Supercritical CO₂ For Food Color Applications

Carotenoids are the naturally occurring pigments that give fruits and vegetables their vibrant orange, yellow, and red colors. The over 600 fat-soluble compounds we will cover are beta-carotene, lutein, zeaxanthin, and astaxanthin. Other than colors, carotenoids are powerful antioxidants essential for human health, with some acting as provitamin A, which is crucial for vision and immune function. Their health benefits have made them indispensable ingredients in the nutraceutical, pharmaceutical, food, and cosmetics industries.

As clean products are becoming the standard, the extraction method used is more important than ever. Solvent extraction methods like hexane, acetone, ethanol, and ethyl acetate are problematic because of the risk of toxic residues, degradation of heat-sensitive compounds, and environmental pollution. Let’s dig into why supercritical carbon dioxide (CO₂) or subcritical water extraction may be a more suitable technology for carotenoids.

How Supercritical CO₂ Extraction Works in Carotenoids

Supercritical CO₂ Extraction is an advanced separation technique that utilizes carbon dioxide (CO₂) above its critical temperature (31.1°C) and pressure (73.8 bar). When CO₂ becomes supercritical, it exhibits the properties of both a liquid and a gas, allowing it to dissolve non-polar compounds like carotenoids while retaining the low viscosity of a gas to penetrate plant material. The SC-CO₂ is passed through the biomass to dissolve the target compounds, then the mixture is depressurized in a separator, causing the CO₂ to revert to a gas, leaving behind an extract. Because the CO₂ completely evaporates, the final product is entirely free of solvent residues.

SFE is very tunable, which makes the technology adaptive to multiple applications. By adjusting temperature and pressure, we are able to target specific molecules like carotenoids. Although pure SC-CO₂ is ideal for non-polar compounds, carotenoid manufacturers often improve the extraction of larger molecules like carotenoids by adding a small amount of food-grade ethanol, which is a polar cosolvent. The cosolvent increases the polarity of the supercritical fluid, which, in the case of carotenoids, increases extraction yields.

Overview of Trending Carotenoids

While there are hundreds of carotenoids, a few have emerged as market leaders due to their well-documented health benefits and versatile applications. These compounds, found in major brands, contain detectable hexane residuals.

Lutein & Zeaxanthin

Lutein and zeaxanthin can be extracted from plants like marigolds and accumulate in the macula of the eye, where they act as antioxidants and filter blue light. Their benefits are supported by major clinical trials, like the National Institutes of Health (NIH) AREDS2 study, which linked their supplementation to a reduced risk of age-related macular degeneration (AMD).

Beta-Carotene

Beta-carotene is arguably the most well-known carotenoid. Humans convert beta-carotene into vitamin A, a nutrient involved in maintaining vision, immune function, and skin health. It’s used in the nutraceutical industry and serves as a natural colorant in the beverage and food industry.

Astaxanthin

Astaxanthin is an antioxidant found in algae and seafood like salmon. It neutralizes free radicals more effectively than many other antioxidants, making it popular among supplements targeting skin health, anti-aging, and athletic performance.

The Markets Pushing For Cleaner Carotenoid Extracts

The global carotenoids market is growing. It’s projected to expand from USD 296.0 million in 2025 to USD 438.2 million by 2035, at a compound annual growth rate (CAGR) of 4.0%. An increasing number of health-conscious consumers is propelling this expansion.

Consumers are demanding supplements free of hexane and are beginning to become skeptical of the current processing methods. As education about diet and long-term health increases, they are seeking carotenoids that are not contaminated by dirty processing methods. Artificial additives are being avoided, and concerns about contaminants such as heavy metals and chemical residues from processing solvents are increasing. This trend suggests that the processing methods used will become a much larger factor for purchasers in the coming years.

Institutions such as the U.S. Food and Drug Administration (FDA) and the European Food Safety Authority (EFSA) have classified common solvents like hexane as hazardous and toxic, compelling manufacturers to abandon solvent-based methods in favor of cleaner technologies. With the increasing demands of consumers and institutions, solvent-free technologies are what’s needed.

The Issues With Relying on Solvent Extractions

The standard method for extracting carotenoids has been using solvents like hexane, acetone, and ethanol. While the yield of these methods is good, the downsides are many.

