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Glycosides are flavorless compounds often found in plants/fruits that are composed of a molecule (often a flavor active compound) bound to a sugar molecule. The glycosidic bond can be broken, releasing the sugar molecule and the potentially flavor active compound. These bonds can be broken with exposure to acid, as well as specific enzymes which can be added synthetically or produced naturally by some microorganisms, including some strains of ''Brettanomyces'' <ref>[https://en.wikipedia.org/wiki/Glycoside "Glycoside." Wikipedia. Retrieved 06/27/2016.]</ref>. When the glycosidic bond is broken by an enzyme produced by a microorganism, it can be classified under the generic term as a [https://en.wikipedia.org/wiki/Biotransformation "biotransformation"] <ref>[http://www.sawislibrary.co.za/dbtextimages/17163.pdf Enzymes in Winemaking: Harnessing Natural Catalysts for Efficient Biotransformations - A Review. P. van Rensburg and I.S. Pretorius. 2000.]</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"></ref>. It is speculated that flavor compounds from hops can also be released from glycosides <ref name="Daenen1"></ref>.
==Glycosides and Beta-Glucosidase Activity==
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, strawberry, and tea <ref name="Maicas">[http://www.ncbi.nlm.nih.gov/pubmed/15635463 "Hydrolysis of terpenyl glycosides in grape juice and other fruit juices: a review." Sergi Maicas, José Juan Mateo. May 2005.]</ref><ref name="Winterhalter"></ref>. They have been found in different parts of plants, including 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.]</ref> (see [http://nutrition.ucdavis.edu/content/infosheets/fact-pro-flavonol.pdf this UC Davis PDF] 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 outnumber 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 glycosidic 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>.
===Acidic Hydrolysis===
Aglycones can be released from glycosides via a low pH. Generally, this occurs at lower pH's and Daenen et al. (2007) attributed most of the breakdown of glycosides to beta-glucosidase enzymes <ref name="Daenen2" />, but different types of glycosides are more readily broken down at different pH's. For example, ocimenols (lemon, lime <ref>[http://www.thegoodscentscompany.com/data/rw1020581.html "Ocimenol". The Good Scents Company. Retrieved 06/26/2017.]</ref>) are formed from glycoside breakdown at a pH of 1, but terpenes such as linalool, nerol, and geraniol (commonly found in hops and other plant material) are formed at a pH of 3, and alpha-terpineol was formed at both pH values. The acidic breakdown of these glycosides were found to contribute to the flavor of wine during aging <ref name="Maicas"></ref>. Daenen et al. (2007) also found that acidic hydrolysis was responsible for the formation of alpha-ionol, beta-damascenone, linalool and alpha-terpineol and to a lesser extent benzyl alcohol <ref name="Daenen2" />.
In beer, it was found that the lower the pH of the beer the higher the amount of the ketone damascenone (floral, rose <ref>[https://en.wikipedia.org/wiki/Damascenone "Damascenone". Wikipedia. Retrieved 06/26/2017.]</ref>) and dimethyl trisulfide (sulfury cooked onion <ref>[http://www.thegoodscentscompany.com/data/rw1008101.html "Dimethyl trisulfide". The Good Scents Company. Retrieved 06/26/2017.]</ref>). In one study, at a pH of 3, beta-damascenone was reported to be ~27 ppb and dimethyl trisulfide was reported to be 650 ppt. At a pH of 4.2, they were 17 ppb and 300 ppt respectively. At a ph of 5, beta-damascenone was around 12 ppb and dimethyl trisulfide 50 ppt. This was believed to be due to the acidic hydrolysis of glycosides, and it was speculated that other glycosides could have a flavor impact on beers that contain fruit or herbs due to acidic hydrolysis of glycosides <ref>How Low pH Can Intensify ?-Damascenone and Dimethyl Trisulfide Production through Beer Aging. LAURENCE GIJS, FABIENNE CHEVANCE, VESNA JERKOVIC, AND SONIA COLLIN. 2002. DOI: 10.1021/jf020563p.</ref>.
* See also: [[Hops#Glycosides|Glycosides In Hops]].
===Beta-Glucosidase===
Aglycones can also be released chemically from glycosides by either exposure to acid (generally pH of 3 or lower, and different pH's giving different results on which glycosides are broken down; this breakdown of glycosides under low pH has been linked to the slow flavor development of aging wine <ref name="Maicas"></ref>), or by enzymes called beta-glucosidases. Enzymatic breakdown of glycosides has been described as producing a more "natural" flavor in wines versus acidic breakdown. Some fruits have been observed (mostly wine grapes) to have limited beta-glucosidase activity within themselves, however it has been observed as being unstable and having low activity at the low pH of wine and sour beer <ref name="Maicas"></ref>.
