Evaluationof50CaliforniaOliveOilSamplesatLeastOneYearafterHarvest

2017

Submittedtothe

OliveOilCommissionofCalifornia

August2018

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Evaluationof50Californiaoliveoilsamplesatleastoneyearafterharvest

TheOliveOilCommissionofCalifornia(OOCC)contractedwiththeUCDavisOliveCentertoanalyze50Californiaoliveoilsamplespurchasedfromretailoutletsthatwereapproximatelyoneyearormorefromtheharvestdates.Thisreportsummarizesthedata,evaluatestheresultsandprovidesrecommendations.

METHODOLOGY

Thestudyteamexaminedtwoprimarysourcesindeterminingretailoutletsinwhichtopurchasesamples:

• UnitedStatesDepartmentofAgriculture(USDA).ThestudyteamconsultedthewebsitefortheUSDAEconomicResearchService(ERS)forinformationonretailtrends.TheUSDAwebsiteincludesa2017reportwithrecentinformationonretailexpendituresforfoodtoconsumeathome.Thereportfoundthat traditional foodstores (primarily supermarketsofmore than9,000square feetwithnonfoodsalesunder15percent,suchasSafewayandTraderJoe’s)accountedfor61percentoffood-at-homeexpendituresasof2012.Marketshareforsupermarketshasslippedsince1999,whenthesharewas80 percent. Expenditures at supercenters, which are mass merchandisers combined with fullsupermarkets(e.g.,WalmartSupercenterandSuperTarget),havegrownfrom3percentto18percentbetween1999and2012.Clubstores,whicharelarge-formatstoresrequiringmembership,suchasCostco and Sam’s Club, accounted for 9 percent of food-at-home sales, followed by massmerchandisers,whicharelargedepartmentstoresthatcarrylimitedgroceryproducts,suchasolderWalmartandTargetstores,accountingfor3percentofexpenditures.Drugstores,dollarstoresandconveniencestorescombinedfor5percentofexpenditures,andotheroutletssuchascommissariesandfarmers’marketsaccountedfor4percent.1

• IRIdata.ThestudyteamconsulteddatafromInformationResources,Inc.(IRI)onoliveoilbrandsalesat several large food stores and supercenters, aswell as aggregate data for private label brands,examiningdatafora52-weekperiodendingOctober2,2016.

Thestudyteamalsowasinterestedingettingabroadrangeofsamplesfromasinglemetropolitanarea.ThisyearthestudyteamfocusedontheFresnometropolitanarea,whichisthe7thlargestmetropolitanstatisticalareainCaliforniaand55thlargestinthenation.2ThestudyteamcompiledalistofretailoutletsinFresnotoapproximatethesalesdescribedintheUSDAandIRIdata.Forty-foursampleswerepurchasedin theFresnoareaonOctober25andOctober26,2017 fromdelimarkets, supermarkets,warehouseclub/supercenterstores,andatastingroom;sixsampleswerecollectedthroughtheUCDavisStudentHousingDiningServiceonNovember22,2017.Thestudyteamoversampledfromdelicatessenstotakeinabroaderrangeofbrandsthaninthepreviousstudy,toaccountforthelimitednumberofCaliforniabrandsatsupercentersandclubstores,andinrecognitionthatCaliforniabrandsarelargelyabsentfromdrugstores,dollarstoresandconveniencestores.

1Volpe,R.,Kuhns,A.,&Jaenicke,T.(2017).StoreFormatsandPatternsinHouseholdGroceryPurchases.EconomicResearchServiceattheUnitedStatesDepartmentofAgriculture.2Wikipedia,“Listofmetropolitanstatisticalareas,”rankasofJuly1,2017asestimatedbytheUnitedStatesCensusBureau.

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Intotal,thestudyteampurchased50extravirginoliveoilsamples:30samples(60percent)fromsevensupermarkets, nine samples (18percent) from twodelicatessens andanoliveoil specialty store, foursamples(8percent)fromtwosupercenters,onesample(2percent)fromaclubstoreandsixsamples(12percent)throughtheUCDavisStudentHousingDiningService.Therewere23brandsrepresentedinthe50samples,comparedto18brandsinthepreviousyear’sstudy.

Thirty-one samples (62 percent) came from OOCC members, 14 samples (28 percent) came fromproducersthatwerenotOOCCmembers(duringtheyearwhentheoilswereproduced)andfivesamples(10percent)camefromstorebrandsthatpresumablyweresourcedfromOOCCmembers.

