Key odorants of the typical aroma of Sherry vinegar

Exp ession o Mul idisciplina y Fla ou Science 419 KEY ODORANTS OF THE TYPICAL AROMA OF SHERRY VINEGAR R.M. CALLEJÓN 1, M.L. Mo ales1, A.M. T oncoso1, and A.C. Sil a Fe ei a2 1 Á ea de Nu ición y B oma ología, Facul ad de Fa macia, Uni e sidad de Se illa. c/ P. Ga cía González nº 2, E- 41012, Se illa, Spain 2 Escola Supe io de Bio ecnología, Uni e sidade Ca ólica Po uguesa. R. D . An onio Be na dino de Almeida, 4200-072 Po o, Po ugal Abs ac A ep esen a i e She y inega was analysed by gas ch oma og aphy-ol ac ome y (GC-O). Two GC-O echniques we e used a ge ing compounds wi h impac on he pe cei ed quali y o She y inega , i.e. de ec ion equency and a oma ex ac dilu ion analysis. A o al o 108 a oma ic no es we e de ec ed and 64 o hem we e iden i ied. Diace yl, isoamyl ace a e, ace ic acid, and so olon eached he highes equency and la ou dilu ion (FD) ac o s. E hyl ace a e accoun ed o he maximum equency bu had only a FD ac o o 4. Simila i y es s we e pe o med be ween he She y inega and model solu ions o all possible combina ions o hese compounds. The highes alue om he simila i y es was obse ed when diace yl, e hyl ace a e and so olon we e added simul aneously. The p o ile o his model solu ion and he ep esen a i e She y inega showed a good simila i y in he gene al a oma desc ip ion, which emphasises he impo an con ibu ion o hese 3 compounds o he global a oma o his inega . In oduc ion The e is a need o he cha ac e iza ion o he ypical senso y p ope ies o adi ional p oduc s no only o he indus ializa ion o ood p oduc ion, bu also o laws on ood sa e y and e en o he de elopmen o inno a i e p oduc s. She y inega is one o he mos enowned p oduc s o his ype in he wo ld. A minimum pe iod o six mon hs o aging in wood ba els is manda o y o hese p oduc s. I s main cha ac e is ics a e a high ace ic deg ee (legally, a minimum o 7º) and a special la ou which esembles ha o She y wine. The a oma composi ion o hese inega s has been s udied by se e al au ho s (1, 2). Howe e , sys ema ic s udies o indica e he odo an s esponsible o he cha ac e is ic bouque o She y inega ha e no been epo ed up o now. Ta ge ing subs ances wi h la ge impac on he pe cei ed quali y o a ood p oduc ep esen s one o he mos challenging asks in la ou esea ch. The main di icul y is co ela ion be ween senso y and chemical da a. Despi e o con o e sial epo s conce ning he bes sui ed echnique o a gi en ma ix, se e al me hods using gas ch oma og aphy wi h ol ac ome y ha e been applied o he pu pose o anking subs ances by hei espec i e impac on he o e all a oma o a oods u (3, 4). This wo k deals wi h he e alua ion o “senso y quali y” o She y wine inega and wi h he p esen a ion o subs ances, which plays an impo an ole on he pe cei ed cha ac e o She y inega s. We ha e used wo gas ch oma og aphy- ol ac ome y (GC-O) echniques: a oma ex ac dilu ion analysis (AEDA) and equency coun ing (FC) using simul aneously wo exi s on a cus omised “mul ipos ” Exp ession o Mul idisciplina y Fla ou Science 420 sni e ODO-II. They ha e been compa ed o de ine hei espec i e disc imina ion abili y. Expe imen al Vinega sample. A ep esen a i e 2 yea -old inega (“Vinag e Rese a”, VR1) was selec ed by he senso y panel