Editing Onion (section)

=== Phytochemicals ===

Onion varieties vary widely in [[phytochemical]] content, particularly for [[polyphenol]]s, with shallots having the highest level, six times the amount found in [[Vidalia onion]]s. Yellow onions have the highest total [[flavonoid]] content, an amount 11 times higher than in white onions. Red onions have considerable content of [[anthocyanin]] [[pigment]]s, with at least 25 different compounds identified representing 10% of total flavonoid content.<ref name="jafc" /> Like [[garlic]],<ref>{{Cite journal |last=Lukes |first=T. M. |date=1986-11-01 |title=Factors Governing the Greening of Garlic Puree |journal=Journal of Food Science  |volume=51 |issue=6 |page=1577 |doi=10.1111/j.1365-2621.1986.tb13869.x}}</ref> onions can show an additional colour – pink-red – after cutting, an effect caused by reactions of [[amino acid]]s with sulfur compounds.<ref>{{Cite journal |last1=Lee |first1=Eun Jin |last2=Rezenom |first2=Yohannes H. |last3=Russell |first3=David H. |last4=Patil |first4=Bhimanagouda S. |last5=Yoo |first5=Kil Sun |date=2012-04-01 |title=Elucidation of chemical structures of pink-red pigments responsible for 'pinking' in macerated onion (''Allium cepa'' L.) using HPLC–DAD and tandem mass spectrometry |journal=Food Chemistry |volume=131 |issue=3 |pages=852–861 |doi=10.1016/j.foodchem.2011.09.059}}</ref> Onion polyphenols are under [[basic research]] to determine their possible biological properties in humans.<ref name="jafc">{{Cite journal |pmid=17997520 |year=2007 |last1=Slimestad |first1=R. |last2=Fossen |first2=T. |last3=Vågen |first3=I. M. |title=Onions: A source of unique dietary flavonoids |journal=Journal of Agricultural and Food Chemistry |volume=55 |issue=25 |pages=10067–10080 |doi=10.1021/jf0712503|bibcode=2007JAFC...5510067S }}</ref><ref>{{cite journal |last1=Olsson |first1=M.E. |last2=Gustavsson |first2=K.E. |last3=Vågen |first3=I.M. |name-list-style=amp |year=2010 |title=Quercetin and isorhamnetin in sweet and red cultivars of onion (''Allium cepa'' L.) at harvest, after field curing, heat treatment, and storage |journal=Journal of Agricultural and Food Chemistry |volume=58 |issue=4 |pages=2323–2330 |doi=10.1021/jf9027014 |pmid=20099844|bibcode=2010JAFC...58.2323O }}</ref>