous CE separations of several classes of food additives. This has so far been applied to soft drinks and preserved fruits, but could also be used for other food products. An MEKC method was published (Lin et al., 2000) for simultaneous separation of intense sweeteners (dulcin, aspartame, saccharin and acesulfame K) and some preservatives (sorbic and benzoic acids, sodium dehydroacetate, methyl-, ethyl-, propyl- and isopropyl- p-hydroxybenzoates) in preserved fruits. Ion pair extraction and SPE cleanup were used prior to CE analysis. The average recovery of these various additives was 90% with good within-laboratory reproducibility of results. Another procedure was described by Frazier et al. (2000b) for separation of intense sweeteners, preservatives and colours as well as caffeine and caramel in soft drinks. Using the MEKC mode, separation was obtained in 15 min. The aqueous phase was 20 mM carbonate buffer at pH 9.5 and the micellar phase was 62 mM sodium dodecyl sulphate. A diode array detector was used for quantification in the range 190-600 nm, and limits of quantification of 0.01 mg/1 per analyte were reported. The authors observed that their procedure requires further validation for quantitative analysis. 

Cachaqa and aguardente de cana are the most consumed distilled spirits in Brazil exclusively made from cane-sugar juice. Sugar and caramel maybe added for colour adjustment. The total content of congeners is between 200 and 650 mg 0.1 L p.e. Like other spirits, the flavour of cacha a is mainly characterised by the presence of fermentation by-products such as higher alcohols, esters, carboxylic acids, and carbonyl compounds [41-43]. 

Lemonade shandy is made with shandy ale , a bitter beer brewed to 6.5% ABV to minimise transport costs. For colouring the product it is important to use an ammonia caramel as the sulphite ammonia caramels used for conventional soft drinks will react with tannins in the beer and precipitate out. 

In White Wines.—White wines may be coloured artificially with caramel or artificial organic dyes (substitutes for caramel, caramelin). The latter are detected as in red wines in this connection it should be borne in mind that the yellow colours usually added to wines do not consist of individual colouring matters but are mixtures of a yellow material with a brown, a red or, sometimes, a blue compound. 

From the colour of the filtrate the amount of caramel added may be judged. 

Cognac may also be coloured by addition of other substances, especially caramel or artificial organic colouring matters. 

Such SMP stored at 52 °C developed a brown colour and caramel odour in only 3.5 weeks, no peaks being evident on the e-gram. Even with storage at 37 °C, both /J-lactoglobulin and /J-casein suffered more modification than at lower temperatures, starting at week 2. 

---