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====Monoterpenes and Glycosides====Monoterpenes generally exist as aromatic and flavorful alcohols are flavorless compounds often found in plants/fruits that tend to smell floral with low odor thresholds (100-400 ppb), and are present in plant material. These alcohols mostly consist composed of linalool a molecule (often a major contributor flavor active compound) bound to hop aroma <ref>[http://www.mbaa.com/brewresources/Pages/Linalool-in-Hops.aspx Linalool in Hopsa sugar molecule. MBAA. Stefan Hanke, University Weihenstephan, Germany. 2009.]</ref>), geraniol, nerolThe glycosidic bond can be broken, releasing the sugar molecule and linalool oxides, but also includes other monoterpenes such as citronellol, alpha-terpineol, hotrienol, nerol oxide, myrcenol, the ocimenols, and other oxides, aldehydes and hydrocarbonspotentially flavor active compound. In wine (and probably sour beer), these alcohols bind These bonds can be broken with acids exposure to create aromatic monoterpene ethyl esters and acetate estersacid, and as well as specific enzymes which can also be transformed into other types added synthetically or produced naturally by some microorganisms, including some strains of monoterpenes by yeast metabolism ''Brettanomyces'' <ref>[httphttps://wwwen.sciencedirectwikipedia.comorg/sciencewiki/article/pii/S0168160510006653 Monoterpene alcohols release and bioconversion by Saccharomyces species and hybridsGlycoside "Glycoside. " A. Gamero, P. Manzanares, A. Querol, C. BellochWikipedia. 2011Retrieved 06/27/2016.]</ref>. The release of flavor molecules from glycosides is thought to contribute to the flavor development of aging wines, as well as kriek (cherry) lambic <ref name="Daenen2">[http://onlinelibrary.wiley.com/doi/10.1111/j.1567-1364.2008.00421.x/pdf Evaluation of the glycoside hydrolase activity of aBrettanomyces strain on glycosides from sour cherry (Prunus cerasus L.) used in the production of special fruit beers. Luk Daenen, Femke Sterckx, Freddy R. Delvaux, Hubert Verachtert & Guy Derdelinckx. 2007.]</ref>. Monoterpenes It is speculated that flavor compounds from hops can also be odorless polyols, some of which can break down easily to produce pleasant aromas. For example, diendiol can break down into hotrienol (tropical, floral, fennel, ginger aroma released from glycosides <ref>[http://www.thegoodscentscompany.com/data/rw1374491.html name="Hotrienol.Daenen1" The Good Scents Company. Retrieved 05/11/2016.]</ref>) and nerol oxide (green, vegetative and floral with a minty undernote <ref>[http://wwwonlinelibrary.thegoodscentscompanywiley.com/datadoi/rw100189110.html "Nerol Oxide." The Good Scents Company. Retrieved 051111/11/2016j.]</ref>)1365-2672. It is thought that some strains of ''Saccharomyces cerevisiae'' might be able to produce monoterpenes such as geraniol during fermentation in ways not related to beta-glucosidase activity <ref>[http://femsle2007.oxfordjournals03566.orgx/content/243/1/107.abstract De novo synthesis full Screening and evaluation of monoterpenes by the glucoside hydrolase activity in Saccharomyces cerevisiae wine and Brettanomyces brewing yeasts. Francisco ML. Carrau, Karina MedinaDaenen, Eduardo Boido, Laura Farina, Carina Gaggero, Eduardo Dellacassa, Giuseppe Versini, Paul A. Henschke. 2005.]