Figure 1.Illustrationofthesilicamonolithmaterial.

Figure 2.AdsorptiononMMSE.

Evaluation of monolithic sorptive extraction (MMSE) as an alternative aroma extraction technique

IntroductionApreconditioninfindingrelationsbetweenresultsfromaromaandsensoryanalysisisthatthe prepared aroma extract resembles the aroma of the actual product. In this study wecomparedtheextractioncapabilityofthewellknownsamplepreparationtechniquesofLargeVolumeStaticHeadspace(LVSH)andHeadspaceSorptiveExtraction(HSSE)witharelativenewextractiontechnologycalledMonolithicMaterialSorptiveExtraction(MMSE).BasedonsensoryevaluationoftheobtainedextractsofstrawberryflavoredmilkitwasshownthattheextractobtainedfromMMSEresemblesthearomaoftheoriginalstrawberryflavoredmilkthebest.Theintradayreproducibility(CV%)andlinearity(r2)forthecomponentsinvestigatedvariedbetween3.3and5.5%and0.94and0.99,respectively.

Sensory evaluationAsensorypanel(N=11)evaluatedtheoriginalmilksampleandthesamplescollectedattheendofthecolumn.Thepanelistwereaskedtodescribethedifferencesbetweensamplesandgiveanindicationaboutthesizeofthedifference.

ResultsThestrawberryflavouredmilkwasextractedbytheLVSH,HSSEandMMSEtechniqueandanalyticallycomparedbasedonGC/MSdata(Figure 3).TheresultsshowthataromaextractspreparedwiththeLVSHandMMSEtechniqueresultincomparablearomaprofiles.

Figure 3.ComparisonoftheLVSH,HSSEandMMSEtechniquebasedonGC/MSanalysis. Fordecodingthecomponentsseetable1.

After thermaldesorption theextractedaromacomponentswerecollected in cooledsemi-skimmed milk and sensorially compared to the original milk sample (also purged with thegascomingfromthecolumnoutlet).Theaimwastodeterminewhichextractiontechniquebest resemblesthearomaof thestrawberrymilksample.Table 3 showstheresultof thissensorycomparison.TheresultsshowclearlythatthearomaextractofMMSEtechniquemostresemblesthearomaoftheoriginalstrawberryflavouredmilk.Experimental set up

Strawberry flavoured milkSemi-skimmedmilkwasfortifiedwithamixtureof7aromacomponents(Table 1)toobtainastrawberryflavouredmilk.

LVSH LVSHwasperformedusingaLVSHdevice.Anamountof25mlofthestrawberryflavouredmilkwastransferredtoaglasstubeandclosedwithaplunger(totalheadspacevolume150ml).Thesamplewascooledto7°C.After30minutestheplungerwasmoveddownandthevolatileswerecollectedonaTENAXtube.

HSSEHSSEwasperformedbyusinga20mlheadspacevialequippedwithaheadspaceinsert.Anamountof3.33mlofthestrawberryflavouredmilkwasaddedandapre-conditionedtwisterwasputintheheadspaceinsert.Extractionwasperformedduring30minutesat7°C.

MMSE Anamountof3.33mlofthestrawberryflavoredmilkwastransferredtoa20mlvial.ViaaspecialholdertheMMSEdevicewasexposedtothevolatilesintheheadspace(30minutes,7°C).

GC/MS AllcollectedsampleswerethermallydesorbedbyprogrammingaTDUfrom30°to250°C(holdingtime10minutes)at60°C/min.AftercryofocussinginaCIS4at-20°CtheCIS4washeatedto250°Cat12°C/s.Thecomponentsofinterestweretransferred(solventventmode)toaWax58(FFAP)CBcolumn(25mx0.25mmI.D.,0.25µmfilmthickness).Theovenwasprogrammedfrom40°C(holdtime2min.)to275°C(holdtime2min.)at15°C/min.Heliumwasusedasacarriergas(flowrate1.5ml/min).Themassspectrometer(EI)wasoperatedintheSIMmode.Twoselectiveionspercomponentwereusedforidentificationandquantification.

Collection of volatiles Afterdecouplingthemassspectrometer,thevolatilecomponentswerecollectedattheendoftheanalyticalcolumnin0.66mlofmilkthatwascooledat0°C.

Determination of intraday repeatability and linearity for the MMSE techniqueRepeatability was measured by determining the peak area of measuring five times theconcentrationofthemiddlecalibrationpoint.Forallcomponentsa5-pointcalibrationcurvewasprepared inconcentration rangesasdescribed inTable 2.d12-hexanalwasusedasaninternalstandard.