Beta-glycosidase enzymes can be added artificially, however there has been much interest in the natural capability of microorganisms to produce beta-glucosidases, particularly 1,4-β-glucosidase <ref name="Winterhalter"></ref>. Microorganisms that can break down glycosides by using beta-glucosidases can then access the resulting sugars for fermentation <ref name="Steensels">[http://www.sciencedirect.com/science/article/pii/S0168160515001865 Brettanomyces yeasts — From spoilage organisms to valuable contributors to industrial fermentations. Jan Steensels, Luk Daenen, Philippe Malcorps, Guy Derdelinckx, Hubert Verachtert, Kevin J. Verstrepen. International Journal of Food Microbiology Volume 206, 3 August 2015, Pages 24–38.]</ref>. There are two major categories of glucosidase activity: endogenous and exogenous. Endogenous enzymatic activity takes place inside of the cell, and exogenous enzymatic activity takes place outside of the cell. Bacteria and fungi that show endogenous glucosidase activity have been shown not to be effective in alcoholic fermentation due to not tolerating low pH (optimum pH of 5), glucose, and/or ethanol. Generally, the flavorless glycosides remain unaffected by yeast fermentation, leaving them unused as a potential source for flavor and aroma <ref name="Winterhalter"></ref>.
Different types of beta-glucosidase enzymes have different optimal pH and temperatures. For example, beta-glucosidase produced from ''A. niger'' is optimal at a pH of 4.5 and a temperature of 58°C (136°F), whereas the enzyme for ''Brettanomyces anomalus'' is optimal at a pH of 5.75 and a temperature of 37°C (98°F) (it was active to some extent between 15°-55°C). The beta-glucosidase enzyme ceases effectiveness below a pH of 4.5 for one strain of ''B anomalus'' studied <ref name="Vervoort"></ref>.
See also:* [http://www.cazy.org/Glycoside-Hydrolases.html Database of glycoside hydrolases.] ===Activity of ''Brettanomyces '' and ''Saccharomyces''=== [http://onlinelibrary.wiley.com/doi/10.1111/j.1365-2672.2007.03566.x/full Daenen et al. (2007)] screened the beta-glucosidase activity of several strains of ''Saccharomyces cerevisiae'', ''Saccharomyces pastorianus'', and several ''Brettanomyces'' species. None of the lager brewing strains showed beta-glucosidase activity. Out of 32 strains of ''S. cerevisiae'', only one strain (a wine strain called "U228") showed beta-glucosidase activity, however its activity was repressed in the presence of glucose. This indicates that most ''S. cerevisiae'' strains do not have the capability of producing beta-glucosidase, but it is possible that some very few strains can <ref name="Daenen1">[http://onlinelibrary.wiley.com/doi/10.1111/j.1365-2672.2007.03566.x/full Screening and evaluation of the glucoside hydrolase activity in Saccharomyces and Brettanomyces brewing yeasts. L. Daenen, D. Saison, F. Sterckx, F.R. Delvaux, H. Verachtert, G. Derdelinckx. 2007.]</ref>. Additionally, beta-glucosidase activity for ''S. cerevisiae'' can be inhibited by the pH levels found in wine and sour beer (optimal at pH 5) <ref name="Mansfield"></ref>. All strains of ''S. cerevisiae'' did release another enzyme called beta-glucanase, which led to varying degrees of breaking down some smaller glycosides found in hops (hop extract was tested, not whole hops) containing the aglycones methyl salicylate, 1-octen-3-ol, and cis-3-hexen-1-ol, but not linalool. None of the ''B. bruxellensis'' strains showed this activity, but the researchers only tested strain of ''B. custersianus'' and both of the ''B. anomala'' strains tested did show cell-associated (intracellular) beta-glucosidase activity. In particular, the ''B. custersianus'' strain was tested against glycosides from hops, in which case high amounts of the aglycones linalool (citrus, orange, lemon, floral <ref>[http://www.thegoodscentscompany.com/data/rw1007872.html "Linalool." The Good Scents Company. Retrieved 05/12/2016.]