Bread is astaple food prepared from adough offlour (usuallywheat) andwater, usually bybaking. Throughoutrecorded history and around the world, it has been an important part of many cultures' diets. It is one of the oldest human-made foods, having been of significance since the dawn ofagriculture, and plays an essential role in both religious rituals and secular culture.
Bread may beleavened by naturally occurring microbes (e.g. sourdough), chemicals (e.g. baking soda), industrially producedyeast, or high-pressure aeration, which creates the gas bubbles that fluff up bread. In many countries, commercial bread often contains additives to improve flavor, texture, color, shelf life, nutrition, and ease of production.
Bread is one of the oldest prepared foods. Evidence from 30,000 years ago in Europe and Australia revealed starch residue on rocks used for pounding plants.[4][5] It is possible that during this time, starch extract from the roots of plants, such as cattails andferns, was spread on a flat rock, placed over a fire and cooked into a primitive form offlatbread. The oldest evidence of bread-making has been found in a 14,500-year-oldNatufian site in Jordan's northeastern desert.[6][7] Around 10,000 BC, with the dawn of theNeolithic age and the spread of agriculture, grains became the mainstay of making bread. Yeast spores are ubiquitous, including on the surface ofcereal grains, so any dough left to rest leavens naturally.[8]
An early leavened bread was baked as early as 6000 BC in southern Mesopotamia, cradle of theSumerian civilization, who may have passed on the knowledge to the Egyptians around 3000 BC. The Egyptians refined the process and started addingyeast to theflour. The Sumerians were already usingash to supplement the dough as it was baked.[9]
There were multiple sources ofleavening available for early bread. Airborne yeasts could be harnessed by leaving uncooked dough exposed to air for some time before cooking.Pliny the Elder reported that theGauls andIberians used the foam skimmed frombeer, calledbarm, to produce "a lighter kind of bread than other peoples" such asbarm cake. Parts of the ancient world that drank wine instead of beer used a paste composed ofgrape juice and flour that was allowed to begin fermenting, or wheat bran steeped inwine, as a source foryeast. The most common source of leavening was to retain a piece of dough from the previous day to use as a form of sourdoughstarter, as Pliny also reported.[10][11]
TheChorleywood bread process was developed in 1961; it uses the intense mechanical working of dough to dramatically reduce thefermentation period and the time taken to produce a loaf. The process, whose high-energy mixing allows for the use of grain with a lower protein content, is now widely used around the world in large factories. As a result, bread can be produced very quickly and at low costs to the manufacturer and the consumer. However, there has been some criticism of the effect on nutritional value.[12][13][14]
Bread is thestaple food of theMiddle East,Central Asia,North Africa,Europe, and in European-derived cultures such as those in theAmericas,Australia, andSouthern Africa. This is in contrast to parts of South and East Asia, whererice ornoodles are the staple. Bread is usually made from awheat-flourdough that is cultured with yeast, allowed to rise, and baked in anoven. Carbon dioxide and ethanol vapors produced during yeast fermentation result in bread's air pockets.[15] Owing to its high levels ofgluten (which give the dough sponginess and elasticity),common or bread wheat is the most common grain used for the preparation of bread, which makes the largest single contribution to the world's food supply of any food.[16]
Bread is also made from the flour of other wheat species (includingspelt,emmer,einkorn andkamut).[17] Non-wheat cereals includingrye,barley,maize (corn),oats,sorghum,millet andrice have been used to make bread, but, with the exception of rye, usually in combination with wheat flour as they have less gluten.[18]
Gluten-free breads are made using flours from a variety of ingredients such as almonds, rice, sorghum, corn, legumes such as beans, and tubers such as cassava. Since these foods lack gluten, dough made from them may not hold its shape as the loaves rise, and their crumb may be dense with little aeration. Additives such asxanthan gum,guar gum,hydroxypropyl methylcellulose (HPMC),corn starch, oreggs are used to compensate for the lack of gluten.[19][20][21][22]
Inwheat,phenolic compounds are mainly found inhulls in the form of insoluble boundferulic acid, where it is relevant to wheat resistance to fungal diseases.[23]
Glutenin andgliadin are functional proteins found in wheat bread that contribute to the structure of bread. Glutenin forms interconnected gluten networks within bread through interchaindisulfide bonds.[26] Gliadin binds weakly to the gluten network established by glutenin via intrachain disulfide bonds.[26] Structurally, bread can be defined as an elastic-plasticfoam (same asstyrofoam). The glutenin protein contributes to itselastic nature, as it is able to regain its initial shape after deformation. The gliadin protein contributes to itsplastic nature, because it demonstrates non-reversible structural change after a certain amount of applied force. Because air pockets within this gluten network result from carbon dioxide production during leavening, bread can be defined as a foam, or a gas-in-solid solution.[27]
