Redox is a chemical reaction in which the oxidation states of atoms are changed. Any such reaction involves both a reduction process and a complementary oxidation process, two key concepts involved with electron transfer processes. Redox reactions include all chemical reactions; the chemical species from which the electron is stripped is said to have been oxidized, while the chemical species to which the electron is added is said to have been reduced. It can be explained in simple terms: Oxidation is the loss of electrons or an increase in oxidation state by a molecule, atom, or ion. Reduction is a decrease in oxidation state by a molecule, atom, or ion; as an example, during the combustion of wood, oxygen from the air is reduced, gaining electrons from carbon, oxidized. Although oxidation reactions are associated with the formation of oxides from oxygen molecules, oxygen is not included in such reactions, as other chemical species can serve the same function; the reaction can occur slowly, as with the formation of rust, or more in the case of fire.
There are simple redox processes, such as the oxidation of carbon to yield carbon dioxide or the reduction of carbon by hydrogen to yield methane, more complex processes such as the oxidation of glucose in the human body. "Redox" is a portmanteau of the words "reduction" and "oxidation". The word oxidation implied reaction with oxygen to form an oxide, since dioxygen was the first recognized oxidizing agent; the term was expanded to encompass oxygen-like substances that accomplished parallel chemical reactions. The meaning was generalized to include all processes involving loss of electrons; the word reduction referred to the loss in weight upon heating a metallic ore such as a metal oxide to extract the metal. In other words, ore was "reduced" to metal. Antoine Lavoisier showed. Scientists realized that the metal atom gains electrons in this process; the meaning of reduction became generalized to include all processes involving a gain of electrons. Though "reduction" seems counter-intuitive when speaking of the gain of electrons, it might help to think of reduction as the loss of oxygen, its historical meaning.
Since electrons are negatively charged, it is helpful to think of this as reduction in electrical charge. The electrochemist John Bockris has used the words electronation and deelectronation to describe reduction and oxidation processes when they occur at electrodes; these words are analogous to protonation and deprotonation, but they have not been adopted by chemists worldwide. The term "hydrogenation" could be used instead of reduction, since hydrogen is the reducing agent in a large number of reactions in organic chemistry and biochemistry. But, unlike oxidation, generalized beyond its root element, hydrogenation has maintained its specific connection to reactions that add hydrogen to another substance; the word "redox" was first used in 1928. The processes of oxidation and reduction occur and cannot happen independently of one another, similar to the acid–base reaction; the oxidation alone and the reduction alone are each called a half-reaction, because two half-reactions always occur together to form a whole reaction.
When writing half-reactions, the gained or lost electrons are included explicitly in order that the half-reaction be balanced with respect to electric charge. Though sufficient for many purposes, these general descriptions are not correct. Although oxidation and reduction properly refer to a change in oxidation state — the actual transfer of electrons may never occur; the oxidation state of an atom is the fictitious charge that an atom would have if all bonds between atoms of different elements were 100% ionic. Thus, oxidation is best defined as an increase in oxidation state, reduction as a decrease in oxidation state. In practice, the transfer of electrons will always cause a change in oxidation state, but there are many reactions that are classed as "redox" though no electron transfer occurs. In redox processes, the reductant transfers electrons to the oxidant. Thus, in the reaction, the reductant or reducing agent loses electrons and is oxidized, the oxidant or oxidizing agent gains electrons and is reduced.
