1.
Food energy
–
Food energy is chemical energy that animals derive from food and molecular oxygen through the process of cellular respiration. Humans and other animals need a minimum intake of energy to sustain their metabolism. Foods are composed chiefly of carbohydrates, fats, proteins, alcohol, water, vitamins, carbohydrates, fats, proteins, alcohol, and water represent virtually all the weight of food, with vitamins and minerals making up only a small percentage of the weight. Organisms derive food energy from carbohydrates, fats and proteins as well as organic acids, polyols. Some diet components that provide little or no energy, such as water, minerals, vitamins, cholesterol. Water, minerals, vitamins, and cholesterol are not broken down, fiber, a type of carbohydrate, cannot be completely digested by the human body. Ruminants can extract energy from the respiration of cellulose because of bacteria in their rumens. Using the International System of Units, researchers measure energy in joules or in its multiples, the kilojoule is most often used for food-related quantities. An older metric system unit of energy, still used in food-related contexts, is the calorie, more precisely. Within the European Union, both the kilocalorie and kilojoule appear on nutrition labels, in many countries, only one of the units is displayed, in the US and Canada labels spell out the unit as calorie or as Calorie. Fats and ethanol have the greatest amount of energy per gram,37 and 29 kJ/g. Proteins and most carbohydrates have about 17 kJ/g, carbohydrates that are not easily absorbed, such as fiber, or lactose in lactose-intolerant individuals, contribute less food energy. Polyols and organic acids contribute 10 kJ/g and 13 kJ/g respectively, the amount of water, fat, and fiber in foods determines those foods energy density. Theoretically, one could measure food energy in different ways, using the Gibbs free energy of combustion, however, the convention is to use the heat of the oxidation reaction producing liquid water. The American chemist Wilbur Atwater worked these corrections out in the late 19th century, based on the work of Atwater, it became common practice to calculate energy content of foods using 4 kcal/g for carbohydrates and proteins and 9 kcal/g for lipids. The system was improved by Annabel Merrill and Bernice Watt of the USDA. Many governments require food manufacturers to label the energy content of their products, in the European Union, manufacturers of packaged food must label the nutritional energy of their products in both kilocalories and kilojoules, when required. In Australia and New Zealand, the energy must be stated in kilojoules
Food energy
–
The nutritional information label on a pack of
Basmati rice in the United Kingdom
2.
Carbohydrate
–
A carbohydrate is a biological molecule consisting of carbon, hydrogen and oxygen atoms, usually with a hydrogen–oxygen atom ratio of 2,1, in other words, with the empirical formula Cmn. This formula holds true for monosaccharides, some exceptions exist, for example, deoxyribose, a sugar component of DNA, has the empirical formula C5H10O4. Carbohydrates are technically hydrates of carbon, structurally it is accurate to view them as polyhydroxy aldehydes and ketones. The term is most common in biochemistry, where it is a synonym of saccharide, a group that includes sugars, starch, the saccharides are divided into four chemical groups, monosaccharides, disaccharides, oligosaccharides, and polysaccharides. Monosaccharides and disaccharides, the smallest carbohydrates, are referred to as sugars. The word saccharide comes from the Greek word σάκχαρον, meaning sugar, while the scientific nomenclature of carbohydrates is complex, the names of the monosaccharides and disaccharides very often end in the suffix -ose. For example, grape sugar is the glucose, cane sugar is the disaccharide sucrose. Carbohydrates perform numerous roles in living organisms, polysaccharides serve for the storage of energy and as structural components. The 5-carbon monosaccharide ribose is an important component of coenzymes and the backbone of the genetic molecule known as RNA, the related deoxyribose is a component of DNA. Saccharides and their derivatives include many other important biomolecules that play key roles in the system, fertilization, preventing pathogenesis, blood clotting. In food science and in informal contexts, the term carbohydrate often means any food that is particularly rich in the complex carbohydrate starch or simple carbohydrates. Often in lists of information, such as the USDA National Nutrient Database, the term carbohydrate is used for everything other than water, protein, fat, ash. This will include chemical compounds such as acetic or lactic acid, carbohydrates are found in wide variety of foods. The important sources are cereals, potatoes, sugarcane, fruits, table sugar, bread, milk, starch and sugar are the important carbohydrates in our diet. Starch is abundant in potatoes, maize, rice and other cereals, sugar appears in our diet mainly as sucrose which is added to drinks and many prepared foods such as jam, biscuits and cakes. Glucose and fructose are found naturally in fruits and some vegetables. Glycogen is carbohydrate found in the liver and muscles, cellulose in the cell wall of all plant tissue is a carbohydrate. It is important in our diet as fibre which helps to maintain a healthy digestive system, formerly the name carbohydrate was used in chemistry for any compound with the formula Cm n
Carbohydrate
–
Grain products: rich sources of carbohydrates
Carbohydrate
3.
Fat
–
Fat is one of the three main macronutrients, along with carbohydrate and protein. Fats, also known as triglycerides, are esters of three fatty acid chains and the alcohol glycerol, the terms oil, fat, and lipid are often confused. Oil normally refers to a fat with short or unsaturated fatty acid chains that is liquid at room temperature, lipid is the general term, as a lipid is not necessarily a triglyceride. Fats, like lipids, are generally hydrophobic, and are soluble in organic solvents. Fat is an important foodstuff for many forms of life, and they are a necessary part of the diet of most heterotrophs. Some fatty acids that are set free by the digestion of fats are called essential because they cannot be synthesized in the body from simpler constituents, there are two essential fatty acids in human nutrition, alpha-linolenic acid and linoleic acid. Other lipids needed by the body can be synthesized from these, fats and other lipids are broken down in the body by enzymes called lipases produced in the pancreas. Fats and oils are categorized according to the number and bonding of the atoms in the aliphatic chain. Fats that are saturated fats have no double bonds between the carbons in the chain, unsaturated fats have one or more double bonded carbons in the chain. The nomenclature is based on the end of the chain. This end is called the end or the n-end. Thus alpha-linolenic acid is called an omega-3 fatty acid because the 3rd carbon from that end is the first double bonded carbon in the counting from that end. Some oils and fats have double bonds and are therefore called polyunsaturated fats. Unsaturated fats can be divided into cis fats, which are the most common in nature, and trans fats. Unsaturated fats can be altered by reaction with hydrogen effected by a catalyst and this action, called hydrogenation, tends to break all the double bonds and makes a fully saturated fat. However, trans fats are generated during hydrogenation as contaminants created by a side reaction on the catalyst during partial hydrogenation. Saturated fats can stack themselves in a closely packed arrangement, so they can easily and are typically solid at room temperature. For example, animal fats tallow and lard are high in saturated fatty acid content and are solids, olive and linseed oils on the other hand are unsaturated and liquid
Fat
–
The
obese mouse on the left has large stores of adipose tissue. For comparison, a mouse with a normal amount of adipose tissue is shown on the right.
Fat
–
A fat, or
triglyceride, molecule. Note the three fatty acid chains attached to the central glycerol portion of the molecule.
4.
Protein (nutrient)
–
Proteins are essential nutrients for the human body. They are one of the blocks of body tissue. As a fuel, proteins provide as much energy density as carbohydrates,4 kcal per gram, in contrast, the most important aspect and defining characteristic of protein from a nutritional standpoint is its amino acid composition. Proteins are polymer chains made of amino acids linked together by peptide bonds, during human digestion, proteins are broken down in the stomach to smaller polypeptide chains via hydrochloric acid and protease actions. This is crucial for the synthesis of the amino acids that cannot be biosynthesized by the body. There are nine amino acids which humans must obtain from their diet in order to prevent protein-energy malnutrition. They are phenylalanine, valine, threonine, tryptophan, methionine, leucine, isoleucine, lysine, there are five dispensable amino acids which humans are able to synthesize in the body. These five are alanine, aspartic acid, asparagine, glutamic acid and these six are arginine, cysteine, glycine, glutamine, proline and tyrosine. Humans need the essential amino acids in certain ratios, some protein sources contain amino acids in a more or less complete sense. This has given rise to various ranking systems for protein sources, Dietary sources of protein include both animals and plants, meats, dairy products, fish and eggs as well as grains, legumes and nuts. Vegetarians and vegans can get enough essential amino acids by eating a variety of plant proteins and it is commonly believed that athletes should consume a higher-than-normal protein intake to maintain optimal physical performance. Protein is a nutrient needed by the body for growth. Aside from water, proteins are the most abundant kind of molecules in the body, Protein can be found in all cells of the body and is the major structural component of all cells in the body, especially muscle. This also includes body organs, hair and skin, proteins are also used in membranes, such as glycoproteins. When broken down into amino acids, they are used as precursors to acid, co-enzymes, hormones, immune response, cellular repair. Additionally, protein is needed to form blood cells, proteins are believed to increase performance in terms of athletics. Amino acids, the blocks of proteins, are used for building muscle tissue. Protein is only used as fuel when carbohydrates are low
Protein (nutrient)
–
Protein milkshakes, made from protein powder (center) and milk (left), are a common
bodybuilding supplement.
