is a combustible black or brownish-black sedimentary rock, formed as rock strata called coal seams. Coal is mostly carbon with variable amounts of other elements; chiefly hydrogen, sulfur, oxygen, and nitrogen. Coal is formed when dead plant matter decays into peat and is converted into coal by the heat and pressure of deep burial over millions of years. Vast deposits of coal originate in former wetlands—called coal forests—that covered much of the Earth’s tropical land areas during the late Carboniferous (Pennsylvanian) and Permian times.
As a fossil fuel burned for heat, coal supplies about a quarter of the world’s primary energy and two-fifths of its electricity. Some iron and steel making and other industrial processes burn coal.
The extraction and use of coal causes many premature deaths and much illness. The coal industry damages the environment, including by climate change as it is the largest anthropogenic source of carbon dioxide, 14 gigatonne (Gt) in 2016, which is 40% of the total fossil fuel emissions and almost 25% of total global greenhouse gas emissions. As part of the worldwide energy transition many countries have stopped using or use less coal, and the UN Secretary General has asked governments to stop building new coal plants by 2020. Coal use peaked in 2013 but to meet the Paris Agreement target of keeping global warming to well below 2 °C (3.6 °F) coal use needs to halve from 2020 to 2030.
The largest consumer and importer of coal is China. China mines almost half the world’s coal, followed by India with about a tenth. Australia accounts for about a third of world coal exports followed by Indonesia and Russia.
is a brewed drink prepared from roasted coffee beans, the seeds of berries from certain Coffea species. Once ripe, coffee berries are picked, processed, and dried. Dried coffee seeds (referred to as “beans”) are roasted to varying degrees, depending on the desired flavor. Roasted beans are ground and then brewed with near-boiling water to produce the beverage known as coffee.
Coffee is darkly colored, bitter, slightly acidic and has a stimulating effect in humans, primarily due to its caffeine content. It is one of the most popular drinks in the world, and it can be prepared and presented in a variety of ways (e.g., espresso, French press, caffè latte). It is usually served hot, although iced coffee is a popular alternative.
Clinical studies indicate that moderate coffee consumption is benign or mildly beneficial in healthy adults, with continuing research on whether long-term consumption reduces the risk of some diseases, although those long-term studies are generally of poor quality.
The earliest credible evidence of coffee-drinking as the modern beverage appears in modern-day Yemen in southern Arabia in the middle of the 15th century in Sufi shrines. It was in what is now Yemen that coffee seeds were first roasted and brewed in a manner similar to how it is now prepared for drinking. But the coffee seeds had to be first exported from East Africa to Yemen, as Coffea arabica is thought to have been indigenous to the former. The Yemenis obtained their coffee via Somali traders from Berbera who in turn procured the beans from the Ethiopian Highlands and began to cultivate the seed. By the 16th century, the drink had reached the rest of the Middle East and North Africa. From there, it spread to Europe and the rest of the world.
The two most commonly grown are C. arabica and C. robusta. Coffee plants are now cultivated in over 70 countries, primarily in the equatorial regions of the Americas, Southeast Asia, the Indian subcontinent, and Africa. As of 2018, Brazil was the leading grower of coffee beans, producing one-third of the world total. Coffee is a major export commodity, being the top legal agricultural export for numerous countries.[failed verification] It is one of the most valuable commodities exported by developing countries. Green, unroasted coffee is one of the most traded agricultural commodities in the world. The way developed countries trade coffee with developing nations has been criticised, as well as the impact on the environment with regards to the clearing of land for coffee-growing and water use. Consequently, the markets for fair trade and organic coffee are expanding.
is rocks and minerals from which metallic iron can be economically extracted. The ores are usually rich in iron oxides and vary in color from dark grey, bright yellow, or deep purple to rusty red. The iron is usually found in the form of magnetite (Fe
3O 4, 72.4% Fe), hematite (Fe2O 3, 69.9% Fe), goethite (FeO(OH), 62.9% Fe), limonite (FeO(OH)·n(H2O), 55% Fe) or siderite (FeCO3, 48.2% Fe).
Ores containing very high quantities of hematite or magnetite (greater than about 60% iron) are known as “natural ore” or “direct shipping ore”, meaning they can be fed directly into iron-making blast furnaces. Iron ore is the raw material used to make pig iron, which is one of the main raw materials to make steel—98% of the mined iron ore is used to make steel. In 2011 the Financial Times has speculated that iron ore is “more integral to the global economy than any other commodity, except perhaps oil”.
is the seed of the grass species Oryza glaberrima (African rice) or Oryza sativa (Asian rice). As a cereal grain, it is the most widely consumed staple food for a large part of the world’s human population, especially in Asia and Africa. It is the agricultural commodity with the third-highest worldwide production (rice, 741.5 million tonnes in 2014), after sugarcane (1.9 billion tonnes) and maize (1.0 billion tonnes).
