Application of UV-VIS absorption spectroscopy in food and beverage quality analysis

Food quality is an important factor in food production. Producing quality food products to avoid contamination and producing healthy foods during production is a major concern.

This in turn requires appropriate analytical tools to test the quality standards of food products. Among them, UV/VIS spectroscopy is the most important analytical technique used to test food and beverages. This UV/VIS spectroscopy technique does not disturb the compounds in the sample and does not produce any byproducts in the form of residue.

Ultraviolet-visible spectroscopy technique is based on the absorption of light by the sample substance. Depending on the nature of the sample, light is partially absorbed and the other transmitted fraction is measured as a function of wavelength using the SR spectrometer series.

This provides the UV/Vis spectrum of the sample. Each substance has its own light-absorbing nature and therefore a specific relationship exists between the UV/VIS spectrum and the nature of the substance. This helps quantify the substance. The resulting UV/VIS spectra are useful for quantitative and qualitative measurements of specific compounds, the concentration of a sample can be determined by absorbance at specific wavelengths.

Ocean SR Series are versatile UV-VIS and NIR spectrometers with quick data acquisition and high SNR, applying for measuring UV-VIS spectral analysis. The UV Visible light is passed through the sample in a cuvette. Depending on the nature of the sample the light is either absorbed, transmitted, or reflected. According to Lambert-Beer law, when the light is passed through the cuvette filled with the sample solution, the intensity of the light is attenuated proportional to the sample concentration i.e., the absorbance of light is more in the higher concentrated sample solution. The light absorption is also proportional to the length of the cuvette. The longer length of the cuvette leads to higher absorption of light.

Now, we are going to discuss UV/VIS spectrophotometry application in the food and beverage industry to improve product quality and consistency.

Based on the above relationship between concentration and absorbance, the UV/VIS spectrum allows you to identify the different components present in the sample and the absorption peaks allow determining the level of presence of the components, the Organic compound or solvent purity can be easily tested with the SR spectrometer.

This SR spectrometer supports quantitative analysis techniques such as food and beverage, biotechnology, chemical industry, pharmaceutical and water testing, etc. In addition to product quality, deterioration and chemical decomposition of packaging materials and stabilizers are also observed.

One of the important applications of UV/VIS spectroscopy in the food and beverage segment is the enzymatic determination of carbohydrates such as starch, glucose, sucrose, fructose and total fiber. The enzyme is specific to a specific molecule and therefore it is suitable for quantitative analysis without the need for sample preparation.

A typical example in food quality analysis is the estimation of nitrate content in processed food products, especially meat products. Inorganic nitrites are naturally present in plant foods and vegetables, but these nitrates are also used as additives in industrially processed foods such as meat. When nitrogen content increases in food, it poses a significant danger to consumers' health. When this nitrogen is converted into nitrosamines it causes thyroid disorders, causes cancer, etc. For the safety of food consumers, it is important to estimate the amount of nitrates contained in meat products.

UV/VIS spectroscopy is also used to determine the purity of different types of olive oils such as extra virgin olive oil, virgin olive oil, olive oil and others. Olive oil is rich in Vitamin E, antioxidants and monounsaturated fatty acids so it is considered healthy when consumed with food.

Lipid-related oxidation plays an important role in oil quality. Unsaturated lipids undergo oxidation to produce allylic hydroperoxides. The diene and triene double bonds present in hydroperoxide show strong absorption at wavelengths from 200nm to 300nm.

Low absorbance in this wavelength range represents the high quality of olive oil. The UV/VIS spectrometer helps determine the absorbance of olive oil samples and thus allows different qualities of olive oil samples to be distinguished.

For the beverage, beer and wine industries, UV-VIS spectroscopy is applied to create better drinks. Now, beverage manufacturers can inject ingredients during production and use UV-VIS technology to adjust the mix in real time.

Better bar beverages, to evaluate the color of beer or wine, many companies use UV-VIS technology. Brewers can also use UV-VIS spectroscopy to analyze other features of beer, including ingredients in the beverage. To balance the bitterness of hoppy beer, like an IPA, sugar is extracted from the barley during the mashing process. The total sugar content in wort or beer can be measured using UV-Vis spectroscopy.

As another example using ultraviolet-visible absorption spectroscopy, grape varieties, wine aging and the role of barrel/container type were studied. UV-VIS absorption spectroscopy is an alternative analytical tool in wine analysis and authentication because it is characterized by simplicity, rapidity, low cost and no need for sample pretreatment. Spectrometers are used to monitor and predict fermentation throughout the process. Monitoring the products of fermentation, such as L-malic acid, acetic acid and residual reducing sugars, can help winemakers tailor sensory attributes such as aroma and mouthfeel. Similarly, phenol dosing can enhance flavor, color and mouthfeel.

Last but not least, UV-VIS absorption spectroscopy is also used to detect contaminants and adulterants. Liquid spectroscopy is used to detect fraud caused by the following practices: mixing with a poor-quality product, using adulterants, pesticides, pollutants that can penetrate through air/water/soil.

In summary, UV/VIS spectrometer is an essential analytical tool that helps test food quality without affecting the nature of food ingredients. Therefore, Ocean Insight spectrometer Ocean SR Series is well-suited for detecting subtle UV and visible absorbance changes in DNA, proteins,... in food products. Each SR spectrometer varies in detecting wavelengths in the UV, Visible, and Shortwave NIR ranges. It also provides entrance slit options in width from 5 μm to 200 μm.