Protein (nutrient)
–
Amino acids are the building blocks of protein.
Protein (nutrient)
–
An education campaign launched by the United States Department of Agriculture about 100 years ago, on cottage cheese as a lower-cost protein substitute for meat.
Protein (nutrient)
–
A child in Nigeria during the
Biafra War suffering from
kwashiorkor – one of the
three protein energy malnutrition ailments afflicting over 10 million children in developing countries.
5.
Dietary element
–
In the context of nutrition, a mineral is a chemical element required as an essential nutrient by organisms to perform functions necessary for life. Minerals originate in the earth and cannot be made by living organisms, most of the minerals in a human diet come from eating plants and animals or from drinking water. As a group, minerals are one of the four groups of essential nutrients, the others of which are vitamins, essential fatty acids, the five major minerals in the human body are calcium, phosphorus, potassium, sodium, and magnesium. All of the elements in a human body are called trace elements. The trace elements that have a specific function in the human body are iron, cobalt, copper, zinc, manganese, molybdenum, iodine. Most chemical elements that are ingested by organisms are in the form of simple compounds, plants absorb dissolved elements in soils, which are subsequently ingested by the herbivores that eat them, and the elements move up the food chain. Larger organisms may also consume soil or use mineral resources, such as salt licks, one element, cobalt, is available for use by animals only after having been processed into complex molecules by bacteria. Minerals are used by animals and microorganisms for the process of mineralizing structures, called biomineralization, used to construct bones, seashells, eggshells, exoskeletons and mollusc shells. At least twenty chemical elements are known to be required to support human biochemical processes by serving structural and functional roles as well as electrolytes, however, as many as twenty-nine elements in total are suggested to be used by mammals, as inferred by biochemical and uptake studies. Phosphorus makes up about 1% of a body weight. The last four major minerals make up only about 0. 85% of the weight of the body, together these eleven chemical elements make up 99. 85% of the body. Minerals are present in a human beings blood at certain mass. The figure below presents the concentrations of each of the elements discussed in this article. Depending on the concentrations, some are in part of the picture. The figure includes the values of other constituents of blood such as hormones. In the figure, minerals are color highlighted in purple, dietitians may recommend that minerals are best supplied by ingesting specific foods rich with the chemical element of interest. The elements may be present in the food or added to the food. The dietary focus on chemical elements derives from an interest in supporting the biochemical reactions of metabolism with the elemental components
Dietary element
–
Reference ranges for blood tests, sorted logarithmically by
mass above the scale and by
molarity below.
6.
Calcium
–
Calcium is a chemical element with symbol Ca and atomic number 20. Calcium is a soft grayish-yellow alkaline earth metal, fifth-most-abundant element by mass in the Earths crust, the ion Ca2+ is also the fifth-most-abundant dissolved ion in seawater by both molarity and mass, after sodium, chloride, magnesium, and sulfate. Free calcium metal is too reactive to occur in nature, Calcium is produced in supernova nucleosynthesis. Calcium is a trace element in living organisms. It is the most abundant metal by mass in animals, and it is an important constituent of bone, teeth. In cell biology, the movement of the calcium ion into, Calcium carbonate and calcium citrate are often taken as dietary supplements. Calcium is on the World Health Organizations List of Essential Medicines, Calcium has a wide variety of applications, almost all of which are associated with calcium compounds and salts. Calcium metal is used as a deoxidizer, desulfurizer, and decarbonizer for production of ferrous and nonferrous alloys. In steelmaking and production of iron, Ca reacts with oxygen, Calcium carbonate is used in manufacturing cement and mortar, lime, limestone and aids in production in the glass industry. It also has chemical and optical uses as mineral specimens in toothpastes, Calcium hydroxide solution is used to detect the presence of carbon dioxide in a gas sample bubbled through a solution. The solution turns cloudy where CO2 is present, Calcium arsenate is used in insecticides. Calcium carbide is used to make acetylene gas and various plastics, Calcium chloride is used in ice removal and dust control on dirt roads, as a conditioner for concrete, as an additive in canned tomatoes, and to provide body for automobile tires. Calcium citrate is used as a food preservative, Calcium cyclamate is used as a sweetening agent in several countries. In the United States, it has been outlawed as a suspected carcinogen, Calcium gluconate is used as a food additive and in vitamin pills. Calcium hypochlorite is used as a swimming pool disinfectant, as an agent, as an ingredient in deodorant. Calcium permanganate is used in rocket propellant, textile production, as a water sterilizing agent. Calcium phosphate is used as a supplement for animal feed, fertilizer, in production for dough and yeast products, in the manufacture of glass. Calcium phosphide is used in fireworks, rodenticide, torpedoes, Calcium sulfate is used as common blackboard chalk, as well as, in its hemihydrate form, Plaster of Paris
Calcium
–
Calcium, 20 Ca
Calcium
–
Travertine terraces
Pamukkale, Turkey
Calcium
–
'Ain Ghazal figure
Calcium
–
500 milligram calcium supplements made from
calcium carbonate
7.
Milligram
–
The kilogram or kilogramme is the base unit of mass in the International System of Units and is defined as being equal to the mass of the International Prototype of the Kilogram. The avoirdupois pound, used in both the imperial and US customary systems, is defined as exactly 0.45359237 kg, making one kilogram approximately equal to 2.2046 avoirdupois pounds. Other traditional units of weight and mass around the world are also defined in terms of the kilogram, the gram, 1/1000 of a kilogram, was provisionally defined in 1795 as the mass of one cubic centimetre of water at the melting point of ice. The final kilogram, manufactured as a prototype in 1799 and from which the IPK was derived in 1875, had an equal to the mass of 1 dm3 of water at its maximum density. The kilogram is the only SI base unit with an SI prefix as part of its name and it is also the only SI unit that is still directly defined by an artifact rather than a fundamental physical property that can be reproduced in different laboratories. Three other base units and 17 derived units in the SI system are defined relative to the kilogram, only 8 other units do not require the kilogram in their definition, temperature, time and frequency, length, and angle. At its 2011 meeting, the CGPM agreed in principle that the kilogram should be redefined in terms of the Planck constant, the decision was originally deferred until 2014, in 2014 it was deferred again until the next meeting. There are currently several different proposals for the redefinition, these are described in the Proposed Future Definitions section below, the International Prototype Kilogram is rarely used or handled. In the decree of 1795, the term gramme thus replaced gravet, the French spelling was adopted in the United Kingdom when the word was used for the first time in English in 1797, with the spelling kilogram being adopted in the United States. In the United Kingdom both spellings are used, with kilogram having become by far the more common, UK law regulating the units to be used when trading by weight or measure does not prevent the use of either spelling. In the 19th century the French word kilo, a shortening of kilogramme, was imported into the English language where it has used to mean both kilogram and kilometre. In 1935 this was adopted by the IEC as the Giorgi system, now known as MKS system. In 1948 the CGPM commissioned the CIPM to make recommendations for a practical system of units of measurement. This led to the launch of SI in 1960 and the subsequent publication of the SI Brochure, the kilogram is a unit of mass, a property which corresponds to the common perception of how heavy an object is. Mass is a property, that is, it is related to the tendency of an object at rest to remain at rest, or if in motion to remain in motion at a constant velocity. Accordingly, for astronauts in microgravity, no effort is required to hold objects off the cabin floor, they are weightless. However, since objects in microgravity still retain their mass and inertia, the ratio of the force of gravity on the two objects, measured by the scale, is equal to the ratio of their masses. On April 7,1795, the gram was decreed in France to be the weight of a volume of pure water equal to the cube of the hundredth part of the metre
Milligram
–
A domestic-quality one-kilogram weight made of
cast iron (the
credit card is for scale). The shape follows
OIML recommendation R52 for cast-iron hexagonal weights
Milligram
–
Measurement of weight – gravitational attraction of the measurand causes a distortion of the spring
Milligram
–
Measurement of mass – the gravitational force on the measurand is balanced against the gravitational force on the weights.