</ref>), methyl salicylate (minty, wintergreen <ref>[http://www.rsc.org/chemistryworld/2015/09/methyl-salicylate-oil-wintergreen-podcast "Methyl salicylate." Chemistry World. Retrieved 05/12/2016.]</ref>), 1-octen-3-ol (mushroom, earthy <ref>[http://www.thegoodscentscompany.com/data/rw1024051.html "1-octen-3-ol." The Good Scents Company. Retrieved 05/12/2016.]</ref>) and cis-3-hexen-1-ol (grassy, melon rind <ref>[http://www.thegoodscentscompany.com/data/rw1005932.html "(Z)-3-hexen-1-ol." The Good Scents Company. Retrieved 05/12/2016.]</ref>) were released from hop extracts <ref name="Daenen1"></ref>. The beta-glucosidase activity was elevated when co-fermenting ''B. custersianus'' with ''S. cerevisiae''. The authors also found dihydroedulan 1 and 2 (elderberry aroma) and theaspirane A and B (woody and campfire aromas), which are classified as norisoprenoids, were released from dry hopping <ref>[http://www.asbcnet.org/events/archives/Documents/2008WBCprogbook.pdf World Brewing Congress, 2008. Pg 80. Retrieved 05/13/2016.]</ref>. ''B. custersianus'' has been isolated from the later stages of lambic fermentation, and it is thought that its ability to produce beta-glucosidase, which gives it the ability to ferment cellobiose and cellotriose, is a possible adaptation from living in oak barrels <ref name="Daenen1"></ref>. Recent studies on hops have linked an increase in fruity thiols from hops (3-mercaptohexan-1-ol and 4-mercapto-4-methylpentan-2-one) being produced during fermentation from the production of beta-lyase enzyme, and this could also explain anecdotal reports of increased fruity aromas from exposing hops to fermentation (see [http://scottjanish.com/genetically-modified-gm-yeast-strains-unlocking-bound-hop-thiols-and-engineering-targeted-fermentation-characteristics/ this article by Scott Janish] on beta-lyase enzymes in GM and non-GM yeast strains). <ref>Private correspondence with Richard Preiss by Dan Pixley. 05/16/2016.</ref><ref>[https://beerandbrewing.com/VuhJRCUAAHMUNfil/article/hops-oils--aroma-uncharted-waters "Hops Oils & Aroma: Uncharted Waters," by Stan Hieronymus. Beer & Brewing. 03/16/2016. Retrieved 05/16/2016.]</ref>. [https://www.academia.edu/23874347/Properties_of_endogenous_%CE%B2_glucosidase_of_a_Saccharomyces_cerevisiae_strain_isolated_from_Sicilian_musts_and_wines Palmeri et al. (2002)] reported one wine strain out of 80 strains of ''S. cerevisiae'' found in Sicilian must that had high beta-glucosidase activity and is active during wine fermentation conditions <ref>[https://www.academia.edu/23874347/Properties_of_endogenous_%CE%B2_glucosidase_of_a_Saccharomyces_cerevisiae_strain_isolated_from_Sicilian_musts_and_wines Spagna, G., Barbagallo, R. N., Palmeri, R., Restuccia, C., & Giudici, P. (2002). Properties of endogenous β-glucosidase of a Saccharomyces cerevisiae strain isolated from Sicilian musts and wines. Enzyme and Microbial Technology, 31(7), 1030–1035. https://doi.org/10.1016/S0141-0229(02)00233-8]</ref>. Another study by [http://onlinelibrary.wiley.com/doi/10.1002/jib.418/abstract Sharp et al.] found that both ale and lager yeasts exhibit a wide range of beta-glucosidase activity, but the results should be repeated using a different substrate because the substrate that was used could have been broken down by beta-glucanase enzyme instead of beta-glucosidase <ref name="Sharp_2017">[http://onlinelibrary.wiley.com/doi/10.1002/jib.418/abstract The effect of hopping regime, cultivar and β-glucosidase activity on monoterpene alcohol concentrations in wort and beer. Daniel C. Sharp, Jan Steensels, Thomas H. Shellhammer. 2017.]</ref>Additionally, Lallemand claims that three brewing strains that they offer produce beta-glucosidase enzymes that can promote hop biotransformation, but the details of this activity have not been published to our knowledge (BRY-97, New England, and Belle Saison) <ref>[http://masterbrewerspodcast.com/119-biotransformation Eric Abbot. Master Brewers Association podcast, episode 119. 02/04/2019.]</ref> (~8:50 min in).
