Barley is one of the oldest cultivated cereals in the world and is classified as a botanical member of the grass family (Poaceae). The primary structural components in the cell wall interiors of the starchy endosperm are (1→3), (1→4)-β-D-β-glucans. They are linear polysaccharides that belong to the group of dietary fibres and are a crucial part of human nutrition. β-glucan’s primary functions are the stabilisation of a plant’s cell wall and the mobilisation of energy produced by its hydrolysis. Our research project’s goals were the histochemical localisation of β-glucans within the grain of barley and the evaluation of fluorescence intensity in four different barley types for the basis of quantitative determination of the content of β-glucans. For source material, we gathered a few grains from three different types of barley with known concentrations of β-glucans, and a few grains of a type of barley with an unknown concentration of β-glucans. The specimens were prepared for cutting and dyeing with the freeze-thaw technique. Dyeing was achieved with two fluorescent dyes; Calcofluor White (Sigma-Aldrich) and the Fluorescent Brightener 28 (Sigma-Aldrich), which bind to the β-1,3 and β-1,4 polysaccharides. We determined that the β-glucans are present within the grain of barley, specifically within the starchy endosperm and the aleurone layer. We measured the intensity of fluorescence on the images of dyed slice samples with the imageJ programme. With the help of the average values of fluorescence intensity, we created a measuring curve, which we used to determine the content of β-glucans in the grain of barley with an unknown content of β-glucans. We can conclude that the histochemical method is appropriate for semi-quantitative assessment of the β-glucan levels in grains of barley, which can then be classified into grades of fewer, medium, and higher β-glucan content.
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