The Role of Vibrational Spectroscopic Techniques in Authenticating Functional Foods

Five spectroscopic techniques, including near-infrared spectroscopy (NIR), Fourier-transform infrared (FT-IR), Raman spectroscopy, hyperspectral imaging (HSI), and terahertz (THz) spectroscopy, are set to advance the detection of food adulteration for the decades to come, according to a new study published in Critical Reviews in Analytical Chemistry (1).

Functional foods, known as nutraceuticals, have received significant consumer interest lately (2). Thanks to their nutritious value and disease prevention benefits, functional foods promote proper growth, making them desirable for consumption (1,2). However, the rise of functional foods like fruits, vegetables, seeds, and legumes, in popularity has also coincided with bad actors taking advantage of this interest by adulterating these products to cut costs or increase profits (1,2).

Assortment of Diverse, Nutrient-Rich Functional Foods Arranged in a Photogenic Manner. Generated with AI. | Image Credit: © TEN.POD - stock.adobe.com

Better analytical methods are needed to detect and identify food adulteration. The problem for scientists is that traditional analytical methods often fall short because of their complexity, high cost, and limited applicability across diverse food matrices (1). This study led by Jinyu Zhang and Yuanzhong Wang from Yunnan Academy of Agricultural Sciences reviewed the five advanced vibrational spectroscopic techniques and how they offer rapid and non-destructive solutions for functional food authentication.

The first technique, NIR spectroscopy, is advantageous in food adulteration efforts because of its ability to penetrate deep into samples and provide detailed molecular information (1). By measuring the absorption of near-infrared light, this method can effectively differentiate between authentic and adulterated foods (1).

The second technique, FT-IR spectroscopy, can identify subtle differences in food ingredients, the authors write (1). The technique works by measuring the IR light absorbed by a sample, providing a unique spectral fingerprint, which can then be used to detect differences in food ingredients (1).

The third technique, Raman spectroscopy, measures the scattering of light. It is well-known for being non-destructive, as well as its specificity and sensitivity (1). The authors write that Raman spectroscopy can detect even trace amounts of adulterants, making it a powerful tool for ensuring food purity (1).

The fourth technique, HSI, combines imaging and spectroscopy to provide spatial and spectral information simultaneously (1). This dual capability allows for the detailed analysis of food samples, enabling the detection of adulterants with high accuracy (1). The authors suggest that HSI, because it can analyze multiple samples rapidly, would be best utilized in large-scale food inspection (1).

The last technique that authors discussed was THz spectroscopy. New to the food analysis scene, THz spectroscopy’s advantages include its ability to penetrate opaque materials and provide non-destructive analysis (1).

By reviewing the five spectroscopic techniques currently being used in food analysis, Zhang and Wang show that the industry is trending in the right direction. When used for the appropriate context, each spectroscopic technique can aid food analysis, ensuring the safety and efficacy of functional foods.

Currently, along with the five techniques mentioned in this review, other spectroscopic techniques are being tested in food analysis. Last year, Colleen Ray and her colleagues at the University of Missouri experimented with using nuclear magnetic resonance (NMR) spectroscopy to detect whether non-refrigerated grated parmesan cheese was modified with fillers like vegetable oil (3).

What this means for the food analysis industry is that new discoveries will lead the increased usage and expansion of spectroscopic techniques in food analysis. As the global market for functional foods continues to grow, the development and implementation of advanced analytical techniques will be crucial in protecting consumers and increasing transparency as to what is in their food.

References

(1) Li, F.; Zhang, J.; Wang, Y. Vibrational Spectroscopy Combined with Chemometrics in Authentication of Functional Foods. Crit. Rev. Anal. Chem. 2024, 54 (2), 333–354. DOI: 10.1080/10408347.2022.2073433

(2) Ajmera, R. What Are Functional Foods? All You Need to Know. Healthline. Available at: https://www.healthline.com/nutrition/functional-foods (accessed 2024-07-30).

(3) Stann, E. New Method Can Provide Rapid Detection of Food Adulteration. Missouri.edu. Available at: https://showme.missouri.edu/2023/new-method-can-provide-rapid-detection-of-food-adulteration/ (accessed 2024-07-30).