วันจันทร์ที่ 25 เมษายน พ.ศ. 2554

Chocolate







     Chocolate is a raw or processed food produced from the seed of the tropical Theobroma cacao tree. Cacao has been cultivated for at least three millennia in Mexico , Central and South America, with its earliest documented use around 1100 BC. The majority of the Mesoamerican people made chocolate beverages, including the Aztecs, who made it into a beverage known as xocolātl , a Nahuatl word meaning "bitter water". The seeds of the cacao tree have an intense bitter taste, and must be fermented to develop the flavor.
     After fermentation, the beans are dried, then cleaned, and then roasted, and the shell is removed to produce cacao nibs. The nibs are then ground to cocoa mass, pure chocolate in rough form. Because this cocoa mass usually is liquefied then molded with or without other ingredients, it is called chocolate liquor. The liquor also may be processed into two components: cocoa solids and cocoa butter. Unsweetened baking chocolate (bitter chocolate) contains primarily cocoa solids and cocoa butter in varying proportions. Much of the chocolate consumed today is in the form of sweet chocolate, combining cocoa solids, cocoa butter or other fat, and sugar. Milk chocolate is sweet chocolate that additionally contains milk powder or condensed milk. White chocolate contains cocoa butter, sugar, and milk but no cocoa solids.
     Cocoa solids contain alkaloids such as theobromine and phenethylamine, which have physiological effects on the body. It has been linked to serotonin levels in the brain. Some research found that chocolate, eaten in moderation, can lower blood pressure.The presence of theobromine renders chocolate toxic to some animals, especially dogs and cats.
     Chocolate has become one of the most popular food types and flavors in the world. Gifts of chocolate molded into different shapes have become traditional on certain holidays: chocolate bunnies and eggs are popular on Easter, chocolate coins on Hanukkah, Santa Claus and other holiday symbols on Christmas, and chocolate hearts or chocolate in heart-shaped boxes on Valentine's Day. Chocolate is also used in cold and hot beverages, to produce chocolate milk and hot chocolate. Around three quarters of the world's cacao bean production takes place in West Africa.



Etymology

     The word "chocolate" entered the English language from Spanish.How the word came into Spanish is less certain, and there are multiple competing explanations. Perhaps the most cited explanation is that "chocolate" comes from Nahuatl, the language of the Aztecs, from the word "chocolātl", which many sources derived from the Nahuatl word "xocolātl" made up from the words "xococ" meaning sour or bitter, and "ātl" meaning water or drink.However, as William Bright noted the word "chocolatl" doesn't occur in central Mexican colonial sources making this an unlikely derivation. Santamariagives a derivation from the Yucatec Maya word "chokol" meaning hot, and the Nahuatl "atl" meaning water. More recently Dakin and Wichmann derive it from another Nahuatl term, "chicolatl" from Eastern Nahuatl meaning "beaten drink".They derive this term from the word for the frothing stick, "chicoli".





