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1 This rtile ppere in journl pulishe y Elsevier. The tthe opy is furnishe to the uthor for internl non-ommeril reserh n eution use, inluing for instrution t the uthors institution n shring with ollegues. Other uses, inluing reproution n istriution, or selling or liensing opies, or posting to personl, institutionl or thir prty wesites re prohiite. In most ses uthors re permitte to post their version of the rtile (e.g. in Wor or Tex form) to their personl wesite or institutionl repository. Authors requiring further informtion regring Elsevier s rhiving n mnusript poliies re enourge to visit:

2 Author's personl opy LWT - Foo Siene n Tehnology 42 (2009) Contents lists ville t SieneDiret LWT - Foo Siene n Tehnology journl homepge: Bitterness, oor properties n voltile ompouns of virgin olive oil with phospholipis ition O. Koprivnjk, *,D.Škevin, S. Petričević, K. Brkić Buol,Ž. Mokrovčk Deprtment of Foo Tehnology & Control, Shool of Meiine, University of Rijek, Brće Brnhett 20, Rijek, Croti Deprtment of Foo Tehnologil Engineering, Fulty of Foo Tehnology n Biotehnology, Pierottijev 6, Zgre, Croti sms Foo Development Centre, Kurtovići, Klis, Croti Institute of Agriulture n Tourism, K. Hugues 8, Poreč, Croti rtile info strt Artile history: Reeive 25 Jnury 2008 Reeive in revise form 31 Mrh 2008 Aepte 8 My 2008 Keywors: Olive oil Phospholipis Bitterness Voltiles Oor properties Bitter hyrophili phenoli ompouns ontine in virgin olive oil (VOO) enefiilly ffet humn helth. However, onsumers mostly o not tolerte oils with pronoune itter tste (itterness inex K ) n this oul limit their onsumption. The possiility of itterness ttenution of quite itter VOO (K 225 ¼ 0.501) y the ition of grnulr soy leithin, s soure of phospholipis, up to the levels present in see oils ( g/kg), ws evlute y sensory ifferene tests. Sttistilly signifint ifferenes were foun strting from 5 g/kg of e phospholipis (p 0.05). Phospholipis ition use signifint erese of the totl onentrtion of 20 voltiles etermine y HS-SPME GC nlysis (slope 0.056; r ¼ ), n the most influene mong them ws E-2-hexenl (slope 0.048; r ¼ ). Results of quntittive esriptive sensory nlysis showe tht the ition of phospholipis in rnge from 5 to 10 g/kg slightly reue olive fruity n green oor notes, signifintly inrese sweetness n erese itterness. The signifint hnges of overll sensory qulity gring were not foun etween pure VOO n smples enrihe with phospholipis. Thus, in the ontext of funtionl foo formultion, ition of phospholipis oul e propose s proeure useful for itterness ttenution of VOO. Ó 2008 Swiss Soiety of Foo Siene n Tehnology. Pulishe y Elsevier Lt. All rights reserve. 1. Introution Chemopreventive phytonutrients re nturlly ourring ingreients of plnt foos tht enefiilly ffet humn helth. Mny efforts in plnt proution n foo proessing re irete to enhne or preserve existing phytonutrients, s well s to rete funtionl foos y their ition to the signifint onentrtion levels. However, lot of known phytonutrients, suh s phenoli ompouns, flvonois, terpenes n gluosinoltes, re itter or stringent (Drewnowski & Gomez-Crneros, 2000). This imposes limittions in enrihment possiilities, euse the onsumers mostly o not tolerte pronoune itter tste of foo. The min phenoli ompouns responsile for the itter tste of virgin olive oils re seoiriois, hyrophili glyone erivtives of oleuropein n ligstrosie. Among them, the mjor ontriution hs lehyi form of oleuropein glyone (Mteos, Cert, Perez- Cmino, & Gri, 2004), lthough high orreltion oeffiients etween oil itterness n the onentrtion of totl phenols hve lso een reporte (Morles & Tsimiou, 2000). Their helth * Corresponing uthor. Fx: þ E-mil ress: koliver@meri.hr (O. Koprivnjk). enefiil effets re relte to the prevention of riovsulr iseses, ner n neuro-egenertive iseses (Servili et l., 2004; Visioli, Glli, Glli, & Cruso, 2002). These impts re primrily ttriute to their ntioxint tivity in vivo, ut some other phrmologil effets, suh s inhiition of ylooxygenses, hve lso een reporte (Yng, Kong, & Zhng, 2007). Despite these positive spets, onsumers prefer virgin olive oils with low or moerte levels of itterness, rejeting very itter ones (Mteos et l., 2004). In orer to improve the eptne of itter foo or rugs, ifferent itter-tste msking sustnes hve een stuie, e.g. sugrs (Kreutzmnn, Christensen, & Eelenos, 2008), sweeteners, soium ions, enosine