===Cyanogenic Glycosides===
All plants contain at least tiny amounts of [https://en.wikipedia.org/wiki/Hydrogen_cyanide hydrogen cyanide] ('''HCN'''), however, some plants also release high amounts of HCN from a class of glycosides called "cyanogenic glycosides", also called "cyanoglycosides". [https://en.wikipedia.org/wiki/Amygdalin Amygdalin] and [https://en.wikipedia.org/wiki/Linamarin linamarin] are common examples of cyanogenic glycosides <ref name="Gleadow_2014"></ref>. Amygdalin is sometimes marketed as a cure for cancer by the health food industry, but this claim is not supported by clinical data, and digestion of too much amygdalin can be dangerous <ref>[https://www.quackwatch.org/01QuackeryRelatedTopics/Cancer/laetrile.html Wilson, Benjamin. "The Rise and Fall of Laetrile". Quackwatch.org website. 01/07/2017. retrieved 03/30/2017.]</ref><ref>[http://www.nejm.org/doi/pdf/10.1056/NEJM198201283060403 A Clinical Trial of Amygdalin (Laetrile) in the Treatment of Human Cancer. Charles G. Moertel, M.D., Thomas R. Fleming, Ph.D., Joseph Rubin, M.D., Larry K. Kvols, M.D., Gregory Sarna, M.D., Robert Koch, M.D., Violante E. Currie, M.D., Charles W. Young, M.D., Stephen E. Jones, M.D., and J. Paul Davignon, Ph.D. 1982. DOI: 10.1056/NEJM198201283060403.]</ref><ref>[https://www.infona.pl/resource/bwmeta1.element.springer-2c7e4ea1-3683-3bbd-9394-a98a551e7c63 Laetrile for cancer: a systematic review of the clinical evidence. Stefania Milazzo, Stephane Lejeune, Edzard Ernst. 2007. DOI: 10.1007/s00520-006-0168-9.]</ref><ref>[http://www.sciencedirect.com/science/article/pii/S0944711316000362 Amygdalin, quackery or cure? Roman A. Blahetaa, Karen Nelsonb, Axel Haferkampa, Eva Juengela. 2016.]</ref>. HCN is released from cyanogenic glycosides just like other types of glycosides: beta-glucosidase enzyme or exposure to low pH breaks the bond between a glucose molecule and an unstable compound called "cyanohydrin" (or "alpha-hydroxynnitrile"), which then disassociates into a ketone or benzaldehyde and an HCN molecule. In progresscyanogenic glycosides, this reaction is called "cyanogenesis". Cyanogenesis is stimulated by maceration, and by bacteria in the human gut <ref name="Speijers">[http://www.inchem.org/documents/jecfa/jecmono/v30je18.htm "Cyanogenic Glycosides", First Draft. Dr G. Speijers. National Institute of Public Health and Environmental Protection Laboratory for Toxicology, Bilthoven, The Netherlands. Retrieved 08/25/2016.]</ref>. Although the optimum pH of cyanogenesis (at least for amygdalin)is 5.0 - 5.8, cyongenesis can occur at a wide range of pH values, and can occur in the presence of acid <ref>[http://www.sciencedirect.com/science/article/pii/S0308814601003132 Total cyanide determination of plants and foods using the picrate and acid hydrolysis methods. M Rezaul Haque, J Howard Bradbury. 2002.]</ref>. If seeds containing cyanogenic glycosides are ground up, the coarseness to which they are ground effects how quickly cyanogenesis occurs. Finely ground seeds extract HCN within an hour, where as coarsely ground seeds extract within 24 hours <ref name="tuncel">[http://www.sciencedirect.com/science/article/pii/030881469599841M The effects of grinding, soaking and cooking on the degradation of amygdalin of bitter apricot seeds. G Tunçel, M.J.R Nout, L Brimer. 1995.]</ref>. HCN boils at a relatively low temperature (25.6°C / 78.1°F) <ref name="Gleadow_2014"></ref>. In some cases, soaking, cooking, and/or sometimes fermenting foods with certain bacteria or yeast (this has not been fully documented with ''Saccharomyces'' or ''Brettanomyces'') that contain cyanogenic glycosides allows the HCN to be released, and then subsequent cooking afterwards will boil off the cyanide <ref>[http://www.sciencedirect.com/science/article/pii/016816059400115M International Journal of Food Microbiology. M.J.R. Nout, G. Tunçe, L. Brimer. 1995.]</ref><ref name="Chaouali"></ref>.