The study teamminimized the impactof heat and lightduring the collectionprocessby covering thesamples in the vehicle and parking in the shade when possible. The temperature in the vehicletransportingthesamplesrangedfrom67°Fto81.5°F,withthehighertemperaturesoccurringforbriefperiodswhilethestudyteamwasinastorepurchasingsamples.SamplesweretakentotheUCDavisOliveCenterLaboratory,wherethesampleswereprotectedfromlightandstoredat65°Fto68°F.

All sampleswere analyzedbasedonCaliforniaoliveoil standards.Adescriptionof the chemistry andsensorytestsaddressedinthestandardsareinTable1.

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TABLE1.Chemistryandsensorytestsforoliveoilqualityanalysis

PARAMETER DETERMINATION INDICATOR METHODOLOGY CAEVOOSTANDARD

FreeFattyAcids(FFA)

Freefattyacidsareformedbythehydrolysisofthetriacylglycerolsduringextraction,processingandstorage.

Anelevatedleveloffreefattyacidindicateshydrolyzedfruitsand/orpoorqualityoilmadefromunsoundfruit,improperlyprocessedorstoredoil.

AnalyticalTitration ≤0.5%asoleicacid

PeroxideValue(PV)

Peroxidesareprimaryoxidationproductsthatareformedwhenoilsareexposedtooxygen,producingundesirableflavorsandodors.

Anelevatedlevelofperoxidesindicatesoxidizedand/orpoorqualityoil.

AnalyticalTitration ≤15meqO2/kgoil

Ultravioletabsorbance(UV)

Conjugateddoublebondsareformedfromnaturalnonconjugatedunsaturationinoilsuponoxidation.TheK232measuresprimaryoxidationproductsandK270measuressecondaryoxidationproducts.

AnelevatedlevelofUVabsorbanceindicatesoxidizedand/orpoorqualityoil.

UVspectrophotometry

K232:≤2.40K1%1cm;K270:≤0.22K1%1cm;ΔK:≤0.01K1%1cm

1,2-Diacylglycerols(DAGs)

Freshextravirginoliveoilcontainsahighproportionof1,2-diacylglycerolsto1,2-and1,3-diacylglycerols,whileoliveoilfrompoorqualityfruitsandrefinedoliveoilshavehigherlevelof1,3-DAGsthanfreshextravirginoliveoils.

Alowratioof1,2-diacylglycerolsto1,2-and1,3-diacylglycerolsisanindicatorforoilthatishydrolyzed,oxidized,and/orofpoorquality.

GasChromatography(GC)

≥35%

Pyropheophytins(PPP)

Chlorophyllpigmentsbreakdowntopheophytinsandthenpyropheophytinsuponthermaldegradationofoliveoil.

Anelevatedlevelofpyropheophytinsisanindicatorforoilthatisoxidizedand/oradulteratedwithrefinedoil.

Highperformanceliquidchromatography(HPLC)

≤17%

Sensory Sensoryreferstotaste,odorandmouthfeel

Sensoryassessmentcanhelpidentifyoilsthatareofpoorquality,oxidized,and/oradulteratedwithotheroils.

IOC-recognizedpanelof8-12peopleevaluatesoilsforsensorycharacteristics.

Medianofdefects=0.0;medianofthefruity>0.0

InductionTime Theagingprocessisacceleratedbymeansofheatingupthereactionvesselandbypassingaircontinuouslythroughthesample.

Oxidativestability(inhours)denotestheresistanceofoilstooxidation.Thelongertheinductiontime,themorestablethesampleis.

Rancimat(120°C,20L/h,3g)

NotrequiredinCaliforniaoliveoilstandards

The UC Davis Olive Center Laboratory conducted chemistry analysis of the samples in January andFebruary2018.Whenasamplefailedchemistryanalysis,itwassentittotheEurofinsCentralAnalyticalLaboratoriesinNewOrleansforretesting.

SensoryanalysiswasperformedbythepanelmanagedbyAppliedSensory,LLCinDecember2017.ThepanelisaccreditedbytheAmericanOilChemists’Society.ForsamplesthatfailedthesensorystandardforExtraVirgingrade,thepanelre-evaluatedtheminJanuary2018.

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The study team considered a sample to have failed California extra virgin standards if it failed anychemistrystandardfrombothlaboratoriesand/orfailedbothsensorypaneltests.