History
Theobroma cacao, native to Mexico, Central and South America, has been cultivated for at least three millennia in that region. Cocoa mass was used originally in Mesoamerica both as a beverage and as an ingredient in foods.
     Chocolate has been used as a drink for nearly all of its history. The earliest record of using chocolate dates back before the Olmec. In November 2007, archaeologists reported finding evidence of the oldest known cultivation and use of cacao at a site in Puerto Escondido, Honduras, dating from about 1100 to 1400 BC.The residues found and the kind of vessel they were found in indicate that the initial use of cacao was not simply as a beverage, but the white pulp around the cacao beans was likely used as a source of fermentable sugars for an alcoholic drink.The Maya civilization grew cacao trees in their backyard, and used the cacao seeds it produced to make a frothy, bitter drink.Documents in Maya hieroglyphs stated that chocolate was used for ceremonial purposes, in addition to everyday life. The chocolate residue found in an early ancient Maya pot in Río Azul, Guatemala, suggests that Maya were drinking chocolate around 400 AD. In the New World, chocolate was consumed in a bitter, spicy drink called xocoatl, and was often flavored with vanilla, chili pepper, and achiote (known today as annatto). Xocoatl was believed to fight fatigue, a belief that is probably attributable to the theobromine content. Chocolate was also an important luxury good throughout pre-Columbian Mesoamerica, and cacao beans were often used as currency.For example, the Aztecs used a system in which one turkey cost one hundred cacao beans and one fresh avocado was worth three beans.South American and European cultures have used cocoa to treat diarrhea for hundreds of years.All of the areas that were conquered by the Aztecs that grew cacao beans were ordered to pay them as a tax, or as the Aztecs called it, a "tribute".
     Until the 16th century, no European had ever heard of the popular drink from the Central and South American peoples.It was not until the Spanish conquest of the Aztecs that chocolate could be imported to Europe. In Spain it quickly became a court favorite. In a century it had spread and become popular throughout the European continent.To keep up with the high demand for this new drink, Spanish armies began enslaving Mesoamericans to produce cacao.Even with cacao harvesting becoming a regular business, only royalty and the well-connected could afford to drink this expensive import. Before long, the Spanish began growing cacao beans on plantations, and using an African workforce to help manage them.The situation was different in England. Put simply, anyone with money could buy it.The first chocolate house opened in London in 1657. In 1689, noted physician and collector Hans Sloane developed a milk chocolate drink in Jamaica which was initially used by apothecaries, but later sold to the Cadbury brothers in 1897.
     Chocolate in its solid form was invented in 1847. Joseph Fry & Son discovered a way to mix some of the cocoa butter back into the dutched chocolate, and added sugar, creating a paste that could be moulded. The result was the first modern chocolate bar.
     For hundreds of years, the chocolate making process remained unchanged. When the people saw the Industrial Revolution arrive, many changes occurred that brought about the food today in its modern form. A Dutch family's (van Houten) inventions made mass production of shiny, tasty chocolate bars and related products possible. In the 18th century, mechanical mills were created that squeezed out cocoa butter, which in turn helped to create hard, durable chocolate.But, it was not until the arrival of the Industrial Revolution that these mills were put to bigger use. Not long after the revolution cooled down, companies began advertising this new invention to sell many of the chocolate treats we see today. When new machines were produced, people began experiencing and consuming chocolate worldwide.





Types

     Several types of chocolate can be distinguished. Pure, unsweetened chocolate contains primarily cocoa solids and cocoa butter in varying proportions. Much of the chocolate consumed today is in the form of sweet chocolate, combining chocolate with sugar. Milk chocolate is sweet chocolate that additionally contains milk powder or condensed milk.        
     European rules specify a minimum of 25% total dry cocoa solids for Milk Chocolate. "White chocolate" contains cocoa butter, sugar, and milk but no cocoa solids. Chocolate contains alkaloids such as theobromine and phenethylamine, which have some physiological effects in humans, but the presence of theobromine renders it toxic to some animals, such as dogs and cats. It has been linked to serotonin levels in the brain. Dark chocolate has been promoted for unproven health benefits, as it seems to possess substantial amount of antioxidants that reduce the formation of free radicals.
     White chocolate is formed from a mixture of sugar, cocoa butter and milk solids. Although its texture is similar to milk and dark chocolate, it does not contain any cocoa solids. Because of this, many countries do not consider white chocolate as chocolate at all. Although first introduced by Hebert Candies in 1955, Mars, Incorporated was the first to produce white chocolate within the United States. Because it does not contain any cocoa solids, white chocolate does not contain any theobromine, meaning it can be consumed by animals.
     Dark chocolate is produced by adding fat and sugar to the cacao mixture. The U.S. Government calls this "sweet chocolate", and requires a 15% concentration of chocolate liquor. European rules specify a minimum of 35% cocoa solids.Dark chocolate, with its high cocoa content, is a rich source of epicatechin and gallic acid, which are thought to possess cardioprotective properties. Dark chocolate has also been said to reduce the possibility of a heart attack when consumed regularly in small amounts.Semisweet chocolate is a dark chocolate with a low sugar content. Bittersweet chocolate is chocolate liquor to which some sugar (typically a third), more cocoa butter, vanilla and sometimes lecithin have been added. It has less sugar and more liquor than semisweet chocolate, but the two are interchangeable in baking.
     Unsweetened chocolate is pure chocolate liquor, also known as bitter or baking chocolate. It is unadulterated chocolate: the pure, ground, roasted chocolate beans impart a strong, deep chocolate flavor.
     Raw chocolate, often referred to as raw cacao, is always dark and a minimum of 75% cacao. Because the act of processing results in the loss of certain vitamins and minerals (such as magnesium), some consider raw cacao to be a more nutritious form of chocolate.
Some people who purchase chocolate off the store shelf can be disappointed when they see whitish spots on the dark chocolate part. This is called chocolate bloom and is not an indication of chocolate gone bad. Instead, this is just an indication that sugar and/or fat has separated due to poor storage.