as being a She y inega “ ype”. Chemical analysis. Majo ola ile compounds we e de e mined by di ec injec ion GC-Flame Ioniza ion De ec o (GC-FID) (5). A o al o 52 mino compounds we e de e mined by Headspace So p i e Ex ac ion-Gas Ch oma og aphy-Mass Spec ome y (HSSE-GC-MS) (6) and so olon by Liquid-Liquid Ex ac ion GC-MS (7). Gas Ch oma og aphy-Ol ac ome y. Dichlo ome hane ex ac s o he VR1 sample we e analysed by GC-O cus omised by D . Sil a Fe ei a´s g oup wi h wo ol ac o y ou le s in o de o ob ain simul aneous odou e alua ions om mul iple panellis s (8). Senso y analysis. Desc ip i e analysis (8) and simila i y es s be ween VR1 and each a oma model solu ion we e ca ied ou (7). A oma model solu ions we e p epa ed in a 7% (w/ ) ace ic acid solu ion by dilu ing he compounds, which eached he highes sco es in GC-O, in he same concen a ions ound o he sample VR1. Resul s The GC-O s udy e ealed he p esence o 108 a oma ic no es among which 64 could be desc ibed by he panellis s. Table 1 shows compounds eaching high de ec ion equency in GC-O. Among hem, a a ie y o odou -ac i e egions, iden i ied as e hyl ace a e, diace yl, isoamyl ace a e, ace ic acid, bu y ic acid, iso ale ic acid and so olon, eached he highes de ec ion equencies (100%). Good co ela ions we e obse ed among he simul aneous AEDA ( > 0.90) ca ied ou by wo panellis s. Only 19 odou compounds showed di e ences o mo e han one dilu ion ac o . By sni ing se ial dilu ions, 26 odou -ac i e compounds accoun ed o FD ac o s ≥ 256. Nine o hem could no be iden i ied. By compa ing esul s ob ained wi h he wo echniques used in his s udy, de ec ion equency and AEDA, we can see ha hey ag ee in many cases. Hence, diace yl, isoamyl ace a e, ace ic acid and so olon, eached he maximum equency and he highes FD ac o s, he e o e, being po en odo an s o She y inega . Howe e , esul s we e no in ag eemen o ce ain odo an s ( < 0.45). Fo example, e hyl ace a e displayed he highes equency (9/9) bu only a FD ac o o 4. Va ious au ho s ha e c i ically compa ed he di e en GC-O me hodologies, using ei he mix u es o e e ences s anda ds o eal ood sys ems (9) and disc epancies in esul s exis ed since hey a e based on di e en p inciples. Each o he GC-O me hodologies has ad an ages and limi a ions. Hence, he use o bo h echniques allows mo e in o ma ion o be ob ained and educes he e o s when using jus one o hem. Simila i y es s be ween solu ions and She y inega we e pe o med o check he senso y impac o hose compounds wi h a FD ac o ≥ 512 and de ec ed in all sni ing ials, i.e. diace yl, isoamyl ace a e and so olon. In addi ion, e hyl ace a e was also selec ed in spi e o i s low FD ac o because i was de ec ed in all sni ing ials. Mo eo e , i is one o he ypical senso y a ibu es o She y inega used as desc ip o in he desc ip i e senso y analysis cha o She y inega s (10). The highes alue om he simila i y es was obse ed when diace yl, e hyl ace a e and so olon we e added simul aneously (Table 2). Exp ession o Mul idisciplina y Fla ou Science 421 Table 1. De ec ion equency and AEDA o he odou s o VR1 She y wine inega . RI Odou Quali y Odo an ( en a i e iden i ica ion)*De ec ion F equency FD1 FD2 1063 Glue E hyl ace a e 9 2 4 1080 S awbe y E hyl isobu y a e 7 512 1024 