STOREINFORMATION

Ateachwarehouse/supercenterandtraditional foodstore/supermarket, thestudy teamrecordedthetemperature from the bottom shelves and top shelves of the olive oil section by using an infraredthermometer.AsshowninFigure1,minimumtemperaturesatthebottomshelvesrangedfrom65°Fto75°Fandmaximumtemperaturesfromthetopshelvesrangedfrom68.5°Fto76.5°F.Thesetemperatureswerewarmerthanthe2016study,inwhichtheminimumstoretemperaturesrangedfrom60°Fto70°Fandthemaximumtemperaturesrangedfrom65°Fto73°F.3

FIGURE1.Temperatureatshelf(°F)

Thestudyteamcountedthenumberofoliveoilbrandsforallgrades,thenumberofselectionsforallbrands,andthenumberofCaliforniaoliveoilbrandsandselections,includingflavoredoliveoils.AsshowninFigure2,thenumberofalloliveoilselectionsrangedfromalowoffourtoahighof74(lastyeartherangewasfourto80)andtheCaliforniaselectionsrangedfromoneto20(lastyeartherangewasfromoneto34).

3Evaluationof50CaliforniaOliveOilatMarketplaces(2016).UCDavisOliveCenter.

75

69.5 68.571

68.5 67.5 67

70.5

6567

71.5 72.5

76.5

73 72.5 73.571.5

73.5

68.5

73

69.5 68.5

72 73

6062646668707274767880

BottomShelf TopShelf

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FIGURE2.Numberofoliveoilsateachstore

Thestudyteamalsomeasuredtheamountoflinearshelfspaceoccupiedbyoliveoilofallgrades,aswellastheproportionofCaliforniaoliveoilofthattotal.Figure3showstheresultsininches,withalowof86inchesatDelimarket#1toahighof564inchesatSupermarket#1foralloliveoils(therangelastyearwas102 inchesto575 inches),anda lowofnine inchesatSupermarket#7toahighof134 inchesatSupermarket #1 for California olive oils (the range last year was from 10 inches to 255 inches). Thepercentage of California olive oils ranged from a low of eight percent at both Supermarket #7 andWarehouse/Supercenter#1toahighof41percentatDelimarket#1(therangelastyearwasfiveto55percent.)

FIGURE3.Shelfspace(inches)foroliveoilsateachstore

9 9 20 9 1 8 5 152 5 4 1

16 27

74

31 1226 36

42

23

64

24 40

102030405060708090100

CaliforniaOliveOils AllOliveOils

35 71 134 37 12 27 31 1119 32 33 18

86257

564

355

140 130204

340

119

421

162 1740

100200300400500600700800

CaliforniaOliveOils AllOliveOils

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Thestudyteamrecordedtheplacementofthesamplesonstoreshelves.Placementonthetopshelfisundesirablebecauseithasthewarmesttemperatureandthegreatestexposuretolight,whichcanhastentheagingoftheoil.Figure4showstheshelvinglocationsofthesamples.Sevenpercentofthesamplesweretakenfromthetopshelf(comparedto19percentinthepreviousyear),and47percentofsamplesweretakenfromthenexttwoshelvesbelow(comparedto53percentinthepreviousyear).

FIGURE4.Shelvinglocationforthepurchasedsamplesfromstores

CHEMISTRYANDSENSORYRESULTS

Ofthe31samplesfromtheOOCCmembers,74percent(23samples)metCaliforniaExtraVirginstandards(lastyearthepassageratewas90percent).Ofthe14samplesnotoverseenbytheOOCC,50percent(7samples) met the standards. This was an improvement over last year’s passage rate for non-OOCCsamples, which was 18 percent. Eighty percent of the five store-brand samples (4 samples)met thestandards(lastyeartheratewas88percent).Noclearcorrelationbetweenthefailedsamplesandtheshelvinglocation(Figure4)wasobserved.

Figure5 shows thatall the samplespassed theFFAandΔK testsata100percent rate.The31OOCCsamples passed the rest of the tests at rates above 90 percent except for sensorywith a 77 percentpassagerate.Fourofthefivestore-brandsamplespassedalltests,withonesamplefailingtheK232andK270UVtests.The14samplesfromnon-OOCCmembershadlowerpassratesthaneithertheOOCCorstore-brandsamplesformosttests:PV(86percent),K270(86percent),K232(79percent),PPP(79percent)andsensory(57percent)andDAGs(93percent).

TopShelf7%

SecondShelf23%

ThirdShelf24%

FourthShelf19%

FifthShelf17%

SixthShelf10%

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FIGURE5.PassrateforOOCCmembersandnon-members(%)

Overall,68percentofthe50samples(34samples)passedallCaliforniaExtraVirginstandards(lastyeartheratewas74percent)and32percent(16samples)failedatleastoneCaliforniastandardforthegrade(lastyear26percent).ThepercentageofsamplespassingorfailingeachtestissummarizedinFigure6.One-hundredpercentofsamplespassedthestandardsforFFAandΔK;96percentpassedthestandardforDAGs;94percentpassedthestandardforPV;92percentpassedthestandardforK270;90percentpassedthestandardforPPP;88percentpassedthestandardforK232;and74percentpassedthestandardforsensory.

