Synthetic colorants carotenoids

Canthaxanthin. The newest of the synthetically produced carotenoid color additives, canthaxanthin [514-78-3] (39) (P-carotene-4-4 -dione), became commercially available about 1969 (60). Its Cl designation is Food Orange 8, Cl No. 40850. Its EEC designation is E 160g. 

The colors of foods are the result of natural pigments or of added colorants. The natural pigments are a group of substances present in animal and vegetable products. The added colorants are regulated as food additives, but some of the synthetic colors, especially carotenoids, are considered nature identical ... 

Three synthetically produced carotenoids are used as food colorants, p-carotene, p-apo-8 -carotenal (apocarotenal), and can-thaxanthin. Because of their high tinctorial power, they are used at levels of 1 to 25 ppm... 

Animals that do not readily accept pelleted feeds may be enticed to do so if the feed carries an odor that induces ingestion. Color development is an important consideration in aquarium species and some animals produced for human food. External coloration is desired in aquarium species. Pink flesh in cultured salmon is desired by much of the consuming pubHc. Coloration, whether external or of the flesh, can be achieved by incorporating ingredients that contain pigments or by adding extracts or synthetic compounds. One class of additives that imparts color is the carotenoids. 

Carotenoids have two general characteristics of importance to the food iadustry they are not pH sensitive ia the normal 2—7 range found ia foods, and they are not affected by vitamin C, making them especially important for beverages. They are more expensive than synthetic food dyes and have a limited color range. In their natural environment they are quite stable, but they become more labile when heated or when they are ia solution. Under those conditions, there is a tendency for the trans-double bonds to isomerize to the cis-stmcture with a subsequent loss of color iatensity. The results of controlled tolerance and toxicity tests, usiag pure carotenoids, iadicate that they are perfecdy safe as food colors (132). 

Detailed information about carotenoids found in food or extracted from food and evaluated for their potential as food colorants appeared in Sections 4.2 and 6.2. We would like to mention some new data about the utilization of pure carotenoid molecules or extracts as allowed food additives. Looking to the list of E-coded natural colorants (Table 7.2.1), we can identify standardized colorants E160a through f, E 161a, and E161b as natural or semi-synthetic derivatives of carotenoids provided from carrots, annatto, tomatoes, paprika, and marigold. In addition, the extracts (powders or oleoresins) of saffron, - paprika, and marigold are considered more economical variants in the United States and European Union. 

There is as yet no agreed international list of permitted food colours. Thus a food dye that is permitted in one country may be considered unacceptable in another. The synthetic food colorants permitted in the European Union are listed in Table 1.8 [60]. All were originally introduced as acid dyes for wool many years ago. Furthermore, more than thirty colorants of natural origin are permitted in most countries. The natural carotenoid dyes are of outstanding importance for colouring edible fats and oils. These yellow to red methine dye structures occur in many families of plants and animals, including vegetables, berries,... 

The structures of four of the synthetic carotenoids (beta-carotene, canthaxanthin, beta-apo-8 -carotenol, beta-apo-8 -carotenoic acid) are shown in Fig. 8.2. By virtue of their conjugated double bond structure, they are susceptible to oxidation but formulations with antioxidants were developed to minimize oxidation. Carotenoids are classified as oil soluble but most foods require water soluble colorants thus three approaches were used to provide water dispersible preparations. These included formulation of colloidal suspensions, emulsification of oily solutions, and dispersion in suitable colloids. The Hoffman-LaRoche firm pioneered the development of synthetic carotenoid colorants and they obviously chose candidates with better technological properties. For example, the red canthaxanthin is similar in color to lycopene but much more stable. Carotenoid colorants are appropriate for a wide variety of foods.10 Regulations differ in other countries but the only synthetic carotenoids allowed in foods in the US are beta-carotene, canthaxanthin, and beta-8-carotenol. 

There is considerable current research under way to determine if the synthetic carotenoids have the same physiological effects, and consequent health benefits, as the naturally occurring compounds. If this proves to be true, we can expect increased interest in this group of colorants. 

Juices extracts (liquorize), spirits (orange, lemon), syrups (black currant), tinctures (ginger), and aromatic waters Mineral pigments (iron oxides), natural colorants, anthocyanins, carotenoids, chlorophylls riboflavine, red beetroot extract, and caramel synthetic organic dyes azo compounds... 

Margarine is colored with carotenoids, and synthetic p-carotene is by far the most widely used. Carotene dissolves very slowly in oil. Therefore, the compound is pulverized to a particle size of 2-5 pm and the microcrystals are suspended in oil to retard oxidation (228). Natural extracts containing carotenoids, for example, annatto (bixin), carrot oil, and red palm oil also have been used. Annatto, which is used in butter, is somewhat sensitive to light and may have an orange or slightly pink hue, particularly when the aqueous phase is acid (4). Mixtures of annatto and turmeric extracts result in a more typical color than annatto alone (229). Many margarine manufacturers purchase blends of colors and vitamins customized for their specific products. 

Various natural pigment classes, such as llavonoids, an-thocyanins, carotenoids, chlorophylls and chlorophyll derivatives, porphyrins, quinones, anthraqinones, be-talains, and so forth are abundant in many famihes of the vegetable and animal kingdoms. As consumers generally dislike the color of synthetic dyes, the concentration and composition of pigments in foods and food products exert a considerable impact on the consumer acceptance and, consequently, on the commercial value of the products. It has been proven many times that one of the main properties employed for the commercial evaluation of the quahty of products is their color that is, an adequate color is an important requirement of marketabihty. 

Of the 600 or so carotenoids found in nature, about 40 are regularly consumed by humans. Carotenoids are commonly found in yellow, orange and green fruit and vegetables, and naturally occurring carotenoids, either synthetic or from natural sources, are added to food to enhance color. Amongst the carotenoids often used as colorants are /3-carotene, lycopene, lutein, astaxanthin and canthaxanthin. 

Despite the availability of a variety of natural and synthetic carotenoids, there is currently renewed interest in microbial sources. Microorganisms accumulate several types of carotenoids as a part of their response to various environmental stresses. Microbial production of carotenoids, when compared with extraction from vegetables or chemical synthesis, seems to be of paramount interest mainly because of the problems of seasonal and geographic variability in the production and marketing of several of the colorants of plant origin. 

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