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35].

      3.2.1 Wheat

      Among the most important grains in the world is wheat, produced annually at quantities reaching approximately 600 million tons. About 70% of this wheat is utilized for the production of foodstuffs [38, 39].

      Triticum aestivum L., commonly known as wheat, is a grain comprising the 3 basic sections of an embryo (also known as the germ), endosperm, and pericarp (also known as the bran). A whole wheat kernel consists of 3% germ, 12% bran, and 82% endosperm [37, 40]. A wheat grain is about 8 mm long and weighs approximately 35 mg, while kernel size changes based on its location within the spike or the head of the plant, and also based on the cultivar. Wheat kernels have longitudinal folds on the ventral side, which run the length of the kernel. This fold makes it difficult for the bran to separate from the endosperm and keeps out both dust particles and various microorganisms. In the seed coat, there is pigmentation that gives the wheat kernel its coloring. Color is determined by genetics but is usually white or red. The grower may choose a preferred kernel color by genetic manipulation. The wheat kernel has an aleurone layer surrounding the endosperm, which is starchy in nature, and the germ. The bran and germ will be detached from the endosperm in the milling process. Most of the endosperm fraction (71%) is found in white flour. Amounts of the remaining parts of the endosperm, like the outermost layer of aleurone, are low [37].

      The endosperm layer of wheat is rich in energy-yielding starch. It contains proteins (13%) and fats (1.5%) apart from carbohydrates. Proteins in the endosperm of wheat are globulins, albumins, gliadins, and glutenins. Gliadins and glutenins are important proteins that make up gluten in dough-making. The mineral and dietary fiber contents of wheat endosperm are quite low. The mineral (ash) content is 0.5% and the dietary fiber content is 1.5% [42, 45].

      Wheat germ has high levels of lipids (8%–13%), proteins (25%), and mineral substances (4.5%). At the same time, it represents a valuable source of vitamin E. While wheat germ contains 50% of the proline and glutamine content of the flour, its amounts of asparagine, arginine, alanine, glycine, threonine, and lysine have been measured to be twice as high [41, 42].

      For dietary antioxidants, whole wheat and wheat bran both constitute valuable sources. The phenolic acids found in wheat, both free and esteri-fied, exert the largest influences among the health effects of wheat [22, 46, 47]. Phenolic acids, which are taken into the body with the consumption of a normal portion of whole wheat, exhibit marked antioxidant activities under in vitro conditions. The solubility and activity of wheat polyphenols are increased by acidic conditions and enzymatic hydrolysis [22, 46].

      3.2.2 Buckwheat

      Fagopyrum esculentum Möench, commonly called buckwheat, is a traditional agricultural product historically grown in Asia and Central and East Europe [50]. It belongs to the family Polygonaceae, unlike most other cereals [51, 52]. However, buckwheat seeds can be classified as a cereal due to their chemical and usage properties, similar to cereal grains [53]. It is also known as a pseudocereal because of its differences from cereals [50, 53, 54]. The fundamental difference in terms of its structure is that buckwheat is dicotyledonous, as opposed to monocotyledonous species of cereal. The buckwheat seed’s embryo is found within the endosperm’s center, having two cotyledons. The embryo, endosperm, and seed coat are tightly surrounded by the hull (also known as the pericarp), which is hard and fibrous. Meanwhile, the walls of the cells that form the endosperm are quite thin [50, 55, 56].

      Although numerous species of buckwheat are harvested globally, only 9 of them possess value for agricultural purposes [57–59]. There are varieties of buckwheat that can be harvested in summer, in autumn, and in the middle of the two seasons [53]. In general, two species are utilized globally: that known as common buckwheat (F. esculentum) and that known as Tartary buckwheat (F. tataricum). While the former is grown in more widely spread and diverse environments, the latter is farmed in mountainous areas [57–59]. Buckwheat seeds are triangular and have blackcolored hulls that cover the kernels, with the kernels ranging in color from white to light shades of green. Color saturation opens towards the kernel’s innermost layers. The density of the hull is lower than that of water; therefore, hulls can be removed more easily from kernels [57, 59]. Hull hardness varies among different species. F. esculentum is generally less hard than F. tataricum. F. esculentum has a harsher flavor, while F. tataricum is slightly bitter. The bitter compounds in F. tataricum seeds can be extracted by assorted techniques, such as various chemical methods and isoelectric precipitation [57, 60].

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