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Syringol
Syringol is the organic compound with the formula HO(CH3O)2C6H3. The molecule is a phenol, with methoxy groups in the flanking (2 and 6) positions. It is the symmetrically dimethylated derivative of pyrogallol. It is a colorless solid, although typical samples are brown owing to air-oxidized impurities. Together with guaiacol, syringol and its derivatives are produced by the pyrolysis of lignin. Specifically, syringol is derived from the thermal decomposition of the sinapyl alcohol component. As such, syringol is an important component of wood smoke. Syringyl/guaiacyl ratio Lignin, comprising a major fraction of biomass, is sometimes classified according to the syringyl component. Pyrolysis of lignin derived from sinapyl alcohol affords syringol. The conversion involves replacement of the propenyl alcohol substituent of the sinapyl alcohol by hydrogen. A high syringyl (or S) content is indicative of lignin from angiosperms. In contrast, pyrolysis of lignin from gymn ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Smoking (food)
Smoking is the process of seasoning, flavoring, browning (partial cooking), browning, cooking, or food preservation, preserving food, particularly meat, fish and tea, by exposing it to smoke from burning or smoldering material, most often wood. In Europe, alder is the traditional smoking wood, but oak is more often used now, and beech to a lesser extent. In North America, hickory, mesquite, oak, pecan, alder, maple, and fruit tree woods, such as apple, cherry, and plum, are commonly used for smoking. Other biomass besides wood can also be employed, sometimes with the addition of flavoring ingredients. Chinese tea-smoking uses a mixture of uncooked rice, sugar, and tea, heated at the base of a wok. Some North American ham and bacon makers smoke their products over burning corncobs. Peat is burned to dry and smoke the barley malt used to make Scotch whisky and some beers. In New Zealand, sawdust from the native Leptospermum scoparium, manuka (tea tree) is commonly used for hot-Sm ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Canolol
Canolol is a phenolic compound found in crude canola oil. It is produced by decarboxylation of sinapic acid during canola seed roasting. See also *Phenolic content in wine *Syringaldehyde *Syringol *Syringic acid * Acetosyringone *Sinapyl alcohol * Sinapaldehyde *Sinapinic acid Sinapinic acid, or sinapic acid (Sinapine - Origin: L. Sinapi, sinapis, mustard, Gr., cf. F. Sinapine.), is a small naturally occurring hydroxycinnamic acid. It is a member of the phenylpropanoid family. It is a commonly used matrix in MALDI mas ... * Sinapine References O-methylated natural phenols Vinyl compounds Vegetable oils {{phenol-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Guaiacol
Guaiacol () is an organic compound with the formula C6H4(OH)(OCH3). It is a phenolic compound containing a methoxy functional group. Guaiacol appears as a viscous colorless oil, although aged or impure samples are often yellowish. It occurs widely in nature and is a common product of the pyrolysis of wood. Occurrence Guaiacol is usually derived from guaiacum or wood creosote. There also appears to be a petrochemical route to it with great commercial use. It is produced by a variety of plants. It is also found in essential oils from celery seeds, tobacco leaves, orange leaves, and lemon peels. The pure substance is colorless, but samples become yellow upon exposure to air and light. The compound is present in wood smoke, resulting from the pyrolysis of lignin. The compound contributes to the flavor of many substances such as whiskey and roasted coffee. Preparation The compound was first isolated by Otto Unverdorben in 1826. Guaiacol is produced by methylation of ''o''-cat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Syringaldehyde
Syringaldehyde is an organic compound that occurs in trace amounts widely in nature. Some species of insects use syringaldehyde in their chemical communication systems. ''Scolytus multistriatus'' uses it as a signal to find a host tree during oviposition. Because it contains many functional groups, it can be classified in many ways - aromaticity, aromatic, aldehyde, phenol. It is a colorless solid (impure samples appear yellowish) that is soluble in ethanol, alcohol and polar organic solvents. Its refractive index is 1.53. Natural sources Syringaldehyde can be found naturally in the wood of spruce and maple trees. Syringaldehyde is also formed in oak barrels and extracted into whisky, which it gives spicy, smoky, hot and smoldering wood aromas. Preparation This compound may be prepared from syringol by the Duff reaction: : See also *Phenolic content in wine *Syringol *Syringic acid *Acetosyringone *Sinapyl alcohol *Sinapinic acid *Sinapaldehyde *Sinapine *Canolol {{Div ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lignin