FIGURE6.Passagerateforthe50samples;CAEVOOstandards(%)

Table2showsthechemistryandsensorydataforthe50samples.Ofthe16samplesnotclassifiedasExtraVirgingrade,11mettheCaliforniastandardforVirgingrade(Samples1,3,8,12,14,19,21,37,43,45and47)andfivemettheCaliforniastandardforCrudegrade(Samples6,23,27,29and39).Thedistributionofchemistryresults issummarized inFigures7–12.ThedistributionofpositiveandnegativesensoryattributesisshowninFigure13.

100 97 94 97 100 97 94

77

100

8679

86

100 93

79

57

100 100

80 80

100 100 100 100

0102030405060708090100

FFA PV K232 K270 ΔK DAGs PPP Sensory

OOCCMembers(31) Non-OOCCMembers(14) StoreBrands(5)

100 9488 92 100 96

90

74

0102030405060708090

100

FFA PV K232 K270 ΔK DAGs PPP Sensory

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TABLE2.Chemistryandsensorydataforthe50samples

SAMPLE#

HARVESTYEAR FFA PV K232 K270 ΔK DAGs PPP INDUCTION

TIMESENSORYDEFECTS GRADE

≤0.5 ≤15 ≤2.40 ≤0.22 ≤0.01 ≥35 ≤17 N/A MeD=0.0 ExVirgin ≤1.0 ≤20 ≤2.60 ≤0.25 ≤0.01 N/A N/A N/A 0.0<MeD≤2.5 Virgin >1.0 >20 >2.60 >0.25 ≤0.01 N/A N/A N/A MeD>2.5 Crude1 2016 0.15 9.1 2.01 0.14 0.00 49 26 11.7 Rancid:0.9,1.0 Virgin2 2016 0.19 13.1 2.15 0.13 0.00 57 8 8.5 ExtraVirgin3 2016 0.35 14.7 2.37 0.15 0.00 38 19 6.1 Rancid:0.6,0.7 Virgin4 2016 0.20 5.3 1.60 0.11 0.00 59 10 12.3 ExtraVirgin5 2015 0.16 8.0 1.93 0.13 0.00 48 15 10.6 ExtraVirgin6 2016 0.16 18.4 3.15 0.15 0.00 53 17 7.1 Crude7 2016 0.20 10.6 2.23 0.17 0.00 59 15 9.6 ExtraVirgin8 2016 0.31 9.8 2.18 0.13 0.00 41 13 7.9 Rancid:0.6,0.8 Virgin9 2016 0.22 6.2 1.57 0.09 0.00 58 9 8.1 ExtraVirgin10 2016 0.33 6.8 1.68 0.14 0.00 41 15 13.2 ExtraVirgin11 2016 0.15 5.5 1.72 0.13 0.00 66 11 14.0 ExtraVirgin12 2016 0.49 8.5 2.24 0.21 0.00 36 14 16.8 Rancid:1.0,0.5 Virgin13 2016 0.18 8.9 1.97 0.12 0.00 62 11 11.5 ExtraVirgin14 2016 0.27 7.5 1.71 0.12 0.00 41 15 8.8 Rancid:0.5,1.0 Virgin15 2016 0.30 4.7 1.77 0.12 0.00 41 16 9.3 ExtraVirgin16 N/A 0.19 4.8 1.79 0.15 0.01 49 13 8.4 ExtraVirgin17 2016 0.18 6.0 1.81 0.17 0.00 59 13 13.4 ExtraVirgin18 2016 0.22 6.6 1.69 0.12 0.00 47 14 9.8 ExtraVirgin19 2016 0.27 2.3 1.71 0.13 0.00 40 17 9.2 Rancid:0.9,0.9 Virgin20 2016 0.19 2.9 1.68 0.14 0.00 55 15 9.8 ExtraVirgin21 2016 0.47 6.6 1.62 0.13 0.00 38 10 10.5 Rancid:0.5,0.8 Virgin22 2016 0.23 6.7 1.72 0.11 0.00 45 13 9.5 ExtraVirgin23 2015 0.23 18.5 3.37 0.24 0.00 41 17 5.9 Rancid:1.2,1.3 Crude24 2016 0.20 5.8 1.70 0.12 0.00 43 17 10.9 ExtraVirgin25 2016 0.31 6.8 1.72 0.13 0.00 36 12 12.0 ExtraVirgin26 2016 0.27 7.1 1.83 0.11 0.00 41 14 9.4 ExtraVirgin27 2015 0.21 10.4 2.46 0.28 0.01 43 32 10.8 Rancid:1.1,1.3 Crude28 2016 0.27 6.4 1.84 0.12 0.00 43 13 9.3 ExtraVirgin29 2016 0.17 11.1 3.13 0.27 0.01 45 17 7.4 Crude30 2016 0.26 6.6 1.83 0.12 0.00 46 14 10.4 ExtraVirgin31 2016 0.31 6.5 1.49 0.11 0.00 38 16 10.5 ExtraVirgin32 2016 0.21 6.6 1.67 0.09 0.00 45 13 8.6 ExtraVirgin33 2016 0.30 7.3 1.55 0.13 0.00 37 14 11.9 ExtraVirgin34 2016 0.28 8.3 1.82 0.10 0.00 42 13 8.9 ExtraVirgin35 2016 0.28 7.4 1.76 0.10 0.00 42 14 9.5 ExtraVirgin36 2016 0.29 8.4 1.86 0.11 0.00 38 16 8.8 ExtraVirgin37 2016 0.18 8.3 1.98 0.12 0.00 49 21 11.1 Virgin38 2016 0.23 5.7 1.57 0.09 0.00 47 17 11.5 ExtraVirgin39 2014 0.35 25.5 3.74 0.26 0.00 33 17 4.1 Rancid:1.5,1.9 Crude40 2016 0.30 10.1 1.99 0.12 0.00 46 10 8.6 ExtraVirgin41 2016 0.32 9.2 1.97 0.15 0.00 40 13 11.4 ExtraVirgin42 2016 0.18 7.9 1.91 0.15 0.00 61 13 13.5 ExtraVirgin43 2016 0.37 7.7 1.68 0.14 0.00 34 19 9.4 Rancid:0.7,1.0 Virgin44 2016 0.43 9.8 2.32 0.22 0.01 37 15 17.5 ExtraVirgin45 2016 0.28 12.5 2.55 0.12 0.00 38 11 6.4 Rancid:0.4,0.8 Virgin46 2016 0.27 7.8 1.86 0.11 0.00 42 12 9.1 ExtraVirgin47 2016 0.17 9.2 1.92 0.13 0.00 54 15 9.5 Rancid:1.5,1.9 Virgin48 2016 0.18 6.6 1.82 0.11 0.00 64 12 12.7 ExtraVirgin49 2016 0.18 6.4 1.86 0.17 0.00 63 14 13.4 ExtraVirgin50 2016 0.22 3.6 1.45 0.09 0.00 52 12 12.7 ExtraVirgin