monophosphte, yloextrins (Binello, Crvotto, Nno, & Spgliri, 2004), flvnones, hyroxyenzoi i vnillylmies (Ley, Blings, Petz, Krmmer, & Bertrm, 2006), lipoproteins n phosphtii i (Ktsurgi et l., 1997). In most ses, itterness-msking potentil hs een evlute in queous solutions of ifferent stnr itter sustnes, suh s ffeine, quinine, propylthiouril, n itter pepties. Little informtion exists out itter-tste msking sustnes pplie to moel systems or rel foo mtrixes. As regrs olive oil phenols, Pripp, Bush, n Vreeker (2004) stuie the effet of soium seinte on itterness of 65% oil in wter emulsion. They hve foun tht the /$34.00 Ó 2008 Swiss Soiety of Foo Siene n Tehnology. Pulishe y Elsevier Lt. All rights reserve. oi: /j.lwt

3 Author's personl opy O. Koprivnjk et l. / LWT - Foo Siene n Tehnology 42 (2009) ition of 1% of soium seinte signifintly reue the itterness of emulsion ontining phenols extrte from virgin olive oil, espite reltively wek ining of these phenols to proteins. Aoring to our knowlege, the ition of itterness-msking sustnes iretly to virgin olive oils hs not een reporte yet. It must e notie tht no itives re permitte in virgin olive oils (Coex Alimentrius, 1981), so in se itterness-msking sustne is use, the resulting olive oil is not e onsiere virgin, ut it oul e interesting s prtiulr funtionl foo formul. Ktsurgi et l. (1997) hve propose phospholipis (PL), i.e. leithin frtions with high ontent of the phosphtiylinositol n phosphtii i, s itterness inhiitor for prtil pplitions. They hve emonstrte tht these frtions suffiiently inhiit the itterness of mny itter sustnes, when they re issolve together in wter solutions, inorporte to the grnules or use s oting of the grnules ontining itter sustnes. Phospholipis re one of the minor onstituents of see oils, in whih they re usully present in onentrtion rnge from 10 to 20 g/kg (Bernrini, 1983). Virgin olive oils ontin mounts of phospholipis tht re times lower thn in see oils (Koiis & Boskou, 2006). Thus, VOO oul e suitle mtrix for ition of those possile itterness inhiitors. In this work we investigte the possiility of itterness ttenution of extr virgin olive oil with pronoune itter tste, y ition of grnulr soy leithin s the soure of PL. To selet the pproprite onentrtion rnge of PL n to verify its influene on the pereption of itter tste, sensory ifferene tests were pplie. Besies, the effet of the inrese PL onentrtion on oor properties ws evlute y quntittive esriptive nlysis n orrelte to the onentrtion hnges of voltile sustnes, etermine y GC nlysis of oil hespe voltile omposition fter soli-phse miroextrtion (SPME). 2. Mterils n methos 2.1. Mterils A filtere extr VOO ws purhse from lol Crotin olive oil prouer. De-oile soy leithin in the form of grnules roun 2 mm in imeter, hrterize y neutrl tste n moertely expresse oor remining ry soyens, ws supplie from Life Time Nutritionl Speilities In. (Anheim, USA). It ontine 30 g/ kg of phosphorus, 37 g/kg of holine, 22 g/kg of inositol, <1% of wter n 97% of phospholipis. Methnol p.. n n-hexne p.. were purhse from Pnre (Brelon, Spin). Superlen TM LC- 18 SPE 1 ml tues were supplie from Supelo In. (Bellefonte, USA). Twenty stnrs of rom ompouns h GC purity 90%. Butyl ette, E-2-hexenl, E-2-otenl, E-2-penten-1-ol, E-2-pentenl, ethyl-2-methylutyrte, otnl, pentn-3-on, Z-2-penten-1-ol n Z-3-hexenyl ette were purhse from Alrih (Steinheim, Germny). 1-Hexnol, 1-penten-3-on, 3-methylutn-1-l, E-2- hexen-1-ol, E-3-hexen-1-ol, hexnl, hexyl ette, Z-2-hexen-1-ol n Z-3-hexen-1-ol were supplie from Fluk (Buhs, Germny), while 3-methylutyl ette from Merk (Drmstt, Germny) Smple preprtion The grnulr leithin in mount of 50 g ws e to 500 ml of VOO, previously wrme up to 40 C. The mixture ws stirre for 30 min with propeller le lortory mixer t 500 rpm. The oil ontining issolve n isperse PL ws seprte from seiment n filtere over quntittive filter pper with meium wie pores, otining the primry solution of PL. The sme tretment ws pplie to pure extr VOO (without PL) in orer to otin fully omprle smples. The oil smples with vrious onentrtion of PL were prepre y iluting the primry solution with proper portions of pure extr VOO Phospholipis quntifition The onentrtion of totl PL in pure extr VOO n in the primry solution ws etermine s etone insolule mtters t 0 C y metho of Lüe, esrie y Prun (1964) n ltely moifie y List, Hekin, Evns, Blk, n Mounts (1978). Oil smple (5 g) ws mixe with 20 ml of etone (in the wter