The pair of an oxidizing and reducing agent that are involved in a particular reaction is called a redox pair. A redox couple is a reducing species and its corresponding oxidizing form, e.g. Fe2+/Fe3+ Substances that have the ability to oxidize other substances are said to be oxidative or oxidizing and are known as oxidizing agents, oxidants, or oxidizers; that is, the oxidant removes electrons from another substance, is thus itself reduced. And, because it "accepts" electrons, the oxidizing agent is called an electron acceptor. Oxygen is the quintessential oxidizer. Oxidants are chemical substances with elements in high oxidation states, or else electronegative elements that can gain extra electrons by oxidizing another substance. Substances that have the ability to reduce other substances are said to be reductive or reducing and are known as
Mother of vinegar
Mother of vinegar is a substance composed of a form of cellulose and acetic acid bacteria that develops on fermenting alcoholic liquids, which turns alcohol into acetic acid with the help of oxygen from the air. It is added to cider, or other alcoholic liquids to produce vinegar. Mother of vinegar is known as Mycoderma aceti, a New Latin expression, from the Greek μύκης plus δέρμα, the Latin aceti; the naming of the bacteria has been rather fluid due to its original identification near the inception of bacteriology. The preferred naming is Acetobacter aceti. Mother of vinegar can form in store-bought vinegar if there is some non-fermented sugar and/or alcohol contained in the vinegar; this is more common in unpasteurized vinegar. While not appetizing in appearance, mother of vinegar is harmless and the surrounding vinegar does not have to be discarded because of it, it can be filtered out using a coffee filter, used to start a bottle of vinegar, or ignored. Acetobacter SCOBY
Vinaigrette is made by mixing an oil with something acidic such as vinegar or lemon juice. The mixture herbs and/or spices, it is used most as a salad dressing, but can be used as a marinade. Traditionally, a vinaigrette consists of 3 parts oil and 1 part vinegar mixed into a stable emulsion, but the term is applied to mixtures with different proportions and to unstable emulsions which last only a short time before separating into layered oil and vinegar phases. "Vinaigrette" is the diminutive form of the French word "vinaigre". It was known as "french dressing" in the 19th century. In general, vinaigrette consists of 3 parts of oil to 1 part of vinegar whisked into an emulsion. Salt and pepper are added. Herbs and shallots are added when it is used for cooked vegetables or grains. Sometimes mustard is used as an emulsifier; some vinaigrettes use a small amount such as maple syrup. Vinaigrette may be made with a variety of vinegars. Olive oil and neutral vegetable oils such as soybean oil, canola oil, corn oil, sunflower oil, safflower oil, peanut oil, or grape seed oil are all common.
In northern France, it may be made with walnut oil and cider vinegar and used for Belgian endive salad. In the United States, vinaigrettes may include a wide range of additions such as lemon, raspberries, sugar and cherries. Cheese, parmesan or blue cheese being the most common, may be added. Commercially bottled versions may include emulsifiers such as lecithin. In Southeast Asia, rice bran oil and white vinegar are used as a foundation with fresh herbs, chili peppers and lime juice. In China and Japan, a similar salad dressing is made with sesame oil/sesame rice vinegar. In north China, sometimes mustard is added to enhance the texture of the sauce. Different vinegars, such as raspberry, create different flavors, lemon juice or alcohol, such as sherry, may be used instead of vinegar. Balsamic vinaigrette is made by adding a small amount of balsamic vinegar to a simple vinaigrette of olive oil and wine vinegar. In Brazil, a mix between olive oil, alcohol vinegar, tomatoes and sometimes bell peppers is called vinagrete.
It is served on Brazilian churrasco on Sundays. In classical French cuisine, a vinaigrette is used as a salad dressing and, as a cold sauce, accompanies cold artichokes and leek. Vinaigrette gave its name to a salad in Russian cuisine called vinegret. Italian dressing
Nipa palm vinegar
Nipa palm vinegar known as sukang sasa or sukang nipa, is a traditional Filipino vinegar made from the sap of the nipa palm. It is one of the four main types of vinegars in the Philippines, along with coconut vinegar, cane vinegar, kaong palm vinegar, it is sold under the generic label of "palm vinegar". Nipa palm vinegar is listed in the Ark of Taste international catalogue of endangered heritage foods by the Slow Food movement. Along with other traditional vinegars in the Philippines, it is threatened by the increasing use of industrially-produced vinegars. Nipa palm vinegar is known as sukang sasa or sukang nipa in native languages in the Philippines. Both nipa and sasa are the native names of the nipa palm in Tagalog, it is known as sukang Paombong after the town of Paombong, Bulacan where it is a traditional industry. The name of the town itself is from Tagalog bumbóng, the main equipment in gathering nipa sap before plastic or glass containers became prevalent, it is sometimes known as sukang tubâ, from tubâ, the general term for palm toddy produced from various palm trees in the Philippines, including coconut, buri palm, kaong palm.
Nipa palm vinegar is gathered from mature nipa palms that grow in muddy soil beside brackish rivers and estuaries. The stalk of the nipa palm is cut and a container is placed underneath to collect sap; the harvesters traditionally shake or kick the base of the leaves as they collect the containers to induce the sap the flow. They may sometimes bend the stalk, they are collected though it may take longer during dry seasons. The collected sap are placed in large earthen jars traditionally used for fermentation; the sap relies on wild yeast to turn the sugars into ethanol. This turns the sap into a traditional palm toddy called tubâ. Leaving it to ferment further, allows Acetobacter from the air to oxidise the ethanol into acetic acid, it is harvested once the level of acidity reaches five percent. The length of time it takes to produce nipa palm vinegar ranges from two to three weeks, though it is faster if a starter culture of yeast is used. Nipa palm sap has a high sugar content, containing 15 to 22% sugar.