Although rare, there have been a few reported deaths due to cyanide poisoning from foods containing cyanogenic glycosides. These reports include deaths from elderberry juice that was thought to contain stems and/or leaves (the stems and leaves contain much higher cyanogenic glycosides than the berries, and ripe berries by themselves are considered safe) <ref>[http://www.cdc.gov/mmwr/preview/mmwrhtml/00000311.htm Poisoning from Elderberry Juice -- California. CDC website. 1998. Retrieved 08/30/2016.]</ref>, apricot kernels (pits), choke cherry pits, and improperly processed cassava (a staple food in parts of North Africa) <ref name="who"></ref>. A lethal dosage of cyanide in humans is estimated to be around 1.52 mg per kilogram of body weight, with 0.56 mg per kilogram of body weight being the lowest recorded (although this lowest figure was obtained from a historical case when the measurements taken may not have been accurate) <ref>[http://www.atsdr.cdc.gov/toxprofiles/tp8.pdf Toxicology Profile for Cyanide. Agency for Toxic Substances & Disease Registry. July 2006. Pg 42. Retrieved 08/25/2016.]</ref>. High exposure can cause light-headedness, nausea, vomiting, stomach cramps, diarrhea, convulsions, harm to the brain and heart, comas, and death. Exposure to 0.05 mg of cyanide per kilogram of body weight per day for 15-364 days is considered to be the minimum accumulative cyanide exposure by the US CDC. Accumulative exposure can cause health risks, such as reproductive, respiratory, neurological, thyroid, and gastrointestinal issues <ref>[http://www.atsdr.cdc.gov/toxprofiles/tp8.pdf Toxicology Profile for Cyanide. Agency for Toxic Substances & Disease Registry. July 2006. Pg 21. Retrieved 08/25/2016.]</ref>. In some foods, such as marzipan and persipan (made from bitter apricot seeds), the processing of this food destroys the natural beta-glucosidase enzyme (which denatures at 75°C), leaving the flora in the human gut to break down the cyanogenic glycosides. Even if an abnormally large portion of marzipan or persipan is ingested, the lack of beta-glucosidase along with the high calories in the food acts as a slow release of cyanide into the human body which the body can deal with <ref>[http://link.springer.com/article/10.1007%2Fs00204-015-1479-8 Bioavailability of cyanide after consumption of a single meal of foods containing high levels of cyanogenic glycosides: a crossover study in humans. Klaus Abraham, Thorsten Buhrke, Alfonso Lampen. 2015.]</ref>.
Upon learning about cyanogenic glycosides, brewers often question the toxicity of ingredients such as cherry pits or apricot kernels in beer. Cherry pits have traditionally been used in [[lambic]] kriek beers in Belgium. However, the dilution of HCN from cherry pits in beer results in benign levels. Assuming full breakdown of these glycosides, and that none of the HCN boils off (25.6°C boiling temperature), levels of HCN introduced from cherry pits are too low to cause harm to adult humans. The EU regulates that alcoholic beverages cannot exceed 1 mg of HCN per ABV percentage (v/v%) per liter <ref>[http://ec.europa.eu/food/fs/sfp/addit_flavor/flav09_en.pdf COUNCIL DIRECTIVE of 22 June 1988 on the approximation of the laws of the Member States relating to flavourings for use in foodstuffs and to source materials for their production (88/388/EEC). The European Food Commission, Food Safety. Retrieved 08/26/2016.]</ref>. Luk Daenen, a glycoside researcher, calculated that for a 4% ABV alcohol beer, 4 mg of HCN per liter is allowed. With 200 grams of cherries per liter, and the pits being 10-14 grams of that weight, there is 22 - 30.8 mg amygdalin per liter of beer. Around 6% of the weight of amygdalin is converted into HCN. Assuming maximum extraction of HCN from the amygdalin glycoside, which is unlikely because the pits are not ground up when used in beer, this equates to 1.3 - 1.82 mg of HCN per liter of beer, which . This amount is less than the 4 mg of HCN per liter that the EU regulation states. Considering that ~42 mg of HCN is required to kill a person that weighs 70 kilograms (154 pounds), that person would need to drink around 23 liters of beer <ref name="daenen">[https://www.uclouvain.be/cps/ucl/doc/inbr/documents/presentation-luk-daenen.pdf "Use of beta-glucosidase activity for flavour enhancement in specialty beers," slideshow by Luk Daenen. 2012. Retrieved 08/26/2016.]</ref>. Considering that 350 mL of pure alcohol would kill a 70 kilogram adult <ref>[http://www.alcohol.org.nz/alcohol-its-effects/health-effects/alcohol-poisoning "Alcohol Poisoning". NZ Health Promotion Agency. Retrieved 08/26/2016.]</ref>. The , the amount of 4% ABV beer required to kill a 70 kg adult from alcohol poisoning is around 8.75 liters. Alcohol would kill such a person far before cyanide poisoning would become a concern. In general, the potential cyanide in most plants will become too dilute to have any health problems when added to beer in normal amounts, however there might still be plants that are extremely high in HCN content that should be avoided in beer (see the table below). If there is a concern that an ingredient containing potentially high levels of HCN could reach unhealthy levels in beer, the beer should be sent for lab analysis so that the HCN levels can be determined before being consumed.