Acrylamide, like in other starchy foods that have been heated higher than 120 °C (248 °F), has been found in recent years to occur in bread. Acrylamide isneurotoxic, has adverse effects on male reproduction and developmental toxicity and iscarcinogenic. A study has found that more than 99 percent of the acrylamide in bread is found in the crust.[28]
A study by theUniversity of Hohenheim found that industrially produced bread typically has a high proportion ofFODMAP carbohydrates due to a short rising time (often only one hour). The high proportion of FODMAP carbohydrates in such bread then causesflatulence. This is particularly problematic in intestinal diseases such asirritable bowel syndrome. While in traditional bread making the dough rises for several hours, industrial breads rise for a much shorter time, usually only one hour. However, a sufficiently long rising time is important to break down the indigestible FODMAP carbohydrates. Some flours (for example,spelt,emmer andeinkorn) contain fewer FODMAPs, but the difference between grain types is relatively small (between 1 and 2percent by weight). Instead, 90% of the FODMAPs that cause discomfort can be broken down during a rising time of four hours. In the study, whole-grain yeast doughs were examined after different rising times; the highest level of FODMAPs was present after one hour in each case and decreased thereafter. The study thus shows that it is essentially the baking technique and not the type of grain that determines whether a bread is well tolerated or not. A better tolerance of bread made from original cereals can therefore not be explained by the original cereal itself, but rather by the fact that traditional, artisanal baking techniques are generally used when baking original cereals, which include a long dough process. The study also showed that a long rising time also breaks down undesirablephytates more effectively, flavors develop better, and the finished bread contains more biologically accessibletrace elements.[29][30]
Bread can be served at manytemperatures; once baked, it can subsequently betoasted. It is most commonly eaten with the hands, either by itself or as a carrier for other foods. Bread can be spread withbutter, dipped into liquids such asgravy,olive oil, orsoup;[31] it can be topped with various sweet and savory spreads, or used to makesandwiches containingmeats, cheeses, vegetables, andcondiments.[32]
Bread is used as an ingredient in other culinary preparations, such as the use ofbreadcrumbs to provide crunchy crusts or thicken sauces; toasted cubes of bread, calledcroutons, are used as a salad topping; seasoned bread is used asstuffing inside roasted turkey; sweet or savourybread puddings are made with bread and various liquids; egg and milk-soaked bread is fried asFrench toast; and bread is used as a binding agent insausages,meatballs and other ground meat products.[33]
Nutritional significance
Bread is a good source ofcarbohydrates and micronutrients such as magnesium, iron, selenium, and B vitamins. Whole grain bread is a good source of dietary fiber and all breads are a common source of protein in the diet, though not a rich one.[34][35]
Crust and crumb
Bread with crust crack (half left at the top) and (lighter) crumb inside
The mass of bread consists of two primary components: thecrust andcrumb.[36]
Bread crust is formed from surface dough during the cooking process. It is hardened and browned through theMaillard reaction using the sugars and amino acids due to the intense heat at the bread surface. The crust of most breads is harder, and more complexly and intensely flavored, than the rest.Old wives' tales suggest that eating the bread crust makes a person's hair curlier.[37] Additionally, the crust is rumored to be healthier than the remainder of the bread. Some studies have shown that this is true as the crust has moredietary fiber andantioxidants such aspronyl-lysine.[38]
Bread crumb is the internal porous material consisting of bubbles with elastic walls. As the bread ages (becomes stale), the crumb becomes more firm.[36]
Preparation
Steps in bread making, here for an unleavened Chilean tortilla
Professional bread recipes are stated using thebaker's percentage notation. The amount of flour is denoted to be 100%, and the other ingredients are expressed as a percentage of that amount by weight. Measurement by weight is more accurate and consistent than measurement by volume, particularly for dry ingredients. The proportion of water to flour is the most important measurement in a bread recipe, as it affects texture and crumb the most. Hard wheat floursabsorb about 62%water, while softer wheat flours absorb about 56%.[40] Common table breads made from these doughs result in a finely textured, light bread. Mostartisan bread formulas contain anywhere from 60 to 75% water. In yeast breads, the higher water percentages result in more CO2 bubbles and a coarser bread crumb.
