Editing Amygdalin (section)

== Chemistry ==
Amygdalin is a cyanogenic glycoside derived from the aromatic amino acid [[phenylalanine]]. Amygdalin and [[prunasin]] are common among plants of the family [[Rosaceae]], particularly the genus ''[[Prunus]]'', [[Poaceae]] (grasses), [[Fabaceae]] (legumes), and in other food plants, including [[flaxseed]] and [[manioc]].  Within these plants, amygdalin and the enzymes necessary to hydrolyze it are stored in separate locations, and only mix as a result of tissue damage. This provides a natural defense system.<ref>{{cite journal | vauthors = Mora CA, Halter JG, Adler C, Hund A, Anders H, Yu K, Stark WJ | title = Application of the Prunus spp. Cyanide Seed Defense System onto Wheat: Reduced Insect Feeding and Field Growth Tests | journal = Journal of Agricultural and Food Chemistry | volume = 64 | issue = 18 | pages = 3501–3507 | date = May 2016 | pmid = 27119432 | doi = 10.1021/acs.jafc.6b00438 | bibcode = 2016JAFC...64.3501M }}</ref>

[[Benzaldehyde]] released from amygdalin provides a bitter flavor. Because of a difference in a recessive gene called ''Sweet kernal [Sk]'', much less amygdalin is present in nonbitter (or sweet) almond than [[bitter almond]].<ref name="Sanchez-PerezJorgensen2008">{{cite journal | vauthors = Sánchez-Pérez R, Jørgensen K, Olsen CE, Dicenta F, Møller BL | title = Bitterness in almonds | journal = Plant Physiology | volume = 146 | issue = 3 | pages = 1040–1052 | date = March 2008 | pmid = 18192442 | pmc = 2259050 | doi = 10.1104/pp.107.112979 }}</ref>

For one method of isolating amygdalin, the stones are removed from the fruit and cracked to obtain the kernels, which are dried in the sun or in ovens. The kernels are boiled in [[ethanol]]; on evaporation of the solution and the addition of [[diethyl ether]], amygdalin is precipitated as minute white crystals.<ref>{{Cite EB1911|wstitle=Amygdalin|volume=1|page=900}}</ref> Natural amygdalin has the (''R'')-configuration at the chiral phenyl center. Under mild basic conditions, this stereogenic center isomerizes; the (''S'')-epimer is called '''neoamygdalin'''. Although the synthesized version of amygdalin is the (''R'')-epimer, the stereogenic center attached to the nitrile and phenyl groups easily [[epimerizes]] if the manufacturer does not store the compound correctly.<ref>{{cite journal | vauthors = Wahab MF, Breitbach ZS, Armstrong DW, Strattan R, Berthod A | title = Problems and Pitfalls in the Analysis of Amygdalin and Its Epimer | journal = Journal of Agricultural and Food Chemistry | volume = 63 | issue = 40 | pages = 8966–8973 | date = October 2015 | pmid = 26431391 | doi = 10.1021/acs.jafc.5b03120 | bibcode = 2015JAFC...63.8966W }}</ref>

Amygdalin is [[hydrolysis|hydrolyzed]] by intestinal [[β-glucosidase]] (emulsin)<ref>{{cite book| vauthors = Mann FG, Saunders BC |title=Practical Organic Chemistry|date=1975|publisher=Longman|location=London|isbn=9788125013808|pages=509–517|edition=4th}}</ref> and [[amygdalin beta-glucosidase]] (amygdalase) to give [[gentiobiose]] and <small>L</small>-[[mandelonitrile]]. Gentiobiose is further hydrolyzed to give [[glucose]], whereas mandelonitrile (the [[cyanohydrin]] of [[benzaldehyde]]) decomposes to give benzaldehyde and [[hydrogen cyanide]]. Hydrogen cyanide in sufficient quantities ([[Acceptable daily intake|allowable daily intake]]: ~0.6&nbsp;mg) causes cyanide poisoning which has a fatal oral dose range of 0.6–1.5&nbsp;mg/kg of body weight.<ref name="ATSDR 2014">{{cite web | title=Medical Management Guidelines (MMGs): Hydrogen Cyanide (HCN) | website=ATSDR | date=21 October 2014 | url=https://www.atsdr.cdc.gov/MMG/MMG.asp?id=1141&tid=249 | access-date=8 July 2019}}</ref>