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Theperformanceofthe50samplesforeachofthetestsinTable2isanalyzedbelow.

FFAFreefattyacids,whichareflavorless,comefromthebreakdownoftriacylglycerolsthroughachemicalreactioncalledhydrolysis.FactorsthatcanleadtoahighFFAinanoilincludepoorqualityoffruit,fruitflyinfestation, fungal diseases, delays between harvesting and milling, poor extraction methods andimproperstorageoftheoil(suchasonsediment).AllsampleshadFFAvaluesbelowtheCaliforniaExtraVirginstandardof0.5.Forty-sixof50samples(92percent)hadFFAvaluesrangingfrom0.15–0.35withonly foursampleshavingFFAvaluesabove0.35.FFAvaluesdonotchangesubstantiallyunderproperstorageconditionsduringtheshelflifeoftheoil.

FIGURE7.Freefattyacidity(CAEVOO≤0.5)

PVPeroxidevalueisacrudemeasurementofinitialoxidationintheoil.Oxidationcancauseperoxidestotransform intoaldehydes andother compounds that are responsible for rancid flavors.Oxidation is anaturalprocessandPV is expected to increaseas theoil ages, althoughPVcan laterdecreaseas theprimaryoxidationproductstransformduringsecondaryoxidation.Threesamples(Samples6,23and39)hadPVgreaterthan15whichwouldplacethemintheVirgingrade.Allthreesamplesfailedatleastoneother Extra Virgin chemistry standard, including one of theUV tests and/or sensory. All of the failedsampleswereoxidized,likelyduetonaturalagingorsuboptimalstorageortransportconditions.Similartolastyear,otherrancidsamplespassedthePVExtraVirginstandard,suggestingthelimitationsofthePVtestinassessingoliveoilquality.

FIGURE8.Peroxidevalue(CAEVOO≤15)

0.000.100.200.300.400.500.60

1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41 43 45 47 49

FFA

Sample#

0.05.0

10.015.020.025.030.0

1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41 43 45 47 49

PV

Sample#

10

K232SimilartoPV,K232measuresinitialoxidationproductsintheoil.Samples27and45hadK232valuesbetween 2.40 and 2.60whichwould place them in the Virgin gradewhile Samples 6, 23, 29 and 39exceeded2.60whichwouldcategorizethemasCrudegrade.Fourofthesesixsamplesalsohadranciddefects and elevated PV (greater than 10). These oils were oxidized, likely due to natural aging orsuboptimalstorageortransportconditions.

