J.Agric.FoodChem.2008,56,3341–33493341AnalysisofPhenolicCompoundsbyHigh-PerformanceLiquidChromatographyandLiquidChromatography/MassSpectrometryinPotatoPlantFlowers,Leaves,Stems,andTubersandinHome-ProcessedPotatoes††††HYONWOONIM,BONG-SOONSUH,SEUNG-UNLEE,NOBUYUKIKOZUKUE,‡§,§MAYUMIOHNISI-KAMEYAMA,CAROLE.LEVIN,ANDMENDELFRIEDMAN*DepartmentofFoodServiceIndustry,UidukUniversity,780-713,Gangdong,Gyeongju,Gyongbuk,Korea,MassAnalysisLaboratory,NationalFoodResearchInstitute,Tsukuba305-8642,Japan,andWesternRegionalResearchCenter,AgriculturalResearchService,U.S.DepartmentofAgriculture,Albany,California94710Potatoplantssynthesizephenoliccompoundsasprotectionagainstbruisingandinjuryfrombacteria,fungi,viruses,andinsects.Becauseantioxidativephenoliccompoundsarealsoreportedtoparticipateinenzymaticbrowningreactionsandtoexhibithealth-promotingeffectsinhumans,aneedexistsforaccuratemethodstomeasuretheircontentinfreshandprocessedpotatoes.Tocontributetoourknowledgeaboutthelevelsofphenoliccompoundsinpotatoes,wevalidatedandusedhigh-performanceliquidchromatographyandliquidchromatography/massspectrometrytomeasurelevelsofchlorogenicacid,achlorogenicisomer,andcaffeicacidinflowers,leaves,stems,andtubersofthepotatoplantandinhome-processedpotatoes.Thetotalphenolicacidcontentofflowers(626mg/100gfreshwt)was21and59timesgreaterthanthatofleavesandstems,respectively.Forallsamples,chlorogenicacidanditsisomercontributed96-98%tothetotal.Totalphenolicacidlevels(ing/100gfreshwt)ofpeelsoffivepotatovarietiesgrowninKorearangedfrom6.5to42.1andoftheflesh(pulp)from0.5to16.5,withpeel/pulpratiosrangingfrom2.6to21.1.Thetotalphenolicacidcontentfor25Americanpotatoesrangedfrom1.0to172.Thehighestamountswerepresentinredandpurplepotatoes.Homeprocessingofpulpwithvariousformsofheatinducedreductionsinthephenoliccontent.Thedescribedmethodologyshouldfacilitatefuturestudiesontheroleofpotatophenoliccompoundsintheplantandthediet.KEYWORDS:Potatoes;flowers;leaves;chlorogenicacid;caffeicacid;HPLC;LC/MS