Editing Polyphenol (section)

====Extraction====
[[Extraction (chemistry)|Extraction]] of polyphenols<ref>{{cite book| vauthors = Escribano-Bailon MT, Santos-Buelga C |chapter=Polyphenol Extraction From Foods | veditors = Santos-Buelga C, Williamson G |title=Methods in Polyphenol Analysis|publisher=Royal Society of Chemistry|year=2003|isbn=978-0-85404-580-8|pages=1–16|chapter-url=http://kurdchemists.org/files/Polyphenols.pdf}}</ref> can be performed using a solvent like water, [[hot water extraction|hot water]], methanol, methanol/formic acid, methanol/water/acetic or formic acid. [[Liquid–liquid extraction]] can be also performed or [[countercurrent chromatography]]. [[Solid phase extraction]] can also be made on C18 sorbent cartridges. Other techniques are ultrasonic extraction, heat reflux extraction, microwave-assisted extraction,<ref>{{cite journal| vauthors = Pan X |year=2003|title=Microwave-assisted extraction of tea polyphenols and tea caffeine from green tea leaves|journal=Chemical Engineering and Processing|volume=42|issue=2|pages=129–133|doi=10.1016/S0255-2701(02)00037-5|bibcode=2003CEPPI..42..129P }}</ref> [[critical carbon dioxide]],<ref name=":0">{{cite journal | vauthors = Aizpurua-Olaizola O, Ormazabal M, Vallejo A, Olivares M, Navarro P, Etxebarria N, Usobiaga A | title = Optimization of supercritical fluid consecutive extractions of fatty acids and polyphenols from ''Vitis vinifera'' grape wastes | journal = Journal of Food Science | volume = 80 | issue = 1 | pages = E101–E107 | date = January 2015 | pmid = 25471637 | doi = 10.1111/1750-3841.12715 }}</ref><ref>{{cite journal | vauthors = Palma M, Taylor LT | title = Extraction of polyphenolic compounds from grape seeds with near critical carbon dioxide | journal = Journal of Chromatography A | volume = 849 | issue = 1 | pages = 117–124 | date = July 1999 | pmid = 10444839 | doi = 10.1016/S0021-9673(99)00569-5 }}</ref> high-pressure [[Extract#Extraction techniques|liquid extraction]]<ref>{{cite journal | vauthors = Alonso-Salces RM, Korta E, Barranco A, Berrueta LA, Gallo B, Vicente F | title = Pressurized liquid extraction for the determination of polyphenols in apple | journal = Journal of Chromatography A | volume = 933 | issue = 1–2 | pages = 37–43 | date = November 2001 | pmid = 11758745 | doi = 10.1016/S0021-9673(01)01212-2 }}</ref> or use of ethanol in an immersion extractor.<ref>{{cite journal| vauthors = Sineiro J, Domínguez H, Núñez MJ, Lema JM |year=1996|title=Ethanol extraction of polyphenols in an immersion extractor. Effect of pulsing flow|journal=Journal of the American Oil Chemists' Society|volume=73|issue=9|pages=1121–1125|doi=10.1007/BF02523372|s2cid=96009875}}</ref> The extraction conditions (temperature, extraction time, ratio of solvent to raw material, particle size of the sample, solvent type, and solvent concentrations) for different raw materials and extraction methods have to be optimized.<ref name=papoutsis2018a>{{cite journal|title=Screening the effect of four ultrasound-assisted extraction parameters on hesperidin and phenolic acid content of aqueous citrus pomace extracts|journal=Food Bioscience|date=2018|pages=20–26|volume=21|last1=Papoutsis|doi=10.1016/j.fbio.2017.11.001|first1=Konstantinos |last2=Pristijono |first2=Penta |last3=Golding |first3=John |last4=Stathopoulos |first4=Costas |last5=Bowyer |first5=Michael |last6=Scarlett |first6=Christopher |last7=Vuong |first7=Quan|url=https://rke.abertay.ac.uk/ws/files/14225156/Stathopoulos_ScreeningTheEffectOfFourUltrasound_AssistedExtractionParameters_Author_2017.pdf }}</ref><ref name=papoutsis2018b>{{cite journal|title=Pretreatment of citrus by-products affects polyphenol recovery: a review|journal=Food Reviews International|date=2018|pages=770–795|volume=34|last1=Papoutsis|doi=10.1080/87559129.2018.1438471|first1=Konstantinos |last2=Vuong |first2=Quan |last3=Golding |first3=John |last4=Hasperué |first4=Joaquín |last5=Pristijono |first5=Penta |last6=Bowyer |first6=Michael |last7=Scarlett |first7=Christopher |last8=Stathopoulos |first8=Costas|issue=8 |hdl=11336/87660 |s2cid=89981908 |url=https://rke.abertay.ac.uk/ws/files/14378631/Stathopoulos_PretreatmentOfCitrusBy_ProductsAffectsPolyphenolRecovery_Author_2018.pdf }}</ref>

Mainly found in the fruit skins and seeds, high levels of polyphenols may reflect only the ''measured extractable'' polyphenol (EPP) content of a fruit which may also contain non-extractable polyphenols. Black tea contains high amounts of polyphenol and makes up for 20% of its weight.<ref>{{cite journal | vauthors = Arranz S, Saura-Calixto F, Shaha S, Kroon PA | title = High contents of nonextractable polyphenols in fruits suggest that polyphenol contents of plant foods have been underestimated | journal = Journal of Agricultural and Food Chemistry | volume = 57 | issue = 16 | pages = 7298–7303 | date = August 2009 | pmid = 19637929 | doi = 10.1021/jf9016652 | hdl = 10261/82508 }}</ref>

Concentration can be made by [[ultrafiltration]].<ref>{{cite journal| vauthors = Nawaz H, Shi J, Mittal GS, Kakuda Y |year=2006|title=Extraction of polyphenols from grape seeds and concentration by ultrafiltration|journal=Separation and Purification Technology|volume=48|issue=2|pages=176–181|doi=10.1016/j.seppur.2005.07.006}}</ref> Purification can be achieved by [[preparative chromatography]].