Biol 1300 Unit 12: Caffeinated Beverages PDF

**Biol 1300 Unit 12** **CAFFEINATED BEVERAGES** Several common plant-derived beverages contain the stimulant alkaloid caffeine, or theobromine in the case of cocoa. These stimulants have similar effects; activate intracellular metabolism, stimulate the heart, and increase stomach acidity and metab...

**Biol 1300 Unit 12** **CAFFEINATED BEVERAGES** Several common plant-derived beverages contain the stimulant alkaloid caffeine, or theobromine in the case of cocoa. These stimulants have similar effects; activate intracellular metabolism, stimulate the heart, and increase stomach acidity and metabolic rates. Economically important caffeinated beverages include coffee, tea, and cocoa. Other common ones are cola (found in soft drinks), maté, and guarana, popular in South America (particularly Brazil, Argentina, Paraguay and Uruguay). Yerba maté is a small evergreen native to South America. It is used for a tea-like beverage. The dried leaves are placed in a gourd with hot water, the heat steeps the leaves. Guarana is somewhat more common as it is used as an ingredient in energy drinks. However, both beverages are uncommon outside South America. **COFFEE** (Coffea arabica and C. canephora) The two coffee species are evergreen large shrub trees native to tropical mountainous regions of central and northeast Africa. They thrive in humid environments with a steady year-round temperature of about 20°C. The fruit is a red berry containing two seeds surrounded by sweet, yellow flesh. The berries are hand-harvested as they mature, with an annual harvest averaging about 2.5 kg per plant. Two commercially grown coffee species are arabica (Coffea arabica) and robusta (C. canephora). Arabica coffee, known for its superior flavor and commonly used in higher-quality fresh brewed coffees, is native to the highlands of Ethiopia and is widely grown in South and Central America, Southeast Asia, and East Africa (Ethiopia, Kenya). Robusta coffee, more bitter and less flavorful, is native to west-central Africa and is used mainly in instant coffees and less expensive blends. It is grown primarily in Central Africa, Brazil, and Southeast Asia (particularly Vietnam). The largest coffee producers today are Brazil, Vietnam, Colombia, and Indonesia, with smaller contributions from Central America (Mexico, Guatemala, and Honduras) and Africa (Ethiopia and Uganda). The final flavor of coffee is influenced by the species and variety grown, growing conditions (e.g., nitrogen in soil and climate), and roasting and blending methods. The processing steps include floating and sorting fresh berries to remove defects (e.g., debris, berries not floating), removing the pulp by machine, fermenting the seeds to remove residual pulp and initiate enzymatic processes, washing and thoroughly drying the seeds, roasting the seeds (now called \"beans\") to impart flavor, and blending the beans to achieve a characteristic flavor. The first recorded use of coffee as a beverage was in the Arabian Peninsula. Venetian merchants introduced coffee to Europe in 1615, where it quickly spread. Coffee was first used in France in 1640, and in England by 1650. By the early 1700s, over 300 coffee houses had been established in London. Lloyd\'s of London, the famous insurance company, began as a coffee house in 1690 and was well known in London business circles. Coffee faced detractors over the years, with various temperance movements attempting to ban it. Initially, all European coffee came from Mocha, Yemen, until the Dutch introduced coffee to Java in 1690 and later to Surinam (northern South America). Venetians claimed this monopoly then the Dutch in Surinam. Coffee was introduced to the Caribbean by the French (Martinique) and English (Jamaica, in 1727). By 1780, coffee was widely grown in Brazil, Central America, and Southeast Asia. **TEA** (Camellia sinensis) Tea, native to northern India and southern China, is a medium-sized shrub 5 m in height pruned into 1-2 m long hedges for easier harvesting. It thrives in tropical to subtropical climates with ample rainfall, steady temperatures around 20°C, and well-drained, slightly acidic soils. Tea is mainly grown in subtropical mountainous regions, with China, India, Kenya, and Sri Lanka being the largest producers. The flavour of tea is attributable to a combination of caffeine, essential oils, and various bitter tannins. The best quality teas are produced from the smallest leaves and leaf buds, which are carefully hand-picked. Machine methods are used for lower quality teas. Freshly picked tea leaves are processed in one of two ways, producing either black or green tea. Black tea is produced mainly in India and Sri Lanka. This type of tea, which is popular on the Indian subcontinent and in Europe and North America, is processed as follows: Young leaves are hand-picked and spread on racks to dry for one day. Slow drying initiates enzymatic processes that impart the unique