Barley (Hordeum vulgare) is a cereal grain. It is of the Gramineae family and has a one-year-long life cycle. Barley’s cultivation probably started from Ethiopia and Southeast Asia.
Barley’s real origin is not yet known but researchers put its origin somewhere around the Zagros mountain range in West or Iran, Southern Anatolia, and Palestine. According to Valiev’s theory, the origin of two-row and six-row barley is Ethiopia and North Africa and the origin of hulless barley is Southeast Asia, especially China, Japan, and Tibet. Barley has been an important food source for the people in cold and dry areas (especially the Middle East and Northern Africa) although it is mostly used today as a food for livestock or to make fermented products.
Like other plants in its family, barley’s stem is hollow and can grow from 30 to 120 cm depending on the conditions. It has between 5 to 10 leaves placed opposite each other on the stem. The leaves are formed of sheath, blade, auricles, and ligule. The sheath not only does photosynthesis but also help with the plant’s rigidity.
The stem leads to the rachis which has several spikelets each with ears that hold the seeds. The internal and external glume stick to the seed even after reaping but after a while when the seed lost some of its moisture it will shrink, wrinkling the internal glume, an important factor in determining the quality of the product. More wrinkle means the glume is thinner and can be better used in fermentation industries because it is softer.
Barley seed chemical structure:
The chemical structure of barley seeds depends on different factors such as its type, cultivar, and environment but is generally composed of carbohydrates, proteins, fats, and ash.
Carbohydrates: they are the main component of barley seeds and make up more than 80% of the dry plant’s weight. Naked barley mainly consists of starch along with other carbohydrates like pentose, beta-glucan, cellulose, and a little bit of monosaccharide and disaccharide. Naked barley’s beta-glucan levels are less (about 61%) than that of the normal barley (which is normally between 30 to 35 %). Beta-glucan levels are important because it has a hydrophilic part that increases its solubility and thus can lead to intestinal viscosity in animals and the inability to properly digest food. Most of the cellulose is stored in the stem and seed of barley which will be reduced after being milled. Naked barley also has lower levels of cellulose compared to normal barley in the time of threshing.
Fat: normally the seed has between 2 to 4 percent fat with about 73.1-79 % of it being triglyceride. 77% of all the fat is stored in the endosperm.
Protein: protein levels in barley starts from 8% in normal barley to 20% in naked barley. They contain hydrogen and their levels are lower than Lysine. Higher protein levels in barley lead to lower levels of Lysin amino acid.