You could hardly start your day without some grains. That might include oats, a bran muffin, or even grits, if that’s your thing.
In fact, grains are a part of our daily diets. The U.S. Department of Agriculture defines grains as any food made from wheat, rice, oats, cornmeal, barley or another cereal grain. That includes bread, pasta, oatmeal, breakfast cereals and tortillas.
What you might not know is near-infrared spectroscopy (NIR) plays a crucial role in monitoring the safety, quality and health benefits of those grains.
NIR spectroscopy is widely applied in food science and technology research. It has become one of the most common analytical techniques in the sector due to its low costs, fast processing and non-destructive nature. Nowadays, NIR spectroscopy is a well-recognized technique in the wheat and cereal-processing industry for routine quality assessment.
Cereals are a staple food supplies worldwide. Wheat, rice, and maize represent the most important agricultural crops. These products provide more than half of the world's dietary calorific, or energy intake, according to the USDA. The quality of food products is strictly dependent on the quality of the raw ingredients used. Therefore, assessing its composition, purity and physicochemical characteristics is of interest to the food industry, breeders and farmers, and for the scientific community serving these industries.
Grains have a number of properties which impact its quality, safety and health values. Protein, moisture, phenolics and fungi are some of those features. Engineers use NIR spectroscopy to detect these characteristics.
The measurement of protein and moisture in wheat and other grains is among the most widespread NIR spectroscopy application in use, according to 2018 research conducted by Nicola Caporaso, Martin Whitworth and Ian Fisk. Spectroscopy provides information about the chemical properties of a material, and NIR spectroscopy is used in cereal grain evaluation. The group showed the potential of NIR-based methods to predict protein content, sprout damage and α-amylase activity in wheat and barley. They also showed an assessment of quality parameters in other cereals such as rice, maize and oats, and the estimation of fungal infection.
Traditional applications of NIR spectroscopy for cereals used ground wheat in the study. Yet, the researchers demonstrated that reliable prediction of wheat composition is possible using NIR directly on whole kernels. This represents a great advance with benefits in terms of sample preparation, cost, and applicability.
NIR spectroscopy has been applied to predict some major components of grains such as moisture, protein, and lipids. It has demonstrated such good performance that in many cases, it is preferred over traditional wet chemistry methods for routine analysis.
Traditionally, the use of ground material removes the information regarding the natural variability of individual kernels within a sample. Its nature implies the measurement of an average. Yet grinding gives a uniform material on the spectrometer. Therefore, researchers usually obtain better predictions compared to whole kernel measurement.
But grinding is time-consuming, and it represents a limitation when engineers need to scan large numbers of samples. NIR spectroscopy is able to scan individual kernels instead of in bulk.
Protein content in wheat has been a major target for NIR spectroscopy for bulk and single kernel applications. For example, NIR reflectance spectroscopy has been applied to assess protein variability in single wheat kernels from various USDA wheat classes. It was also shown that protein content in wheat may be estimated by single kernel NIR reflectance spectra at a performance equivalent to conventional bulk kernel NIR instrumentation.
NIR spectroscopy achieved accurate predictions for total phenolics and free p-coumaric acid content in barley. NIR spectroscopy has also been used to predict protein and amylase content in rice flour.
Maize mycotoxins are a common problem in every producing country, according to the researchers. Toxigenic fungal growth can dramatically affect the quality and safety of the products, both for human and animal nutrition. Traditional NIR spectroscopy has been used in several applications for the detection of mycotoxigenic fungi and their toxic metabolites.
HORIBA Scientific makes a number of NIR spectrometers, including manual units and as part of custom-built systems.
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