Production

     Roughly two-thirds of the entire world's cocoa is produced in Western Africa, with 43% sourced from Côte d'Ivoire,where child labor is a common practice to obtain the product.See the Wikipedia article children in cocoa production for a description of this and proposed solutions. According to the World Cocoa Foundation, some 50 million people around the world depend on cocoa as a source of livelihood. In the UK, most chocolatiers purchase their chocolate from them, to melt, mold and package to their own design.Despite some disagreement in the EU about the definition,[clarification needed] chocolate is any product made primarily of cocoa solids and cocoa butter.
     Production costs can be decreased by reducing cocoa solid content or by substituting cocoa butter with another fat. Cocoa growers object to allowing the resulting food to be called "chocolate", due to the risk of lower demand for their crops. The sequencing in 2010 of genome of the cacao tree may allow yields to be improved.
     There are two main jobs associated with creating chocolate candy, chocolate makers and chocolatiers. Chocolate makers use harvested cacao beans and other ingredients to produce couverture chocolate. (Concerning "couverture", think "covering" or "coating", but see the reference, as well.) Chocolatiers use the finished couverture to make chocolate candies (bars, truffles, etc.).



Cacao varieties

     Cacao trees are small, understory trees that need rich, well-drained soils. They naturally grow within 20 degrees of either side of the equator because they need about 2000 millimeters of rainfall a year, and temperatures in the range of 21 to 32 degrees Celsius. Cacao trees cannot tolerate a temperature lower than 15 degrees Celsius (59 degrees Fahrenheit).
     The three main varieties of cacao beans used in chocolate are criollo, forastero, and trinitario.
     Representing only five percent of all cocoa beans grown, criollo is the rarest and most expensive cocoa on the market and is native to Central America, the Caribbean islands and the northern tier of South American states. There is some dispute about the genetic purity of cocoas sold today as Criollo, as most populations have been exposed to the genetic influence of other varieties. Criollos are particularly difficult to grow, as they are vulnerable to a variety of environmental threats and produce low yields of cocoa per tree. The flavor of Criollo is described as delicate yet complex, low in classic chocolate flavor, but rich in "secondary" notes of long duration.
     The most commonly grown bean is forastero, a large group of wild and cultivated cacaos, most likely native to the Amazon basin. The African cocoa crop is entirely of the Forastero variety. They are significantly hardier and of higher yield than Criollo. The source of most chocolate marketed, forastero cocoas are typically strong in classic "chocolate" flavor, but have a short duration and are unsupported by secondary flavors, producing "quite bland" chocolate.
     Trinitario is a natural hybrid of Criollo and Forastero. Trinitario originated in Trinidad after an introduction of Forastero to the local Criollo crop. Nearly all cacao produced over the past five decades is of the Forastero or lower-grade Trinitario varieties.







Processing

Cacao pods are harvested by cutting the pods from the tree using a machete, or by knocking them off the tree using a stick. The beans with their surrounding pulp are removed from the pods and placed in piles or bins to ferment. The fermentation process is what gives the beans their familiar chocolate taste. It is important to harvest the pods when they are fully ripe because if the pod is unripe, the beans will have a low cocoa butter content, or there will be insufficient sugars in the white pulp for fermentation, resulting in a weak flavor. After fermentation, the beans must be quickly dried to prevent mold growth. Climate and weather permitting, this is done by spreading the beans out in the sun from 5 to 7 days.
     The dried beans are then transported to a chocolate manufacturing facility. The beans are cleaned (removing twigs, stones, and other debris), roasted, and graded. Next the shells are removed to extract the nib. Finally, the nibs are ground and liquefied, resulting in pure chocolate in fluid form: chocolate liquor. The liquor can be further processed into two components: cocoa solids and cocoa butter.