This makes nipa palm vinegar sweeter and less sharp than coconut vinegar. It is slightly salty due to sodium content of the sap from the habitat of nipa palms; the vinegar when newly made is cloudy white. Due to the high iron content of the sap, the vinegar tends to turn orange to dark red as it ages; the vinegar contains calcium and potassium. The sourness of the vinegar depends on; the production of nipa palm vinegar is associated with the town of Paombong in the province of Bulacan, where it is a prevalent local industry. However, it is produced in other parts of the Philippines; the production of nipa palm vinegar is labor-intensive and it is predominantly only sold in local markets. In roadside stands or by hawkers along with tubâ palm wines. Along with other traditional vinegars in the Philippines, which have problems penetrating the national market, it is threatened by the increasing use of industrially-produced vinegars. Many nipa farmers are converting their nipa plantations into fish farms.
It is listed in the Ark of Taste international catalogue of endangered heritage foods by the Slow Food movement. Vinegar is one of the most important ingredients in traditional Filipino cuisine. Like other types of vinegars, nipa palm vinegar is used in dipping sauces, it may be sold spiced with ginger and chili peppers. It can be used in salad dressings as well as an ingredient in various dishes like paksiw and atchara pickles. Kaong palm vinegar Basi Tapuy
Gram-negative bacteria are bacteria that do not retain the crystal violet stain used in the gram-staining method of bacterial differentiation. They are characterized by their cell envelopes, which are composed of a thin peptidoglycan cell wall sandwiched between an inner cytoplasmic cell membrane and a bacterial outer membrane. Gram-negative bacteria are found everywhere, in all environments on Earth that support life; the gram-negative bacteria include the model organism Escherichia coli, as well as many pathogenic bacteria, such as Pseudomonas aeruginosa, Neisseria gonorrhoeae, Chlamydia trachomatis, Yersinia pestis. They are an important medical challenge, as their outer membrane protects them from many antibiotics. Additionally, the outer leaflet of this membrane comprises a complex lipopolysaccharide whose lipid A component can cause a toxic reaction when these bacteria are lysed by immune cells; this toxic reaction can include fever, an increased respiratory rate, low blood pressure — a life-threatening condition known as septic shock.
Several classes of antibiotics have been designed to target gram-negative bacteria, including aminopenicillins, ureidopenicillins, beta-lactam-betalactamase combinations, Folate antagonists and carbapenems. Many of these antibiotics cover gram positive organisms; the drugs that target gram negative organisms include aminoglycosides and Ciprofloxacin. Gram-negative bacteria display these characteristics: An inner cell membrane is present A thin peptidoglycan layer is present Has outer membrane containing lipopolysaccharides in its outer leaflet and phospholipids in the inner leaflet Porins exist in the outer membrane, which act like pores for particular molecules Between the outer membrane and the cytoplasmic membrane there is a space filled with a concentrated gel-like substance called periplasm The S-layer is directly attached to the outer membrane rather than to the peptidoglycan If present, flagella have four supporting rings instead of two Teichoic acids or lipoteichoic acids are absent Lipoproteins are attached to the polysaccharide backbone Some contain Braun's lipoprotein, which serves as a link between the outer membrane and the peptidoglycan chain by a covalent bond Most, with few exceptions, do not form spores Along with cell shape, gram-staining is a rapid diagnostic tool and once was used to group species at the subdivision of Bacteria.
The kingdom Monera was divided into four divisions based on gram-staining: Firmacutes, Gracillicutes and Mendocutes. Since 1987, the monophyly of the gram-negative bacteria has been disproven with molecular studies; however some authors, such as Cavalier-Smith still treat them as a monophyletic taxon and refer to the group as a subkingdom "Negibacteria". Bacteria are traditionally classified based on their gram-staining response into the gram-positive and gram-negative groups, it was traditionally thought that the groups represent lineages, i.e. the extra membrane only evoved once, such that gram-negative bacteria are more related to one another than to any gram-positive bacteria. While this is true, the classification system breaks down in some cases, with lineage groupings not matching the staining result. Thus, gram-staining cannot be reliably used to assess familial relationships of bacteria. Staining gives reliable information about the composition of the cell membrane, distinguishing between the presence or absence of an outer lipid membrane.