A primary concern is the presence of residual solvents in the final extract. Hexane, a common choice, is a known neurotoxin and is classified as a hazardous air pollutant and toxic to reproduction. Ethanol degrades sensitive compounds when high heat is used for removal and introduces contaminants when used improperly, which occurs when operations reuse their solvents repeatedly, only replacing them when the solvent becomes highly contaminated, leaching into the products.

High temperatures, which can degrade carotenoids, can lead to a loss of potency and bioactivity. Flammable and toxic solvents also pose significant safety, environmental, and disposal challenges, which add to operational costs and can negatively impact consumer perception.

A Case for Supercritical CO₂ Over Solvents

There is evidence that solvent-free botanical extraction is a superior extraction technology that addresses the fundamental weaknesses of solvent extraction, with carotenoids being just one of many botanicals that perform better under solventless extractions.

Organic at No Added Cost

You can achieve organic extracts with supercritical CO₂ extraction at no added cost. Carbon dioxide is inexpensive, non-toxic, and readily available. Compared to solvents, which need to be purchased organically, they are more expensive and also require costly post-processing for removal. Since CO₂ is completely removed from the final product through simple depressurization, the extracts are inherently free of solvent residues, eliminating the material cost of organic solvents and the need for additional purification steps.

Purer Extracts. Larger Yield.

Since CO₂ evaporates from the extract upon depressurization, the final product is free of solvent residues. This process eliminates the risk of solvent contamination. SFE has greater precision when isolating target carotenoids and leaves behind unwanted compounds, which often results in more potent extracts with higher yields compared to less selective methods.

Degradation No Longer An Issue

Carotenoids are sensitive to heat, light, and oxygen, all of which can cause degradation. Supercritical CO₂ extractors operate at mild temperatures (typically between 40-60°C), which is great for preservation, whereas the same thing cannot be said of solvent extraction. Since the process is free from oxygen, oxidation does not occur, ensuring the extracted carotenoids remain unaltered.

No Need to Store Hazardous Waste

Hazardous and flammable solvents are costly to store, use, and dispose of as hazardous waste. The spent biomass also contains significant amounts of solvents that remain after extraction, which emit VOCs and HAPs. Carbon dioxide, on the other hand, is non-toxic, non-flammable, doesn’t require excessive storage, and is “Generally Recognized As Safe” (GRAS) by regulatory bodies like the FDA and EFSA. This inherent safety simplifies facility requirements, reduces the risks of accidents, and guarantees that the final products are safe for consumption in foods, supplements, and pharmaceuticals.

It’s Sustainable

SFE can recycle and reuse nearly all of the CO₂ in a closed-loop system, significantly reducing solvent waste and environmental impact. It’s ideal for achieving corporate sustainability goals and meeting the growing demand from consumers for environmentally responsible products.

The Current State of Carotenoid Extraction

Though cleaner extraction technologies are gaining ground for carotenoid ingredients, many established ingredient producers still utilize a mix of production methods, including synthetic routes and conventional solvent extraction.

However, leading innovators are rapidly adopting supercritical CO₂ extraction to meet the growing demand for pure ingredients. Companies that continue to rely on older solvent-based methods risk not adapting to the trends, as purity becomes the standard rather than the niche. Adopting supercritical CO₂ is a strategic move that many businesses are making to future-proof their operations and further innovate in their markets.

Next Steps for Ingredient Innovators

Future success belongs to businesses that implement technologies that deliver pure and potent carotenoids safely and without compromise. Supercritical CO₂ extraction has emerged as that technology. It addresses the core issues of solvent residues, thermal degradation, and environmental impact, making it an excellent method for carotenoid extraction.

Deploy a Pilot Run

Reach out to a manufacturer and take advantage of their pilot run services. By conducting a pilot run of your carotenoids with supercritical CO₂, you can calculate the extract purity, yield, operational cost, and other valuable metrics, allowing you to determine whether to make the investment.

Talk To An Expert

Consult with an expert to determine whether CO₂ extraction technology is the right fit for your business. Don’t navigate this shift alone. The extraktLAB team has guided ingredient producers across the food, nutraceutical, cosmetics, and pharmaceutical industries through the same transition. We’ll walk you through the process, answer your questions, and help you build a business case that gets buy-in from your stakeholders.

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