</ref>. Glycosides are a very diverse group of non-volatile and flavorless molecules that generally encompass any molecule that has a sugar bound to a non-sugar molecule (thus separating them from polysaccharides)D. The sugar (monosaccharide or oligosaccharide) component of the molecule is known as the "glycone"Saison, and the non-sugar component is known as the "aglycone"F. By breaking the glycosidic bond of a glycosideSterckx, the aglycone component is releasedF. The aglycone component of glycosides are often polyphenols or the floral monoterpene alcohols described aboveR. Glycosides can be categorized based on their glycone (glucose vs fructose), type of glycosidic bond (α-glycosides or β-glycosides), or by their aglycone (alcoholic, anthraquinone, coumarin, cyanogenic, flavonoid, phenolicDelvaux, aponins, steroidal/cardiac, steviol, or thioglycosides)H. Glycosides play important roles in living organisms, especially many types of plants which store glycosides in their tissue and then break the bond between the sugar and non-sugar aglycone when the aglycone is needed for certain biological functions <ref>[http://www.newworldencyclopedia.org/entry/Glycoside "Glycoside." New World Encyclopedia. Retrieved 05/06/2016.]</ref>. These include protecting cells from toxins in the plant and attracting insects via the fragrance of flowers <ref name="Winterhalter"></ref>.  Aglycones have been identified in many fruits and herbs such as grapes, apricots, peaches, yellow plums, quince, sour cherry, passion fruit, kiwi, papaya, pineapple, mango, lulo, raspberry, strawberryVerachtert, and tea <ref name="Maicas">[http://wwwG.ncbi.nlm.nih.gov/pubmed/15635463 "Hydrolysis of terpenyl glycosides in grape juice and other fruit juices: a review." Sergi Maicas, José Juan MateoDerdelinckx. May 20052007.]</ref><ref name="Winterhalter"></ref>. They have been found in different parts of plants, including See the green leafy parts, fruit, roots, rhizomes, petals, and seeds. Aglycones in plants are highly complex structures and very diverse, and their percentages can vary from crop to crop. In plants, these include alcohol type aglycones such as terpenols, terpenes, linalool oxides, as well as other flavor precursors including various alcohols, norisoprenoids, phenolic acids and probably volatile phenols such as vanillin <ref name="Maicas"></ref>. In fruits, there are mostly just 4 types of flavonol type aglycones: [https://en.wikipedia.org/wiki/Quercetin quercetin] (found in nearly all fruits), [https://en.wikipedia.org/wiki/Kaempferol kaempherol] (found in 80% of fruit), and less commonly [https://en.wikipedia.org/wiki/Quercetin quercetin] and [https://en.wikipedia.org/wiki/Isorhamnetin isorhamnetin] <ref>[https://books.google.com/books?id=vHqke7F4lWYC&pg=PA59&lpg=PA59&dq=aglycones+in+fruit&source=bl&ots=7Gb10SPZk7&sig=6gaZlwpVaHuteoiVP68zvt6HcpE&hl=en&sa=X&ved=0ahUKEwjk0qW9wp3NAhUCKZQKHfUzDrQQ6AEIKTAC#v=onepage&q=aglycones%20in%20fruit&f=false Fruit Phenolics. Jean-Jacques Macheix, Annie Fleuriet. CRC Press, Mar 20, 1990. Pgs 57-61.Glycosides]</ref> (see [http://nutrition.ucdavis.edu/content/infosheets/fact-pro-flavonol.pdf this UC Davis PDF] page for amounts in different fruit and potential health benefits as antioxidants). In many cases of fruit, the amount of aromatic aglycones that are bound up in glycosides out number the amount that are free in a ratio of 2:1 to 8:1 <ref name="Maicas"></ref>. Aglycones that are bound up in glycosides tend to be more water soluble and less reactive once unbound than the naturally free version. By providing enzymes that break the glicosidic bond, discarded parts of plants (peels, stems, skins, etc.) have been used to produce natural flavorings from the remaining and abundant glycosides <ref name="Winterhalter">[http://link.springer.com/chapter/10.1007%2FBFb0102063 "Glycoconjugated aroma compounds: Occurrence, role and biotechnological transformation." Peter Winterhalter, George K. Skouroumounis. 1997.]</ref>details.