FIGURE9.AbsorbencyinultravioletK232(CAEVOO≤2.40)

K270K270(orK268)measuressecondaryoxidationproducts,whichindicatethatoxidationhasadvancedpastinitialoxidation.Foursamples(Samples23,27,29and39)exceededtheCaliforniaExtraVirginstandardof0.22whileoneExtraVirginsample(Sample44)wasontheK270borderlineof0.22.ThefailedsampleshadK270valuesrangingfrom0.24to0.28,andthreeofthemwouldmeettheCrudestandard(K270>0.25).ThreeofthefoursamplesalsohadahighlevelofK232(greaterthan2.40)andasignificantintensityofranciddefect(greaterthan1.0),suggestingthatadvancedoxidationhastakenplace.Threeofthefoursampleswereamongtheoldestinthestudy(twoyearsormorefromharvest).

ΔKΔKmeasuresthedifferencebetweentheabsorbanceat270nmand266-274nm,andisusefultodetectthepresenceofrefinedorpomaceoil.AllsampleswerebelowtheCaliforniaExtraVirginstandardof0.01.

FIGURE10.AbsorbencyinultravioletK270(CAEVOO≤0.22)

DAGsDiacylglycerolsareformedwhenatriacylglycerolmoleculeundergoeshydrolysis.TheresultingDAGcontainstwofattyacidsonaglycerolbackboneina1,2position.Asoilagesorisheated,thesemolecules

0.00

1.00

2.00

3.00

4.00

1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41 43 45 47 49

K 232

Sample#

0.000.050.100.150.200.250.30

1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41 43 45 47 49

K 270

Sample#

11

equilibrate, inapredictableand linearmanner, toa1,3positon.TheDAGstestassessestheextentofaging or heating by analyzing the ratio of 1,2 and 1,3 DAGs. DAGs are also related to the hydrolysisreaction,inamannersimilartoFFA,andthereforecanbeaffectedbythequalityofolivesandpost-harvestpractices.AhighlevelofFFAinfreshoilandelevatedstoragetemperatureaffecttherateofhydrolysisandcauseDAGstodecreasemorerapidly.Afreshhigh-qualityoilwillhaveaDAGsratioabove90percent,and thispercentagewilldropas theoilagesand the fattyacids shift fromthe1,2position to the1,3position.Becausethesamplesinthisstudyweretestedayearormoreafterharvest,itisreasonablethatnoneofthesampleswouldhavethehighDAGsvaluesfoundinfreshoils(>90percent).Twosamples(Samples39and43)failedtheCaliforniaExtraVirginstandardwithDAGsvaluesbelow35.Anadditionalninesamples(Samples3,12,21,25,31,33,36,44and45)hadborderlineDAGslevelsbetween36and38,withfourofthesesamplescategorizedbysensoryanalysisasVirgingrade.

FIGURE11.1,2-Diacylglycerols(CAEVOO≥35)

PPPPyropheophytinsaredegradationproductsofchlorophyllaasaresultofagingorheating.Chlorophyllaconvertstopheophytinsaandthentopyropheophytinsa.Theratioofpyropheophytinatothetotalpheophytinsisusefultodetectoilsthatareagedorhavebeenheatedintherefiningprocessasthisratioincreaseslinearlywithtime.Fivesamples(Samples1,3,27,37and43)exceededtheCaliforniaExtraVirginstandardof17.Fourofthesesamplesfailedotherstandardsandhadranciddefects.Thesesamplesmayhavebeenstoredinsuboptimalpackagingorconditionsastemperatureandlightcansignificantlyaffecttherateofchlorophylladegradation.

FIGURE12.Pyropheophytins(CAEVOO≤17)

010203040506070

1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41 43 45 47 49

DAGs

Sample#

0

10

20

30

40

1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41 43 45 47 49

PPP

Sample#

12

SensoryThirteensamples(Samples1,3,8,12,14,19,21,23,27,39,43,45and47)failedtheExtraVirgingradeforbothsensorypanelevaluations.AllofthesesampleshadaranciddefectwithintheVirgingrade(medianofdefectof≤2.5).Therewasgenerallyastrongrelationshipbetweenthesensoryresultsandchemistry results: seven of the 13 samples that failed the sensory standard also failed at least onechemistrystandard(Samples1,3,23,27,39,43and45).Threeofthefoursamplesthathadthemedianofranciddefectover1.0alsohadhighvaluesofK232and/orK270whileoneofthefourhadasignificantlyelevatedvalueofPPPat32–allfoursampleswerecategorizedasCrudegrade.