Of these two structurally distinct groups of prokaryotic organisms, monoderm prokaryotes are thought to be ancestral. Based upon a number of different observations including that the gram-positive bacteria are the major reactors to antibiotics and that gram-negative bacteria are, in general, resistant to them, it has been proposed that the outer cell membrane in gram-negative bacteria evolved as a protective mechanism against antibiotic selection pressure; some bacteria such as Deinococcus, which stain gram-positive due to the presence of a thick peptidoglycan layer, but possess an outer cell membrane are suggested as intermediates in the transition between monoderm and diderm bacteria. The diderm bacteria can be further differentiated between simple diderms lacking lipopolysaccharide; the conventional LPS-diderm group of gram-negative bacteria are uniquely identified by a few conserved signature indel in the HSP60 protein. In addition, a number of bacterial taxa that are either part of the phylum Firmicutes or branches in its proximity are found to possess a diderm cell structure.
They lack the GroEL signature. The presence of this CSI in all se
Sherry vinegar is a gourmet wine vinegar made from Sherry. It is produced in the Spanish province of Cádiz and inside the triangular area between the city of Jerez de la Frontera and towns of Sanlúcar de Barrameda and El Puerto de Santa María, known as the "sherry triangle". In the USA, to be called vinagre de Jerez, by law the Sherry vinegar must undergo ageing in American oak for a minimum of six months, can only be aged within the "sherry triangle" and must have a minimum of 7 degrees acidity. Most Sherry vinegars are aged using the same solera system as Brandy de Jerez; the production and quality of sherry vinegar is monitored and controlled by the Consejo Regulador and Sherry vinegar has its own Denominación de Origen, protected by Spanish and EU law. The only other vinegars with similar protected designation of origin are "Aceto Balsamico Tradizionale" from Modena and Reggio Emilia in Italy and "Condado de Huelva" in Spain. Vinagre de Jerez has a minimum of 6 months aging in wood. Vinagre de Jerez Reserva has a minimum of 2 years aging in wood.
Vinagre de Jerez Gran Reserva is a new category with a minimum of 10 years aging in wood. The style of sherry vinegar depends on the grape variety used to produce the wine it is made from. Palomino: Most sherry vinegar is produced from wines which were made from the Palomino grape; the wine being used to produce the vinegar can be young wine or can be a wine which has aged. Al Pedro Ximénez: Wines produced from the Pedro Ximénez grape are sweet very sweet, the vinegars produced from these wines are sweeter than other sherry vinegars or at the least have a sweet raisin nose. Sometimes Palomino vinegars are sweetened with the addition of a small amount of Pedro Ximénez wine. Moscatel: Small amounts of sherry vinegar are produced from the Moscatel grape. Sherry vinegar is used extensively in both French cuisine. In 2008 France was the largest market for sherry vinegar. Vinaigrette made from sherry vinegar is flavourful compared to vinaigrette made from standard wine vinegar and matches well with many foods.
In Jerez de la Frontera a traditional dish is "Riñones al Jerez": lambs kidneys with a sauce made from sherry wine and sherry vinegar. The best sherry vinegars have a deep, complex flavour and enhance the flavours in soups, sauces and dressings. Vinegar from sherry has been around since sherry was first produced around Jerez. In the sherry bodegas wines which had undergone acetic fermentation and turned to vinegar were considered failures, however since the 1950s winemakers started to view sherry vinegar as a product in its own right and now encourage it, they began to age their vinegars in the same way as their wines and brandies. Barrels containing vinegar are always removed from the wine bodega, this is to prevent other barrels of wine turning to vinegar. Any barrels which have contained vinegar cannot be used to store wine again due to the risk of acetic fermentation. In the past the vinegar was sold at the bodega door; some barrels were stored separately and forgotten about. These vinegars, many over 50 years old, are now being re-discovered.
