Raman Spectroscopy: Enabling the Detection of Rapeseed Oil

author: Jayne

2024-08-23

Raman Spectroscopy: Enabling the Detection of Rapeseed Oil

Near Infrared refers to the region of the spectrum extending from about 700 nm to 2500 nm regularly. The principle of Raman spectroscopy is mainly based on Raman scattering, the Raman characteristic peaks of substances with the excitation wavelength to produce a fixed shift. Usually, the excitation wavelength of Raman spectroscopy is 785nm, 1064nm, etc. The Raman shift is usually recorded as the shift of the right direction of the excitation wavelength (Stokes Raman Scattering, infrared direction).

With the increasing consumer demand for food safety and quality, the purity and safety of authenticity in the edible oil market have become the focus of attention. Among a variety of edible oils, canola oil is highly favored for its unique nutritional value and health benefits. However, there is no lack of unscrupulous merchants in the market who adulterate it by mixing it with other fats and oils such as soybean oil, which brings harm to consumers' rights and interests.

In order to quickly and accurately measure the adulteration in rapeseed oil and the composition of rapeseed oil, researchers have been seeking efficient and accurate detection methods. Raman spectroscopy, as a non-destructive, rapid and sample-preparation-free detection technique, shows great potential in the field of edible oil adulteration detection. Through Raman spectroscopy, the vibrational information of molecules in edible oil can be obtained, and then its chemical composition and structure can be analyzed.

1.Technology empowerment, accurate detection
When soybean oil is adulterated in canola oil and the oleic acid or No. 6 solvent residue in canola oil is measured, the molecular vibration characteristics of these substances will differ from those of canola oil. Using Raman spectroscopy, these differences can be captured and the spectra can be analyzed by data analysis software to achieve qualitative and quantitative analysis of the adulterated substances. Raman spectroscopy, as a non-destructive, rapid and sample-preparation-free detection method, shows great potential in the field of edible oil adulteration detection. By capturing the vibration information of the molecules in edible oil, Raman spectroscopy can deeply analyze their chemical composition and structure, and realize the qualitative and quantitative analysis of adulterated substances. Whether it is a trace amount of soybean oil adulteration, or oleic acid, No. 6 solvent and other harmful residues, Raman spectroscopy can accurately identify them, ensuring the purity and safety of canola oil.

2.experiments verified, remarkable effect

In our experiments, we used the advanced NY6000 Edible Oil Comprehensive Analyzer (near-infrared band) to comprehensively detect adulteration in canola oil. By configuring soybean oil and oleic acid samples with different gradients, we established a precise detection model and successfully verified its accuracy. The experimental results showed that the Raman spectroscopy technique was able to detect the adulteration of canola oil with soybean oil with the modeling R-squared value as high as 0.97, which demonstrated an extremely strong correlation. Meanwhile, during the validation process, the measurement results were highly consistent with the real values, further proving the reliability of Raman spectroscopy technique.

Rapeseed oil adulteration measurement data

Configuration of rapeseed oil adulteration of soybean oil adulteration samples were tested, the stability of the instrument test is good, the absolute error of the test is within 2.5%. It can be seen that Raman can measure soybean oil adulteration in rapeseed oil.

Oleic acid modeling

As shown above, the correlation coefficient of the calibration set is 0.99. The correlation coefficient of the validation set is 0.98, the root mean square (RMS) is 0.02, and the PRD value is 7.85 (which is usually greater than the value of 1.4, which is of strong quantitative significance), so it can be seen that the modeling of the oleic acid in canola oil by using the top of the Raman spectroscopy has good linear correlation with a small root mean square error.

Tests on the configuration of oleic acid samples, the stability of the instrument test is good test within 3% of the absolute error. It can be seen that the use of Raman can be measured on oleic acid (C18:1).

Solvent No. 6

The spectrum of the standard solution of solvent VI (10 mg/ml) was measured as shown above, and by the characteristic peaks, it was possible to identify the solvent VI at that concentration.

3.Guard your health, start at the source

The application of Raman spectroscopy technology not only provides a powerful means to regulate the edible oil market, but also builds a solid line of defense for consumers' health. The use of Ausnutria's NY6000 Edible Oil Comprehensive Analyzer enables fast and accurate testing, helping us to detect and combat adulteration and counterfeiting in a timely manner, and safeguarding the legitimate rights and interests of consumers. At the same time, it will also prompt edible oil producers to strengthen self-discipline, improve product quality and promote the healthy development of the whole industry.

Laser wavelength	1064nm
Spectral range	200-2600cm-1(1064nm)；Wave number range supports customization
Detector	Ultra-high sensitivity cooled (-10°C) back-illuminated 2048*64 array detector
Maximum laser power	450mW
Spectral stability	σ/μ < 0.5% (COT 8 hours)
Temperature stability	Spectral Shift ≤ 1 cm-1 (10-40 ℃)
SNR	>3000:1
Laser diameter	Outer diameter 12.7mm，Aperture8.5mm
Software function	Quantitative measurement of adulteration in edible oils
Interface	USB2.0，Network port
Power supply	DC5V，3.5A
Weight	＜10 Kg

Conclusion

The NY6000 can identify soybean oil adulteration in canola oil, and the error of qualitative measurement is within 2.5%, which can realize the high-end edible oil adulteration and counterfeiting. The instrument can qualitatively identify oleic acid (C18:1) with an error of 3% or less, which can be helpful in rating and identifying rapeseed oil, and creating high-end quality edible oil brands such as high oleic acid rapeseed oil. The instrument can recognize solubility VI (10mg/ml), NY6000 as a non-destructive, fast and no sample pretreatment instrument, in the field of edible oil adulteration detection shows great potential.