Dough recipes commonly call for 500grams (about 1.1 pounds) of flour, which yields a single loaf of bread or twobaguettes.
Flour is grain ground into a powder. Flour provides the primary structure, starch and protein to the final baked bread. Theprotein content of the flour is the best indicator of the quality of the breaddough and the finished bread. While bread can be made from all-purpose wheat flour, a specialty bread flour, containing more protein (12–14%), is recommended for high-quality bread. If one uses a flour with a lower protein content (9–11%) to produce bread, a shorter mixing time is required to develop gluten strength properly. An extended mixing time leads to oxidization of the dough, which gives the finished product a whiter crumb, instead of the cream color preferred by most artisan bakers.[41]
Wheat flour, in addition to its starch, contains three water-soluble protein groups (albumin,globulin, andproteoses) and two water-insoluble protein groups (glutenin andgliadin). When flour is mixed with water, the water-soluble proteins dissolve, leaving the glutenin and gliadin to form the structure of the resulting bread. When relatively dry dough is worked bykneading, or wet dough is allowed to rise for a long time (seeno-knead bread), the glutenin forms strands of long, thin, chainlike molecules, while the shorter gliadin forms bridges between the strands of glutenin. The resulting networks of strands produced by these two proteins are known asgluten. Gluten development improves if the dough is allowed toautolyse.[42]
Fortification
Processing of flours usually involves removal of the outer layers, which contain important nutrients. Such flours, and bread made from them, may be fortified by adding nutrients. Fortification with added calcium, iron, thiamine (Vitamin B1) and niacin (Vitamin B3) is a legal requirement in the UK (wholemeal flours, from which the nutrients have not been stripped, are exempt).[43] The unregulated term "wheatmeal" is used to describe flour containing some but not all of the outer covering and central part of the wheat grain.[44]
Liquids
Water, or some other liquid, is used to form the flour into a paste or dough. The weight or ratio of liquid required varies between recipes, but a ratio of three parts liquid to five parts flour is common for yeast breads.[45] Recipes that use steam as the primary leavening method may have a liquid content in excess of one part liquid to one part flour. Instead of water, recipes may use liquids such as milk or otherdairy products (includingbuttermilk oryogurt), fruit juice, or eggs. These contribute additional sweeteners, fats, or leavening components, as well as water.[46]
Fats or shortenings
Fats, such as butter, vegetable oils, lard, or that contained in eggs, affect the development of gluten in breads by coating and lubricating the individual strands of protein. They also help to hold the structure together. If too much fat is included in a bread dough, the lubrication effect causes the protein structures to divide. A fat content of approximately 3% by weight is the concentration that produces the greatest leavening action.[47] In addition to their effects on leavening, fats also serve to tenderize breads and preserve freshness.
