The stability of natural colorants is not a uniform property: it changes radically from pigment to pigment, even before depending on the process or the matrix.
Curcumin, beta-carotene, chlorophylls, cochineal carmine, and beetroot – all present in the Bayo range of water-soluble natural colorants – respond completely differently to light, heat, pH, and oxygen.
Selecting the right pigment means knowing these profiles before starting matrix tests.
This guide analyzes the stability of natural colorants from the pigment’s perspective, not the process – which is already covered in the article on savoury colorant stability. The two articles are complementary and should be read together to get the full picture.
Why stability varies between pigments
Water-soluble natural colorants are extracted from plant matrices with very different chemical compositions.
A carotenoid like beta-carotene has a lipophilic structure with conjugated double bonds, which are sensitive to oxidation.
A polyphenol like anthocyanins is much more significantly sensitive to pH than any carotenoid.
Chlorophyll reacts to acidity by shifting from green to olive brown.
This chemical diversity is precisely the reason why colorant degradation is not addressed with general rules, but with specific knowledge of the chosen pigment.
Stability profiles pigment by pigment
Curcumin – lemon yellow
Photosensitivity: high. This is the main critical point of curcumin. In transparent packaging or under intense lighting, color decay is rapid and visible.
Thermal stability: good within typical pasteurization ranges. It withstands temperatures up to 80-90°C without significant loss of intensity.
pH sensitivity: present. In an alkaline environment, it shifts toward reddish tones. In an acidic environment, it maintains a bright yellow better.
Recommended applications: beverages and syrups in opaque packaging, bakery glazes, preparations with a short shelf life, or controlled light exposure.
Beta-carotene – orange
Sensitivity to oxidation: high. The polyene structure of beta-carotene makes it vulnerable to oxygen, especially in the presence of trace metals or in matrices with high water activity.
Thermal stability: good within standard ranges. It withstands pasteurization and processes at moderate temperatures.
Photosensitivity: moderate, lower than curcumin but present during prolonged exposure.
The preservation of colored foods based on beta-carotene requires attention to packaging: airtight sealing, protective atmosphere, and limitation of oxygen exposure during processing.
Recommended applications: orange-flavored beverages, gelato bases, syrups, and preparations with airtight packaging.
Chlorophyll – green
Sensitivity to acidic pH: high. In an acidic environment, chlorophyll loses the magnesium ion and shifts toward olive or brown tones. It is the green pigment most sensitive to process conditions.
Thermal stability: limited in an acidic environment. In neutral or slightly alkaline pH, thermal resistance improves significantly.
The color degradation of colorants based on chlorophyll is the main risk in acidic fruit sauces, preparations with citrus juices, and acidified yogurts.
Recommended applications: green tea beverages, herbal syrups, preparations with neutral or alkaline pH. It should be added after the most severe heat treatment where possible.
Cochineal carmine – red
Thermal stability: high. It is among the most heat-resistant natural pigments (if chelated with aluminum salts). It maintains color intensity after pasteurization and sterilization.
pH stability: good across a wide range. It maintains bright red in acidic conditions, with a slight shift toward purple in an alkaline environment.
Photosensitivity: moderate-low, superior to synthetics and among the best among natural options.
It is the most reliable choice for applications requiring robustness across multiple variables simultaneously: pasteurized products, jellies, desserts, and long shelf-life beverages.
Note: requires attention to label communication – some consumers are sensitive to the animal origin of carmine.
Beetroot – red/purplish
Heat sensitivity: high. Betanin degrades rapidly above 70-75°C with loss of intensity and color shift.
Photosensitivity: high. Among water-soluble natural pigments, beetroot is among the most sensitive to light.
pH stability: best in an acidic environment (pH 3.5-5). It degrades in neutral or alkaline environments.
The shelf life of colored products based on beetroot is the most critical to manage. It should be reserved for products with low process temperatures, opaque packaging, and limited shelf life.
Recommended applications: yogurt, cold desserts, beverages not heat-treated or pasteurized at low temperatures.
