外文翻译CHANGES IN ODOUR OF BARTLETT PEAR BRANDY INFLUENCED BY SUNLIGHT IRRADIATION

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1、CHANGESINODOUROFBARTLETTPEARBRANDYINFLUENCEDBYSUNLIGHTIRRADIATIONI.KraljCigi6,L.Zupan~i~-KraljUniversityofLjubljana,FacultyofChemistryandChemicalTechnologyA~ker~eva5,SI-1000Ljubljana,SloveniaABSTRACTSensoryevaluationofBartlettpearbrandyrevealeddifferencesintasteandsmellbetweenthebrandyincolourles

2、sandgreenbottles.Todeterminethedifferencesinchemicalcomposition,headspacesamplingwithsolid-phasemicroextractioncombinedwithgaschromatography-massspectrometrywasapplied.Themajoraromacomponentsinpearbrandystoredingreenbottleswereethyltrans-2-cis-4-decadienoate(68ppm),ethyltrans-2-trans-4-decadienoa

3、te(21ppm)andmethyltrans-2-cis-4-decadienoate(27ppm).Inpearbrandykeptincolourlessbottles,theconcentrationoftrans-2-cis-4-isomereswaslowerandtheconcentrationsofotherpossibleisomereswerehigher.Resultsshowapronounceddifferenceintheconcentrationratiosamongisomeresofethyl2,4-decadienoateandmethyl2,4-de

4、cadienoateinbothsamples.Sunlightirradiationwasfoundtobethereasonforthesechanges.Itwasconfirmedthattrans-2-cis-4-isomerepartlyconvertstotheotherthreeisomeresduringUVirradiation.INTRODUCTIONAromaisoneofthemostimportantqualitiesofdistilledbeverages,e.g.brandy.Itisdeterminedbythepresenceandthelevelof

5、volatilecompounds(complexmixtureofcarbonylcompounds,alcohols,carboxylicacidsandtheiresters)andallproductionstagescannoticeablycontributeandinfluencethefinalaromacompositionofbrandies.EarlierstudiesonBartlettpeararomahaveshownthatthecharacterimpactcompoundsaremethylandethylestersoftrans-2-cis-4-de

6、cadienoicacid[1].Thepleasantpear-likeodourhasbeenfoundtochangeduringfermentationasaresultofthetrans-2-cis-4-decadienoatesbeingpartlyisomerizedtotrans-2-trans-4-decadienoates,whichhaveanon-typicalsmell[2].Theodourcharacteristicsofsomevolatilecompoundsaresometimesaffectedbytheirgeometricisomerism[3

7、].Headspace(HS)samplingwithsolid-phasemicroextraction(SPME)incombinationwithgaschromatography-massspectrometry(GC-MS)isthemainmethodforanalysingaromacompounds[1].Theaimofourworkwastodeterminethedifferencesinchemicalcom