SUSTAINABLE ALTERNATIVES TO HEXANE EXTRACTION
Moving beyond hexane
Solvent extraction plays a crucial role in many industries, including food, cosmetics, pharmaceuticals, bioenergy, and fine chemicals. This process helps isolate valuable compounds such as triglycerides, polyphenols, and carotenoids, which are essential for formulating various products.
Among the most widely used solvents, hexane has long been the industry standard due to its efficiency. However, concerns related to its toxicity, environmental impact or evolving regulations have led to an increased demand for safer and more sustainable alternatives.
What are the Alternatives to Hexane?
To address these challenges, more sustainable and health-friendly solutions are emerging.
Supercritical CO₂
A clean, efficient but costly method.
Bio-based solvents (ethanol, 2-Methyloxolane, ethyl acetate, etc.)
Sustainable options with potential for highest degree of ingredient extraction.
Solvent-free mechanical techniques
A chemical-free approach with potential for lower yields.
Key factors in choosing a hexane alternative
When selecting a replacement for hexane, several factors must be considered to ensure optimal performance, compliance, and sustainability.
This section provides some key points to consider.
Supercritical CO2 extraction
Advantages
- High Purity of Extracts : Supercritical CO₂ allows for selective extraction, producing highly pure and uncontaminated extracts, making it ideal for industries like food, pharmaceuticals, and cosmetics.
- Minimal Residual Solvents – Unlike organic solvents, CO₂ evaporates after extraction, leaving virtually no trace in the final product. However, certain biomass compounds require a liquid co-solvent to enhance solubility during the extraction. In these cases, co-solvent residues must be considered and managed to meet regulatory limits.
- Environmentally Friendly – CO₂ is non-toxic, non-flammable, and can be recycled within the system, reducing waste and emissions.
- Adjustable Solvent Power – By varying pressure and temperature, CO₂ can selectively extract different compounds, offering precise control over extraction parameters.
Disadvantages
- High Initial Investment – Requires expensive, highly specific facilities including high-pressure vessels and compressors making it a significant capital expenditure for businesses.
- Energy Intensive – The high pressure and temperature needed to maintain supercritical conditions consumes a considerable amount of energy.
- Limited Solubility for Some Compounds – CO₂ is not highly effective for extracting very polar compounds, limiting its applicability in certain industries.
- Low extraction volume – The high capital expenditure (CAPEX) requirements for supercritical CO₂ extraction systems generally limit its application to low-volume, high-value products such as pharmaceuticals, cosmetics, and specialty food ingredients. This makes it less viable for large-scale commodity extraction where cost efficiency is a key factor.
Bio-Based Solvents (ethanol, 2-methyloxolane, ethyl Acetate, etc.)
Advantages
- Renewable and Sustainable – Bio-based solvents are derived from natural sources such as sugarcane, corn, or biomass, reducing reliance on fossil fuels.
- Lower Toxicity – Compared to hexane, these solvents are generally less toxic, making them safer for workers and consumers.
- Regulatory Compliance – Some bio-solvents are approved for food and pharmaceutical use, simplifying compliance with safety standards.
- Versatile Extraction Capabilities – Can be adapted to extract a wide range of compounds, depending on polarity and solvent affinity.
- Fewer Potential Hidden Cost than Hexane – When factoring in the hidden costs of using hexane —such as health and safety risks to workers exposed to hexane, the potential financial impact of toxic spills, and the reputational risks linked to rising consumer awareness of hexane’s toxicity—the overall cost difference becomes much smaller, and in some cases, bio-based options may prove more economical in the long run.
Disadvantages
- Flammability – Many bio-based solvents, including ethanol, are highly flammable, requiring strict safety protocols and specialized storage.
- Solvent Residue Risks – Liquid solvents always leave trace amounts in extracted products. For this reason, only toxicologically assessed and regulatory-approved solvents can be used for food and feed extraction. Authorities establish a Tolerable Daily Intake (TDI) for each solvent (mg/kg body weight/day) to ensure cumulative exposure remains within safety limits.
- Higher Raw Material Cost Than Hexane – While more sustainable, bio-based solvents can still be more expensive than traditional petrochemical solvents. However, this depends on how we define the boundaries of cost analysis.
Mechanical Extraction Methods (Cold Pressing, Expeller Pressing, Filtration)
Advantages
- Solvent-Free – No chemicals are involved, making this method the safest in terms of toxicity and environmental impact.
- Preserves Natural Quality – Often used for food and cosmetic applications (e.g., cold-pressed oils), as it retains more natural flavors, aromas, and nutrients.
- Lower Energy Consumption – Compared to supercritical CO₂, mechanical extraction methods require significantly less energy.
- Simple and Low-Cost Equipment – Machinery is often less expensive than solvent-based systems and easier to maintain.
Disadvantages
- Lower Extraction Efficiency – Mechanical methods cannot extract as much oil or bioactive compounds as solvent-based extractions, leading to potential yield losses.
- Lower yield results in higher processing costs.
- High Residual Oil Content in the Meal – Extracted substrates with residual oil levels above 5% may have a shorter shelf life due to oxidation. This will develop impurities that creates off-flavors and rancidity. This will impact product quality, stability, and consumer acceptance.
- Limited to Certain Applications – Works well for high-oil-content materials but is less effective for plant-based polyphenols, carotenoids, and other complex compounds.
- May Cause Heat Damage – While less energy-intensive, mechanical pressure can generate heat, which may degrade thermally sensitive compounds, such as proteins.
Which Method is Best for Your Needs?
Each extraction technique has specific advantages and trade-offs. The choice depends on your industry, target compounds, regulatory requirements, and production scale.
DISCOVER HEXANE
Watch the following video to learn how hexane affects your daily life