Oryza sativa with small wind-pollinated flowers
Since sizable portions of sugarcane and maize crops are used for purposes other than human consumption, rice is the most important grain with regard to human nutrition and caloric intake, providing more than one-fifth of the calories consumed worldwide by humans. There are many varieties of rice and culinary preferences tend to vary regionally.
Cooked brown rice from Bhutan
Jumli Marshi, brown rice from Nepal
Rice can come in many shapes, colors and sizes.
Rice, a monocot, is normally grown as an annual plant, although in tropical areas it can survive as a perennial and can produce a ratoon crop for up to 30 years. Rice cultivation is well-suited to countries and regions with low labor costs and high rainfall, as it is labor-intensive to cultivate and requires ample water. However, rice can be grown practically anywhere, even on a steep hill or mountain area with the use of water-controlling terrace systems. Although its parent species are native to Asia and certain parts of Africa, centuries of trade and exportation have made it commonplace in many cultures worldwide.
Oryza sativa, commonly known as Asian rice
The traditional method for cultivating rice is flooding the fields while, or after, setting the young seedlings. This simple method requires sound planning and servicing of the water damming and channeling, but reduces the growth of less robust weed and pest plants that have no submerged growth state, and deters vermin. While flooding is not mandatory for the cultivation of rice, all other methods of irrigation require higher effort in weed and pest control during growth periods and a different approach for fertilizing the soil.
The name wild rice is usually used for species of the genera Zizania and Porteresia, both wild and domesticated, although the term may also be used for primitive or uncultivated varieties of Oryza.
is a mineral composed primarily of sodium chloride (NaCl), a chemical compound belonging to the larger class of salts; salt in its natural form as a crystalline mineral is known as rock salt or halite. Salt is present in vast quantities in seawater, where it is the main mineral constituent. The open ocean has about 35 grams (1.2 oz) of solids per liter of sea water, a salinity of 3.5%.
Salt is essential for life in general, and saltiness is one of the basic human tastes. Salt is one of the oldest and most ubiquitous food seasonings, and salting is an important method of food preservation.
Some of the earliest evidence of salt processing dates to around 6,000 BC, when people living in the area of present-day Romania boiled spring water to extract salts; a salt-works in China dates to approximately the same period. Salt was also prized by the ancient Hebrews, the Greeks, the Romans, the Byzantines, the Hittites, Egyptians, and the Indians. Salt became an important article of trade and was transported by boat across the Mediterranean Sea, along specially built salt roads, and across the Sahara on camel caravans. The scarcity and universal need for salt have led nations to go to war over it and use it to raise tax revenues. Salt is used in religious ceremonies and has other cultural and traditional significance.
Salt is processed from salt mines, and by the evaporation of seawater (sea salt) and mineral-rich spring water in shallow pools. Its major industrial products are caustic soda and chlorine; salt is used in many industrial processes including the manufacture of polyvinyl chloride, plastics, paper pulp and many other products. Of the annual global production of around two hundred million tonnes of salt, about 6% is used for human consumption. Other uses include water conditioning processes, de-icing highways, and agricultural use. Edible salt is sold in forms such as sea salt and table salt which usually contains an anti-caking agent and may be iodised to prevent iodine deficiency. As well as its use in cooking and at the table, salt is present in many processed foods.
Sodium is an essential nutrient for human health via its role as an electrolyte and osmotic solute. Excessive salt consumption may increase the risk of cardiovascular diseases, such as hypertension, in children and adults. Such health effects of salt have long been studied. Accordingly, numerous world health associations and experts in developed countries recommend reducing consumption of popular salty foods. The World Health Organization recommends that adults should consume less than 2,000 mg of sodium, equivalent to 5 grams of salt per day.
or soya bean (Glycine max) is a species of legume native to East Asia, widely grown for its edible bean, which has numerous uses.
Traditional unfermented food uses of soybeans include soy milk, from which tofu and tofu skin are made. Fermented soy foods include soy sauce, fermented bean paste, nattō, and tempeh. Fat-free (defatted) soybean meal is a significant and cheap source of protein for animal feeds and many packaged meals. For example, soybean products, such as textured vegetable protein (TVP), are ingredients in many meat and dairy substitutes.