Milligram
–
The Arago kilogram, an exact copy of the "Kilogramme des Archives" commissioned in 1821 by the US under supervision of French physicist
François Arago that served as the US's first kilogram standard of mass until 1889, when the US converted to primary metric standards and received its current kilogram prototypes, K4 and K20.
8.
Butter
–
Butter is a dairy product containing up to 80% butterfat which is solid when chilled and at room temperature in some regions and liquid when warmed. It is made by churning fresh or fermented cream or milk to separate the butterfat from the buttermilk. It is generally used as a spread on plain or toasted bread products and a condiment on cooked vegetables, as well as in cooking, such as baking, sauce making, Butter consists of butterfat, milk proteins and water, and in some types, added salt. Butter may also be sold with added flavourings, such as garlic butter, most frequently made from cows milk, butter can also be manufactured from the milk of other mammals, including sheep, goats, buffalo, and yaks. Salt such as salt, flavorings and preservatives are sometimes added to butter. Rendering butter produces clarified butter or ghee, which is almost entirely butterfat, Butter is a water-in-oil emulsion resulting from an inversion of the cream, in a water-in-oil emulsion, the milk proteins are the emulsifiers. Butter remains a solid when refrigerated, but softens to a spreadable consistency at room temperature, the density of butter is 911 g/L. It generally has a yellow color, but varies from deep yellow to nearly white. Its unmodified color is dependent on the feed and genetics but is commonly manipulated with food colorings in the commercial manufacturing process. The word butter derives from the Latin butyrum, which is the latinisation of the Greek βούτυρον and this may have been a construction meaning cow-cheese, from βοῦς, ox, cow + τυρός, cheese. Nevertheless, the earliest attested form of the stem, turos, is the Mycenaean Greek tu-ro. The root word persists in the name butyric acid, a found in rancid butter. In general use, the term refers to the spread dairy product when unqualified by other descriptors. The word commonly is used to describe puréed vegetable or seed and nut products such as peanut butter and it is often applied to spread fruit products such as apple butter. Fats such as butter and shea butter that remain solid at room temperature are also known as butters. Unhomogenized milk and cream contain butterfat in microscopic globules and these globules are surrounded by membranes made of phospholipids and proteins, which prevent the fat in milk from pooling together into a single mass. Butter is produced by agitating cream, which damages these membranes and allows the milk fats to conjoin, variations in the production method will create butters with different consistencies, mostly due to the butterfat composition in the finished product. Butter contains fat in three forms, free butterfat, butterfat crystals, and undamaged fat globules
Butter
–
Butter at the Borough Market,
London
Butter
–
Butter is often served for spreading on bread with a
butter knife.
Butter
–
Churning cream into butter using a hand-held mixer.
Butter
–
Liquid
clarified butter
9.
Cream
–
Cream is a dairy product composed of the higher-butterfat layer skimmed from the top of milk before homogenization. In un-homogenized milk, the fat, which is less dense, in the industrial production of cream, this process is accelerated by using centrifuges called separators. In many countries, cream is sold in several grades depending on the total butterfat content, Cream can be dried to a powder for shipment to distant markets. Cream has high levels of saturated fat, Cream skimmed from milk may be called sweet cream to distinguish it from whey cream skimmed from whey, a by-product of cheese-making. Whey cream has a fat content and tastes more salty, tangy. In many countries, cream is usually sold partially fermented, sour cream, crème fraîche, Cream has many culinary uses in sweet, bitter, salty and tangy dishes. This is also the origin of butters yellow color, Cream from goats milk, or from cows fed indoors on grain or grain-based pellets, is white. Cream is used as an ingredient in foods, including ice cream, many sauces, soups, stews, puddings, and some custard bases. Whipped cream is served as a topping on ice cream sundaes, milkshakes, egg nog, irish cream is an alcoholic liqueur which blends cream with whiskey, and often honey, wine, or coffee. Cream is also used in Indian curries such as masala dishes, Cream is often added to coffee in the US and Canada. Both single and double cream can be used in cooking, double cream or full-fat crème fraîche are often used when cream is added to a hot sauce, to prevent any problem with it separating or splitting. Double cream can be thinned with milk to make an approximation of single cream, the French word crème denotes not only dairy cream, but also other thick liquids such as sweet and savory custards, which are normally made with milk, not cream. Different grades of cream are distinguished by their fat content, whether they have been heat-treated, whipped, in many jurisdictions, there are regulations for each type. In the United States, cream is sold as, Most cream products sold in the United States at retail contain the minimum permissible fat content for their product type. Half and half almost always contains only 10. 5% butterfat, not all grades are defined by all jurisdictions, and the exact fat content ranges vary. Cream must contain no less than 350 g/kg of milk fat, in Canada, light cream is very low-fat cream, usually with 5% or 6% butterfat. Specific product characteristics are generally uniform throughout Canada, but names vary by geographic and linguistic area and by manufacturer. It can be confusing, coffee cream may be 10% or 18% and half-and-half may be 3%, 5%, 6% or 10%, all depending on location
Cream
–
A milk bottle showing cream risen to the top
Cream
–
Stewed
nectarines and heavy cream
Cream
–
Meiji whipping cream
10.
Soured milk
–
Soured milk is a food product produced by the acidification of milk. Acidification, which gives the milk a tart taste, is achieved either through the addition of an acid, such as lemon juice or vinegar, the acid causes milk to coagulate and thicken, inhibiting the growth of harmful bacteria and improving the products shelf life. Soured milk that is produced by fermentation is more specifically called fermented milk or cultured milk. Modern commercial soured milk differs from milk that has become sour naturally, traditionally, soured milk was simply fresh milk that was left to ferment and sour by keeping it in a warm place for a day, often near a stove. The milk would become sour and then ferment, soured milk that is produced by the addition of an acid, with or without the addition of microbial organisms, is more specifically called acidified milk. It is also made at home or sold in supermarkets and consumed in the Great Lakes region of Eastern Africa and it is also a traditional food of the Bantu people of Southern Africa. Since the 1970s, some producers have used chemical acidification in place of biological agents, raw milk that has not gone sour is sometimes referred to as sweet milk, because it contains the sugar lactose. Fermentation converts the lactose to lactic acid, which has a sour flavor, before refrigeration, raw milk commonly became sour before it could be consumed, and various recipes incorporate such leftover milk as an ingredient. Modern food safety standards mean that milk that has gone sour is considered safe to drink, buttermilk is a common modern substitute for naturally soured milk
Soured milk
–
Soured milk
11.
Fermented dairy product
–
The fermentation process increases the shelf-life of the product, while enhancing the taste and improving the digestibility of milk. There is evidence that fermented milk products have produced since around 10,000 BC. A range of different Lactobacilli strains has been grown in laboratories allowing for a range of cultured milk products with different tastes. Many different types of cultured milk products can be found around the world, * Streptococcus lactis has been renamed to Lactococcus lactis subsp
Fermented dairy product
–
Dadiah is a traditional fermented milk of
West Sumatra,
Indonesia prepared with fresh,
raw and unheated
buffalo milk
12.
Lactic acid bacteria
–
These bacteria, usually found in decomposing plants and milk products, produce lactic acid as the major metabolic end product of carbohydrate fermentation. This trait has, throughout history, linked LAB with food fermentations, proteinaceous bacteriocins are produced by several LAB strains and provide an additional hurdle for spoilage and pathogenic microorganisms. Furthermore, lactic acid and other products contribute to the organoleptic. The lactic acid bacteria are either rod-shaped, or spherical, and are characterized by a tolerance to acidity. This aspect helps LAB to outcompete other bacteria in a natural fermentation, laboratory media used for LAB typically include a carbohydrate source, as most species are incapable of respiration. They consist of the organelles of a simple bacterial structure, LAB are amongst the most important groups of microorganisms used in the food industry. Two main hexose fermentation pathways are used to classify LAB genera, under conditions of excess glucose and limited oxygen, homolactic LAB catabolize one mole of glucose in the Embden-Meyerhof-Parnas pathway to yield two moles of pyruvate. Intracellular redox balance is maintained through the oxidation of NADH, concomitant with reduction to lactic acid. This process yields two moles of ATP per mole of glucose consumed, representative homolactic LAB genera include Lactococcus, Enterococcus, Streptococcus, Pediococcus, and group I lactobacilli. Heterofermentative LAB use the pentose phosphate pathway, alternatively referred to as the pentose phosphoketolase pathway, one mole of glucose-6-phosphate is initially dehydrogenated to 6-phosphogluconate and subsequently decarboxylated to yield one mole of CO2. The resulting pentose-5-phosphate is cleaved into one mole glyceraldehyde phosphate and one mole acetyl phosphate, GAP is further metabolized to lactate as in homofermentation, with the acetyl phosphate reduced to ethanol via acetyl-CoA and acetaldehyde intermediates. In theory, end products are produced in quantities from the catabolism of one mole of glucose. Obligate heterofermentative LAB include Leuconostoc, Oenococcus, Weissella, and group III lactobacilli, formerly, streptococci were segregated primarily based on serology, which has proven to correlate well with the current taxonomic definitions. Lactococci are used extensively as fermentation starters in dairy production, with humans estimated to consume 1018 lactococci annually, partly due to their industrial relevance, both L. lactis subspecies are widely used as generic LAB models for research. L. lactis ssp. cremoris, used in the production of cheeses, is represented by the laboratory strains LM0230. In similar manner, L. lactis ssp. lactis is employed in soft cheese fermentations, in 2001, Bolotin et al. sequenced the genome of IL1403, which coincided with a significant shift of resources to understanding LAB genomics and related applications. The relationship between bacteriophages and their hosts is very important in the context of the food fermentation industry. Sources of phage contamination, measures to control their propagation and dissemination, the first contact between an infecting phage and its bacterial host is the attachment of the phage to the host cell
Lactic acid bacteria
–
Lactobacillales
Lactic acid bacteria
–
Streptococcus
13.
