The non-destructive rapid detection instrument for plant polyphenols and chlorophyll is a device used to detect the content of polyphenols and chlorophyll in plants, which is usually applied in fields such as agriculture, food, and plant biology research. Through non-destructive testing methods, the concentrations of polyphenols and chlorophyll in plant samples can be measured in real-time and quickly without damaging them.
1、 The functions and importance of plant polyphenols and chlorophyll
Plant polyphenols:
Polyphenols are a naturally occurring class of bioactive substances in plants, with multiple biological activities such as antioxidant, antibacterial, and anti-inflammatory.
It mainly exists in the leaves, fruits, and seeds of plants, and is closely related to plant resistance to diseases, stress, and other factors.
chlorophyll:
Chlorophyll is a key molecule in plant photosynthesis and the core pigment involved in the conversion of light energy into chemical energy.
The content of chlorophyll is closely related to the growth, health, photosynthetic efficiency, and productivity of plants.
2、 The principle of non-destructive rapid testing method
Non destructive rapid testing methods usually use spectroscopic techniques such as near-infrared spectroscopy (NIR), visible light spectroscopy (VIS), fluorescence spectroscopy, etc. By analyzing the spectral response of plant surfaces or tissues, the content of polyphenols and chlorophyll in plants can be indirectly inferred. These methods have high sensitivity, fast response speed, and good real-time monitoring capability.
1. Near infrared spectroscopy (NIR) method
Principle: Near infrared spectroscopy technology analyzes the spectral information reflected or transmitted by the sample by emitting near-infrared light towards the sample. Different chemical components have different absorption characteristics in the near-infrared spectral range, and their content can be accurately determined by matching with the characteristic absorption peaks of polyphenols and chlorophyll.
Advantages: No need for sample processing, fast and real-time data acquisition.
2. Visible light spectroscopy (VIS) method
Principle: Visible light spectroscopy infers the composition of a sample by measuring its absorption intensity at specific wavelengths of light. Chlorophyll and polyphenols have specific absorption peaks, which can be used for quantitative analysis.
Chlorophyll absorption peak: Chlorophyll mainly exhibits significant absorption in the range of red light (650-670nm) and blue light (430-450nm).
Polyphenolic absorption peak: Polyphenolic compounds exhibit absorption peaks in the ultraviolet (250-280nm) and visible light (320-400nm) regions.
3. Fluorescence spectroscopy method
Principle: Fluorescence spectroscopy generates specific fluorescence by exciting a sample, and then measures its emission spectrum. Different chemical components, such as polyphenols and chlorophyll, produce specific fluorescent signals, and their content can be estimated by analyzing the fluorescence intensity and wavelength position.
Chlorophyll fluorescence characteristics: Chlorophyll emits fluorescence in the range of 680-750nm at excitation wavelengths of 430-450nm.
Polyphenolic fluorescence characteristics: Polyphenolic substances also have certain fluorescence emission characteristics under ultraviolet excitation.
3、 Method for determination of plant polyphenols and chlorophyll
1. Near infrared spectroscopy (NIR) measurement
Steps:
Place the plant sample to be tested at the measurement position of the near-infrared spectrometer.
Select the appropriate wavelength range (usually 800-2500nm) for reflection or transmission spectral scanning.
Compare the obtained spectral data with the characteristic spectra of polyphenols and chlorophyll, and perform quantitative analysis using chemometric models such as partial least squares regression (PLSR).
Obtain the concentration values of polyphenols and chlorophyll.
Advantages: Non destructive, real-time, fast, suitable for large-scale sample testing.
Disadvantage: High equipment requirements and the need to establish a chemometric model in advance.
2. Visible light spectroscopy (VIS) measurement
Steps:
Use a visible light spectrometer (usually in the wavelength range of 400-700nm) to irradiate the surface of plants.
Measure the absorption intensity of plants towards different wavelengths of light, with a focus on the absorption peaks of chlorophyll (red and blue light regions) and polyphenols (ultraviolet and visible light regions).
Quantitative analysis is performed using a calibration curve by comparing the absorption intensity with a known standard sample.
Advantages: Easy to use, low equipment cost.
Disadvantages: Requires a relatively large sample area, and spectral interference may affect measurement accuracy.
3. Fluorescence spectroscopy determination
Steps:
Using ultraviolet light to excite the sample, the excitation wavelength is usually selected between 320-400nm.
Measure the fluorescence emission spectrum of plant samples, especially the fluorescence intensity in the range of 680-750nm (chlorophyll fluorescence) or 300-400nm (polyphenol fluorescence).
Perform quantitative analysis based on the comparison of fluorescence intensity with standard samples.
Advantages: High sensitivity, suitable for low concentration detection.
Disadvantages: May be affected by fluorescence interference, and the device requires high precision.
4、 Measurement parameters and data analysis
Spectral feature extraction: Extract the absorption or fluorescence characteristics of chlorophyll and polyphenols at different wavelengths.
Data preprocessing: including smoothing, denoising, normalization, and other steps to improve the quality of spectral data.
Quantitative analysis: By establishing calibration models (such as multiple regression analysis, partial least squares regression, etc.), quantitative prediction of plant polyphenol and chlorophyll content can be achieved.
Calibration and validation: Use standard samples with known concentrations for calibration, and validate the accuracy of the model through methods such as cross validation.
V. Summary
The non-destructive rapid detection instrument for plant polyphenols and chlorophyll can quickly and accurately determine the content of polyphenols and chlorophyll in plants through different spectral techniques, such as near-infrared spectroscopy, visible light spectroscopy, and fluorescence spectroscopy. Choosing appropriate technologies and methods can not only provide real-time data, but also ensure the integrity of plant samples without damage, providing effective support for fields such as agriculture, plant biology research, and food safety.