Barley in Human Nutrition and Health

Abstract

Barley was one of the first and the earliest crops domesticated by humans, cultivated around 7,000 to 5,000 BC. Region of Fertile Crescent has been suggested as the location where barley was originally domesticated. During the sixth and fifth millennium BC, barley spread from its centre of diversity to eastern parts of the Mediterranean basin, highlands of Ethiopia and the Indian subcontinent, and the Caucasus and Trans Caucasus regions. Barley reached China during the second half of the second millennium BC, from where it spread further to the Korean peninsula and Japan. The six-rowed types of barley reached Central and Northern Europe during the fourth and third millenniums BC, while two-rowed ear types have been introduced with seeds brought along by the crusaders from the Near East only during the twelfth and thirteenth centuries. Barley is the fourth most important crop in the world after wheat, rice and maize today. Different morphological types of this crop are present today, such as two-rowed or six-rowed genotypes, hulled or hull-less, and genotypes of different colours (black, blue, purple or yellow). Barley is grown on about 50 million hectares in the world in recent years, and the total annual grain production in the world is more that 140 million tons. Regarding cereal crops grown in the EU, the most important overall is barley. Barley grain has three major uses: livestock feed, raw material for alcohol and starch production, and food. It is still a major staple food in several regions of the world: in the highlands of Central Asia, Andean countries and Baltic States, some areas of North Africa and Near East, and the Horn of Africa. China is the largest consumer of barley as food (4 million tonnes), followed by USA (2.9 million tonnes), Russia, Germany, Morocco, Ethiopia and Saudi Arabia (from 1 to 1.3 million tonnes). In China, most of the barley was consumed in Tibet (56% of the total food production), with approximately 2.1 million people consuming barley. Saudi Arabia and Morocco have the highest average consumption (more than 35 kg per person per year), followed by Germany, Ethiopia (around 14 kg per person per year), UK, USA, Russia (about 10 kg per person per year), Brazil, China (3 to 4 kg per person per year). India has the lowest average annual consumption (0.7 kg per person).
Due to its high nutritional and healthy value discovered over recent years, there has been a growing interest for use of barley as human food. The high content of soluble dietary fibres present in barley have boosted the status of barley as a food ingredient. Products with new functional and nutritional properties are a precondition for a higher acceptance of barley, for instance as products with a high content of dietary fibres. Soluble fibre forms, a gel like substance, delays the gastric emptying and retains water. Cellulose is beneficial for digestion efficiency, binding to other micronutrients, and toxins such as bile acids. Lignin contains many different chemicals, such as ferulic acid, coumaric acid, vanillic acid, vanillin, syringaldehyde and furfural. Hemicelluloses are important components of dietary fibres, which exhibit strong sorptive properties for heavy metals, increasing health-promoting value of food. β-glucan decreases cholesterol level, has potentially cancer-protecting properties and controls blood glucose level. Human consumption of whole grains (e.g. barley, oat, brown rice, buckwheat, bulgur, millet, maize) has significant role in controlling weight, prevention the risks of gastrointestinal disorders including cancer, vascular and coronary diseases, and type II diabetes.