Caramel – amber
Thermal stability: excellent. It is the most stable brown colorant available in water-soluble format.
pH stability: high over a very wide range, from acidic to neutral.
Photosensitivity: low.
For the shelf life of long-preservation products, caramel is often the default choice when an amber tone is acceptable in the finished product.
Colorant preservation: warehouse and operational management
The preservation of colorants before use directly impacts production yield.
A pigment stored in incorrect conditions arrives at the line already partially degraded, with direct consequences for color yield and repeatability between batches.
Temperature
All water-soluble natural colorants benefit from storage in a cool place, away from heat sources.
Bayo micro-dosable powders maintain their characteristics under standard warehouse conditions but must be protected from thermal fluctuations that accelerate the degradation process.
Humidity
Water-soluble powders can be hygroscopic.
Moisture absorption in the warehouse modifies solubility and dispersion, and in some cases accelerates the chemical degradation of the pigment.
Airtight packaging, raised pallets, and periodic monitoring of relative humidity in the warehouse are essential operational practices.
Light
Curcumin, beta-carotene, and beetroot degrade even in open containers if exposed to artificial warehouse light.
Adherence to the airtight closing procedure after each use is not a formality: it is a technical measure with a direct impact on yield.
Stock rotation
The FIFO principle – first in, first out – is particularly relevant for natural colorants, where the ingredient’s shelf life is shorter compared to synthetics.
Ready-to-use water-soluble solutions require the same attention: they must be kept closed, protected from light, and used within the terms indicated in the technical data sheet.
Shelf life of colorants: from production to consumer
The shelf life of colorants in the finished product is not calculated starting from the shelf life of the ingredient.
These are two distinct values that follow different logics.
The shelf life of the ingredient concerns the preservation of the pure colorant in the warehouse under the conditions indicated in the technical data sheet.
The shelf life of colorants in the finished product depends on the interaction of the pigment with the entire matrix: pH, fats, proteins, salt, heat treatment undergone, packaging, and distribution conditions.
Determining the shelf life of finished products requires dedicated tests on representative samples under the actual storage conditions intended for the consumer.
Accelerated tests – with temperature or light higher than normal – provide useful preliminary indications during the development phase.
They do not replace validation on actual shelf life before commercial launch.
Instrumental color measurement with colorimeters allows for the definition of qualitative and comparable acceptability limits between batches.
Production monitoring
Monitoring the stability of natural colorants on the line allows for the interception of color variations before the batch is completed.
Portable spectrophotometers and vision systems can measure tone and intensity after mixing, signaling deviations from defined standards.
Recording pH, temperature, and process time for each batch creates a useful documentary base for deviation analysis and quality audits requested by customers.
Colorant degradation between successive batches is often a signal of an uncontrolled process variable: change in raw material supplier, variation in process water pH, or process temperature out of specification.
A control plan that includes color as a batch acceptance parameter – not just a final check – reduces the risk of rework and waste.
How to choose the most stable colorant for the process
Selection starts from the stability profile of the pigment, not the tone.
The tone is the destination. Stability is the starting point.
For processes with severe heat treatments: carmine and caramel are the most robust choices. Beta-carotene and curcumin hold up in moderate ranges. Chlorophyll and beetroot require post-process insertion or low-temperature processes.
For products with acidic pH: beetroot and curcumin work well. The use of chlorophyll is critical.
For long shelf lives with transparent packaging: caramel and carmine are the most reliable. Curcumin and beetroot require protective packaging.
For organic productions: all natural colorants in the Bayo range are compatible with organic standards – synthetics are not.
The complete range is described on the food colorants page. For a comparison between water-soluble and fat-soluble natural colorants, the dedicated article covers selection criteria and applications by sector.
Bayo support for stability in production
Bayo provides water-soluble natural colorants in micro-dosable powder and ready-to-use solution, with a complete technical data sheet for each reference: solubility specifications, matrix compatibility, storage indications, and documentation for compliance with EC Regulation 1333/2008.
ISO 9001 and FSSC 22000 certifications guarantee total traceability from raw material to finished product.
The Bayo technical team supports customers in selecting the correct pigment and in application tests on the actual matrix.