Bread improvers anddough conditioners are often used in producing commercial breads to reduce the time needed for rising and to improve texture and volume and to giveantistaling effects. The substances used may be oxidising agents to strengthen the dough or reducing agents to develop gluten and reduce mixing time, emulsifiers to strengthen the dough or to provide other properties such as making slicing easier, or enzymes to increase gas production.[48]
Salt
Salt (sodium chloride) is very often added to enhance flavor and restrict yeast activity. It also affects the crumb and the overall texture by stabilizing and strengthening[49] the gluten. Some artisan bakers forego early addition of salt to the dough, whether wholemeal or refined, and wait until after a 20-minute rest to allow the dough toautolyse.[50]
A dough trough, located inAberdour Castle, once used for leavening bread
Leavening is the process of adding gas to a dough before or during baking to produce a lighter, more easily chewed bread. Most bread eaten in the West is leavened.[51]
Chemicals
A simple technique for leavening bread is the use of gas-producing chemicals. There are two common methods. The first is to usebaking powder or aself-raising flour that includes baking powder. The second is to include an acidic ingredient such asbuttermilk and addbaking soda; the reaction of the acid with the soda produces gas.[51] Chemically leavened breads are calledquick breads andsoda breads. This method is commonly used to makemuffins,pancakes, American-stylebiscuits, and quick breads such asbanana bread.
Many breads are leavened byyeast. The yeast most commonly used for leavening bread isSaccharomyces cerevisiae, the same species used for brewing alcoholic beverages. This yeastferments some of the sugars producingcarbon dioxide. Commercial bakers often leaven their dough with commercially producedbaker's yeast. Baker's yeast has the advantage of producing uniform, quick, and reliable results, because it is obtained from apure culture.[51] Many artisan bakers produce their own yeast with a growth culture. If kept in the right conditions, it provides leavening for many years.[52]
The baker's yeast andsourdough methods follow the same pattern. Water is mixed with flour, salt and the leavening agent. Other additions (spices, herbs, fats, seeds, fruit, etc.) are not needed to bake bread, but are often used. The mixed dough is then allowed torise one or more times (a longer rising time results in more flavor, so bakers often "punch down" the dough and let it rise again), loaves are formed, and (after an optional final rising time) the bread is baked in anoven.[51]
Many breads are made from a "straight dough", which means that all of the ingredients are combined in one step, and the dough is baked after the rising time;[51] others are made from a "pre-ferment" in which the leavening agent is combined with some of the flour and water a day or so ahead of baking and allowed to ferment overnight. On the day of baking, the rest of the ingredients are added, and the process continues as with straight dough. This produces a more flavorful bread with better texture. Many bakers see the starter method as a compromise between the reliable results of baker's yeast and the flavor and complexity of a longer fermentation. It also allows the baker to use only a minimal amount of baker's yeast, which was scarce and expensive when it first became available. Most yeasted pre-ferments fall into one of three categories: "poolish" or "pouliche", a loose-textured mixture composed of roughly equal amounts of flour and water (by weight); "biga", a stiff mixture with a higher proportion of flour; and "pâte fermentée", which is a portion of dough reserved from a previous batch.[53][54]
Sourdough is a type of bread produced by a long fermentation of dough using naturally occurring yeasts andlactobacilli. It usually has a mildly sour taste because of thelactic acid produced duringanaerobicfermentation by the lactobacilli. Longer fermented sourdoughs can also containacetic acid, the main non-water component of vinegar.[55][56][57]
Sourdough breads are made with a sourdough starter. The starter cultivates yeast and lactobacilli in a mixture of flour and water, making use of the microorganisms already present on flour; it does not need any added yeast. A starter may be maintained indefinitely by regular additions of flour and water. Some bakers have starters many generations old, which are said to have a special taste or texture.[55] At one time, all yeast-leavened breads were sourdoughs. Recently there has been a revival of sourdough bread in artisan bakeries.[58]
Traditionally, peasant families throughout Europe baked on a fixed schedule, perhaps once a week. The starter was saved from the previous week's dough. The starter was mixed with the new ingredients, the dough was left to rise, and then a piece of it was saved to be the starter for next week's bread.[51]
Steam
The rapid expansion of steam produced during baking leavens the bread, which is as simple as it is unpredictable. Steam-leavening is unpredictable since the steam is not produced until the bread is baked. Steam leavening happens regardless of the raising agents (baking soda, yeast, baking powder, sour dough, beaten egg white) included in the mix. The leavening agent either contains air bubbles or generates carbon dioxide. The heat vaporises the water from the inner surface of the bubbles within the dough. The steam expands and makes the bread rise. This is the main factor in the rising of bread once it has been put in the oven.[59]CO2 generation, on its own, is too small to account for the rise. Heat kills bacteria or yeast at an early stage, so the CO2 generation is stopped.