FIGURE13.Mediumscoresofsensoryattributesonrancid,fruitiness,bitternessandpungency

Induction time In addition to analyzing the samples for the quality parameters in California olive oilstandards,theresearchteamalsomeasuredinductiontimeusingaRancimatinstrument.Inductiontimeestimates a sample’s oxidative stability by accelerating the aging process. The Rancimat subjects thesample to excessive heatwhile passing air continuously through the sample. Induction time allows asimpleassessmentof the relative stabilityofoils, although themethoddoesnotprovideanaccurateassessmentofshelflifeduetothecomplexchemicalreactionsthatoccurduringtheoxidativeprocess.Figure14showsthatinductiontimeforthe50samplesrangedfrom4.1hoursto17.5hours.Ifinductiontime accurately predicted shelf life then one would expect that oils that fail Extra Virgin standards(indicatedbyreddotsFigure14)wouldhavethelowestinductiontimes,however,only11outof16failedsampleshadinductiontimelowerthan10hours(Samples3,6,8,14,19,23,29,39,43,45and47).

FIGURE14.Inductiontimeofoliveoilsamples

0.00.51.01.52.02.53.03.54.0

1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41 43 45 47 49

MeD

Sample#

Rancid

Fruitiness

Bitterness

Pungency

0.0

5.0

10.0

15.0

20.0

1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41 43 45 47 49

Indu

ctionTime

Sample#

13

COMPARING2016RESULTSTO2017RESULTS

Thestudyteamcomparedtheresultsofthisstudyandlastyear’sstudytoprovidesomeinsightsastopotential reasons forwhy the values in the 2016 data differed in someways from the 2017 data. Inprovidingthiscomparison,itisimportanttobearinmindthatthesamplesetswerenotidenticalinthetwostudies.Forexample,the2016studyincluded18brandswhilethe2017studyhad23brands.Eightypercentofthe2016samplescamefromsupermarketscomparedto60percentforthe2017samples.Ahigherproportionofthe2016samplescamefromthelargestprocessors(54percent)comparedto2017(48percent).Withthesecaveatsinmind,weexaminekeydifferencesinthe2017datacomparedtothe2016data.

Slightlywiderand/or less favorablerangeforsomechemistry tests in2017comparedto2016ExtraVirginsamplescollectedfromFresnoandSanJoaquinCountiesin2017hadslightlywiderrangesforFFA,PV,K270andΔKcompared toExtraVirgin samples collected fromtheSacramento region in2016. Thevaluesin2017cameclosertothelimitsforthegradethanin2016.

ForDAGs,the2017datarangeof36to66waslessfavorablecomparedto2016(43to74).HigherDAGsvaluesarefoundinfresheroliveoilsamples.

TABLE3.ComparisonofrangeofvaluesforsamplesgradedasExtraVirginin2016and2017

EVOOSAMPLERANGE CALIMIT

YEAROFSTUDY 2016(37outof50samples)

2017(34outof50samples)

STORELOCATION(COUNTY) Yolo,SacramentoandSonoma FresnoandSanJoaquin FFA 0.13-0.31 0.15-0.43 ≤0.5PV 3.9-12.5 2.9-13.1 ≤15.0K232 1.11-2.34 1.45-2.32 ≤2.40K270 0.07-0.19 0.09-0.22 ≤0.22ΔK 0.00-0.00 0.00-0.01 ≤0.01

DAGs 43-74 36-66 ≥35PPP 6-17 8-17 ≤17

PercentageofExtraVirginsampleswaslowerforOOCCsamplesin2017Table4comparesthegradeofthe samples collected in 2016 to the grade of samples collected in 2017. The total number ofOOCCsampleswasthesameforbothyearsat62percent(31of50samples),however,thepercentageofExtraVirginsamplesdecreasedfrom90percent(28of31samples)to74percent(23of31samples)from2016to 2017while the numbers of Virgin samples increased from10 percent (three of 31 samples) to 19percent(sixof31samples)andCrudesamplesfromzerotosixpercent(twoof31samples).Table4alsoshows that thenumberof“non-OOCCmembers” increased from22percent (11of50samples) to28percent(14of50samples)from2016to2017,andthatthenumberofExtraVirginsamples increasedfrom18percent(twoof11samples)in2016to50percent(sevenof14samples)in2017.

