The frequency range in THz spectroscopy and its relationship to the water content in food: A first approach (original) (raw)
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A Comprehensive Review on Food Applications of Terahertz Spectroscopy and Imaging
Comprehensive Reviews in Food Science and Food Safety, 2019
Food product safety is a public health concern. Most of the food safety analytical and detection methods are expensive, labor intensive, and time consuming. A safe, rapid, reliable, and nondestructive detection method is needed to assure consumers that food products are safe to consume. Terahertz (THz) radiation, which has properties of both microwave and infrared, can penetrate and interact with many commonly used materials. Owing to the technological developments in sources and detectors, THz spectroscopic imaging has transitioned from a laboratory-scale technique into a versatile imaging tool with many practical applications. In recent years, THz imaging has been shown to have great potential as an emerging nondestructive tool for food inspection. THz spectroscopy provides qualitative and quantitative information about food samples. The main applications of THz in food industries include detection of moisture, foreign bodies, inspection, and quality control. Other applications of THz technology in the food industry include detection of harmful compounds, antibiotics, and microorganisms. THz spectroscopy is a great tool for characterization of carbohydrates, amino acids, fatty acids, and vitamins. Despite its potential applications, THz technology has some limitations, such as limited penetration, scattering effect, limited sensitivity, and low limit of detection. THz technology is still expensive, and there is no available THz database library for food compounds. The scanning speed needs to be improved in the future generations of THz systems. Although many technological aspects need to be improved, THz technology has already been established in the food industry as a powerful tool with great detection and quantification ability. This paper reviews various applications of THz spectroscopy and imaging in the food industry.
Terahertz (THz) Applications in Food and Agriculture: A Review
Transactions of the ASABE, 2013
Terahertz (THz) rays interact with materials at intermolecular levels, and because of this they are the focus of many active research areas. The developments in THz technology were hindered by lack of hardware, but the advent of the femtosecond laser in the 1980s started the advancement in THz generation and detection technologies. THz technology is transitioning from laboratory scale to many practical applications, including security screening, pharmaceuticals, plastics, and others, but there are few studies pertaining to food and agricultural applications. This study reviews the articles related to food and agriculture applications of THz spectroscopy and THz imaging. It also briefly introduces important THz techniques. The survey of the literature reveals great potential for this emerging and promising technology in agriculture. Food inspection, crop inspection, and material characterization could be potential research areas.
2012
The Terahertz (THz) region of the electromagnetic spectrum, spanning the range between 100 GHz and 30 THz, has recently enjoyed a renaissance due to technological developments in source and detector components. With the development of THz instrumentation, applications of THz spectroscopy and imaging for quality control of food products have expanded in scope and improved in performance. This article gives an overview of the fundamentals of THz technology and a comprehensive review of applications of THz time domain spectroscopy and imaging for food quality and control. Technical challenges and future outlook for these emerging techniques are also discussed.
Toward quality control of food using terahertz [6799-55]
2008
Terahertz radiation or T-rays, show promise in quality control of food products. As T-rays are inherently sensitive to water, they are very suitable for moisture detection. This proves to be a valuable asset in detecting the moisture content of dried food, a critical area for some products. As T-rays are transparent to plastics, food additives can also be probed through the packaging, providing checks against a manufacturer's claims, such as the presence of certain substances in foods.
Non-destructive inspection of food and technical oils by terahertz spectroscopy
Scientific Reports, 2018
Quality control and non-destructive monitoring are of notable interest of food and pharmaceutical industries. It relies on the ability of non-invasive inspection which can be employed for manufacturing process control. We hereby apply terahertz (THz) time-domain spectroscopy as non-destructive technique to monitor pure and degraded oils as well as hydrocarbon chemicals. Significant differences in the spectra of refractive index (RI) and absorption coefficient arising from the presence of ester linkages in the edible and technical oils were obtained. Explicit increase from 1.38 to 1.5 of the RI in all THz spectrum range was observed in hydrocarbons and mono-functional esters with the increase of molar mass. This fact is in contrast of RI dependence on molar mass in multi-functional esters, such as Adipate or vegetable oils, where it is around 1.54. Degradation products, Oleic Acid (OA) and water in particular, lead only to some changes in absorption coefficient and RI spectra of vegetable oils. We demonstrate that complex colloidal and supramolecular processes, such as dynamics of inverse micelles and oil hydrolysis, take part during oil degradation and are responsible for non-uniform dependence of optical properties on extent of degradation.