{| class="wikitable sortable"
|-
! Plant !! mg HCN/kg or mg/liter<nowiki>*</nowiki> || Prominent Glycoside
|-
| Cereal grains and their products || 0.001-0.45 <ref name="who">[http://www.who.int/ipcs/publications/cicad/en/cicad61.pdf Concise International Chemical Assessment Document 61. HYDROGEN CYANIDE AND CYANIDES: HUMAN HEALTH ASPECTS. World Health Organization. 2004. Pg 13. Retrieved 08/29/2016.]</ref>||
|-
| Soy protein products || 0.07-0.3 <ref name="who"></ref> || Linmarin <ref name="soybean"></ref>
|-
| Soybean hulls || 1.24 <ref name="who"></ref> || Linmarin <ref name="soybean"></ref>
|-
| Apricot pits, wet weight Home-made cherry juice from pitted fruits || 89-2170 (depends on region/strain) 5.1 <ref name="Chaoualiwho"></ref>|| Amygdalin <ref name="whoGleadow_2014"></ref>
|-
| Home-made cherry juice from pitted fruits containing 100% crushed pits || 5.1 23 <ref name="who"></ref> || Amydalin <ref name="Gleadow_2014"></ref>
|-
| HomeAlmonds (wild bitter) || 1062-made cherry juice containing 100% crushed pits 4690 <ref name="Chaouali">[https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3793392/ Potential Toxic Levels of Cyanide in Almonds (Prunus amygdalus), Apricot Kernels (Prunus armeniaca), and Almond Syrup. Nadia Chaouali, Ines Gana, Amira Dorra, Fathia Khelifi, Anouer Nouioui, Wafa Masri, Ines Belwaer, Hayet Ghorbel, and Abderazzek Hedhili. 2013.]</ref><ref>[http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1273391/ Cyanide poisoning after bitter almond ingestion. T A Shragg, T E Albertson, and C J Fisher, Jr. 1982.]</ref> || 23 Amygdalin <ref name="whowikipedia_almond">[https://en.wikipedia.org/wiki/Almond "Almond". Wikipedia. Retrieved 09/06/2016.]</ref>
|-
| Almonds (wild bittersweet domesticated) || 1062-4690 25 <ref name="Chaouali">[https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3793392/ Potential Toxic Levels of Cyanide in Almonds (Prunus amygdalus), Apricot Kernels (Prunus armeniaca), and Almond Syrup. Nadia Chaouali, Ines Gana, Amira Dorra, Fathia Khelifi, Anouer Nouioui, Wafa Masri, Ines Belwaer, Hayet Ghorbel, and Abderazzek Hedhili. 2013.</ref>|| Amygdalin <refname="wikipedia_almond">[http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1273391/ Cyanide poisoning after bitter almond ingestion. T A Shragg, T E Albertson, and C J Fisher, Jr. 1982.]</ref>
|-
| Almonds (sweet domesticated) Cherries with pit || 25 6.5-9.1 <ref name="Chaoualidaenen"></ref> || Amygdalin <ref name="Gleadow_2014"></ref>
|-
| Cherries with pit Cherry pits only (black) || 6.5-9.1 161 <ref name="daenenBolarinwa_2014"/>|| Amygdalin <ref name="Bolarinwa_2014" /ref>
|-
| Fresh Apricots with kernel Cherry pits only (red) || 233 <ref name="Bolarinwa_2014" /> || Amygdalin <ref name="Bolarinwa_2014" />
|-
| '''Commercial fruit juices''' Cherry pits only (morello) ||3900 <ref name="VOLDŘICH_1992" /> || Amygdalin <ref name="VOLDŘICH_1992" />
|-
| Cherry Apricot pits, wet weight || 4.6 89-2170 (depends on region/variety) <ref name="Chaouali"></ref><ref name="who"></ref> || Amgydalin <ref name="Gleadow_2014"></ref>
|-
| Apricot Sweet Apricots with kernel (14-24 fruits for 1 kg; single kernel avg weight is 6 grams <ref name="calapricot">[http://www.califapricot.com/marking_regulations.html California Apricots. Marking Regulations. Retrieved 09/01/16.]</ref>) || 4.2- 7.2 (avg 0.3 mg per kernel <ref name="wiki_apric_kernel">[https://en.wikipedia.org/wiki/Apricot_kernel "Apricot Kernel". Wikipedia. Retrieved 09/01/2016.]</ref>) || Amygdalin <ref name="whoGleadow_2014"></ref>
|-
