Editing Cider apple (section)

=== Polyphenols and tannins ===
[[Polyphenol]]s are an important component of ciders, contributing astringency, bitterness, [[colloidal]] stability and colour.<ref>{{Cite journal|last1=Guyot|first1=Sylvain|last2=Marnet|first2=Nathalie|last3=Sanoner|first3=Philippe|last4=Drilleau|first4=Jean-François|date=2003|title=Variability of the Polyphenolic Composition of Cider Apple (Malus domestica) Fruits and Juices|journal=Journal of Agricultural and Food Chemistry|language=en|volume=51|issue=21|pages=6240–6247|doi=10.1021/jf0301798|pmid=14518950|bibcode=2003JAFC...51.6240G |issn=0021-8561}}</ref> The content in apples varies depending on cultivar, production practices, and part of the fruit, with the peel of an apple having more polyphenols than the flesh.<ref>{{Cite journal|last1=Thompson-Witrick|first1=Katherine A.|last2=Goodrich|first2=Katheryn M.|last3=Neilson|first3=Andrew P.|last4=Hurley|first4=E. Kenneth|last5=Peck|first5=Gregory M.|last6=Stewart|first6=Amanda C.|date=2014-10-06|title=Characterization of the Polyphenol Composition of 20 Cultivars of Cider, Processing, and Dessert Apples (Malus × domestica Borkh.) Grown in Virginia|journal=Journal of Agricultural and Food Chemistry|language=EN|volume=62|issue=41|pages=10181–10191|doi=10.1021/jf503379t|pmid=25228269|bibcode=2014JAFC...6210181T |issn=0021-8561}}</ref> The primary polyphenol in apples is [[procyanidin]]s, followed by [[hydroxycinnamic acid]]s in the flesh and [[flavonols]] in peel.<ref>{{Cite journal|last1=Khanizadeh|first1=Shahrokh|last2=Tsao|first2=Rong|last3=Rekika|first3=Djamila|last4=Yang|first4=Raymond|last5=Charles|first5=Marie Thérèse|last6=Vasantha Rupasinghe|first6=H.P.|date=2008|title=Polyphenol composition and total antioxidant capacity of selected apple genotypes for processing|journal=Journal of Food Composition and Analysis|volume=21|issue=5|pages=396–401|doi=10.1016/j.jfca.2008.03.004|issn=0889-1575}}</ref> Much of the polyphenols in the fruit are not pressed into the juice, because they bind to polysaccharides in the fruit cell wall, becoming bound to the [[pomace]], when the cell wall is ruptured during the pressing process.<ref name=":02">{{Cite journal|last1=Kahle|first1=Kathrin|last2=Kraus|first2=Michael|last3=Richling|first3=Elke|date=2005|title=Polyphenol profiles of apple juices|journal=Molecular Nutrition & Food Research|language=en|volume=49|issue=8|pages=797–806|doi=10.1002/mnfr.200500064|pmid=15991215 |issn=1613-4125}}</ref> Procyanidins are especially prone to binding to the pomace with about 30% extracted into the juice.<ref>{{Cite journal|last1=Guyot|first1=S.|last2=Le Bourvellec|first2=C.|last3=Marnet|first3=N.|last4=Drilleau|first4=J.F.|date=2002|title=Procyanidins are the most Abundant Polyphenols in Dessert Apples at Maturity|journal=LWT - Food Science and Technology|volume=35|issue=3|pages=289–291|doi=10.1006/fstl.2001.0843|issn=0023-6438}}</ref> Cider apples can have five times the total phenolic content compared to [[Table apple|dessert apples]], but there is a limited supply of bittersweet and bittersharp apples in the U.S. to meet the needs of the fast-growing cider industry.<ref name=":02"/> Some cider makers add exogenous [[tannin]]s to improve phenolic characteristics, and researchers are working on improving polyphenol extraction technology.<ref>Micah, Martin; Padilla-Zakour; Gerling (Spring 2017). "Tannin Additions to Improve the Quality of Hard Cider Made from Dessert Apples" (PDF). ''New York Fruit Quarterly''. '''25''': 25–28 – via New York State Horticultural Society.</ref> In countries with more well-established cider industries, such as the U.K. and France, there is an adequate supply of high tannin cider apples. About one half of the apples processed for cider in Europe are bittersweet fruit.<ref>{{Cite journal|date=2017|title=European Cider Trends|url=http://aicv.org/file.handler?f=CiderTrends2017.pdf|journal=The European Cider & Fruit Wine Association|archive-date=2018-05-15|access-date=2018-05-14|archive-url=https://web.archive.org/web/20180515112716/http://aicv.org/file.handler?f=CiderTrends2017.pdf|url-status=dead}}</ref>