Blending

     Chocolate liquor is blended with the cocoa butter in varying quantities to make different types of chocolate or couvertures. The basic blends of ingredients for the various types of chocolate (in order of highest quantity of cocoa liquor first), are as follows:
Dark chocolate: sugar, cocoa butter, cocoa liquor, and (sometimes) vanilla
Milk chocolate: sugar, cocoa butter, cocoa liquor, milk or milk powder, and vanilla
White chocolate: sugar, cocoa butter, milk or milk powder, and vanilla
Usually, an emulsifying agent such as soy lecithin is added, though a few manufacturers prefer to exclude this ingredient for purity reasons and to remain GMO-free, sometimes at the cost of a perfectly smooth texture. Some manufacturers are now using PGPR, an artificial emulsifier derived from castor oil that allows them to reduce the amount of cocoa butter while maintaining the same mouthfeel.
      The texture is also heavily influenced by processing, specifically conching (see below). The more expensive chocolate tends to be processed longer and thus have a smoother texture and "feel" on the tongue, regardless of whether emulsifying agents are added.
Different manufacturers develop their own "signature" blends based on the above formulas, but varying proportions of the different constituents are used.
      The finest, plain dark chocolate couvertures contain at least 70% cocoa (both solids and butter), whereas milk chocolate usually contains up to 50%. High-quality white chocolate couvertures contain only about 35% cocoa.
      Producers of high quality, small batch chocolate argue that mass production produces bad quality chocolate.Some mass-produced chocolate contains much less cocoa (as low as 7% in many cases) and fats other than cocoa butter. Vegetable oils and artificial vanilla flavor are often used in cheaper chocolate to mask poorly fermented and/or roasted beans.
In 2007, the Chocolate Manufacturers Association in the United States, whose members include Hershey, Nestlé, and Archer Daniels Midland, lobbied the Food and Drug Administration to change the legal definition of chocolate to let them substitute partially hydrogenated vegetable oils for cocoa butter in addition to using artificial sweeteners and milk substitutes. Currently, the U.S. Food and Drug Administration (FDA) does not allow a product to be referred to as "chocolate" if the product contains any of these ingredients.





Conching

     The penultimate process is called conching. A conche is a container filled with metal beads, which act as grinders. The refined and blended chocolate mass is kept in a liquid state by frictional heat. Chocolate prior to conching has an uneven and gritty texture. The conching process produces cocoa and sugar particles smaller than the tongue can detect, hence the smooth feel in the mouth. The length of the conching process determines the final smoothness and quality of the chocolate. High-quality chocolate is conched for about 72 hours, lesser grades about four to six hours. After the process is complete, the chocolate mass is stored in tanks heated to approximately 45–50 °C (113–122 °F) until final processing.

Tempering

     The final process is called tempering. Uncontrolled crystallization of cocoa butter typically results in crystals of varying size, some or all large enough to be clearly seen with the naked eye. This causes the surface of the chocolate to appear mottled and matte, and causes the chocolate to crumble rather than snap when broken. The uniform sheen and crisp bite of properly processed chocolate are the result of consistently small cocoa butter crystals produced by the tempering process.
      The fats in cocoa butter can crystallize in six different forms (polymorphous crystallization). The primary purpose of tempering is to assure that only the best form is present. The six different crystal forms have different properties.

Crystal
Melting temp.
Notes
I
17 °C (63 °F)
Soft, crumbly, melts too easily.
II
21 °C (70 °F)
Soft, crumbly, melts too easily.
III
26 °C (79 °F)
Firm, poor snap, melts too easily.
IV
28 °C (82 °F)
Firm, good snap, melts too easily.
V
34 °C (93 °F)
Glossy, firm, best snap, melts near body temperature (37 °C).
VI
36 °C (97 °F)
Hard, takes weeks to form.