Aerated bread is leavened by carbon dioxide being forced into dough under pressure. From the mid-19th to mid-20th centuries, bread made this way was somewhat popular in the United Kingdom, made by theAerated Bread Company and sold in its high-streettearooms. The company was founded in 1862, and ceased independent operations in 1955.[62]
The Pressure-Vacuum mixer was later developed by the Flour Milling and Baking Research Association for theChorleywood bread process. It manipulates the gas bubble size and optionally the composition of gases in the dough via the gas applied to the headspace.[63]
Cultural significance
A Ukrainian woman in national dress welcoming withbread and salt
In manycultures, bread is ametaphor for basic necessities and living conditions in general. For example, a "bread-winner" is a household's main economic contributor and has little to do with actual bread-provision. This is also seen in the phrase "putting bread on the table". The Roman poetJuvenal satirized superficial politicians and the public as caring only for "panem et circenses" (bread and circuses).[66] InRussia in 1917, the Bolsheviks promised "peace, land, and bread."[67][68] The term "breadbasket" denotes an agriculturally productive region. In parts ofNorthern,Central,Southern andEastern Europebread and salt is offered as a welcome to guests.[69] InIndia, life's basic necessities are often referred to as "roti, kapra aur makan" (bread, clothes, and house).[70]
Words for bread, including "dough" and "bread" itself, are used inEnglish-speaking countries assynonyms formoney.[1] A remarkable or revolutionary innovation may be called the best thing since "sliced bread".[71] The expression "to break bread with someone" means "to share a meal with someone".[72] The English word "lord" comes from the Anglo-Saxonhlāfweard, meaning "bread keeper."[73]
Bread is sometimes referred to as "the staff of life", although this term can refer to other staple foods in different cultures: theOxford English Dictionary defines it as "bread (or similar staple food)".[74][75] This is sometimes thought to be a biblical reference, but the nearest wording is in Leviticus 26 "when I have broken the staff of your bread".[76] The term has been adopted in the names of bakery firms.[77]
Fictional breads
Lembas bread: a fictional bread fromThe Lord of the Rings. It was given to Frodo by Galadriel and kept him alive through his journey.[citation needed]
Bread of the two elders: a magical type of bread fromHungarian Folk Tales (from the Ördög és a kenyér story). It was able to talk and ward off theÖrdög.[78]
^Diakonov, Igor M. (1999).The Paths of History.Cambridge University Press. p. 79.ISBN978-0-521-64398-6.Slavic langues retain many Gothic words, reflecting cultural borrowings: thuskhleb, (bread) from an earlierkhleiba from Gothichlaifs, or, rather, from the more ancient formhlaibhaz, which meant bread baked in an oven (and, probably, made with yeast), as different from a l-iepekha, which was a flat cake moulded (liepiti) from paste, and baked on charcoal. [the same nominal stem *hlaibh- has been preserved in modern English as loaf; cf. Lord, from ancienthlafweard bread-keeper]
^Amaia Arranz-Otaegui, Lara Gonzalez Carretero, Monica N. Ramsey, Dorian Q. Fuller, and Tobias Richter:Archaeobotanical evidence reveals the origins of bread 14,400 years ago in northeastern Jordan. PNAS, 11 July 2018 (onlineArchived 19 October 2018 at theWayback Machine)
^abArzani A.:Emmer (Triticum turgidum spp. dicoccum) flour and breads. In Preedy V.R., Watson R.R., Patel V.B. (Eds. 2011),Flour and Breads and their Fortification in Health and Disease Prevention, Academic Press, California, pp. 69-78.
