In recent years, there has been a growing interest in adopting environmentally friendly practices across various industries. The field of lipid extraction is no exception, as researchers have started exploring alternative methods to replace conventional extraction techniques with more sustainable approaches. This article aims to explain the findings of a research study conducted by Yesim Ozogul and colleagues in 2018, titled “Comparison of Green and Conventional Extraction Methods on Lipid Yield and Fatty Acid Profiles of Fish Species.”

1. What are the different extraction methods used to compare the lipid yield and fatty acid profiles of fish species?

The study compared two green extraction methods, ultrasound-assisted extraction (UAE) and microwave-assisted extraction (MAE), with two conventional methods, Soxhlet extraction and Bligh and Dyer extraction. These methods were chosen based on their effectiveness and widespread use in lipid extraction from various sources.

  • Soxhlet extraction: This is a conventional method that involves continuous solvent extraction. It requires a relatively large amount of solvent and a longer extraction period.
  • Bligh and Dyer extraction: Another conventional method, it involves a mixture of chloroform, methanol, and water to extract lipids. It is relatively faster than Soxhlet extraction.
  • Ultrasound-assisted extraction (UAE): This green extraction method utilizes ultrasonic waves to break down the cell structure and release lipids. It is known for its efficiency and reduced solvent consumption.
  • Microwave-assisted extraction (MAE): This green extraction method uses microwave energy to heat the sample and accelerate lipid extraction. It is a rapid and efficient technique.

2. Which extraction method is more efficient in terms of lipid content?

The results of the study indicated that the Bligh and Dyer method and UAE were generally more efficient than the other extraction methods in terms of lipid yield. These findings suggest that green extraction methods, particularly UAE, can be viable alternatives to conventional methods for lipid extraction from fish species.

3. What are the saturated, monounsaturated, and polyunsaturated fatty acid contents of the fish species?

The study analyzed the fatty acid composition of the extracted fish oil and found statistical differences in fatty acid profiles between the four extraction methods. The saturated (SFA), monounsaturated (MUFA), and polyunsaturated fatty acid (PUFA) contents varied among the fish species. The range of fatty acid contents per 100g of fish was as follows:

  • Saturated fatty acids (SFA): 29.51mg (Soxhlet) to 1400mg (UAE)
  • Monounsaturated fatty acids (MUFA): 15.52mg (UAE) to 2237.18mg (Bligh and Dyer)
  • Polyunsaturated fatty acids (PUFA): 14.36% (Soxhlet) to 646mg (Bligh and Dyer)

These results indicate significant variations in fatty acid contents across different extraction methods and fish species.

4. How do the extraction methods affect the fatty acid composition in fish oil?

The study found that the choice of extraction method had a significant impact on the fatty acid composition of the extracted fish oil. The Bligh and Dyer method consistently yielded higher values of saturated, monounsaturated, and polyunsaturated fatty acids in surmullet, red mullet, and common pandora. On the other hand, the MAE and UAE methods performed better in terms of fatty acid composition for goldband goatfish and European eel, respectively.

These findings emphasize the importance of considering the extraction method when analyzing the fatty acid profiles of fish oil. Different methods can yield varying results, and researchers must choose the most suitable method based on their specific objectives.

5. Which extraction method is most effective for extracting lipids with high content of PUFA, especially EPA and DHA?

The study specifically focused on identifying the extraction method that is most effective for extracting lipids with a high content of polyunsaturated fatty acids (PUFAs), particularly eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). The results indicated that the Bligh and Dyer method yielded higher values of EPA and DHA in surmullet, red mullet, and common pandora compared to the other extraction methods.

However, for goldband goatfish and European eel, the MAE and UAE methods showed better results in terms of PUFA content, including EPA and DHA.

These findings highlight the importance of selecting an appropriate extraction method depending on the fish species and the specific fatty acid of interest. Researchers aiming to extract lipids with a high content of PUFA, especially EPA and DHA, should consider utilizing the Bligh and Dyer method for certain species and the MAE or UAE methods for others.

Takeaways

In conclusion, the research study conducted by Ozogul and colleagues compared different green and conventional extraction methods for their efficiency in extracting lipids and determining the fatty acid profiles of various fish species. The findings demonstrated that the choice of extraction method significantly affected the lipid yield and fatty acid composition of the extracted fish oil.

The Bligh and Dyer method and UAE were generally more efficient in terms of lipid content, and the MAE and UAE methods performed better in terms of fatty acid composition for certain fish species. Moreover, the extraction methods influenced the saturated, monounsaturated, and polyunsaturated fatty acid contents of the fish species’ oil.

These findings have important implications for researchers and industries involved in lipid extraction from fish species. By understanding the differences in extraction methods, they can select the most appropriate technique to extract lipids with specific characteristics, such as high PUFA content, which is of great nutritional and commercial value.

Source: https://onlinelibrary.wiley.com/doi/abs/10.1002/ejlt.201800107

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