Lactococcus lactis
–
They have a homofermentative metabolism and have been reported to produce exclusive L--lactic acid. However, reported D--lactic acid can be produced when cultured at low pH, the capability to produce lactic acid is one of the reasons why L. lactis is one of the most important microorganisms in the dairy industry. Based on its history in food fermentation, L. lactis has generally recognized as safe status with few case reports of being an opportunistic pathogen, L. lactis is of crucial importance for manufacturing dairy products, such as buttermilk and cheeses. When L. lactis ssp. lactis is added to milk, the byproduct of ATP energy production is lactic acid. The lactic acid produced by the bacterium curdles the milk that then separates to form curds, L. lactis is one of the best characterized low GC Gram positive bacteria with detailed knowledge on genetics, metabolism and biodiversity. L. lactis is mainly isolated from either the environment or plant material. Dairy isolates are suggested to have evolved from plant isolates through a process in which genes without benefit in the rich medium milk were either lost or down-regulated and this process, also called genome erosion or reductive evolution is also described in several other lactic acid bacteria. The proposed transition from the plant to the environment was reproduced in the laboratory through experimental evolution of a plant isolate that was cultivated in milk for a prolonged period. Consistent with the results from comparative genomics this resulted in L. lactis losing or down-regulating genes which are dispensable in milk, hundreds of novel small RNAs were identified by Meulen et al. in the genome of L. lactis MG1363. One of them, LLnc147 was shown to be involved carbon uptake, lactis is used in the early stages for the production of many cheeses, including brie, camembert, Cheddar, Colby, Gruyère, Parmesan, and Roquefort. The state Assembly of Wisconsin, also the number one cheese-producing state in the United States and it would have been the first and only such designation by a state legislature in the nation, however the legislation was not picked up by the Senate. The use of L. lactis in dairy factories is not without issues, bacteriophages specific to L. lactis cause significant economic losses each year by preventing the bacteria from fully metabolizing the milk substrate. Several epidemiologic studies showed the phages mainly responsible for these losses are from the species 936, c2, type strain of Lactococcus lactis at BacDive - the Bacterial Diversity Metadatabase
Lactococcus lactis
–
Lactococcus lactis
14.
Lactobacillus bulgaricus
–
Bulgaricus is one of several bacteria used for the production of yogurt. It is also found in naturally fermented products. First identified in 1905 by the Bulgarian doctor Stamen Grigorov, the bacterium feeds on lactose to lactic acid. The bacterium is also grown artificially in many other countries and it is a gram-positive rod that may appear long and filamentous. It is non-motile and does not form spores and it is regarded as aciduric or acidophilic, since it requires a low pH to grow effectively. The bacterium has complex nutritional requirements, bulgaricus is commonly used alongside Streptococcus thermophilus as a starter for making yogurt. The two species work in synergy, with L. d. bulgaricus producing amino acids from milk proteins, both species produce lactic acid, which gives yogurt its tart flavor and acts as a preservative. The resulting decrease in pH also partially coagulates the proteins, such as casein. While fermenting milk, L. d. bulgaricus produces acetaldehyde, some strains of L. d. bulgaricus, such as L. bulgaricus GLB44, also produce bacteriocins, which have been shown to kill undesired bacteria in vitro. Some of the biggest importers of the bacterium are Japan, the USA, and it has also been considered a contaminant of beer due to its homofermentative production of lactic acid, an off-flavor in many styles of beer. In other styles of beer, however, lactic acid bacteria can contribute to the appearance, aroma, taste, and/or mouthfeel. Bulgaricus was first identified in 1905 by Stamen Grigorov, who named it Bacillus bulgaricus, ilya Metchnikoff, a professor at the Pasteur Institute in Paris, researched the relationship between the longevity of Bulgarians and their consumption of yogurt. He had the idea that aging is caused by activity, or proteolysis. Proteolytic bacteria such as clostridia, which are part of the intestinal flora, produce toxic substances including phenols, ammonia. It was already known at time that fermentation with lactic acid bacteria inhibits the deterioration of milk because of its low pH. Lactobacillus bulgaricus is a constituent in VSL#3 and this proprietary, standardized, formulation of live bacteria may be used in combination with conventional therapies to treat ulcerative colitis and requires a prescription. Etude sur le lait fermenté comestible, le Kissélo-mléko de Bulgarie, revue Médicale de la Suisse Romande. Balows A, Truper HG, Dworkin M, Harder W, the Prokaryotes, A Handbook on the Biology of Bacteria
Lactobacillus bulgaricus
–
Lactobacillus bulgaricus
15.
Acidity
–
An acid is a molecule or ion capable of donating a hydron, or, alternatively, capable of forming a covalent bond with an electron pair. The first category of acids is the donors or Brønsted acids. In the special case of solutions, proton donors form the hydronium ion H3O+ and are known as Arrhenius acids. Brønsted and Lowry generalized the Arrhenius theory to include non-aqueous solvents, acids form aqueous solutions with a sour taste, can turn blue litmus red, and react with bases and certain metals to form salts. The word acid is derived from the Latin acidus/acēre meaning sour, an aqueous solution of an acid has a pH less than 7 and is colloquially also referred to as acid, while the strict definition refers only to the solute. A lower pH means a higher acidity, and thus a higher concentration of hydrogen ions in the solution. Chemicals or substances having the property of an acid are said to be acidic, common aqueous acids include hydrochloric acid, acetic acid, sulfuric acid, and citric acid. As these examples show, acids can be solutions or pure substances, strong acids and some concentrated weak acids are corrosive, but there are exceptions such as carboranes and boric acid. The second category of acids are Lewis acids, which form a covalent bond with an electron pair, however, hydrogen chloride, acetic acid, and most other Brønsted-Lowry acids cannot form a covalent bond with an electron pair and are therefore not Lewis acids. Conversely, many Lewis acids are not Arrhenius or Brønsted-Lowry acids, in modern terminology, an acid is implicitly a Brønsted acid and not a Lewis acid, since chemists almost always refer to a Lewis acid explicitly as a Lewis acid. Modern definitions are concerned with the chemical reactions common to all acids. Most acids encountered in life are aqueous solutions, or can be dissolved in water, so the Arrhenius. The Brønsted-Lowry definition is the most widely used definition, unless otherwise specified, hydronium ions are acids according to all three definitions. Interestingly, although alcohols and amines can be Brønsted-Lowry acids, they can function as Lewis bases due to the lone pairs of electrons on their oxygen and nitrogen atoms. The Swedish chemist Svante Arrhenius attributed the properties of acidity to hydrogen ions or protons in 1884, an Arrhenius acid is a substance that, when added to water, increases the concentration of H+ ions in the water. Thus, an Arrhenius acid can also be described as a substance that increases the concentration of ions when added to water. Examples include molecular substances such as HCl and acetic acid, an Arrhenius base, on the other hand, is a substance which increases the concentration of hydroxide ions when dissolved in water. Thus, an Arrhenius acid could also be said to be one that decreases hydroxide concentration, in an acidic solution, the concentration of hydronium ions is greater than 10−7 moles per liter
Acidity
–
Zinc, a typical metal, reacting with
hydrochloric acid, a typical acid
Acidity
–
Svante Arrhenius
Acidity
–
Hydrochloric acid (in
beaker) reacting with
ammonia fumes to produce
ammonium chloride (white smoke).
