The Role and Standards of Colouring Matters in Food

Walk down the dairy aisle of any supermarket and you’ll notice something immediately: the rich golden hue of cheddar, the warm yellow of butter, the inviting orange of processed cheese. These colors don’t always occur naturally at consistent levels – and in many cases, they’re the result of carefully regulated food-grade colourants. Two of the most widely used in dairy and food production are β-Carotene and Annatto. Understanding what these colourants are, how they’re specified, and where they’re permitted is essential for food quality assurance professionals and manufacturers who must balance consumer expectations with strict safety standards.

Why colouring matters in food 🔗

Colour is one of the first quality signals a consumer receives. Before tasting or smelling a product, people judge it visually – and colour directly influences perceived freshness, flavour, and quality. Food colourants are defined as any dye, pigment, or substance that imparts colour when added to food or beverages. They are supplied as liquids, powders, gels, or pastes and serve purposes beyond aesthetics: restoring colour lost during processing, ensuring batch-to-batch visual consistency, and meeting the expectations of consumers who associate specific shades with specific products.

The global market for food colouring reflects this importance. Demand has grown steadily, driven by the need for visually appealing products in both commercial manufacturing and consumer food preparation. Food colourants fall into two broad categories: synthetic (certified) colours, which require individual batch certification by regulatory authorities, and natural or nature-identical colours that are exempt from certification but still subject to identity, purity, and use-level requirements. β-Carotene and Annatto both fall in the latter category – approved worldwide, but tightly governed by specifications designed to ensure safety and purity.

β-Carotene: the gold standard for dairy colouring 🔗

β-Carotene (E160a) is an orange-red pigment from the carotenoid family. Chemically, it is an unsaturated hydrocarbon with the molecular formula C₄₀H₅₆, composed of eight isoprene units – making it a member of the terpenoid class. It is lipophilic (fat-soluble) and practically insoluble in water. This fat-solubility makes it especially compatible with dairy matrices like butter, cream, and cheese, where it disperses readily into the fat phase.

Sources and production 🔗

β-Carotene is found naturally in carrots, sweet potatoes, pumpkin, and dark leafy greens. For food-grade use, it is produced in several ways: solvent extraction from plant sources such as carrots and palm fruit; fermentation using the fungus Blakeslea trispora, which yields a highly pure all-trans form of the pigment; and extraction from the microalgae Dunaliella salina, which accumulates particularly high levels of the pigment in high-salinity environments. Synthetic β-Carotene is also produced via chemical synthesis (notably by BASF using the Wittig condensation method), and it is considered nature-identical – chemically the same as the naturally occurring compound, differing mainly in the spectrum of accompanying substances.

For commercial applications in fat-rich dairy products such as butter and margarine, β-Carotene is typically used in oil-dissolved form. For water-containing systems, it is formulated as a micro- or nanoemulsion, producing a stable and homogeneous colour across the product matrix. Emulsion formulations typically contain around 1-10% β-Carotene and are adjusted with stabilisers to resist heat and light degradation.

Purity specifications and regulatory status 🔗

For a colourant to be food-grade, it must meet precise purity criteria. Under US FDA regulations (21 CFR 73.95), β-Carotene must be a solid, with a loss on drying of not more than 0.2%, a residue on ignition not exceeding 0.2%, lead content no greater than 10 parts per million (ppm), arsenic no greater than 3 ppm, and an assay purity of 96-101% by spectrophotometric determination. These tight limits reflect the need to exclude harmful impurities – particularly heavy metals – that could arise from extraction or synthesis processes.

The FDA classifies β-Carotene as both a colour additive exempt from certification and as Generally Recognized As Safe (GRAS). This dual recognition means manufacturers can use it without batch-by-batch regulatory approval, provided they comply with Good Manufacturing Practice (GMP) and the identity and purity criteria outlined in its listing regulations.

At the international level, the Joint FAO/WHO Expert Committee on Food Additives (JECFA) has assigned β-Carotene from vegetable sources an ADI of “not specified,” provided use levels do not exceed those naturally found in vegetables. For synthetic β-Carotene, JECFA withdrew the group ADI at its 87th meeting (2019) due to complexities involving its application to heavy smokers – a population-specific concern that prevents the establishment of a universal daily intake figure.

Applications in dairy products 🔗

β-Carotene imparts yellow to orange tones that closely match consumer expectations for naturally produced dairy. It is widely used in butter, margarine, cheese, yogurts, cake fillings, and custards. Without added colouring, margarine would be nearly white by nature – a small amount of β-Carotene brings it to the familiar butter-yellow tone consumers expect. Beyond colour, β-Carotene carries added value as a provitamin A compound: the body can convert it to retinol (vitamin A) as needed, and it also functions as an antioxidant, potentially supporting the oxidative stability of products like butter.

Annatto: the dairy industry’s oldest colourant 🔗

Annatto (E160b) is derived from the seeds of Bixa orellana, a tropical tree native to South America. Its use as a food colour dates back over two centuries, with its earliest commercial applications in cheese – particularly the characteristic orange hue of Cheddar and Red Leicester. Today it is one of the most extensively used natural colourants across dairy, bakery, confectionery, and meat products.

Chemical identity: bixin and norbixin 🔗

The colouring power of Annatto comes from two principal pigments: bixin and norbixin. Chemically, both belong to the carotenoid group – but unlike β-Carotene (a C40 carotenoid), bixin is a C25 diapo-carotenoid, and norbixin is a C30 terpenoid derived from lycopene by oxidative cleavage. Bixin is the primary pigment in oil-soluble annatto extracts, naturally occurring mainly in the 9-cis configuration. Norbixin is produced when bixin is hydrolysed (saponified) in alkaline conditions and becomes the principal pigment of water-soluble annatto preparations. This distinction between the two forms governs which products each variant can colour effectively.