Table 2.Upperlimitsforusedconcentrationranges.

Descriptionofdifference Numberofpanelistscomparedtoreference HHSE MMSE LVSH

No 0 1 1Small 2 4 1Reasonable 3 6 2Large 2 0 7VeryLarge 4 0 0

Thesensorypanelwasalsoaskedwhichextracthasanaromathatisthemostcomparabletotheoriginalstrawberryflavouredmilk.9outof11panelistsansweredthatthearomaofMMSEmimicsthebestthearomaoftheoriginalstrawberryflavouredmilk.

FortheMMSEtechniquetheintradayreproducibilityandlinearitywasfurtherinvestigated.Table 4presentstheresultsofthisstudy.Theobservedintradayreproducibilityandlinearityareinlinewithvaluesnormallyfoundfortheinvestigatedconcentrationrange.

Component RSD(%) r2

Propanoicacid,2-methyl,ethylester 3,31 0,95Butanoicacidethylester 4,13 1,00Butanoicacid,2-methyl,ethylester 2,26 1,00Hexanoicacid,ethylester 0,83 0,98(Z)-3-hexen-1-olacetate 2,32 1,00(Z)-3-hexen-1-ol 4,75 0,99(E)Hex-2-en-1-ol 5,45 0,99

What is MMSE?MMSE makes use of a new generationmedia for adsorption and extractiondeveloped by using silica monolithtechnology.Basedonthissilicamonolithtechnology an innovative hybridadsorbentofsilicaandactivatedcarbon(or graphite carbon) having a largesurface area bonded with octadecylsilane (C18,ODS) was manufactured(Figure 1 and 2). The ODS bondedhybrid medium application showedadsorptioncapabilitiestoawidevarietyofcompounds.ItwasalsoreportedthatanadvantageofMMSEisalargesurfacearea, a high recovery and a shortextractionandconditioningtime[1,2].

# Component ConcentrationinMilk (µg/l)1 Propanoicacid,2-methyl,ethylester 3002 Butanoicacidethylester 8003 Butanoicacid,2-methyl,ethylester 8004 Hexanoicacid,ethylester 6005 (Z)-3-hexen-1-olacetate 5006 (Z)-3-hexen-1-ol 8007 (E)Hex-2-en-1-ol(E) 200

Table 1.Usedaromamixtureandfinalmilkconcentrations.

Component Upperlimitconcentration rangeinMilk(µg/l)Propanoicacid,2-methyl,ethylester 160Butanoicacidethylester 320Butanoicacid,2-methyl,ethylester 320Hexanoicacid,ethylester 320(Z)-3-hexen-1-olacetate 266(Z)-3-hexen-1-ol 6400(E)Hex-2-en-1-ol 1600

Table 3.Resultsofthecomparisonofthearomaofstrawberrymilk(purgedwithgascomingfromtheGC-columnoutlet)andthearomaextractspreparedwiththeHHSE,MMSEandLVSHtechnique.

Table 4.Resultsof intradayreproduci-bility(RSD%)andlinearity(r2)oftheMMSEtechnique.

ConclusionsA comparison of aroma extraction techniques showed that an aroma extract preparedwithMMSEbestresemblestheextractofstrawberryflavouredmilk.Consequently, fortheinvestigated matrix and aroma, the MMSE technique is therefore very powerful in findingrelationsbetweenanalyticalandsensorydata.LinearityandreproducibilityoftheMMSEshowedgoodresultsindicatingthatMMSEisusefulforquantitativeanalysisofaromacomponents.

References[1] Anovelapproachforaromacomponentsanalysisusingamonolithichybridadsorbent

asanewgenerationmedium.”MonoTrap”,Atsushi Sato, Katsuhiko Sotomaru, Manami Takeda,Poster40thInternationalSymposiumonEssentialOils,2009

[2] HeadspaceenrichmentofbergamotandmandarinjuicesbymeansofMonolithicMaterialSorptiveExtraction(MMSE),Rosaria Costa, Paola Dugo, Giovanni Dugo and Luigi Mondello,Poster34thInternationalSymposiumonCapillaryChromatography’,2010

ContactMartyMartensFrieslandCampinaInnovationHarderwijkerstraat67418BADeventerTheNetherlands

t +31570695942m marty.martens@frieslandcampina.com

MARTY MARTENS, HERMEN HogEkAMp, RiTA BoERRigTER-EENliNg ANd CARiNA poNNE, FRiESlANdCAMpiNA iNNovATioN, HARdERwijkERSTRAAT 6, 7418 BA dEvENTER