Lignin is a class of complex organic polymers that form key structural materials in the support tissues of most plants. Lignins are particularly important in the formation of cell walls, especially in wood and bark, because they lend rigidity and do not rot easily. Chemically, lignins are polymers made by cross-linking phenolic precursors. History Lignin was first mentioned in 1813 by the Swiss botanist A. P. de Candolle, who described it as a fibrous, tasteless material, insoluble in water and alcohol but soluble in weak alkaline solutions, and which can be precipitated from solution using acid. He named the substance "lignine", which is derived from the Latin word '' lignum'', meaning wood. It is one of the most abundant organic polymers on Earth, exceeded only by cellulose and chitin. Lignin constitutes 30% of terrestrial non-fossil organic carbon on Earth, and 20 to 35% of the dry mass of wood. Lignin is present in red algae, which suggest that the common ancestor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acetosyringone
Acetosyringone is a phenolic natural product and a chemical compound related to acetophenone and 2,6-dimethoxyphenol. It was first described in relation to lignan/phenylpropanoid-type phytochemicals, with isolation from a variety of plant sources, in particular, in relation to wounding and other physiologic changes. Occurrence and biological role Historically, this substance has been best known for its involvement in plant-pathogen recognition, especially its role as a signal attracting and transforming unique, oncogenic bacteria in genus ''Agrobacterium''. The ''virA'' gene on the Ti plasmid of ''Agrobacterium tumefaciens'' and the Ri plasmid of '' Agrobacterium rhizogenes'' is used by these soil bacteria to infect plants, via its encoding for a receptor for acetosyringone and other phenolic phytochemicals exuded by plant wounds. This compound also allows higher transformation efficiency in plants, as shown in ''A. tumefaciens''-mediated transformation procedures, and so is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sinapaldehyde
Sinapaldehyde is an organic compound with the formula HO(CH3O)2C6H2CH=CHCHO. It is a derivative of cinnamaldehyde, featuring one hydroxy group and two methoxy groups as substituents. It is an intermediate in the formation of sinapyl alcohol, a lignol that is a major precursor to lignin. Biosynthetic role In sweetgum (''Liquidambar styraciflua''), sinapaldehyde arises in two steps from coniferyl aldehyde beginning with hydroxylation mediated by coniferyl aldehyde 5-hydroxylase. The diphenol is then methylated at the 5-OH by the action of caffeate ''O''-methyltransferase. Sinapaldehyde is reduced to the alcohol by the action of dehydrogenase enzymes. In ''Arabidopsis thaliana'', the enzyme dihydroflavonol 4-reductase uses NADP+ to reduce sinapaldehyde to sinapyl alcohol. It is found in '' Senra incana'' (Hibisceae). It is a low molecular weight phenol that is susceptible to extraction from cork stoppers into wine.Polyphenolic Composition of ''Quercus suber'' Cork from Differe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Syringic Acid
Syringic acid is a naturally occurring phenolic compound and dimethoxybenzene that is commonly found as a plant metabolite. Natural occurrence Syringic acid can be found in several plants including '' Ardisia elliptica'' and ''Schumannianthus dichotomus''. It is biosynthesized by the shikimic acid pathway in plants. Synthesis Syringic acid can be prepared by selectively hydrolyzing ( demethylating) eudesmic acid with 20% sulfuric acid. Presence in food Syringic acid can be found in several fruits including olives, dates, spices, pumpkin, grapes, acai palm, honey, red wine, among others. Its presence in the ancient Egyptian drink shedeh could confirm it was made out of grape, as syringic acid is released by the breakdown of the compound malvidin, also found in red wine. It is also found in vinegar. Applications Various studies have found syringic acid to have potentially useful properties such as anti-oxidant, anti-microbial, anti-inflammation, anti-cancer, a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pyrolysis Oil