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TABLE4.Distributionofsamplesinthreegrades(EVOO,VirginandCrude)

OOCCMEMBER NON-OOCCMEMBER STOREBRAND#OF

SAMPLES2016 62%(31of50) 22%(11of50) 16%(8of50)2017 62%(31of50) 28%(14of50) 10%(5of50)

EVOO2016 90%(28of31) 18%(2of11) 88%(7of8)2017 74%(23of31) 50%(7of14) 80%(4of5)

Virgin2016 10%(3of31) 54%(6of11) 12%(1of8)2017 19%(6of31) 38%(5of14) 0(0of5)

Crude2016 0(0of31) 27%(3of11) 0(0of8)2017 6%(2of31) 14%(2of14) 20%(1of5)

Ranciditywastheonlysensorydefectin2017In2016,fivesampleshadfusty/muddysedimentdefectsinadditiontoranciditydefectswhereas in2017theonlydetectablesensorydefectwasrancidity.Thissuggeststhatgrowersandhandlerswereabletoavoidprocessingsubstandard/fermentedfruitpriortoprocessingin2017,oratleastnotclassifyingtheresultingoilasExtraVirgingrade.

Thereareseveralpotentialexplanationsforthedifferencesbetweenthe2016and2017results:

• Selectingabroadernumberofbrandsin2017comparedto2016(23and18,respectively)ledtoaslightlybroaderrangeofsomechemicalqualityparametersin2017.

• The2017samplesexperiencedhighertemperaturesthanthe2016samples.Aspreviouslynoted,thestudyteamfoundhighershelftemperaturesin2017comparedto2016(Figure1).Moreover,theaverageannualtemperaturesinFresnoandSanJoaquinCountiesishigherthaninthe2016study’sSacramento,YoloandSonomaCounties.Forexample,theaveragesummertemperatureinFresnoandSanJoaquinCountiesis96°FwhilethatoftheSacramentoRegionis92°F.4

• Therewerefour2017samplesthatwereatleasttwoyearsold,doubletheamountin2016.Oldersamplestendedtohavethelowestchemicalquality.

Variabilityinthetwostudiesmightalsoberelatedtowarehousetemperaturesandproduct-turnoverrate,butthesefactorswerebeyondthescopeofthestudy.

CONCLUSIONS

SamplesfromOOCCmemberspassedCaliforniaExtraVirginstandardsat74percentandstorebrandspassedthestandardsat80percent.Thesepassageratesarelowerthantheratesofthesamplesanalyzedinthe2016study(90percentand88percent,respectively).Thedifference inthetwostudiesmayberelatedtoalargernumberofbrandsin2017withmorevariability,highertemperaturesin2017intheFresnoregionandontheshelves,andalargernumberofsamplesmorethantwoyearsoldinthisyear’sstudy.

4https://www.ncdc.noaa.gov/.NationalCentersforEnvironmentalInformation.

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The 14 samples from handlers outside of the OOCC had a passage rate of 50 percent, which wassignificantlyhigherthanthe18percentrateinlastyear’sstudy.Thesegrowersandhandlersmaybenefitfrombetterprocessingandstoragepracticesandimprovedtrackingoftheirproductshelflife.

Thesensoryandchemistryresultssuggestedthatoxidationwasthemajorreasonwhysomesamplesdidnot pass California Extra Virgin standards, as indicated by results for the PV, UV, PPP and sensory.Minimizingoxidationisthekeychallengeforhandlers,distributorsandretailerstoprotectoliveoilqualityoveritsshelflife.

RECOMMENDATIONS

• TheOOCCmaywishtoconductworkshopstodisseminatethelessonslearnedfromthelasttwoyear’s studies and best practices on post-harvesting, processing and storage. The OOCCmayrevisit the study in two or three years, using the results from 2016 and 2017 as a qualitybenchmarkforCaliforniaoliveoil.

• TheOOCCmaywishtodevelopanddistributeguidelinestoproducersandretailersthatwouldhelpminimizeoxidationwhenCaliforniaoliveoilsareintransit,ontheshelfandinstorage.Forexample, the commission may wish to investigate the feasibility of using temperature loginstrumentsinoliveoilcasesorbottlestotracktemperaturesintransportationandstorageandtoencourageretailerstomovetheoliveoilcategorytoacoolersectionofthestore.

• TheOOCCmayhelptodevelopbestpracticesonthelabellingofbest-beforedateandlotnumberfor thepurposeof trackingproductquality. Several samples thatdidnotpassCaliforniaExtraVirginstandardslacktheinformationoflotnumberand/orbest-beforedateonthelabel,whichmadeitdifficulttoassessthepossiblecause(s)forqualitydegradation.

• TheOOCCmaywishtoinvestigatewhethertherearegrowersandhandlershandlingmorethan5,000 gallons of California oliveoil annually andwhoarenot currently being assessedby thecommission.