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^Pliny the Elder (1938).Natural History. Loeb Classics. p. 1.255.Generally however they do not heat it up at all, but only use the dough kept over from the day before; manifestly it is natural for sourness to make the dough ferment
^"Wheat". Grains & Legumes Nutrition Council. Archived fromthe original on 5 October 2016. Retrieved1 October 2016.Aside from bread wheat and durum, other types of wheat include spelt, emmer, einkorn and kamut. These wheat varieties are commonly referred to as 'ancient' grains and are increasingly being used in the manufacture of niche wheat-based food products.
^Cauvain, Stanley (2015).Technology of Breadmaking. Springer. p. 377.ISBN978-3-319-14687-4.In the past, maize (corn), barley, oats, sorghum, millet and rice have all found their way into bread products at some time, usually when wheat and rye have been in short supply.
^Volta U, Caio G, De Giorgio R, Henriksen C, Skodje G, Lundin KE (June 2015). "Non-celiac gluten sensitivity: a work-in-progress entity in the spectrum of wheat-related disorders".Best Pract Res Clin Gastroenterol.29 (3):477–91.doi:10.1016/j.bpg.2015.04.006.PMID26060112.After the confirmation ofNCGS diagnosis, according to the previously mentioned work-up, patients are advized to start with a GFD [49]. (...) NCGS patients can experience more symptoms than CD patients following a short gluten challenge [77].(NCGS=non-celiac gluten sensitivity; CD=coeliac disease; GFD=gluten-free diet)
^Hischenhuber C, Crevel R, Jarry B, Mäki M, Moneret-Vautrin DA, Romano A, Troncone R, Ward R (1 March 2006). "Review article: safe amounts of gluten for patients with wheat allergy or coeliac disease".Aliment Pharmacol Ther.23 (5):559–75.doi:10.1111/j.1365-2036.2006.02768.x.PMID16480395.S2CID9970042.For bothwheat allergy and coeliac disease the dietary avoidance of wheat and other gluten-containing cereals is the only effective treatment.
^Gelinas, Pierre; McKinnon, Carole M. (2006). "Effect of wheat variety, farming site, and bread-baking on total phenolics".International Journal of Food Science and Technology.41 (3): 329.doi:10.1111/j.1365-2621.2005.01057.x.
^Boskov Hansen, H.; Andreasen, M.F.; Nielsen, M.M.; Melchior Larsen, L.; Bach Knudsen, K.E.; Meyer, A.S.; Christensen, L.P. & Hansen, Å. (2002). "Changes in dietary fibre, phenolic acids and activity of endogenous enzymes during rye bread-making".European Food Research and Technology.214: 33.doi:10.1007/s00217-001-0417-6.S2CID85239461.
^Strandås, C.; Kamal-Eldin, A.; Andersson, R.; Åman, P. (2008). "Phenolic glucosides in bread containing flaxseed".Food Chemistry.110 (4):997–99.doi:10.1016/j.foodchem.2008.02.088.PMID26047292.
^McGee, Harold (2004).On Food and Cooking: The Science and Lore of the Kitchen. New York: Scribner. pp. 515–80.
^Surdyk, Nicolas; Rosén, Johan; Andersson, Roger; Åman, Per (April 2004). "Effects of Asparagine, Fructose, and Baking Conditions on Acrylamide Content in Yeast-Leavened Wheat Bread".Journal of Agricultural and Food Chemistry.52 (7):2047–2051.Bibcode:2004JAFC...52.2047S.doi:10.1021/jf034999w.PMID15053550.
^"Our 10 best bread recipes".The Guardian. 6 September 2014. Retrieved2 October 2016.Our most dutiful mealtime companion becomes the main ingredient in this inventive array of recipes, from a hearty clam chowder to a luxurious take on a pudding favourite...
^Hamelman, Jeffrey (2004).Bread: a baker's book of techniques and recipes. New York: John Wiley. pp. 7–13.ISBN978-0-471-16857-7.A high gluten white flour will require more mix time than a white flour with a lower gluten content,...
^Edwards, W.P. (2007).The science of bakery products. Cambridge: Royal Society of Chemistry. p. 68.ISBN978-0-85404-486-3. Retrieved8 December 2012.When bread expands in the oven the resulting expansion is known as oven spring. It has been calculated that water expansion was responsible for some 60% of the expansion.
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