| Prune Bitter Apricots with kernel (14-24 fruits for 1 kg; single kernel avg weight is 6 grams <ref name="calapricot"></ref>) || 25.2 - 43.2 (avg 1.9 8 mg per kernel <ref name="wiki_apric_kernel"></ref>) || Amygdalin <ref name="whoGleadow_2014"></ref>
|-
| '''Tropical foodstuffs''' Elderflower (leaves/stems) ||1600 <ref name="nordicfoodlab">[https://web.archive.org/web/20190812014649/http://nordicfoodlab.org:80/blog/2013/10/elder-a-love-story "Elder – a love story". Justine de Valicourt. Nordic Food Lab. 10/03/2013. Retrieved 09/07/2016.]</ref> || Sambunigrin (or sometimes prunasin, holocalin, or zierin) <ref name="elderflowers">[https://www.researchgate.net/publication/233262135_Cyanogenic_Glycosides_from_Sambucus_Nigra Cyanogenic Glycosides from Sambucus Nigra. Marina Dellagreca, Antonio Fiorentino, Pietro Monaco, Lucio Previtera & Ana M. Simonet. 2006.]</ref>
|-
| CassavaElderberries (bitterfully ripe; under-ripe will contain more)/dried root cortex || 2360-2450 30 <ref name="whonordicfoodlab"></ref>|| Sambunigrin (or sometimes prunasin, holocalin, or zierin) <ref name="Speijerselderflowers"></ref>
|-
| Cassava(bitter)Peach seeds/leaves kernels || 30054-2600 (variety dependent; mostly reported between 54-310 666) <ref name="whoVOLDŘICH_1992">[https://www.scopus.com/record/display.uri?eid=2-s2.0-84987336720&origin=inward&txGid=713c7a86664b8d2865e54a25eaafc9b5 Cyanogenesis in Canned Stone Fruits. VOLDŘICH, M., KYZLINK, V. 1992. DOI: 10.1111/j.1365-2621.1992.tb05446.x.]</ref><ref name="SpeijersBolarinwa_2014">[https://www.sciencedirect.com/science/article/pii/S0308814613016245 Amygdalin content of seeds, kernels and food products commercially-available in the UK. Islamiyat F. Bolarinwa, Caroline Orfila, Michael R.A. Morgan. 2014. DOI: https://doi.org/10.1016/j.foodchem.2013.11.002.]</ref><ref>[https://www.scopus.com/record/display.uri?eid=2-s2.0-0021674858&origin=inward&txGid=ee159dc998e0469bc88f0685e8d41ecb The cyanide content of laetrile preparations, apricot, peach and apple seeds. Holzbecher, M.D., Moss, M.A., Ellenberger, H.A 1984.]</ref> || Amygdalin <ref name="Bolarinwa_2014" />
|-
| CassavaNectarine seeds (bittersummer fire)/whole tubers || 380-395 7.2 <ref name="whoBolarinwa_2014"></ref>|| Amygdalin <ref name="SpeijersBolarinwa_2014"></ref>
|-
| CassavaPlum seeds (sweetgreen)/leaves || 451-468 1050 <ref name="whoBolarinwa_2014"></ref>|| Amygdalin <ref name="SpeijersBolarinwa_2014"></ref>
|-
| CassavaPlum seeds (sweetblack; firar black)/whole tubers || 445-462 600 <ref name="whoBolarinwa_2014"></ref>|| Amygdalin <ref name="SpeijersBolarinwa_2014"></ref>
|-
| Gari flour Plum seeds (Nigeriapurple; larry anne) || 10.6-22.1 130 <ref name="whoBolarinwa_2014"/>|| Amygdalin <ref name="Bolarinwa_2014" /ref>
|-
| Sorghum/whole immature plant Plum seeds (yellow; son gold) || 2400-2500 92 <ref name="whoBolarinwa_2014"></ref>|| Amygdalin <ref name="SpeijersBolarinwa_2014"></ref>
|-
| Bamboo/immature shoot tip Plum seeds (red; laetitia) || 7700-8000 26 <ref name="whoBolarinwa_2014"></ref>|| Amygdalin <ref name="SpeijersBolarinwa_2014"></ref>
|-
| Lima beans from Java Apple seeds (colouredroyal gala) || 3000-3120 178 <ref name="whoBolarinwa_2014"></ref>|| Amygdalin <ref name="SpeijersBolarinwa_2014"></ref>
|-
| Lima beans from Puerto Rico Pear (blackconference) || 2900-3000 77 <ref name="whoBolarinwa_2014"></ref>|| Amygdalin <ref name="SpeijersBolarinwa_2014"></ref>
|-
