ReviewAnthraquinones, the Dr Jekyll and Mr Hyde of the food pigment family
Introduction
Natural pigments and colorants used in food belong to diverse chemical groups, such as carotenoids, anthocyanins, chlorophylls, betalains, melanins, or flavins. The stability of these natural colorants is quite an issue because they are highly unsaturated compounds sensitive to light, heat, and oxygen. Carminic acid, carmine and cochineal extract are among the more stable food pigments and colorants. Their structures are based on the anthraquinone skeleton (Fig. 1). Among this largest group of pigments of quinoid nature (700 compounds), most of the anthraquinones of interest are derivatives of the basic structure 9,10-anthracenedione, tricyclic aromatic organic compounds with formula C14H8O2. Hydroxyanthraquinoid (HAQN) usually refers to hydroxylated 9,10-anthracenedione (from mono-, di-, tri-, tetra-, up (theoretically) to octa-). HAQNs absorb visible light and are colored. Anthraquinones can be found in plants, insects, lichens and filamentous fungi (Caro et al., 2012, Gessler et al., 2013).
The present review summarizes the past and current uses of anthraquinone derivatives in the food industry, compares the benefits (Dr Jekyll) and the inconveniences (Mr Hyde) of three molecules, and gives exploration trends about new sources or production processes.
Section snippets
Case study #1: European madder root extract
The roots of the well-known plant madder Rubia tinctorum L. (family: Rubiaceae) (Fig. 2a) supply a number of coloring HAQN substances. Its pigments are present as glycosides and aglycones, up to 2–3.5% of dry weight. The color shades of madder vary from scarlet, carmine red, pink (high content of pseudopurpurin and/or purpurin, called pink madder or rose madder), to red with a bluish tint (alizarin lakes).
Madder color was long accepted for use as a food additive in Japan and South-Korea, but
Case study #2: carminic acid, carmine, cochineal extract
Carminic acid, carmine, and cochineal extract are produced in Peru, Bolivia, Mexico, Chile and Spain (Canary islands) from the dried bodies of female cochineal insects (Dactylopius coccus) (Fig. 2B), primarily grown on Opuntia cacti. The pigments can create red, orange, purple and pink shades depending on formulation.
These dyes are allowed by most of the food laws in different countries, such as the Food and Drug Administration (FDA) of the USA and the European Union where the food additive
Case study #3: fungal Arpink Red™, now Natural Red™
Penetration of the fermentation-derived ingredients into the food industries is increasing year after year. Examples could be taken from the following fields: thickening or gelling agents (xanthan, curdlan, gellan), flavor enhancers (yeast hydrolysate, monosodium glutamate), flavor compounds (gamma-decalactone, diacetyl, methyl-ketones), acidulants (lactic acid, citric acid), etc. Efforts have been made in order to reduce the production costs of pigments produced by microbial fermentation
Other fungal anthraquinones
Anthraquinones are widely spread in the kingdom of fungi and could be alternative sources independent of agro-climatic conditions compared to plant ones. For example, anthraquinones were found in Aspergillus spp., Eurotium spp., Fusarium spp., Drechslera spp., Penicillium spp., Emericella purpurea, Curvularia lunata, Mycosphaerella rubella, Microsporum sp., etc. (Caro et al., 2012, Gessler et al., 2013).
Anthraquinones exhibit a broad range of biological activities, including bacteriostatic,
Conclusions
Focus on anthraquinones as potential food colorants is quite a recent issue (Caro et al., 2012). Unsubstituted anthraquinone has a weak yellow color and substituents confer various hues to the molecule (yellow, orange, orange-brown, red, brown, bronze, violet…).
Many plant and fungal anthraquinones have long been used in folk medicine. Anthraquinones are active components of many plant blends used as medicines (Yan, Zhang, Sun, Jiang, & Xiao, 2006) and have laxative, diuretic, anticancer,
Acknowledgments
Laurent Dufossé, the head of Microbial Pigment Group at Laboratoire de Chimie des Substances Naturelles et des Sciences des Aliments, Université de La Réunion, would like to thank his colleagues Yanis Caro and Mireille Fouillaud for their involvement in fungal anthraquinone research, Cathie Milhau for logistic and technical help, and trainees Linda Anamale, Juliana Lebeau and Mélissa Llorente for conducting lab experiments.
References (23)
- et al.
Popsicle-induced anaphylaxis due to carmine dye allergy
Annals of Allergy, Asthma, and Immunology
(1997) - et al.
Natural dyes extraction from cochineal (Dactylopius coccus). New extraction methods
Food Chemistry
(2012) - et al.
Filamentous fungi are large-scale producers of pigments and colorants for the food industry
Current Opinion in Biotechnology
(2014) - et al.
Microorganisms and microalgae as sources of pigments for food use: A scientific oddity or an industrial reality?
Trends in Food Science & Technology
(2005) - et al.
Induction of kidney and liver cancers by the natural food additive madder color in a two-year rat carcinogenicity study
Food and Chemical Toxicology
(2009) - et al.
Protection against the bacterial mutagenicity of heterocyclic amines by purpurin, a natural anthraquinone pigment
Mutation Research
(1999) - et al.
Preventive effects of anthraquinone food pigments on the DNA damage induced by carcinogens in Drosophila
Mutation Research
(2001) - et al.
Nephrotoxicity study of total rhubarb anthraquinones on Sprague Dawley rats using DNA microarrays
Journal of Ethnopharmacology
(2006) - et al.
Occupational asthma and food allergy due to carmine
Allergy
(1998) - et al.
Food anaphylaxis following ingestion of carmine
Annals of Allergy, Asthma, and Immunology
(1995)
Natural hydroxyanthraquinoid pigments as potent food grade colorants: An overview
Natural Products and Bioprospecting
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