     Making chocolate considered "good" is about forming as many type V crystals as possible. This provides the best appearance and texture and creates the most stable crystals so the texture and appearance will not degrade over time. To accomplish this, the temperature is carefully manipulated during the crystallization.
     Generally, the chocolate is first heated to 45 °C (113 °F) to melt all six forms of crystals. Next, the chocolate is cooled to about 27 °C (81 °F), which will allow crystal types IV and V to form. At this temperature, the chocolate is agitated to create many small crystal "seeds" which will serve as nuclei to create small crystals in the chocolate. The chocolate is then heated to about 31 °C (88 °F) to eliminate any type IV crystals, leaving just type V. After this point, any excessive heating of the chocolate will destroy the temper and this process will have to be repeated. However, there are other methods of chocolate tempering used. The most common variant is introducing already tempered, solid "seed" chocolate. The temper of chocolate can be measured with a chocolate temper meter to ensure accuracy and consistency. A sample cup is filled with the chocolate and placed in the unit which then displays or prints the results.
Two classic ways of manually tempering chocolate are:Working the molten chocolate on a heat-absorbing surface, such as a stone slab, until thickening indicates the presence of sufficient crystal "seeds"; the chocolate is then gently warmed to working temperature.
Stirring solid chocolate into molten chocolate to "inoculate" the liquid chocolate with crystals (this method uses the already formed crystals of the solid chocolate to "seed" the molten chocolate).
     Chocolate tempering machines (or temperers) with computer controls can be used for producing consistently tempered chocolate, particularly for large volume applications.




Storage

     Chocolate is very sensitive to temperature and humidity. Ideal storage temperatures are between 15 and 17 °C (59 and 63 °F), with a relative humidity of less than 50%. Chocolate is generally stored away from other foods as it can absorb different aromas. Ideally, chocolates are packed or wrapped, and placed in proper storage with the correct humidity and temperature. Additionally chocolate is frequently stored in a dark place or protected from light by wrapping paper. Various types of "blooming" effects can occur if chocolate is stored or served improperly. If refrigerated or frozen without containment, chocolate can absorb enough moisture to cause a whitish discoloration, the result of fat or sugar crystals rising to the surface. Moving chocolate from one temperature extreme to another, such as from a refrigerator on a hot day, can result in an oily texture. Although visually unappealing, chocolate suffering from bloom is perfectly safe for consumption.




Potential health effects
     Even though chocolate is regularly eaten for pleasure, there are potentially a lot of health effects, both negative and positive. Cocoa or dark chocolate may positively affect the circulatory system.Other possible effects under basic research include anticancer, brain stimulator, cough preventor and antidiarrhoeal activities. An aphrodisiac effect is yet unproven.
     According to research, limited amounts of dark chocolate appear to help prevent heart disease. The oxidation of LDL cholesterol is considered a major factor in the promotion of coronary disease. When this waxy substance oxidizes, it tends to stick to artery walls, increasing the risk of a heart attack or stroke. Research has shown the polyphenols in chocolate inhibit oxidation of LDL cholesterol.
     On the other hand, the unconstrained consumption of large quantities of any energy-rich food such as chocolate is thought to increase the risk of obesity without a corresponding increase in activity. Raw chocolate is high in cocoa butter, a fat which is removed during chocolate refining, then added back in in varying proportions during the manufacturing process. Manufacturers may add other fats, sugars, and milk as well, all of which increase the caloric content of chocolate.
     Chocolate absorbs lead from the environment during production and there is a slight concern of mild lead poisoning for some types of chocolate. The average lead concentration of cocoa beans was a very low ≤ 0.5 ng/g, one of the lowest reported values for a natural food. Lead concentration of chocolate was as high as 70 ng/g for chocolate products and 230 ng/g for manufactured cocoa. 200,000 ng is the WHO tolerable daily limit for lead consumption. Additionally, chocolate is toxic to many animals because of insufficient capacity to metabolize theobromine.
     A study by the BBC reported and indicated that melting chocolate in one's mouth produced an increase in brain activity and heart rate that was more intense than that associated with passionate kissing, and also lasted four times as long after the activity had ended.
     In later research, chocolate has been linked with multiple health benefits and liabilities. Research on elderly people shows that chocolate might cause osteoporosis. However, more research has shown that it will boost cognitive abilities. Further, dark chocolate and cocoa butter have been linked with multiple positive effects. Scientific evidence has suggests that dark chocolate can help reduce the risk of cardiovascular problems and also reduce blood pressure in both overweight and normal adults. Finally, studies have shown that dark chocolate can lower cholesterol levels in adults.