"Sherry" by Julian Jeffs Revised Edition 2004 ISBN 1-84000-923-3 "Sherry. The Noble Wine" by Manuel González Gordon and revised by John Doxat 1990 ISBN 1-870948-40-8 Consejo Regulador ORDEN de 22 de febrero de 2000, por la que se aprueba el Reglamento de la Denominación de Origen Vinagre de Jerez Resolución de 24 de marzo de 2009, de la Dirección General de Industria y Mercados Alimentarios, por la que se concede la protección nacional transitoria a la Denominación de Origen Protegida "Vinagre de Jerez"
Traditional Balsamic Vinegar
Traditional Balsamic Vinegar is a type of balsamic vinegar produced in Modena and the wider Emilia Romagna region of Italy. Unlike inexpensive "Balsamic Vinegar of Modena", Traditional Balsamic Vinegar is produced from cooked grape must, aged at least 12 years, protected under the European Protected Designation of Origin system, fetching higher prices. Although the names are similar, TBV and the inexpensive imitation BVM are different. A comprehensive study of the original production procedures, the aging conditions, the sensory profile is not available; this and the few and often-confusing documents make the reconstruction of the true history of TBV a challenge. The term balsamico derives from the Latin word “balsamum” and from the Greek word “βάλσαμον”, in the sense of "restorative" or "curative"; the art of cooking the must of grapes dates back to the ancient Romans: it was used both as a medicine and in the kitchen as a sweetener and condiment. The first accepted document referring to a precious vinegar produced in the area of Modena and Reggio Emilia is the poem written in the 12th century by the monk Donizo of Canossa, although the word "balsamic" is never mentioned.
The first testimonies speaking about "balsamic vinegar", as well as of recipes and making procedure, appear from the 19th century if little is known about the original recipes and related production practices. The adjective "balsamic" has been used to designate any kind of generically aromatic vinegar and products not just obtained from the fermentation of grape must alone; as far as the aging method is concerned, it is similar to the Solera system used in Spain after the Napoleonic Wars which spread abroad after the second half of the 19th century. The oldest and most detailed description of the method and techniques for the production of balsamic vinegar is reported in a letter written in 1862 by Francesco Aggazzotti to his friend Pio Fabriani, in which he describes the secrets of his family's "acetaia". TBV is produced in two different geographical areas of the Emilia Romagna Region so that two different designations were granted by the European Council, i.e. Traditional Balsamic Vinegar of Modena and Traditional Balsamico Vinegar of Reggio Emilia.
The two special vinegars are similar products as the overall making procedure is the same. The sensory profile of TBV is evaluated by hedonic judgment expressed through a numeric score; the sensory score achieved is used to rank TBV in different commercial classes. The specific regulations allow adding "Extra Vecchio" to the official designation when the product is aged for 25 years at least. However, under existing regulations, neither the definition of "aging" nor the methods for its objective evaluation are specified. TBV results as a blend of vinegars of different composition and age due to the traditional making procedure. An easy-to-use mathematical method for evaluating the actual residence time of TBV within each cask of the barrel set has been published; this method is an adequate tool helping aging certification. An easy-to-use spreadsheet of the theoretical model is available for download here. At present, independent agencies that state TBV authenticity of both the TBVM and TBVRE haven't adopted it or any analogous procedure as an evaluation system.
Making process of the TBV starts from freshly squeezed grape juice and finishes with sensory evaluation of the aged vinegar. From a technological perspective, basic steps are required, including cooking of the grape must, alcoholic fermentation by yeasts, acetic oxidation by acetic acid bacteria, slow aging within a barrel set. Cooking of the grape juice is carried out in open vessels directly heated by fire for 12 – 24 hours reducing the grape juice by about 50%; the production regulations require starting from a grape must with 15°Bx at least to reach at the end of cooking 30°Bx for TBVRE. It is possible to find cooked musts with sugar concentration beyond 50°Bx; the operation allows profound chemical and physical modifications affecting the end quality of TBV. Cooking stops all enzymatic browning reactions that occur inside fresh grape musts by polyphenol oxidase and progressively promotes grape must discoloration due to the heat-induced deactivation of proteins including browning enzymes.
In addition, cooking promotes nonenzymatic browning chemical reactions involving sugar conversion, formation of high molecular weight melanoidins and furanic compounds such as 5-hydroxymethylfurfural. Water vaporization induces the concentration of sugars, organic acids, polyphenols, resulting in the increase of density and refractive index, conversely, the lowering of water activity and pH value. Sugar fermentation and ethanol oxidation occur as a two-step biological transformation of the cooked must; the first requires the second aerobic conditions. The two biological conversions occur inside a dedicated vessel, called the badessa; the alcoholic fermentation is carried out by yeasts belonging to a plethora of genera. In the