16.
Lactic acid
–
Lactic acid is an organic compound with the formula CH3CHCO2H. In its solid state, it is white and water-soluble, in its liquid state, it is clear. It is produced naturally and synthetically. With a hydroxyl group adjacent to the group, lactic acid is classified as an alpha-hydroxy acid. In the form of its base called lactate, it plays a role in several biochemical processes. In solution, it can ionize a proton from the carboxyl group, compared to acetic acid, its pKa is 1 unit less, meaning lactic acid deprotonates ten times more easily than acetic acid does. This higher acidity is the consequence of the hydrogen bonding between the α-hydroxyl and the carboxylate group. Lactic acid is chiral, consisting of two optical isomers, one is known as L--lactic acid or -lactic acid and the other, its mirror image, is D--lactic acid or -lactic acid. A mixture of the two in equal amounts is called DL-lactic acid, or racemic lactic acid, DL-lactic acid is miscible with water and with ethanol above its melting point which is around 17 or 18 °C. D-lactic acid and L-lactic acid have a melting point. In animals, L-lactate is constantly produced from pyruvate via the enzyme lactate dehydrogenase in a process of fermentation during normal metabolism and exercise. The concentration of lactate is usually 1–2 mmol/L at rest. In industry, lactic acid fermentation is performed by lactic acid bacteria and these bacteria can also grow in the mouth, the acid they produce is responsible for the tooth decay known as caries. In medicine, lactate is one of the components of lactated Ringers solution. These intravenous fluids consist of sodium and potassium cations along with lactate and chloride anions in solution with distilled water and it is most commonly used for fluid resuscitation after blood loss due to trauma, surgery, or burns. Lactic acid was isolated for the first time by the Swedish chemist Carl Wilhelm Scheele in 1780 from sour milk, the name reflects the lact- combining form derived from the Latin word for milk. In 1808, Jöns Jacob Berzelius discovered that lactic acid also is produced in muscles during exertion and its structure was established by Johannes Wislicenus in 1873. In 1856, Louis Pasteur discovered Lactobacillus and its role in the making of lactic acid, lactic acid started to be produced commercially by the German pharmacy Boehringer Ingelheim in 1895
Lactic acid
–
DL -Lactic acid
Lactic acid
17.
Fermentation (biochemistry)
–
Fermentation is a metabolic process that converts sugar to acids, gases, or alcohol. It occurs in yeast and bacteria, and also in oxygen-starved muscle cells, Fermentation is also used more broadly to refer to the bulk growth of microorganisms on a growth medium, often with the goal of producing a specific chemical product. French microbiologist Louis Pasteur is often remembered for his insights into fermentation, the science of fermentation is known as zymology. Fermentation takes place when the transport chain is unusable. In this case it becomes the primary means of ATP production. Fermentation turns NADH and pyruvate produced in glycolysis into NAD+. In the presence of O2, NADH and pyruvate are used to generate ATP in respiration and this is called oxidative phosphorylation, and it generates much more ATP than glycolysis alone. For that reason, cells generally benefit from avoiding fermentation when oxygen is available, the exception being obligate anaerobes which cannot tolerate oxygen. The first step, glycolysis, is common to all fermentation pathways, two ADP molecules and two Pi are converted to two ATP and two water molecules via substrate-level phosphorylation. Two molecules of NAD+ are also reduced to NADH, in oxidative phosphorylation the energy for ATP formation is derived from an electrochemical proton gradient generated across the inner mitochondrial membrane via the electron transport chain. Humans have used fermentation to produce drinks and beverages since the Neolithic age, Fermentation can even occur within the stomachs of animals, such as humans. To many people, fermentation simply means the production of alcohol, grains and fruits are fermented to produce beer, if a food soured, one might say it was off or fermented. Here are some definitions of fermentation and they range from informal, general usage to more scientific definitions. Preservation methods for food via microorganisms, any process that produces alcoholic beverages or acidic dairy products. Any large-scale microbial process occurring with or without air, any energy-releasing metabolic process that takes place only under anaerobic conditions. Fermentation does not necessarily have to be carried out in an anaerobic environment, for example, even in the presence of abundant oxygen, yeast cells greatly prefer fermentation to aerobic respiration, as long as sugars are readily available for consumption. The antibiotic activity of hops also inhibits aerobic metabolism in yeast, Fermentation reacts NADH with an endogenous, organic electron acceptor. Usually this is formed from the sugar during the glycolysis step. Sugars are the most common substrate of fermentation, and typical examples of products are ethanol, lactic acid, carbon dioxide
Fermentation (biochemistry)
–
Fermentation in progress: Bubbles of
CO2 form a froth on top of the fermentation mixture.
Fermentation (biochemistry)
–
Louis Pasteur in his laboratory
18.
Lactose
–
Lactose is a disaccharide sugar composed of galactose and glucose that is found in milk. Lactose makes up around 2–8% of milk, although the amount varies among species and individuals and it is extracted from sweet or sour whey. The name comes from lac, the Latin word for milk and it has a formula of C12H22O11 and the hydrate formula C12H22O11·H2O, making it an isomer of sucrose. The first crude isolation of lactose, by Italian physician Fabrizio Bartoletti, was published in 1633, in 1700, the Venetian pharmacist Lodovico Testi published a booklet of testimonials to the power of milk sugar to relieve, among other ailments, the symptoms of arthritis. In 1715, Testis procedure for making milk sugar was published by Antonio Vallisneri, lactose was identified as a sugar in 1780 by Carl Wilhelm Scheele. In 1812, Heinrich Vogel recognized that glucose was a product of hydrolyzing lactose, in 1856, Louis Pasteur crystallized the other component of lactose, galactose. By 1894, Emil Fischer had established the configurations of the component sugars, lactose was named by the French chemist Jean Baptiste André Dumas in 1843. Lactose is a derived from the condensation of galactose and glucose. Lactose is hydrolysed to glucose and galactose, isomerised in alkaline solution to lactulose, lactose monohydrate crystals have a characteristic tomahawk shape that can be observed with a light microscope. Several million tons are produced annually as a by-product of the dairy industry, whey is made up of 6. 5% solids of which 4. 8% is lactose that may be purified by crystallisation. Whey or milk plasma is the liquid remaining after milk is curdled and strained, lactose makes up about 2–8% of milk by weight. Industrially, lactose is produced from whey permeate – that is whey filtrated for all major proteins, the protein fraction is used in infant nutrition and sport nutrition while the permeate can be evaporated to 60–65% solids and crystallized while cooling. Lactose can also be precipitated from whey using ethanol, since it is insoluble in ethanol, lactose precipitates, in about 65% yield. Infant mammals nurse on their mothers to drink milk, which is rich in lactose, the intestinal villi secrete the enzyme called lactase to digest it. This enzyme cleaves the molecule into its two subunits, the simple sugars glucose and galactose, which can be absorbed. Since lactose occurs mostly in milk, in most mammals, the production of lactase gradually decreases with maturity due to a lack of continuing consumption. Many people with ancestry in Europe, West Asia, South Asia, the Sahel belt in West Africa, East Africa, in many of these areas, milk from mammals such as cattle, goats, and sheep is used as a large source of food. Hence, it was in these regions that genes for lifelong lactase production first evolved, the genes of adult lactose tolerance have evolved independently in various ethnic groups
Lactose
–
Chemistry
Lactose
–
Lactose (milk sugar)
19.