flavour-aroma of black tea. The leaves are machine-shredded, rupturing the cells and oxidizing the tannins and phenols. Oxidation is continued under cool, damp conditions until the shredded leaves turn a coppery-brown colour. The final product is dried or \"fired\" to give black tea its characteristic dark colour. Green tea is produced mainly in China and Japan, and much of this production is consumed locally. Green tea is processed as follows: The freshly-picked leaves are partially shredded. The shredded leaves are quickly dried, minimizing the amount of oxidation. As a result, green tea has a light flavour and characteristic grassy aroma. Green tea has been a beverage in China for over 3,000 years and in Japan for about 1,500 years. The Portuguese learned about tea in 1557, but green tea wasn\'t shipped to Europe until the early 1600s by the Dutch East India Company. By the mid-1600s, tea reached France, Russia, Germany, and England, where it became popular among the British aristocracy by 1690 although it was initially promoted as a medicinal tonic. By 1750, tea was the \"national drink\" of England, consumed by all members of society as promoted by the British East India Company (profited immensely from the tea trade with China). The British established tea plantations in India and Sri Lanka (formerly Ceylon) in the mid-1800s. Today, tea is enjoyed worldwide, including in Europe, North America, the Arabian region, Japan, China, India, Pakistan, Iran, Burma, and Russia. **COCOA or CHOCOLATE** (Theobroma cacao) The cocoa plant, native to South America\'s tropical rain forests (living in the understory-the layer of vegetation that grows beneath the forest canopy but above the forest floor), thrives in high humidity, stable temperatures, and rich soil. It requires extensive cultivation and management. There are several varieties like criollo-green (20%), forastero-yellow (70%), and trinitario-red (10%). Today, cocoa is primarily grown in tropical West Africa (especially Côte d\'Ivoire and Ghana), with smaller amounts in Indonesia and South America (Brazil and Ecuador). Cocoa \"beans\" are individual seeds surrounded by a yellow-white sweetish pulp, contained in a large pod-like fruit that is botanically a berry. Each fruit has about 40 seeds. The flowers and fruit grow on the main trunk and large branches of the tree. The active stimulant in cocoa is theobromine, similar to caffeine but has a different methyl group. Cocoa requires extensive processing to obtain the final product: The mature fruit are harvested and seeds (\"beans\") removed. The pulp surrounding the seeds is then allowed to ferment for a few days until it turns sticky and brown. The beans are then dried on racks. Fermentation and drying induce chemical changes (oxidation) that impart the characteristic colour, odour and flavour of cocoa. The beans are shipped for further processing, usually to North America or Europe. Initial processing involves roasting the dried \"beans\" at 140°C for a few hours. The roasted beans are ground to render a brown oily mass known as cocoa liquor. Cocoa liquor is processed by removing cocoa butter, resulting in a cocoa press cake, which is powdered and treated with alkali (a process known as \"Dutching\") to remove bitterness. Chocolate is made by grinding and blending cocoa with added cocoa butter, emulsifiers (to prevent the congealing and separation of fats), and sugar (to reduce the bitterness). Dark chocolate is over 70% cocoa, milk chocolate is about 50% cocoa with added milk and vanilla, and white chocolate contains no cocoa, only cocoa butter, sugar, milk, and vanilla. Inexpensive chocolate is mostly sugar and additives, with only 5-10% cocoa. Cocoa held significant importance in Mayan and Aztec cultures, being used in various rituals and ceremonies. Introduced to Europe by the Spanish in 1550, it initially gained popularity in France, Italy, Spain, and Portugal. By the 1650s, chocolate \"houses\" emerged in London and Amsterdam, but chocolate remained unpopular until the mid-1800s due to its high cost, quick rancidity, and tendency to coagulate. In 1828, Dutch inventor van Houten patented methods to separate cocoa butter (fat) from cocoa and process cocoa with an alkalizing agent (the so-called \"Dutching\" process), reducing its bitterness. These advancements, especially the addition of stabilizing agents and emulsifiers, led to the creation of chocolate bars in the mid-1800s and Swiss milk chocolate in 1875. **COLA or KOLA NUT (Cola nitida)** Cola is a large understory shrub native to tropical Africa, closely related to cocoa. It produces fruit with reddish brown seeds containing 3% caffeine and aromatic essential oils. In West Africa, particularly Nigeria, cola seeds are chewed as a mild stimulant and medicinal agent. The caffeine and flavor of cola nuts is extracted with hot water to produce a syrup used in some cola drinks. Major production areas include Nigeria, Ghana, and Côte d\'Ivoire.