Labelling

     Some manufacturers provide the percentage of chocolate in a finished chocolate confection as a label quoting percentage of "cocoa" or "cacao". It should be noted that this refers to the combined percentage of both cocoa solids and cocoa butter in the bar, not just the percentage of cocoa solids.
     Chocolates that are organic or fair trade certified carry labels accordingly.
     In the United States, some large chocolate manufacturers lobbied the federal government to permit confection containing cheaper hydrogenated vegetable oil in place of cocoa butter to be sold as "chocolate". In June 2007, as a response to consumer concern after the proposed change, the FDA re-iterated that "Cacao fat, as one of the signature characteristics of the product, will remain a principal component of standardized chocolate."




Manufacturers
     Many chocolate manufacturers have created products from chocolate bars to fudge, hoping to attract more consumers with each creation. Both The Hershey Company and Mars have become the largest manufacturers in the world.[citation needed] Other significant players include Cadbury, Nestlé, Kraft Foods and Lindt.
The Hershey Company, known for their Hershey bar, Hershey's kisses and Reese's Peanut Butter Cups, is the largest chocolate manufacturer in North America. Mars, Incorporated, one of the largest privately owned U.S. corporations, is a worldwide manufacturer of confectionery and other food products with US$21 billion in annual sales in 2006. Mars is known for Mars Bar, as well as other confectionery such as Milky Way, M&M's, Twix, Skittles and Snickers.
     Food conglomerates Nestlé SA and Kraft Foods both have chocolate brands. Nestlé acquired Rowntree's in 1988 and now market chocolates under their own brand, including Smarties and Kit Kat; Kraft Foods through its 1990 acquisition of Jacobs Suchard, now own Milka and Suchard. In February 2010, Kraft also acquired British-based Cadbury plc, the world's largest confectionery manufacturer. Cadbury is well known for its Dairy Milk range and Creme Egg; Fry's, Trebor Basset, the fair-trade brand Green & Black's also belong to the group.
     The chocolate industry is a steadily growing, $50 billion-a-year worldwide business centered on the sale and consumption of chocolate. This industry is prevalent on five out of seven continents. Big Chocolate, as it is also called, is essentially an oligopoly between major international chocolate companies in Europe and the U.S. These U.S. companies such as Mars and Hershey’s alone generate $13 billion a year in chocolate sales and account for two thirds of U.S. manufacturers. However, Europe accounts for 45% of the world's chocolate revenue.
     For a discussion of child labor in the chocolate industry, see Children in cocoa production.




In popular culture







Holidays

     Chocolate is one of the most popular holiday gifts. On Valentine's Day, a box of chocolates is traditional, usually presented with flowers and a greeting card. It may be gifted on other holidays, including Christmas, Easter, Thanksgiving, and birthdays. At Easter, chocolate eggs are traditional. This is a confectionery made primarily of chocolate, and can either be solid, hollow, or filled with other sweets or fondant.




Books and film

     Chocolate has been the center of several successful book and film adaptations. In 1964, Roald Dahl published a children's novel titled Charlie and the Chocolate Factory. The novel centers on a poor boy named Charlie Bucket who takes a tour through the greatest chocolate factory in the world, owned by Willy Wonka. Two film adaptations of the novel were produced. The first was Willy Wonka & the Chocolate Factory, a 1971 film which later became a cult classic. Thirty-four years later, a second film adaptation was produced, titled Charlie and the Chocolate Factory. The 2005 film was very well received by critics and was one of the highest grossing films of its year, earning over US$470,000,000 worldwide. Charlie and the Chocolate Factory was also recognized at the 78th Academy Awards, where it was nominated for Best Costume Design for Gabriella Pesucci.
Like Water for Chocolate (Como agua para chocolate) is a 1989 love story by novelist Laura Esquivel that was adapted to film in 1992. The plot incorporates magical realism with Mexican cuisine and the title is a double entendre in its native language, referring both to a recipe for hot chocolate and to an idiom that is a metaphor for sexual arousal. The film earned 11 Ariel Awards from the Academia Mexicana de Artes y Ciencias Cinematográficas including Best Picture.
Chocolat is a 1999 novel by Joanne Harris. It tells the story of Vianne Rocher, a young mother, whose confections change the lives of the townspeople. The 2000 film adaptation, Chocolat, also proved successful, grossing over US$150,000,000 worldwide, and receiving Academy Award and Golden Globe nominations for Best Picture, Best Actress, and Best Original Score

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