Terahertz Spectroscopy Shows Promise in Food Quality Control

According to a recent review published in the journal Trends in Food Science & Technology by lead author Da-Wen Sun from University College Dublin (UCD), terahertz (THz) spectroscopy has become the technique of choice in food process analysis and related applications (1).

Terahertz spectroscopy, particularly terahertz time-domain spectral imaging (THz-TDS), has shown significant promise in assessing various quality parameters during food processing. This innovative non-destructive examination technique is gaining attention for its rapid and accurate detection capabilities, making it a promising tool for online food quality control (2). The technique involves using electromagnetic waves in the terahertz frequency range to analyze the composition and structure of food products (1). According to Sun and his colleagues, THz-TDS systems, when combined with advanced chemometric methods, can achieve high prediction accuracy, making them suitable for real-time, on-site process analysis (1).

Assortment of healthy food dishes. Top view. | Image Credit: © Yaruniv-Studio - stock.adobe.com

Sun and team covered how THz-TDS spectroscopy can be used during many stages of food processing. In their review article, the authors wrote how THz-TDS spectroscopy has been used in the following stages: dehydration; storage; freezing; and fermentation (1).

Among these different stages, the ability of THz-TDS spectroscopy to monitor moisture changes during dehydration and storage under natural drying conditions stands out. By integrating THz-TDS with other processing methods like hot air drying (HAD) and microwave vacuum dehydration (MVD), researchers have been able to enhance the efficiency and accuracy of moisture content analysis (1).

One of the key areas where THz-TDS has shown promise is in monitoring moisture changes during dehydration and storage processes (1). Moisture content is a critical factor in determining the shelf life and quality of food products (1). The use of THz-TDS allows for precise, non-invasive measurement of moisture levels, helping to optimize drying processes and ensure product consistency (1).

THz-TDS has been employed to study the effects of repeated freezing and thawing on meat quality and the growth rate of ice crystals (1). These analyses are crucial for maintaining the texture and safety of frozen foods. The ability of THz-TDS to detect subtle changes in the food matrix during freezing and thawing cycles provides valuable insights for improving freezing techniques and extending product shelf life (1).

THz-TDS also benefitted fermentation processes. Although research in this area is still developing, preliminary studies have demonstrated the feasibility of using THz spectroscopy to monitor fermentation progress (1). This could lead to more precise control over fermentation parameters, resulting in better-quality fermented products.

Despite its potential, the widespread adoption of THz-TDS in the food industry faces several challenges. One significant obstacle is the high cost of the technology, which can be prohibitive for many food producers (1,2). Additionally, high moisture content in samples can interfere with terahertz measurements, and the presence of other constituents such as proteins can cause disturbances in the spectral data (1).

To overcome these challenges, further research is needed to refine calibration and chemometric methods, enhancing the accuracy and reliability of THz-TDS. THz technology is expensive and suffers from limited sensitivity and penetration (2). Advances in technology that reduce costs and improve the robustness of terahertz systems will also be essential for broader adoption (1,2).

The review by Da-Wen Sun and his team at University College Dublin underscores the potential of terahertz spectroscopy as a powerful tool for food process analysis. By providing rapid, non-destructive, and accurate measurements, THz-TDS can significantly enhance food quality control, benefiting both producers and consumers.

References

(1) Fun, Y.; Ren, Y.; Sun, D.-W. Novel Analysis of Food Processes by Terahertz Spectral Imaging: A Review of Recent Research Findings. Trends Food Sci. Technol. 2024, 147, 104463. DOI: 10.1016/j.tifs.2024.104463

(2) Afsah-Hejri, L.; Hajeb, P.; Ara, P.; Ehsani, R. J. A Comprehensive Review on Food Applications of Terahertz Spectroscopy and Imaging. Comprehensive Rev. in Food Sci and Food Saf. 2019, 18 (5), 1563–1621. DOI: 10.1111/1541-4337.12490