Terahertz time-domain spectroscopy of edible oils
Chemical degradation of edible oils has been studied using conventional spectroscopic methods spanning the spectrum from ultraviolet to mid-IR. However, the possibility of morphological changes of oil molecules that can be detected at terahertz frequencies is beginning to receive some attention. Furthermore, the rapidly decreasing cost of this technology and its capability for convenient, in situ measurement of material properties, raises the possibility of monitoring oil during cooking and processing at production facilities, and more generally within the food industry. In this paper, we test the hypothesis that oil undergoes chemical and physical changes when heated above the smoke point, which can be detected in the 0.05–2 THz spectral range, measured using the conventional terahertz time-domain spectroscopy technique. The measurements demonstrate a null result in that there is no significant change in the spectra of terahertz optical parameters after heating above the smoke point for 5 min.
State-of-the-Art in Terahertz Sensing for Food and Water Security – A Comprehensive Review
Trends in Food Science & Technology
Past few years have witness a dramatic change in the field of terahertz (THz) technology. The recent advancements in the technology for generation, manipulation and detection exploiting THz radiation have brought revolution in the field. Many researchers around the world have been inspired by the potential of invaluable new applications of THz sensing for food and water contamination detection. The microbial pollution in water and food is one the crucial issues with regard to the sanitary state for drinking water and daily consumption of food. To address this risk, the detection of microbial contamination is of utmost importance since the consumption of insanitary or unhygienic food can lead to catastrophic illness. This paper presents a first-time review of the open literature focused on the advances in the THz sensing for microbiological contamination of food and water and state-of-theart network architectures, applications, industrial trends and recent developments. Finally, open challenges and future research directions are presented with in the field.
Detection of Harmful Residues in Honey Using Terahertz Time-Domain Spectroscopy
Applied Spectroscopy, 2013
Terahertz time-domain spectroscopy (THz-TDS) has been applied for the detection and discrimination of harmful chemical residues in honey. Three antibiotics (sulfapyridine, sulfathiazole, and tetracycline) and two acaricides (coumaphos and amitraz) were characterized in the THz frequency regime between 0.5 THz and 6.0 THz. All chemical substances present distinct absorption peaks. THz transmission measurements of honey mixtures with antibiotics have been performed, revealing that antibiotic residues are traceable in highly absorptive food products, such as honey, at concentrations down to 1% weight percentage, thanks to their THz fingerprints. Moreover, multiple antibiotics were identified in their mixture with honey, pointing out the potential of the technique to be used in the near future as a fast, real-time technique for detecting and discriminating multi-residues strictly related to food safety issues.
Towards quality control of food using terahertz
BioMEMS and Nanotechnology III, 2007
Terahertz radiation or T-rays, show promise in quality control of food products. As T-rays are inherently sensitive to water, they are very suitable for moisture detection. This proves to be a valuable asset in detecting the moisture content of dried food, a critical area for some products. As T-rays are transparent to plastics, food additives can also be probed through the packaging, providing checks against a manufacturer's claims, such as the presence of certain substances in foods.
The 1st International Electronic Conference on Food Science and Functional Foods, 2020
Terahertz time-domain spectroscopy is a useful technique for determining some physical characteristics of materials, and is based on selective frequency absorption of a broad-spectrum electromagnetic pulse. In order to investigate the potential of this technology to classify cocoa percentages in chocolates, the terahertz spectra (0.5-10 THz) of five chocolate samples (50%, 60%, 70%, 80% and 90% of cocoa) were examined. The acquired data matrices were analyzed with the MATLAB 2019b application, from which the dielectric function was obtained along with the absorbance curves, and were classified by using 24 mathematical classification models, achieving differentiations of around 93% obtained by the Gaussian SVM algorithm model with a kernel scale of 0.35 and a one-against-one multiclass method. It was concluded that the combined processing and classification of images obtained from the terahertz time-domain spectroscopy and the use of machine learning algorithms can be used to successfully classify chocolates with different percentages of cocoa.