Food Colourings

Category: Health | Vida Vertical

Summary

The appearance of food strongly influences expectations of taste and quality. To compensate for colour changes caused by processing and to standardise products, the food industry uses natural and synthetic colourings. This article describes their biochemical categories and toxicological assessment, including debate about azo dyes and the European Union’s ban on titanium dioxide (E171) as a food additive. It concludes by considering how controlled hydroponic and aquaponic cultivation can provide naturally pigmented plant foods without added colourings.

1. Introduction: the psychology of colour and industrial uses

Eating is a multisensory process, and visual appearance shapes perceptions of freshness, ripeness and safety. Heating, storage and oxidation can fade natural pigments in mass-produced foods. Colour additives are therefore used to improve or standardise appearance and support product identity.

Some colourings originate from natural materials while others are synthesised. Origin alone does not determine safety: each authorised substance must be assessed by identity, exposure and toxicological evidence.

2. Biochemical classification of colourings

The European Union authorises a range of food colours, many within E-numbers 100 to 180. They can be described in several broad categories:

2.1 Colours from natural sources

These pigments are obtained from plant, animal or mineral sources and correspond to compounds found in nature. Examples include:

• Chlorophylls (E140):Green photosynthetic pigments used, for example, in some confectionery and preserved vegetables.
• Carotenoids (E160a):Yellow-to-orange pigments used in products including butter, margarine and cheese.
• Betanin (E162):The intense red pigment from beetroot.
• Anthocyanins (E163):Water-soluble plant pigments that appear red, purple or blue depending on pH.

2.2 Synthetic colours, including azo dyes

Azo dyes are an important group of synthetic food colours valued for stability, lightfastness and low production cost. Examples include tartrazine (E102), quinoline yellow (E104), sunset yellow FCF (E110) and allura red AC (E129), used in some confectionery, drinks, desserts and snacks.

2.3 Nature-identical colours

These have the same chemical structure as compounds found in nature but are manufactured synthetically, such as some beta-carotene or riboflavin (E101). Regulatory classification may depend on production method and specification.

3. Toxicology and pharmacokinetic properties

The European Food Safety Authority (EFSA) assesses food additives and establishes acceptable daily intakes or use conditions where appropriate. Some synthetic colours containsulfonate groups in their molecular structure.

that increase water solubility. This can limit partitioning into fatty tissues and facilitate gastrointestinal passage, metabolism or renal excretion. It does not by itself prove absence of toxicity; safety assessment also considers metabolites, exposure, hypersensitivity, genotoxicity and other endpoints.

4. Physiological risks and regulatory consequences

4.1 Certain colours and children’s activity

The Southampton study reported small group-level effects on activity and attention after children consumed mixtures of certain colours with sodium benzoate. The study did not isolate the effect of each colour and individual responses vary. EU rules nevertheless require foods containing E102, E104, E110, E122, E124 or E129 to carry the warning:

“May have an adverse effect on activity and attention in children.”

4.2 Hypersensitivity potential

Both synthetic and naturally sourced colours, including cochineal carmine (E120), can rarely cause hypersensitivity reactions such as urticaria or asthma symptoms in susceptible people.

4.3 The ban on titanium dioxide (E171)

Titanium dioxide was formerly used as a white pigment and opacifier in foods. EFSA’s 2021 re-evaluation concluded that concern for genotoxicity after oral exposure could not be ruled out. The EU subsequently prohibited E171 as a food additive from 2022 under a precautionary approach. Uses in medicines and other products are regulated separately.

5. Relevance to Vida Vertical: natural pigment synthesis in controlled cultivation

As a specialist in aquaponics and hydroponics, I view pigments not only as food additives but also asplant secondary metaboliteswith functions in plants. Anthocyanins, carotenoids and chlorophylls participate in light capture, photoprotection and responses to environmental stress. In human diets, naturally pigmented foods provide a mixture of nutrients and phytochemicals, but individual pigments should not automatically be treated as potent disease-preventing agents.

Controlled vertical cultivation can influence pigment biosynthesis without adding colours to harvested foods:

1. Light spectrum and pigmentationPlants adapt pigment production to light conditions. Blue light or carefully controlled UV-A exposure can stimulate anthocyanin and carotenoid synthesis in some crops. Lettuce, microgreens and herbs may develop stronger colour and altered antioxidant measurements, but results depend on species, dose and environment and are not always superior to field-grown produce.

2. Microgreens as sources of pigmentsMicrogreens can contain high concentrations of certain phytochemicals and pigments compared with mature tissues, but differences vary widely by species, compound, growing method and serving size. Hydroponic microgreens provide these compounds within an intact food matrix.

3. Transparency and crop protectionClosed systems may reduce some pest pressures but do not make pest management automatically unnecessary. Fresh harvests contain no industrial food colourings or preservatives unless added later. Safe inputs, hygiene and integrated pest management remain essential.

6. Conclusion

Food colourings serve several technological and sensory purposes. Authorised additives are evaluated and regulated, but some can cause hypersensitivity and specified colours require a warning about activity and attention in children. The E171 decision shows that safety conclusions may change as evidence develops; it does not mean that all synthetic substances accumulate or are inherently unsafe.

Fresh, minimally processed, naturally colourful foods are a practical way to obtain diverse nutrients and phytochemicals without added colours. Controlled vertical or aquaponic growing can influence plant pigmentation through light and cultivation conditions, but health depends on the overall diet rather than colour intensity or a single antioxidant measurement.

Note: This article provides general scientific information and does not replace individual medical or allergy advice. Anyone who suspects intolerance or hypersensitivity to food additives should seek clinical assessment.

References:

• European Food Safety Authority (EFSA). (2021). Safety assessment of titanium dioxide (E171) as a food additive.EFSA Journal, 19(5), 6585.
• McCann, D., et al. (2007). Food additives and hyperactive behaviour in 3-year-old and 8/9-year-old children in the community: a randomised, double-blinded, placebo-controlled trial. The Lancet, 370(9598), 1560–1567.
• Regulation (EC) No 1333/2008 of the European Parliament and of the Council on food additives.
• German Federal Ministry of Food and Agriculture (BMEL): authorisation and use of food additives.
• Monteiro, C. A., et al. (2016). NOVA. The star shines bright. World Nutrition, 7(1-3), 28–38.

Author: Uwe | Vida Vertical – Health