| Non-Rosaceae fruit seeds (courgette, cucumber, marrow, honey dew melon, squash varieties) || 0.6-12.6 <ref name="Bolarinwa_2014" /> || Amygdalin <ref name="Bolarinwa_2014" />|-| '''Commercial fruit juices''' |-| Cherry || 4.6 <ref name="who"></ref> || Amygdalin <ref name="Gleadow_2014"></ref>|-| Apricot || 2.2 <ref name="who"></ref> || Amygdalin <ref name="Gleadow_2014"></ref>|-| Prune || 1.9 <ref name="who"></ref> || Amygdalin <ref name="Gleadow_2014"></ref>|-| '''Tropical foodstuffs''' |-| Cassava(bitter)/dried root cortex || 2360-2450 <ref name="who"></ref><ref name="Speijers"></ref> || Linamarin <ref name="Gleadow_2014"></ref>|-| Cassava(bitter)/leaves || 300-310 <ref name="who"></ref><ref name="Speijers"></ref> || Linamarin <ref name="Gleadow_2014"></ref>|-| Cassava(bitter)/whole tubers || 380-395 <ref name="who"></ref><ref name="Speijers"></ref> || Linamarin <ref name="Gleadow_2014"></ref>|-| Cassava(sweet)/leaves || 451-468 <ref name="who"></ref><ref name="Speijers"></ref> || Linamarin <ref name="Gleadow_2014"></ref>|-| Cassava(sweet)/whole tubers || 445-462 <ref name="who"></ref><ref name="Speijers"></ref> || Linamarin <ref name="Gleadow_2014"></ref>|-| Gari flour (Nigeria) || 10.6-22.1 <ref name="who"></ref> || Linamarin <ref name="Gleadow_2014"></ref>|-| Sorghum/whole immature plant || 2400-2500 <ref name="who"></ref><ref name="Speijers"></ref> || Dhurrin <ref name="Gleadow_2014"></ref>|-| Bamboo/immature shoot tip || 7700-8000 <ref name="who"></ref><ref name="Speijers"></ref> || Taxiphyllin <ref>[http://www.ingentaconnect.com/contentone/ben/cnf/2016/00000012/00000002/art00012 Cyanogenic Toxicity and Human Health. Singhal, Poonam; Satya, Santosh; N . Naik, Satya. 2016.]</ref>|-| Lima beans from Java (coloured) || 3000-3120 <ref name="who"></ref><ref name="Speijers"></ref> || Linmarin <ref name="soybean">[http://pubs.acs.org/doi/abs/10.1021/jf00116a021 Determination of cyanide in soybeans and soybean products. David H. Honig, M. Elaine Hockridge, Robert M. Gould, Joseph J. Rackis. 1983.]</ref>|-| Lima beans from Puerto Rico (black) || 2900-3000 <ref name="who"></ref><ref name="Speijers"></ref> || Linmarin <ref name="soybean"></ref>|-| Lima beans from Burma (white) || 2000-2100 <ref name="who"></ref><ref name="Speijers"></ref> || Linmarin <ref name="soybean"></ref>|-| Flaxseed || 910 <ref name="flax">[http://pubs.acs.org/doi/abs/10.1021/bk-1997-0662.ch010 Cyanogenic Glycosides of Flaxseeds. Fereidoon Shahidi and P. K. J. P. D. Wanasundara. 1997.]</ref> || Linamarin, linustatin and neolinustatin <ref name="flax"></ref>
|-
|}
: <nowiki>*</nowiki> Amounts are averages, or are single examples. Actual levels may vary greatly between strains and growth conditions.
See also:
* [https://www.facebook.com/groups/MilkTheFunk/permalink/1401402279887982/ MTF thread on cyanide potential in beer.]
==See Also==
===Additional Articles on MTF Wiki===
* [[Hops#Hop_Derived_Compounds_In_Beer_and_Biotransformations|Hop Biotransformations]]
* [[Brettanomyces]]
* [[Pediococcus]]
* [[Mixed Fermentation]]
* [[Soured Fruit Beer]]
* [[Soured Herb, Spice, and Vegetable Beer]]
===External Resources===
* [https://www.uclouvain.be/cps/ucl/doc/inbr/documents/presentation-jean-marie-rock.pdf "Dry Hopping Myths versus Reality," slideshow by Jean-Marie Rock, ex-brewmaster for Orval.]
* [https://www.uclouvain.be/cps/ucl/doc/inbr/documents/presentation-luk-daenen.pdf "Use of beta-glucosidase activity for flavour enhancement in specialty beers," slideshow by Luk Daenen.]
* [http://nordicfoodlab.org/blog/2013/10/elder-a-love-story "Elder: a love story", by Justine de Valicourt (cyanide in elderberries).]
* [http://www.dpi.nsw.gov.au/__data/assets/pdf_file/0013/111190/prussic-acid-poisoning-in-livestock.pdf Overview of HCN in various grass/straw/hay/livestock feed species.]
* [http://scottjanish.com/?s=glycosides Scott Janish blog articles about glycosides.]
==References==