PH
–
In chemistry, pH is a numeric scale used to specify the acidity or basicity of an aqueous solution. It is approximately the negative of the base 10 logarithm of the concentration, measured in units of moles per liter. More precisely it is the negative of the logarithm to base 10 of the activity of the hydrogen ion, solutions with a pH less than 7 are acidic and solutions with a pH greater than 7 are basic. Pure water is neutral, at pH7, being neither an acid nor a base, contrary to popular belief, the pH value can be less than 0 or greater than 14 for very strong acids and bases respectively. The pH scale is traceable to a set of standard solutions whose pH is established by international agreement, the pH of aqueous solutions can be measured with a glass electrode and a pH meter, or an indicator. In the first papers, the notation had the H as a subscript to the p, as so. The exact meaning of the p in pH is disputed, but according to the Carlsberg Foundation and it has also been suggested that the p stands for the German Potenz, others refer to French puissance. Another suggestion is that the p stands for the Latin terms pondus hydrogenii, potentia hydrogenii and it is also suggested that Sørensen used the letters p and q simply to label the test solution and the reference solution. Currently in chemistry, the p stands for decimal cologarithm of, PH is defined as the decimal logarithm of the reciprocal of the hydrogen ion activity, aH+, in a solution. P H = − log 10 = log 10 For example and this definition was adopted because ion-selective electrodes, which are used to measure pH, respond to activity. For H+ number of electrons transferred is one and it follows that electrode potential is proportional to pH when pH is defined in terms of activity. The reference electrode may be a silver chloride electrode or a calomel electrode, the hydrogen-ion selective electrode is a standard hydrogen electrode. Reference electrode | concentrated solution of KCl || test solution | H2 | Pt Firstly, the cell is filled with a solution of hydrogen ion activity. Then the emf, EX, of the cell containing the solution of unknown pH is measured. PH = pH + E S − E X z The difference between the two measured emf values is proportional to pH and this method of calibration avoids the need to know the standard electrode potential. The proportionality constant, 1/z is ideally equal to 12.303 R T / F the Nernstian slope, to apply this process in practice, a glass electrode is used rather than the cumbersome hydrogen electrode. A combined glass electrode has a reference electrode. It is calibrated against buffer solutions of hydrogen ion activity
PH
–
Lemon juice tastes sour because it contains 5% to 6%
citric acid, which has a pH of 2.2.
PH
–
Chart showing the variation of color of universal indicator paper with pH
PH
–
pH values of some common substances
20.
Casein
–
Casein is the name for a family of related phosphoproteins. These proteins are found in mammalian milk, making up 80% of the proteins in cows milk. Casein has a variety of uses, from being a major component of cheese, to use as a food additive. As a food source, casein supplies amino acids, carbohydrates, casein contains a high number of proline residues, which do not interact. There are also no disulfide bridges, as a result, it has relatively little tertiary structure. It is relatively hydrophobic, making it soluble in water. However, in sharp contrast to surfactant micelles, the interior of a micelle is highly hydrated. The caseins in the micelles are held together by calcium ions, any of several molecular models could account for the special conformation of casein in the micelles. One of them proposes the micellar nucleus is formed by several submicelles, another model suggests the nucleus is formed by casein-interlinked fibrils. Finally, the most recent model proposes a link among the caseins for gelling to take place. All three models consider micelles as colloidal particles formed by casein aggregates wrapped up in soluble κ-casein molecules, the isoelectric point of casein is 4.6. Since milks pH is 6.6, casein has a charge in milk. While it is insoluble in neutral salt solutions, it is readily dispersible in dilute alkalis and in salt solutions such as aqueous sodium oxalate. The enzyme trypsin can hydrolyze a phosphate-containing peptone and it is used to form a type of organic adhesive. Casein paint is a fast-drying, water-soluble medium used by artists and it is still widely used by scene painters, although acrylic has made inroads in that field as well. Casein-based glues, formulated from casein, water, hydrated lime and sodium hydroxide were popular for woodworking, including for aircraft, casein glue is also used in transformer manufacturing due to its oil permeability. While largely replaced with synthetic resins, casein-based glues still have a use in niche applications, such as laminating fireproof doors. Cheese consists of proteins and fat from milk, usually the milk of cows, buffalo, goats and it is produced by coagulation of casein
Casein
–
Casein preparation in an old etching operation in Müllheim
Casein
–
Cheesemaking
21.
Precipitation (chemistry)
–
Precipitation is the creation of a solid from a solution. When the reaction occurs in a solution, the solid formed is called the precipitate. The chemical that causes the solid to form is called the precipitant, without sufficient force of gravity to bring the solid particles together, the precipitate remains in suspension. After sedimentation, especially when using a centrifuge to press it into a compact mass, Precipitation can be used as a medium. The precipitate-free liquid remaining above the solid is called the supernate or supernatant, powders derived from precipitation have also historically been known as flowers. When the solid appears in the form of fibers which have been through chemical processing. Sometimes the formation of a precipitate indicates the occurrence of a chemical reaction, if silver nitrate solution is poured into a solution of sodium chloride, a chemical reaction occurs forming a white precipitate of silver chloride. When potassium iodide solution reacts with lead nitrate solution, a precipitate of lead iodide is formed. Precipitation may occur if the concentration of a compound exceeds its solubility, Precipitation may occur rapidly from a supersaturated solution. Precipitation in solids is routinely used to synthesize nanoclusters, an important stage of the precipitation process is the onset of nucleation. The creation of a solid particle includes the formation of an interface, which requires some energy based on the relative surface energy of the solid. If this energy is not available, and no suitable nucleation surface is available, Precipitation reactions can be used for making pigments, removing salts from water in water treatment, and in classical qualitative inorganic analysis. Precipitation is also useful to isolate the products of a reaction during workup, ideally, the product of the reaction is insoluble in the reaction solvent. Thus, it precipitates as it is formed, preferably forming pure crystals, an example of this would be the synthesis of porphyrins in refluxing propionic acid. Thereafter, the precipitate may easily be separated by filtration, decanting, an example would be the synthesis of chromic tetraphenylporphyrin chloride, water is added to the DMF reaction solution, and the product precipitates. Precipitation is also useful in purifying products, crude bmim-Cl is taken up in acetonitrile, and dropped into ethyl acetate, another important application of an antisolvent is in ethanol precipitation of DNA. In metallurgy, precipitation from a solution is also a useful way to strengthen alloys. An example of a reaction, Aqueous silver nitrate is added to a solution containing potassium chloride
Precipitation (chemistry)
–
Crystals of meso -tetratolylporphyrin from a
reflux of
propanoic acid precipitate on cooling
Precipitation (chemistry)
–
Chemical Precipitation
Precipitation (chemistry)
–
Copper from a wire
displaces silver in a silver nitrate solution it is dipped into, and solid silver precipitates out.
22.
Viscous
–
The viscosity of a fluid is a measure of its resistance to gradual deformation by shear stress or tensile stress. For liquids, it corresponds to the concept of thickness, for example. Viscosity is a property of the fluid which opposes the motion between the two surfaces of the fluid in a fluid that are moving at different velocities. For a given velocity pattern, the stress required is proportional to the fluids viscosity, a fluid that has no resistance to shear stress is known as an ideal or inviscid fluid. Zero viscosity is observed only at low temperatures in superfluids. Otherwise, all fluids have positive viscosity, and are said to be viscous or viscid. A fluid with a high viscosity, such as pitch. The word viscosity is derived from the Latin viscum, meaning mistletoe, the dynamic viscosity of a fluid expresses its resistance to shearing flows, where adjacent layers move parallel to each other with different speeds. It can be defined through the situation known as a Couette flow. This fluid has to be homogeneous in the layer and at different shear stresses, if the speed of the top plate is small enough, the fluid particles will move parallel to it, and their speed will vary linearly from zero at the bottom to u at the top. Each layer of fluid will move faster than the one just below it, in particular, the fluid will apply on the top plate a force in the direction opposite to its motion, and an equal but opposite one to the bottom plate. An external force is required in order to keep the top plate moving at constant speed. The magnitude F of this force is found to be proportional to the u and the area A of each plate. The proportionality factor μ in this formula is the viscosity of the fluid, the ratio u/y is called the rate of shear deformation or shear velocity, and is the derivative of the fluid speed in the direction perpendicular to the plates. Isaac Newton expressed the forces by the differential equation τ = μ ∂ u ∂ y, where τ = F/A. This formula assumes that the flow is moving along parallel lines and this equation can be used where the velocity does not vary linearly with y, such as in fluid flowing through a pipe. Use of the Greek letter mu for the dynamic viscosity is common among mechanical and chemical engineers. However, the Greek letter eta is used by chemists, physicists
Viscous
–
Pitch has a viscosity approximately 230 billion (2.3 × 10 11) times that of water.
Viscous
–
A simulation of substances with different viscosities. The substance above has lower viscosity than the substance below
Viscous
–
Example of the viscosity of milk and water. Liquids with higher viscosities make smaller splashes when poured at the same velocity.
Viscous
–
Honey being drizzled.
23.
