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Published on: August 14, 2019
Pressurised liquid extraction of flavonoids in onions. Method development and validation
Malene Søltoft1, Jan H Christensen, John Nielsen
1Department of Food Chemistry, National Food Institute, Technical University of Denmark, DK-2860 Søborg, Denmark.
Talanta
|September 29, 2009
Summary
Researchers developed a fast, reliable method using pressurized liquid extraction (PLE) and HPLC to quantify flavonoids in onions. PLE offers automation, reduced solvent use, and protection for sensitive compounds, proving effective for various plant analyses.
Area of Science:
- Analytical Chemistry
- Food Science
- Phytochemistry
Background:
- Flavonoids are important bioactive compounds in onions with various health benefits.
- Accurate quantification of flavonoids requires efficient extraction and sensitive analytical techniques.
- Existing extraction methods may have limitations in efficiency, solvent consumption, or protection of sensitive analytes.
Purpose of the Study:
- To develop and validate a rapid and reliable analytical method for quantifying flavonoids in onions.
- To compare the efficiency and reproducibility of five different extraction methods.
- To identify the optimal extraction technique for flavonoid analysis in onions.
Main Methods:
- Five extraction methods were evaluated: water bath, pressurized liquid extraction (PLE), ultrasonication, ultrasonic liquid processor, and microwave extraction.
- High-performance liquid chromatography (HPLC) with UV detection was used for the quantification of seven specific flavonoids.
- Method parameters including temperature, sample weight, flush volume, and solvent type were optimized for PLE.
Main Results:
- Pressurized liquid extraction (PLE) demonstrated superior efficiency compared to conventional water bath extraction.
- Ultrasonication, ultrasonic liquid processor, and microwave extraction showed similar efficiencies to PLE.
- PLE was preferred due to its high automation potential, low solvent consumption, cleaner extracts, and ability to protect light/oxygen-sensitive compounds.
- The optimized one-step PLE method exhibited good selectivity, precision (RSDs 3.1-11%), and high recovery (98-99%) for extractable flavonoids.
- The method proved versatile, applicable to other compounds like phenolic acids in potatoes and carrots.
Conclusions:
- Pressurized liquid extraction (PLE) is a highly efficient and reliable method for flavonoid quantification in onions.
- The developed method is rapid, automatable, and environmentally friendly, suitable for sensitive compounds.
- This analytical approach demonstrates broad applicability to other plant matrices and compound classes, such as phenolic acids.