Oil suspensions of annatto typically contain 0.1-8% bixin, while water solutions contain 0.1-4.0% norbixin. Water-soluble annatto powders may contain 1-15% norbixin, and emulsified forms for use in mixed systems typically fall in the range of 1-2.5% bixin/norbixin.

Extraction methods and their significance 🔗

The method of extraction directly determines the form of Annatto produced and influences its purity and application suitability. JECFA recognises several distinct commercial preparations:

• Solvent-extracted bixin (Annatto B): Seeds are extracted with food-grade solvents to dissolve the pigment, followed by solvent removal, crystallisation, and drying. The resulting product contains a minimum of 85% bixin.
• Solvent-extracted norbixin (Annatto C): Processed similarly to Annatto B, with an additional alkaline hydrolysis step to convert bixin to norbixin, yielding a minimum of 85% norbixin.
• Oil-processed bixin suspension (Annatto D): Seeds are abraded in cold aqueous alkali and the resulting suspension is acidified to precipitate bixin, then dried and milled. Used in oil-based dairy applications.
• Alkali-processed norbixin (Annatto F/G): Alkali abrasion followed by additional alkaline heating and acid precipitation, producing preparations with at least 35% norbixin (acid-precipitated) or 15% norbixin (not acid-precipitated).

Each of these preparations has a defined specification under JECFA, and only extracts that comply with the relevant specification qualify under the corresponding Acceptable Daily Intake (ADI).

Purity specifications and permissible limits 🔗

Annatto extract must conform to stringent identity and purity criteria. Under US FDA regulations (21 CFR 73.30), annatto extract must contain no more than 3 ppm arsenic and no more than 10 ppm lead. When food-grade solvents are used in extraction, residual solvent levels must comply with the applicable oleoresin solvent residue regulations. The extract must be prepared exclusively from the seeds of Bixa orellana using permitted food-grade extractants, including alkaline aqueous solutions, ethyl alcohol, edible vegetable oils, mono- and diglycerides, or a defined range of food-grade organic solvents.

At the international level, JECFA’s 67th meeting (2006) established an ADI for bixin of 0-12 mg/kg body weight per day, and a group ADI for norbixin and its sodium/potassium salts of 0-0.6 mg/kg body weight per day (expressed as norbixin). The European Food Safety Authority (EFSA) has set more conservative limits: 6 mg bixin/kg body weight per day and 0.3 mg norbixin/kg body weight per day. These different figures reflect the ongoing evolution of the safety evidence base and the varying approaches to risk assessment used by different regulatory bodies. Importantly, EFSA has confirmed that bixin-based annatto does not raise genotoxicity concerns.

Use in dairy products 🔗

Annatto extracts have been used for over two centuries most prominently in cheese, but their applications in dairy now extend to butter, margarine, ice cream, frozen desserts, and other dairy-based products. The choice between bixin-based and norbixin-based annatto is determined by the fat content and aqueous structure of the product being coloured. Oil-soluble bixin is suited to high-fat products like butter and cream cheese, while water-soluble norbixin is used in lower-fat dairy products and aqueous emulsion systems.

The Codex Alimentarius Commission has adopted maximum permitted levels (MPLs) for bixin-based annatto (INS 160b(i)) in more than 65 food categories and for norbixin-based annatto (INS 160b(ii)) in more than 55 food categories – reflecting the widespread regulatory acceptance of this colourant across global markets.

Adulteration risks and the importance of specification compliance 🔗

One challenge with natural colourants is the risk of adulteration at the raw material stage. Annatto adulteration has been documented since as far back as 1856, with reports of preparations containing only 30% of the stated pigment content, diluted with flour, chalk, salt, and other extraneous matter. Although production standards have improved vastly since then, the regulatory requirement for third-party certificate-of-analysis testing from raw material suppliers remains an important safeguard. The purity specifications – particularly minimum bixin or norbixin content and maximum heavy metal limits – exist precisely to catch such compromises in quality.

For β-Carotene, while adulteration is less common, the concern lies in ensuring the correct isomeric profile and excluding harmful synthesis by-products. Specifications requiring a minimum assay purity of 96% and strict lead and arsenic limits provide this assurance. Both colourants, despite being exempt from batch certification in many jurisdictions, must comply with their respective identity and purity criteria before they can legally be used in food products.

Synthetic versus natural: a regulatory distinction that matters 🔗

The FDA distinguishes between “certified” and “exempt” colour additives. Certified colours are synthetic dyes requiring individual lot approval; exempt colours – including β-Carotene and Annatto extract – are derived from natural sources and do not require batch certification, but must still meet defined identity and purity specifications. In both the EU and the US, regulatory frameworks define the origin and preparation method of each additive in detail – specifying permitted solvents, residue limits, and the source material. Any deviation from these specifications renders the additive and the food containing it adulterated.

The key regulatory takeaway for food manufacturers is this: being “natural” does not mean being unregulated. Both β-Carotene and Annatto are held to precise chemical standards, maximum contaminant thresholds, and use-level restrictions that vary by product category. Compliance with these standards is not optional – it is the foundation of product safety, quality assurance, and consumer trust.

What do you think? As food manufacturers increasingly reformulate products to meet clean-label demands, do you think the current regulatory framework for natural colourants like β-Carotene and Annatto provides sufficient transparency for consumers? And with bixin and norbixin carrying different ADIs and solubility profiles, how should dairy technologists decide which form of Annatto is most appropriate for a given product formulation?

References

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8. https://www.fao.org/fileadmin/templates/agns/pdf/jecfa/cta/67/annatto.pdf
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