Soda bread
–
Soda bread is a variety of quick bread traditionally made in a variety of cuisines in which sodium bicarbonate is used as a leavening agent instead of the traditional yeast. The ingredients of traditional soda bread are flour, bread soda, salt, the buttermilk in the dough contains lactic acid, which reacts with the baking soda to form tiny bubbles of carbon dioxide. Other ingredients can be added such as butter, egg, raisins, an advantage of quick breads is their ability to be prepared quickly and reliably, without requiring the time-consuming skilled labor and temperature control needed for traditional yeast breads. In the US, soda breads were first publicised by Amelia Simmons as a quick and cheap method of making in her book American Cookery. By 1824, The Virginia Housewife by Mary Randolph was published containing a recipe for Soda Cake, in Europe, soda breads began to appear in the mid-19th century when bicarbonate of soda first became available for use as a raising agent. Breads, griddle cakes and scones with bicarbonate of soda, plus cream of tartar or tartaric acid became popular in Austria, Britain, traditional soda bread, eaten in Serbian cuisine, also uses bicarbonate of soda, particularly the traditional česnica, a soda bread made at Christmas. In Ireland, the flour is made from soft wheat, so soda bread is best made with a cake or pastry flour. In some recipes, the buttermilk is replaced by live yogurt or even stout, because the leavening action starts immediately, bakers recommend the minimum amount of mixing of the ingredients before baking, the dough should not be kneaded. Various forms of bread are popular throughout Ireland. Soda breads are made using wholemeal, white flour, or both, in Ulster, the wholemeal variety is usually known as wheaten bread and is normally sweetened, while the term soda bread is restricted to the white savoury form. In the southern provinces of Ireland, the variety is usually known as brown bread and is almost identical to the Ulster wheaten. In some parts of Fermanagh, the white form of the bread is described as fadge. The griddle cakes, griddle bread take a more rounded shape and have a cut in the top to allow the bread to expand. The griddle cake or farl is a flattened type of bread. It is cooked on a griddle, allowing it to take a flat shape. The soda farl is one of the elements of the Ulster fry. Bannocks are flat cakes of barley or oatmeal dough formed into a round or oval shape, the most authentic versions are unleavened, but from the early 19th century bannocks have been made using baking powder, or a combination of baking soda and buttermilk or clabbered milk. Before the 19th century, bannocks were cooked on a bannock stone, several varieties of bannock include Selkirk bannocks, beremeal bannocks, Michaelmas bannock, Yetholm bannock, and Yule bannock
Soda bread
–
A soda
farl; made by cutting a flattened round of dough into four pieces, then baking.
Soda bread
–
Whole wheat soda bread (known as wheaten bread in parts of
Ireland)
Soda bread
–
Home-made Irish brown soda bread
Soda bread
–
Members of a Serbian family break soda bread [
citation needed] or
česnica at a Christmas dinner
24.
Leavening agent
–
A leaven /ˈlɛvən/, often called a leavening agent /ˈlɛvənɪŋ/, is any one of a number of substances used in doughs and batters that cause a foaming action that lightens and softens. An alternative or supplement to leavening agents is an action by which air is incorporated. Leavening agents can be biological or synthetic chemical compounds, the gas produced is often carbon dioxide, or occasionally hydrogen, or another. When a dough or batter is mixed, the starch in the flour, then the starch gelatinizes and sets, leaving gas bubbles that remain. Most are based on a combination of acid and a salt of bicarbonate, after they act, these compounds leave behind a chemical salt. Chemical leavens are used in breads and cakes, as well as cookies. Chemical leavening were publicized by Amelia Simmons in her American Cookery, published in 1796 and these are generally referred to as baking powders. Sour milk and carbonates were used in the 1800s, the breakthrough in chemical leavening agents occurred in the 1930s with the introduction of monocalcium phosphates. Other leavening agents developed include sodium sulfate, disodium pyrophosphate. These compounds combine with sodium bicarbonate to give carbon dioxide in a predictable manner, steam and air are used as leavening agents when they expand upon heating. To take advantage of this style of leavening, the baking must be done at high temperatures to flash the water to steam. This effect is used in popovers, Yorkshire puddings. Nitrous oxide is used as a propellant in aerosol whip cream cans, large densities of N2O are dissolved in cream at high pressure. When expelled from the can, the nitrous oxide escapes emulsion instantly, creaming is the process of beating sugar crystals and solid fat together in a mixer. This integrates tiny air bubbles into the mixture, since the sugar crystals physically cut through the structure of the fat, creamed mixtures are usually further leavened by a chemical leaven like baking soda. This is often used in cookies, using a whisk on certain liquids, notably cream or egg whites, can also create foams through mechanical action. This is the method employed in the making of sponge cakes, the process has nevertheless been adapted by industrial bakers in other parts of the world. Aerated Bread Company, bakeries started in 1862 in the UK that made carbon dioxide leavened bread Baking powder Chametz Unleavened bread Matz, S. Bakery Technology and Engineering, wikibooks Cookbook has a recipe/module on Leavening agent
Leavening agent
–
Types
25.
Marination
–
Marination is the process of soaking foods in a seasoned, often acidic, liquid before cooking. The origin of the word alludes to the use of brine in the pickling process, the liquid in question, the marinade, can be either acidic or enzymatic. In addition to ingredients, a marinade often contains oils, herbs. It is commonly used to flavor foods and to tenderize tougher cuts of meat, the process may last seconds or days. Different marinades are used in different cuisines, for example, in Indian cuisine the marinade is usually prepared with a mixture of spices. In meats, the causes the tissue to break down. A good marinade has a balance of acid, oil, if raw marinated meat is frozen, the marinade can break down the surface and turn the outer layer mushy. Often confused with marinating, macerating is a form of food preparation. Raw pork, seafood, beef and poultry may contain harmful bacteria which may contaminate the marinade, marinating should be done in the refrigerator to inhibit bacterial growth. Used marinade should not be made into a sauce unless rendered safe by boiling directly before use, otherwise, the container used for marinating should be glass or food safe plastic. Metal, including pottery glazes which can lead, reacts with the acid in the marinade
Marination
–
Chicken in marinade
Marination
–
Beef marinating for a Korean barbecue dish
Marination
–
Poultry and game
Marination
26.
Chicken (food)
–
Chicken is the most common type of poultry in the world. In developed countries, chickens are usually subject to intensive farming methods, the modern chicken is a descendant of red junglefowl hybrids along with the grey junglefowl first raised thousands of years ago in the northern parts of the Indian subcontinent. Chicken as a meat has been depicted in Babylonian carvings from around 600 BC, Chicken was one of the most common meats available in the Middle Ages. It was eaten over most of the Eastern hemisphere and a number of different kinds of such as capons, pullets. It was one of the ingredients in the so-called white dish. In the United States in the 1800s, chicken was more expensive than other meats, Chicken consumption in the United States increased during World War II due to a shortage of beef and pork. In Europe, consumption of chicken overtook that of beef and veal in 1996, modern varieties of chicken such as the Cornish Cross, are bred specifically for meat production, with an emphasis placed on the ratio of feed to meat produced by the animal. The most common breeds of chicken consumed in the US are Cornish, chickens raised specifically for food are called broilers. In the United States, broilers are typically butchered at a young age, modern Cornish Cross hybrids, for example, are butchered as early as 8 weeks for fryers and 12 weeks for roasting birds. Capons produce more and fattier meat, for this reason, they are considered a delicacy and were particularly popular in the Middle Ages. Main Breast, These are white meat and are relatively dry, leg, Comprises two segments, The drumstick, this is dark meat and is the lower part of the leg, the thigh, also dark meat, this is the upper part of the leg. Wing, Often served as a meal or bar food. Buffalo wings are a typical example, Comprises three segments, the drumette, shaped like a small drumstick, the middle flat segment, containing two bones, and the tip, sometimes discarded. Other Chicken feet, These contain relatively little meat, and are mainly for the skin. Although considered exotic in Western cuisine, the feet are common fare in other cuisines, especially in the Caribbean, giblets, organs such as the heart, gizzards, and liver may be included inside a butchered chicken or sold separately. Head, Considered a delicacy in China, the head is split down the middle, kidneys, Normally left in when a broiler carcass is processed, they are found in deep pockets on each side of the vertebral column. Neck, This is served in various Asian dishes and it is stuffed to make helzel among Ashkenazi Jews. Oysters, Located on the back, near the thigh, these small, pygostyle and testicles, These are commonly eaten in East Asia and some parts of South East Asia
Chicken (food)
–
Oven-roasted rosemary and lemon chicken
Chicken (food)
–
Chicken fry
Chicken (food)
–
Chicken in a public market
Chicken (food)
–
A poussin, or juvenile chicken
27.
