Catechins are natural phenolic compounds that are widely found in plant foods such as tea, fruits, and vegetables. Catechins have a variety of biological activities, such as antioxidant, anti-inflammatory, antibacterial, anti-tumor, etc., and have a variety of benefits for human health.
Catechins include catechins, epicatechins, and gallic catechins. Among them, catechins are the most common one, with obvious antioxidant and anti-inflammatory effects. Epicatechins have antibacterial and antitumor activities and can be used for a variety of diseases. Gallocatechin has a strong antioxidant and antibacterial effect, and can be used in food preservation and oral hygiene.
There are many methods for the extraction and purification of catechins, such as solvent extraction, adsorption separation, supercritical fluid extraction, etc. Catechins can also be obtained by synthetic methods, such as transesterification, oxidation, etc. These methods can all be used for large-scale production of catechins to meet the needs of different fields. The following is an introduction to the detection methods for catechins.
1. Solvent extraction method.
Solvent extraction is one of the commonly used extraction methods for catechins. In this method, the solubility of catechins in different polar solvents was used to select the appropriate solvent for extraction. Commonly used solvents include methanol, ethanol, acetone, water, etc. In general, after the tea sample is crushed, an appropriate amount of solvent is added for soaking, stirring or ultrasonic-assisted extraction, and then filtration, concentration, drying and other steps are carried out to obtain the extract of catechins.
2. Ultrasonic-assisted extraction.
Ultrasonic-assisted extraction is an efficient and rapid extraction method for the extraction of target components from solid or semi-solid samples. This method uses the mechanical action and cavitation of ultrasound waves to accelerate the release of target components from the sample and facilitate their dissolution and diffusion. Compared with the traditional solvent extraction method, the ultrasonic-assisted extraction method has the advantages of short extraction time and high efficiency.
3. Microwave-assisted extraction.
Microwave-assisted extraction is a method that uses microwave energy for extraction. This method uses microwave heating to quickly release the target components from the sample and facilitate their dissolution and diffusion. Compared with the traditional solvent extraction method, the microwave-assisted extraction method has the advantages of short extraction time, high efficiency and low solvent dosage.
Fourth, supercritical fluid extraction.
Supercritical fluid extraction is an extraction method that uses supercritical fluid as an extractant. This method takes advantage of the special properties of supercritical fluids, such as high permeability and low viscosity, to achieve efficient extraction of target components. Commonly used supercritical fluids include carbon dioxide, ethane, etc. The supercritical fluid extraction method has the advantages of high extraction efficiency, low solvent dosage, and mild operating conditions.
5. High performance liquid chromatography.
High-performance liquid chromatography (HPLC) is a commonly used separation and detection method for the separation and detection of catechins. This method utilizes different columns and mobile phases to separate and analyze catechins. High performance liquid chromatography has the advantages of good separation effect, fast analysis speed and high sensitivity.
6. Ultraviolet-visible spectrophotometry.
UV-Vis spectrophotometry is a commonly used quantitative method for the determination of catechins. In this method, the absorption characteristics of catechins in the ultraviolet-visible region were used to establish a standard curve and measure the absorbance of the sample, so as to calculate the content of catechins. UV/VIS spectrophotometry has the advantages of simple operation, fast operation and high sensitivity.
7. Liquid chromatography-mass spectrometry analysis.
Liquid chromatography-mass spectrometry (LC/MS) is a method that combines liquid chromatography with mass spectrometry and is suitable for the analysis of catechins. In this method, catechins were separated by liquid chromatography, and their molecular structures were identified and quantified by mass spectrometry. Liquid chromatography-mass spectrometry (LC-MS) has the advantages of high sensitivity, high resolution, and high accuracy.
8. Gas chromatography.
Gas chromatography is a commonly used separation and analysis method for the analysis of catechins. Catechins are separated using different columns and mobile phases, which are then quantified and identified by flame ionization detectors or mass spectrometry. Gas chromatography has the advantages of high separation efficiency and high selectivity.
9. Infrared spectroscopy.
Infrared spectroscopy is a method that uses infrared light to analyze the structure of sample molecules, which is suitable for identifying the structure of catechins. The method measures the absorption spectrum of the sample molecule in the infrared region, combined with spectral interpretation and a database of known spectra for structural identification. Infrared spectroscopy has the advantages of high resolution and high sensitivity.
10. Nuclear magnetic resonance spectroscopy.
Nuclear magnetic resonance spectroscopy (NMR) is a method for structural analysis of sample molecules using nuclear magnetic resonance technology, which is suitable for identifying the structure of catechins. This method measures the NMR signal of hydrogen atoms or other nucleons in the sample molecule, combined with a known spectral database for structural elucidation. Nuclear magnetic resonance spectroscopy has the advantages of high resolution and high sensitivity.