It is imperative to ensure food meets all legal and hygiene standards before putting it on the market. Everything from temperature, polarity, and pH to viscosity and pressure are critical characteristics of food that determine human consumption safety and quality. Food generally consists of water, proteins, fat, carbohydrates, and proteins, which, in turn, have several minor components. These components’ qualities are governed by their intra- and intermolecular interactions within the food system and molecular structure.
However, testing and assessing food quality is easier said than done, as it comprises everything from microbial, biological, and chemical factors to aspects like color, texture, appearance, and flavor. Since the public interest in food safety has intensified dramatically, so has the demand for top-notch analytical tools for quality control.
That is where spectroscopy comes into play. Spectrometers are used nowadays to evaluate food quality, as they are devices that often demand minimal to no sample preparation, allow for several tests on a single sample, and provide quick and precise analysis. Spectroscopy in food testing involves nuclear magnetic resonance (NMR), UV-Vis (ultraviolet-visible), infrared (IR), mid-infrared (MIR), and near-infrared (NIR).
You may find it a bit daunting (and it is, indeed, a complex subject), but once you understand its very basics, you will familiarize yourself with spectroscopy and, why not, apply it.
What is spectroscopy?
Before delving into the subject, let us clarify what spectroscopy is all about in the simplest terms we could have employed. Thus, spectroscopy studies the emission and absorption of light and other radiation through matter. It measures and reads the electromagnetic spectrum deriving from the interaction between matter and electromagnetic radiation (simply put, light). Color, in this case, plays a crucial role, as it changes on the basis of the various kinds of light used in this assessment (ultraviolet, visible, infrared, near-infrared, mid-infrared, etc.).
Spectroscopy allows for studying multiple matters; that is why it is widely used in chemistry, astronomy, physics, and materials science. The substances subject to analysis are assessed at the molecular, atomic, and macro scale and over astronomical distances. Spectroscopy also has a wide range of applications
Chemical compounds interact with light at different wavelengths, so exact measurement is mandatory. But conventional measurement instruments or methods are often not helpful enough in determining the precise wavelength between matter and light. That is why spectroscopy is preferred, especially in food and healthcare industries and even law enforcement (to aid crime investigations by substance analysis). In the latter case, it helps identify legal and illegal drugs by molecular composition.
What are spectrometers?
Spectrometers are scientific devices used to measure and separate spectral characteristics of a physical phenomenon. “Spectrometer” is a generic term, as there are various spectrometer types, including NMR (nuclear magnetic resonance) spectrometers, mass spectrometers, and optical spectrometers. Each spectrometer varies based on the required measurement method for your application. Depending on the type of product or matter analyzed, there are measurements in UV or visible, infrared, near-infrared, mid-infrared, etc. wavelengths.
Infrared spectroscopy
Infrared spectroscopy (IRS) has become a powerful tool in food analysis, as it can be used to examine numerous families of food groups, including fish, meat, dairy, cereals, fruits and vegetables. IRS instruments measure the absorption of infrared frequencies by a food sample under an infrared beam. It is, in essence, a very simple and practical way to examine the quality of common foods that we frequently put on our tables. In fact, its highly practical character, as well as relatively low associated costs, made IRS one of the most popular food testing and analysis methods out there.
Near-infrared spectroscopy
Near-infrared spectroscopy (NIRS) is one of the most used and practical ways to test the quality of ingredients, raw materials, and final products and spot food fraud. It has gained momentum lately, as researchers have studied its benefits, coming to the conclusion that it is a rapid and sound manner to assess various kinds of foods, including gels, liquids, powders, and solids. Plus, it has no harm to the food, as it is based on light, unlike traditional methods, where only chemistry comes into place. Using NIRS, manufacturers and scientists can measure several properties of the food item simultaneously and achieve more uniform quality based on the company’s health and safety requirements.
The measurement itself shall not be complicated, as it implies taking a sample of the food subject to analysis, placing it in a special cup, and then putting the cup in the associated spectrometer. The evaluation will generally take place in less than a minute, so you will likely see the result faster than expected. As this is not harmful to the sample, you can return it to production after the evaluation has been made.
The food item’s parameters are evaluated based on the measured optical spectrum and then read with modern data analysis. In this case, spectrometers are adjusted to assess the required parameters through mathematical algorithms. So, everything regarding NIRS is going to be exact.
UV-Vis spectroscopy
UV visible spectroscopy is a widespread method in food testing, as it helps, among others, determine the origin of food and beverages and detect adulteration. UV-Vis spectroscopy implies the interaction of samples with an electromagnetic wave. Since each matter absorbs light differently, there would not be the same kind of relationship between the nature of this matter and the UV visible spectrum. That is why a UV-Vis spectrometer is required. These instruments can examine various materials, from organic and inorganic molecules to glass or films.
UV-Vis spectroscopy is used to measure qualitative and quantitative properties of particular compounds, but it is predominantly employed in the food industry to assess the quality of edible oils. One of the many parameters involved in this sense is the anisidine value, a measurement of the oxidation of fats.
The various ways the food industry leverages spectroscopy:
- Real-time field analysis
- Food authentication
- Industrial grading and sorting
- Pesticide detection
- Horticulture lighting
The need for safe and healthy food has given rise to developments such as spectrometers used in measuring the many food components in relation to light. Outcomes are incredible – food that complies with safety and health standards all around the globe!