1084 Bu e Diace yl 9 4096 4096 1118 Che y, s awbe y Bu yl ace a e 6 128 1024 1123 Banana, mulbe y, s awbe y Isoamyl ace a e 9 4096 4096 1422 Pungen Ace ic acid 9 1024 1024 1468 Mulbe y, ui , banana, s awbe y Unknown 8 1 2 1484 Boiled po a o Me hional 7 4 4 1496 S awbe y, swee Unknown 8 8 16 1532 Ri e wa e , apou Unknown 9 1 2 1557 Mulbe y, ui Benzaldehyde 7 2 4 1563 Aspi in, mulbe y E hyl nonanoa e 8 128 256 1595 Cheese, ee Isobu y ic acid 8 64 128 1655 Bu ned, bu ned hai Unknown 7 8 16 1661 Cheese, omi Bu y ic acid 9 256 256 1705 Cheese Iso ale ic acid 9 128 128 2054 Clo e Eugenol 8 2 2 2151 Flowe , ui , banana Unknown 7 128 512 2201 Cu y, liquo ice, “olo oso she y wine” So olon 9 512 512 2255 Swee - ancid, wood, liquo Unknown 7 512 512 2360 Liquo , liquo ice, swee Unknown 7 512 512 * Iden i ica ion o odo an s: Compa ison o mass spec a, ch oma og aphic e en ion index (RI) and odou desc ip ion wi h expe imen al and li e a u e da a. Table 2. Resul s ob ained om senso ial analysis by compa ison es . A oma Model Solu ions Simila i y Value (SV) S anda d De ia ion (SD) a.s. + [1] + [2] + [4] 5.38 0.55 a.s. + [1] [2] + [3] + [4] 4.59 0.58 a.s. + [1] + [3] + [4] 4.57 0.58 a.s. + [2] + [3] + [4] 4.35 0.62 a.s. + [2] + [4] 4.11 0.58 a.s. + [3] + [4] 4.08 0.61 a.s. + [2] +[3] 3.57 0.55 a.s. + [1] + [4] 3.55 0.55 a.s. + [1] + [2] 3.25 0.62 a.s. + [1] + [2] +[3] 3.15 0.58 a.s. + [4] 2.76 0.58 a.s. + [2] 1.83 0.62 a.s. + [1] +[3] 1.79 0.62 a.s. + [1] 1.70 0.55 a.s. +[3] 1.54 0.58 a.s.: ace ic acid solu ion (7 % / ); [1] diace yl, [2] e hyl ace a e; [3] isoamyl ace a e; [4] so olon The p o ile o his model solu ion and he ep esen a i e She y inega showed simila in ensi ies in he “swee a oma”, “pungen sensa ion” and “alcohol/liquo ” desc ip o s, in addi ion o a good simila i y in he “gene al imp ession” (Figu e 1).This esul emphasises he impo an con ibu ion o hese 3 molecules (diace yl, e hyl ace a e and so olon) o he global a oma o his She y inega . Hence, hey can be conside ed as key odo an s o She y inega . Exp ession o Mul idisciplina y Fla ou Science 422 0.0 1.0 2.0 3.0 4.0 5.0 Gene al Imp ession E hyl ace a e Pungen sensa ion Woody odo Swee a oma Alcohol/Liquo Raisin Wine cha ac e VR1 D+AE+S Figu e 1. Fla ou p o iles o VR1 sample (black line) and a oma model (g ey line). Re e ences 1. Mo ales M.L., González G.A., Casas J.A., T oncoso A.M. (2001) Eu . Food Res. Technol. 212: 676-682. 2. Gue e o E.D., Na e a R., Cas o R., Ba oso C.G. (2007) J. Ch oma og . A 1167: 18-26. 3. Campo E., Fe ei a V., Escude o A., Ma qués J.C., Cacho J. (2006) Anal. Chim. Ac a 563: 180-187. 4. Sil a Fe ei a A.C., Hogg T., Guedes de Pinho P. (2003) J. Ag ic. Food Chem. 51: 1377-1381. 5. Mo ales M.L., Tes aye W., Ga cía-Pa illa M.C., Casas J.A., T oncoso A.M. (2001) J. Sci. Food Ag ic. 81: 611-619. 6. Callejón R.M., T oncoso A.M., Mo ales M.L. (2008) J. Ch oma og . A 1204: 93- 103. 7. Sil a Fe ei a A.C., Ba be J.C., Be and A. (2003) J. Ag ic. Food Chem. 51: 4356-4363. 8. Callejón R.M., Mo ales M.L., T oncoso A.M., Sil a Fe ei a A.C. (2008) J. Ag ic. Food Chem. 56: 6631-6639. 9. an Ru h S.M. (2004) J. Ch oma og . A. 1054: 33-37. 10. Tes aye W., Ga cía-Pa illa M.C., T oncoso A.M. (2002) Senso y S udies 17: 132-140.