Soy beans contain significant amounts of phytic acid, dietary minerals and B vitamins. Soy vegetable oil, used in food and industrial applications, is another product of processing the soybean crop. Soybean is the most important protein source for feed farm animals (that in turn yields animal protein for human consumption
is the generic name for sweet-tasting, soluble carbohydrates, many of which are used in food. Table sugar, granulated sugar, or regular sugar, refers to sucrose, a disaccharide composed of glucose and fructose. By law in the United States sucrose is the only substance which can be called “sugar” on food labels.
Simple sugars, also called monosaccharides, include glucose, fructose, and galactose. Compound sugars, also called disaccharides or double sugars, are molecules composed of two monosaccharides joined by a glycosidic bond. Common examples are sucrose (table sugar) (glucose + fructose), lactose (glucose + galactose), and maltose (two molecules of glucose). In the body, compound sugars are hydrolysed into simple sugars.
Longer chains of monosaccharides are not regarded as sugars, and are called oligosaccharides or polysaccharides. Some other chemical substances, such as glycerol and sugar alcohols, may have a sweet taste, but are not classified as sugar.
Sugars are found in the tissues of most plants. Honey and fruit are abundant natural sources of unbounded simple sugars. Sucrose is especially concentrated in sugarcane and sugar beet, making them ideal for efficient commercial extraction to make refined sugar. In 2016, the combined world production of those two crops was about two billion tonnes. Maltose may be produced by malting grain. Lactose is the only sugar that cannot be extracted from plants. It can only be found in milk, including human breast milk, and in some dairy products. A cheap source of sugar is corn syrup, industrially produced by converting corn starch into sugars, such as maltose, fructose and glucose.
is an aromatic beverage commonly prepared by pouring hot or boiling water over cured leaves of the Camellia sinensis, an evergreen shrub (bush) native to East Asia. After water, it is the most widely consumed drink in the world. There are many different types of tea; some, like Darjeeling and Chinese greens, have a cooling, slightly bitter, and astringent flavour, while others have vastly different profiles that include sweet, nutty, floral or grassy notes. Tea has a stimulating effect in humans primarily due to its caffeine content.
Tea originated in the region encompassing today’s north Burma and southwestern China, where it was used as a medicinal drink by various ethnic groups in the region. An early credible record of tea drinking dates to the 3rd century AD, in a medical text written by Hua Tuo. It was popularised as a recreational drink during the Chinese Tang dynasty, and tea drinking spread to other East Asian countries. Portuguese priests and merchants introduced it to Europe during the 16th century. During the 17th century, drinking tea became fashionable among the English, who started large-scale production and commercialisation of the plant in India. Combined, China and India supplied 62% of the world’s tea in 2016.
The term herbal tea refers to drinks not made from Camellia sinensis: infusions of fruit, leaves, or other parts of the plant, such as steeps of rosehip, chamomile, or rooibos. These are sometimes called tisanes or herbal infusions to prevent confusion with tea made from the tea plant.
is a grass widely cultivated for its seed, a cereal grain which is a worldwide staple food. The many species of wheat together make up the genus Triticum; the most widely grown is common wheat (T. aestivum). The archaeological record suggests that wheat was first cultivated in the regions of the Fertile Crescent around 9600 BCE. Botanically, the wheat kernel is a type of fruit called a caryopsis.
Wheat is grown on more land area than any other food crop (220.4 million hectares, 2014). World trade in wheat is greater than for all other crops combined. In 2017, world production of wheat was 772 million tonnes, with a forecast of 2019 production at 766 million tonnes, making it the second most-produced cereal after maize. Since 1960, world production of wheat and other grain crops has tripled and is expected to grow further through the middle of the 21st century. Global demand for wheat is increasing due to the unique viscoelastic and adhesive properties of gluten proteins, which facilitate the production of processed foods, whose consumption is increasing as a result of the worldwide industrialization process and the westernization of the diet.
Wheat is an important source of carbohydrates. Globally, it is the leading source of vegetable protein in human food, having a protein content of about 13%, which is relatively high compared to other major cereals but relatively low in protein quality for supplying essential amino acids. When eaten as the whole grain, wheat is a source of multiple nutrients and dietary fiber.
In a small part of the general population, gluten – the major part of wheat protein – can trigger coeliac disease, noncoeliac gluten sensitivity, gluten ataxia, and dermatitis herpetiformis.