A Complete Overview of Fish Oil Extraction Methods and Technologies

Fish oil extraction is essential for producing high-quality oil rich in omega-3 fatty acids, particularly EPA and DHA. The extraction process impacts yield, purity, and chemical stability, making the selection of methods crucial for optimizing nutritional and commercial value. Fish extract contributes to 2% of the world's consumption of fats and oils, which are scientifically proven to influence human health positively. Initially, fish oil was only obtained as a by-product in the fish meal industry. However, its content is high in several small fishes such as anchovies, sardines, herring, and eels, which are the center of world attention and are more often used as raw materials for the fish-derived oil industry. Extraction processes are required to maintain the quality of it. This article explores various fish oil extraction techniques, their efficiencies, and refinement processes to ensure optimal quality.

Fish Oil Extraction Process

Fish oil can be extracted through several techniques, including wet pressing, solvent extraction, supercritical fluid extraction, and silage-based extraction. Each method influences the final quality, composition, and commercial viability of this oil.

1. Wet Pressing Method

Wet pressing is one of the most common methods for extracting fish oil. It involves heating fish or fish by-products to release oil, followed by mechanical pressing to separate the oil from the solid and aqueous phases. The process is highly dependent on factors such as temperature, time, and the species of fish.

Wet pressing is favored for its simplicity and ability to produce oil with minimal oxidation. However, it may not be suitable for all fish species, as some, like hake and squid, form emulsions that hinder oil separation.

2. Solvent Extraction

Solvent extraction is another widely used method, particularly for fish species with lower oil content. This method involves using organic solvents like hexane, chloroform, or methanol to dissolve the oil, which is then separated from the solvent.

Solvent extraction is the most widely used method to extract lipids from material. The extraction process of natural products follows these steps: 

1. Step 1: The solvent penetrates the materials

2. Step 2: The solute dissolves in the solvents

3. Step 3: The solute is diffused out of the solid matrix

4. Step 4: The results of extraction are collected. 

The extraction techniques using various solvents facilitate decomposing solute components based on their distribution properties. Fish extract are materials that easily dissolve in various organic solvents, namely benzene, chloroform, ethanol, acetone, hexane, and cyclohexane. Several factors, including solvent type, particle size, solvent-to-raw-material ratio, temperature, and reaction duration, must be meticulously managed to ensure the highest quality and yield of omega-3 oil.

While solvent extraction can achieve high yields, it often requires additional refining steps to remove residual solvents and impurities.

3. SAdvanced Fluid Extraction Method (SFE)

SFE is an advanced method that uses supercritical CO₂ as a solvent. This technique is highly efficient and environmentally friendly, as it avoids the use of harmful chemicals.

SFE is particularly effective for concentrating omega-3 fatty acids and reducing contaminants like mercury and cadmium.SFE produces premium omega-3 oil but requires significant investment in equipment.

4. Fish Oil Extraction by Silage

Silage-based extraction uses enzymatic, biological, or chemical additives to break down fish tissues, releasing oil efficiently.

Enzymatic extraction is ideal for producing high-purity oil with minimal environmental impact.

A Comparative Analysis

Each fish oil extraction method has its strengths and limitations. The following table outlines the main techniques and their differences:

Purification and Enrichment of Fish Oil

Once extracted, fish extract undergoes refining to remove impurities like phospholipids, free fatty acids, and oxidation products. The refining process includes:

1. Degumming: Eliminates phospholipid impurities
2. Neutralization: Eliminates free fatty acids.
3. Bleaching: Removes pigments and contaminants.
4. Deodorization: Reduces volatile compounds that cause off-flavors.

For omega-3 concentration, techniques like winterization, supercritical fluid fractionation, and enzymatic methods are used. 

Winterization, for example, separates saturated fats from PUFAs by controlled cooling, resulting in oil with higher omega-3 content.

PUFA Concentration in Fish Oil

Increasing the concentration of polyunsaturated fatty acids (PUFAs) is essential for high-quality fish-derived oil. Several methods are employed:

1. Winterization

Winterization involves cooling omega-3 oil to separate saturated fats, improving PUFA concentration.

• Optimal solvent: Hexane (40%) at 0°C
• PUFA concentration increased by 9.2%
• Saturated fats reduced by 13.3%

2. Fractionation via Supercritical Fluids

This method isolates omega-3 fatty acids like DHA and EPA, enhancing oil quality.

• Best conditions: 20,000 kPa, 33-40°C
• Effective PUFA recovery using ethanol as a co-solvent

Fish Oil Extraction Machines

Modern fish-based oil extraction machines play a crucial role in optimizing the extraction process. Many companies offer complete systems that ensure high yields and superior oil quality. Its plug-and-play design makes it easy to integrate into existing processes.

These setups generally consist of:

1. Heating Systems: Precise temperature control to release oil without degrading its quality.
2. Centrifugal Separators: Efficiently separate oil from water and protein.
3. Vacuum Dryers: Reduce moisture content to as low as 0.05%, enhancing shelf life and clarity.

Conclusion

The fish oil extraction process is a complex but essential procedure that significantly impacts the quality and nutritional value of the final product. By understanding the various fish oil extraction methods and leveraging advanced fish-based oil extraction machines, producers can optimize yields and produce high-quality oil rich in omega-3 fatty acids. Whether through wet pressing, solvent extraction, or supercritical fluid extraction, each method offers unique advantages that cater to different production needs. As technology advances, the industry continues to innovate, ensuring that this oil remains a vital source of essential nutrients for human health.

By adopting sustainable and efficient extraction techniques, the fish oil industry can meet growing global demand while maintaining the highest standards of quality and environmental responsibility.