Pork
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Pork is the culinary name for meat from the domestic pig. It is the most commonly consumed meat worldwide, with evidence of pig husbandry dating back to 5000 BC, Pork is eaten both freshly cooked and preserved. Curing extends the life of the pork products. Ham, smoked pork, gammon, bacon and sausage are examples of preserved pork, charcuterie is the branch of cooking devoted to prepared meat products, many from pork. Pork is the most popular meat in East and Southeast Asia and it is highly prized in Asian cuisines for its fat content and pleasant texture. Consumption of pork is forbidden by Jewish and Muslim dietary law, the sale of pork is illegal or severely restricted in Israel and in certain Muslim countries, particularly those where sharia law is part of their constitution. The pig is one of the oldest forms of livestock, having been domesticated as early as 5000 BC and it is believed to have been domesticated either in the Near East or in China from the wild boar. The adaptable nature and omnivorous diet of this creature allowed early humans to domesticate it much earlier than other forms of livestock. Pigs were mostly used for food, but people also used their hides for shields and shoes, their bones for tools and weapons, and their bristles for brushes. Charcuterie is the branch of cooking devoted to prepared meat products such as bacon, ham, sausage, terrines, galantines, pâtés, and confit, primarily from pork. Originally intended as a way to preserve meats before the advent of refrigeration, in 15th century France, local guilds regulated tradesmen in the food production industry in each city. The guilds that produced charcuterie were those of the charcutiers, the members of this guild produced a traditional range of cooked or salted and dried meats, which varied, sometimes distinctively, from region to region. The only raw meat the charcutiers were allowed to sell was unrendered lard, the charcutier prepared numerous items, including pâtés, rillettes, sausages, bacon, trotters, and head cheese. Due to the nature of the meat in Western culinary history. The year-round availability of meat and fruits has not diminished the popularity of this combination on Western plates, Pork is the most widely eaten meat in the world, accounting for about 38% of meat production worldwide. Consumption varies widely from place to place, the meat is taboo to eat in the Middle East and most of the Muslim world because of Jewish kosher and Islamic Halal dietary restrictions. But pork is widely consumed in East and Southeast Asia, Europe, Sub-Saharan Africa, as the result, large numbers of pork recipes are developed throughout the world. Feijoada for example, the dish of Brazil, is traditionally prepared with pork trimmings, ears, tail
Pork
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Pork belly cut, shows layers of muscle and fats
Pork
Pork
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Slow-roasting pig on a
rotisserie
Pork
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Pork being prepared in
France during the mid-19th century
28.
Churning (butter)
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Churning is the process of shaking up cream to make butter, and various forms of butter churn have been used for the purpose. In Europe from the Middle Ages until the Industrial Revolution, this was generally as simple as a barrel with a plunger in it, afterward, mechanical means of churning were usually substituted and are considered to be far better. Butter is essentially the fat of milk and it is usually made from sweet cream. In the USA, Ireland, the UK and the Nordic countries, unsalted butters are most commonly used in the rest of Europe. However, it can also be made from acidulated or bacteriologically soured cream, well into the 19th century butter was still made from cream that had been allowed to stand and sour naturally. The cream was then skimmed from the top of the milk, buttermaking was done by hand in butter churns. The natural souring process is, however, a sensitive one. The commercial cream separator was introduced at the end of the 19th century, changing whole milk to butter is a process of transforming a fat-in-water emulsion to a water-in-fat emulsion. Whole milk is an emulsion of tiny fat globules surrounded by lipoprotein membranes that keep the fat globules separate from one another. Butter is made from cream that has separated from whole milk and then cooled. However, making good butter also depends upon factors, such as the fat content of the cream. The process can be summarized in 3 steps, Churning physically agitates the cream until it ruptures the fragile membranes surrounding the milk fat, once broken, the fat droplets can join with each other and form clumps of fat. As churning continues, larger clusters of fat collect until they begin to form a network with the air bubbles that are generated by the churning, as the fat clumps increase in size, there are also fewer to enclose the air cells. So the bubbles pop, run together, and the foam begins to leak, the cream separates into butter and buttermilk. The buttermilk is drained off, and the butter is kneaded to form a network of fat crystals that becomes the continuous phase, or dispersion medium. Working the butter also creates its desired smoothness, eventually, the water droplets become so finely dispersed in the fat that butter’s texture seems dry. Then it is frozen into cubes, then melted, then again into bigger chunks to sell. Butter churns have varied over time as technology and materials have changed, Butter was first made by placing the cream in a container made from animal material and shaking until the milk has broken down into butter
Churning (butter)
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Farmer girl churning butter
Churning (butter)
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Butter churner pot
Churning (butter)
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A barrel-type butter churn.
Churning (butter)
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Churn with plunger Ethnographic Museum of Western Liguria, Cervo, Italy
29.
Pasteurized
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Pasteurization or pasteurisation is a process that kills microbes in food and drink, such as milk, juice, canned food, and others. It was invented by French scientist Louis Pasteur during the nineteenth century, in 1864 Pasteur discovered that heating beer and wine was enough to kill most of the bacteria that caused spoilage, preventing these beverages from turning sour. The process achieves this by eliminating pathogenic microbes and lowering microbial numbers to prolong the quality of the beverage, today, pasteurization is used widely in the dairy industry and other food processing industries to achieve food preservation and food safety. Unlike sterilization, pasteurization is not intended to kill all microorganisms in the food, instead, it aims to reduce the number of viable pathogens so they are unlikely to cause disease. Commercial-scale sterilization of food is not common because it affects the taste. Certain foods, such as products, may be superheated to ensure pathogenic microbes are destroyed. The process of heating wine for preservation purposes has been known in China since 1117, much later, in 1768, an Italian priest and scientist Lazzaro Spallanzani proved experimentally that heat killed bacteria, and that they do not reappear if the product is hermetically sealed. He placed the food in glass jars, sealed them with cork and sealing wax, in that same year, the French military offered a cash prize of 12,000 francs for a new method to preserve food. After some 14 or 15 years of experimenting, Appert submitted his invention and won the prize in January 1810, later that year, Appert published LArt de conserver les substances animales et végétales. This was the first cookbook of its kind on modern food preservation methods, la Maison Appert, in the town of Massy, near Paris, became the first food-bottling factory in the world, preserving a variety of food in sealed bottles. Apperts method was to fill thick, large-mouthed glass bottles with produce of every description, ranging from beef and fowl to eggs, milk and his greatest success for publicity was an entire sheep. He left air space at the top of the bottle, the bottle was then wrapped in canvas to protect it, while it was dunked into boiling water and then boiled for as much time as Appert deemed appropriate for cooking the contents thoroughly. Appert patented his method, sometimes called appertisation, in his honor, Apperts method was so simple and workable that it quickly became widespread. In 1810, British inventor and merchant Peter Durand, also of French origin, patented his own method, in 1812, Englishmen Bryan Donkin and John Hall purchased both patents and began producing preserves. Just a decade later, Apperts method of canning had made its way to America, Apperts preservation by boiling involved heating the food to an unnecessarily high temperature, and for an unnecessarily long time, which could destroy some of the flavor of the preserved food. A less aggressive method was developed by the French chemist Louis Pasteur during an 1864 summer holiday in Arbois, in honour of Pasteur, the process became known as pasteurization. Pasteurization was originally used as a way of preventing wine and beer from souring, in the United States in the 1870s, it was common for milk to contain substances intended to mask spoilage before milk was regulated. Milk is an excellent medium for growth, and when stored at ambient temperature bacteria
Pasteurized
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Cream pasteurizing and cooling coils at Murgon Butter Factory, 1939
Pasteurized
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400 lbs of milk in cheese vat
30.
Homogenization (chemistry)
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Homogenization or homogenisation is any of several processes used to make a mixture of two mutually non-soluble liquids the same throughout. This is achieved by turning one of the liquids into a state consisting of small particles distributed uniformly throughout the other liquid. A typical example is the homogenization of milk, where the fat globules are reduced in size. Homogenization is the process of converting two immiscible liquids into an emulsion, homogenization is achieved by a mechanical device called a homogenizer. One of the oldest applications of homogenization is in milk processing and it is normally preceded by standardization. The fat in milk normally separates from the water and collects at the top, homogenization breaks the fat into smaller sizes so it no longer separates, allowing the sale of non-separating milk at any fat specification. Milk homogenization is accomplished by mixing massive amounts of harvested milk to create a constant, yet another method of homogenization uses extruders, hammermills, or colloid mills to mill solids. Milk homogenization is a tool of the milk food industry to prevent creating various levels of flavor. Another application of homogenization is in soft drinks like cola products, the reactant mixture is rendered to intense homogenization, to as much as 35,000 psi, so that various constituents do not separate out during storage or distribution. Ultrasonic homogenizer Shake well French pressure cell press Homogenizer Cell disruption Explanation of the technology along with theories on how the mechanism actually works
Homogenization (chemistry)
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Homogenizing valve, a method to homogenize at high pressure.
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