Carotenoids as food colorants

Klaiii, H. and Bauernfeind, J.C., Carotenoids as food color, in Carotenoids as Colorants and Vitamin A Precursors, Bauernfeind, J.C., Ed., Academic Press, New York, 1981, 48. 

HT Gordon, JC Bauernfeind. Carotenoids as food colorants. CRC Crit Rev Food Sci Nutr 18 59-97, 1982. 

KLAUI H and BAUERNFEIND J c (1981), Carotenoids as food color , in Bauemfeind J C, Carotenoids as colorants and vitamin A precursors. Academic Press Inc., New York, pp 1-47. 

Gordon, HT and Bauemfeind, JC (1982) Carotenoids as food colorants. Crit. Rev. Food Sci. Nutr., 18, 59-97. 

Because of the multiple conjugated olefinic stmcture in the molecule, pure crystalline carotenoids are very sensitive to light and air and must be stored in sealed containers under vacuum or inert gas to prevent degradation. Thus, commercial utilization as food colorings was initially limited however, stable forms were developed and marketed as emulsions, oil solutions and suspensions, and spray-dried forms. 

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). 

Carotenoids are also present in animal products such as eggs, lobsters, greyflsh, and various types of hsh. In higher plants, they occur in photosynthetic tissues and choloroplasts where their color is masked by that of the more predominant green chlorophyll. The best known are P-carotene and lycopene but others are also used as food colorants a-carotene, y-carotene, bixin, norbixin, capsanthin, lycopene, and P-apo-8 -carotenal, the ethyl ester of P-apo-8-carotenic acid. These are Upid-soluble compounds, but the chemical industry manufactures water-dispersible preparations by formulating coUoid suspensions by emulsifying the carotenoids or by dispersing them in appropriate colloids. ... 

Breithanpt, D.E., Simultaneons HPLC determination of carotenoids nsed as food coloring additives applicability of accelerated solvent extraction. Food Chem., 86, 449, 2004. 

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. 

The chemical structure of some typical carotenoids is shown in Fig. 8.2. Beta-carotene occurs in nature usually associated with a number of chemically closely related pigments and extracts have been used as food colorants for many years. For example, palm oil has a high concentration of carotenoid pigments, primarily beta-carotene and about 20 others. Cmde palm oil has been used extensively as a cooking oil because of its desirable flavor and as a general... 

Lutein is a major component of many plants. It is a component of most of the carotenoid extracts suggested as food colorants. 

Several of the carotenoids are now commercially synthesized and used as food colors. A possible method of synthesis is described by Borenstein and Bunnell (1967). Beta-ionone is obtained from lemon grass oil and converted into a C14 aldehyde. The C14 aldehyde is changed to a C16 aldehyde, then to a C19 aldehyde. Two moles of the C19 aldehyde are condensed with acetylene dimagnesium bromide and, after a series of reactions, yield p-carotene. 

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... 

Vitamin A is used to fortify margarine and skim milk. It is added to margarine at a level of 3,525 IU per 100 g. Some of the carotenoids (provitamin A) are used as food colors. 

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