CLASSIFICATION OF FOOD COLORANTS
Food colorants have been categorized on the basis of different systems as indicated in Table 6.1. In these classification structures, the same type of colorants could be arranged in different groups. However, today, the most important classification trend is based on the origin and legislations of the colorants (Delgado-Vargas, Jimenez, & Paredes-L(5pez, 2000).
Considering the origin of the naturally occurring food colorants, they are categorized into natural, synthetic, or inorganic. Natural food colors originate from a wide range of sources like vegetables, fruits, plants, minerals, and other edible natural sources. They impart color when added to foods or
TABLE 6.1 Different Systems for Classification of Food Colorants
|
Classification System |
Groups |
Examples |
|
Origin of colorants |
Natural |
Carotenoids, anthocyanins, |
|
Synthetic |
FD&Ca colorants |
|
|
Inorganic |
TiO2 |
|
|
Structural characteristics |
Tetrapyrrole derivatives |
Chlorophylls and heme colors |
|
Isoprenoid derivatives |
Carotenoids and iridoids |
|
|
N-heterocyclic compounds different from tetrapyrroles |
Purines, pterins, flavins, phenazines, phenoxazines, and betalains |
|
|
Benzopyran derivatives (oxygenated heterocyclic compounds) |
Anthocyanins and other flavonoid pigments. |
|
|
Quinones Melanins |
Benzoquinone, naphthoquinone, anthraquinone |
|
|
Chemical structure of the colorants |
Chromophores with conjugated systems |
Carotenoids, anthocyanins, betalains, caramel, synthetic pigments and lakes. |
|
Metal-coordinated porphyrins |
Myoglobin, chlorophyll, and their derivatives |
aFD&C = Certifiable colorants permitted to be used for foods, drugs, and cosmetics.
beverages. Natural colors comprise a broad range of colorants indicating divergent solubility and stability properties. So, the chemical structure and stability of the intended natural colorants should be studied prior to usage in the food products in order to adapt them to the changing circumstances during processing, packaging, and distribution (Hendry & Houghton, 1996; Blanc, 2002).
Synthetic colorants generally have a negative impact on consumers, due to the possible deleterious effects of some synthetic pigments on human health, including allergic reactions, genotoxicity, and potential carcinogenicity (Caro et al., 2012). As a result, today the public prefers to consume foods which contain natural additives and are health-promoting. Thus, over the last few years, the interest of the food industry in replacing the artificial colorants with natural ones has enhanced dramatically, which is in line with the safety and regulatory issues as well as consumer concerns (Delgado-Vargas et al., 2000; Caro et al., 2012).
Generally, concerning the chemical structure of food colorants, they can be classified into six classes, namely, heme groups, carotenoids, chlorophylls, betalains, flavonoids, and miscellaneous colorants.