Pyrolysis oil, sometimes also known as biocrude or bio-oil, is a synthetic fuel with few industrial applications and under investigation as substitute for petroleum. It is obtained by heating dried biomass without oxygen in a reactor at a temperature of about with subsequent cooling, separation from the aqueous phase and other processes. Pyrolysis oil is a kind of tar and normally contains levels of oxygen too high to be considered a pure hydrocarbon. This high oxygen content results in non-volatility, corrosiveness, partial miscibility with fossil fuels, thermal instability, and a tendency to polymerize when exposed to air. As such, it is distinctly different from petroleum products. Removing oxygen from bio-oil or nitrogen from algal bio-oil is known as upgrading. Standards There are few standards for pyrolysis oil because of few efforts to produce it. One is from ASTM. Feedstock decomposition Pyrolysis is a well established technique for decomposition of organic materia ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sinapinic Acid
Sinapinic acid, or sinapic acid (Sinapine - Origin: L. Sinapi, sinapis, mustard, Gr., cf. F. Sinapine.), is a small naturally occurring hydroxycinnamic acid. It is a member of the phenylpropanoid family. It is a commonly used matrix in MALDI mass spectrometry. It is a useful matrix for a wide variety of peptides and proteins. It serves well as a matrix for MALDI due to its ability to absorb laser radiation and to also donate protons (H+) to the analyte of interest. Sinapic acid can form dimers with itself (one structure) and ferulic acid (three different structures) in cereal cell walls and therefore may have a similar influence on cell-wall structure to that of the diferulic acids. Sinapine is an alkaloidal amine found in black mustard seeds. It is considered a choline ester of sinapinic acid. Natural occurrences Sinapinic acid can be found in wine, vinegar, and black plums. Metabolism Sinapate 1-glucosyltransferase is an enzyme that uses UDP-glucose and sinapate to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phenolic Content In Wine
Phenolic compounds— natural phenol and polyphenols—occur naturally in wine. These include a large group of several hundred chemical compounds that affect the taste, color and mouthfeel of wine. These compounds include phenolic acids, stilbenoids, flavonols, dihydroflavonols, anthocyanins, flavanol monomers ( catechins) and flavanol polymers (proanthocyanidins). This large group of natural phenols can be broadly separated into two categories, flavonoids and non-flavonoids. Flavonoids include the anthocyanins and tannins which contribute to the color and mouthfeel of the wine. The non-flavonoids include the stilbenoids such as resveratrol and phenolic acids such as benzoic, caffeic and cinnamic acids. Origin of the phenolic compounds The natural phenols are not evenly distributed within the grape. Phenolic acids are largely present in the pulp, anthocyanins and stilbenoids in the skin, and other phenols ( catechins, proanthocyanidins and flavonols) in the skin a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plywood
Plywood is a composite material manufactured from thin layers, or "plies", of wood veneer that have been stacked and glued together. It is an engineered wood from the family of manufactured boards, which include plywood, medium-density fibreboard (MDF), oriented strand board (OSB), and particle board (or chipboard). All plywoods bind resin and wood fibre sheets (cellulose cells are long, strong and thin) to form a composite material. The sheets of wood are stacked such that each layer has its grain set typically (see below) perpendicular to its adjacent layers. This alternation of the grain is called ''cross-graining'' and has several important benefits: it reduces the tendency of wood to split when nailed at the edges; it reduces thickness swelling and shrinkage, providing improved dimensional stability; and it makes the strength of the panel consistent across all directions. There is usually an odd number of plies, so that the sheet is balanced, that is, the surface layers ha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