ie th t 0 C) n filtere over hille quntittive filter pper with meium wie pores. The tretment ws repete four times n the filter pper with the seiment (ontining etone insolule mtters) ws rie t 70 C n weighe. Results re expresse s PL in grms per kg of the oil. The ext onentrtion of PL issolve in the primry solution ws lulte s ifferene etween the PL onentrtion in the primry solution n pure extr VOO Sensory nlysis Two pnels, eh ompose of eight ssessors trine to VOO sensory nlysis, prtiipte in three sensory test sessions, rrying out one session per y. Approximte miniml PL onentrtion (AMC) effetive in VOO itterness ttenution ws etermine pplying simple rnking test on set of four smples ontining 0, 10, 20 n 30 g/kg of PL. Eh ssessor performe one nlysis n, in totl, 16 responses were otine. AMC ws efine s the lowest PL onentrtion t whih signifint ifferene of itterness (p 0.05) in reltion to pure VOO ws foun. Afterwrs, effiieny of PL onentrtion lower thn AMC vlue (i.e. in the mile of intervl etween AMC n the losest lower onentrtion from the rnking set) ws verifie using the tringle ifferene test, ompring this onentrtion with pure VOO. Sixteen ssessors nlyze one or two series of smples, in orer to otin 24 responses. Assessors who nlyze two series h 30- min rek etween series. The ssessors were ske to ientify the ifferent smple n to speify if it ws more or less itter thn remining two. Responses were onsiere orret when oth nswers were ext. The sme proeure ws use to hek the ifferene in itterness etween AMC n the ove-esrie PL onentrtion lower thn AMC. In oth rnking n tringle test, oil smples (15 g) were presente to ssessors in lue-olore glsses, oe with three-igit numers, t 29 1 C, in rnom orer. Apple, risp re n wter were provie to rinse the mouth etween tsting smples. One pnel of eight trine ssessors performe the quntittive esriptive nlysis n qulity gring of five smples in one session (single etermintion), oring to the metho esrie in Europen Communities Regultion (1991). Different oor (olive fruity, ripe fruits, green grss or leves) n tste ttriutes (itter, pungent n sweet) were quntifie using six-point intensity orinl rting sle from 0 (no pereption), 1 (sre), 2 (light), 3 (mile), 4 (strong) to 5 (extreme). For qulity gring, nine-point overll gring sle from 1 (lowest qulity) to 9 (est qulity) ws pplie. VOO with sore equl to or higher thn 6.5 is onsiere of extr qulity. Smples were presente n oe s esrie for sensory tests Bitterness inex etermintion The itterness inex (K 225 ) ws etermine pplying the metho esrie y Gutiérrez Rosles, Periquero, Gutiérrez, n Olis (1992). The nlyses were run in triplite.

4 Author's personl opy 52 O. Koprivnjk et l. / LWT - Foo Siene n Tehnology 42 (2009) Voltile ompouns nlyses Fuse-sili fier ote with highly rosslinke ivinylenzene/roxen/polyimethylsiloxne (DVB/CAR/PDMS), 1 m length, 50/30 mm film thikness (Supelo, Bellefonte, USA) ws use for the SPME n onentrtion of voltiles. The smple (3.5 g) ws ple in 10-ml vil ontining mirostirring r n sele with PTFE/silione septum (Restek, Bellefonte, USA). Before extrtion, the hespe in the vil ws stilize y equilirtion for 10 min t 40 C n gently gitte for 3 min with mgneti stirrer. The extrtion ws rrie out t 40 C for 40 min. The therml esorption of the nlytes ws hieve y inserting the fire into the injetion port of the GC system equippe with n 0.80 mm i.. SPME liner in splitless moe for 3 min t 245 C. Before smpling, the fire ws reonitione for 10 min in n injeting port t 245 C n lnk runs were one perioilly uring the stuy. No rry-over effet ws etete fter tht time. GC nlyses were performe using Vrin 3350 gs hromtogrph equippe with flme ioniztion etetor operte t 248 C n 30 m 0.25 mm i mm film thikness pillry olumn Rtx-WAX (Restek, Bellefonte, USA). Initil oven temperture ws kept 8 min t 40 C, thn rise to 85 C t 2.5 C/min n finlly inrese to 245 Ct10 C/min n kept 20 min. The rrier gs ws helium t pressure of 15 psi t the olumn he. Voltiles were ientifie y ompring their retention times to those of the pure stnrs. Clirtion grphs use for the quntifitions were prepre y GC nlysis of freshly refine sunflower oil solutions ontining known mounts of the stnrs. Clirtion urves (reltive pek re vs. onentrtion of ompoun) n ll quntifitions were performe y the externl stnr metho using Vrin Str 4.51 softwre. All the nlyses were run in triplite Sttistil nlysis The Friemn-type sttisti for rnk t n nonprmetri nlog to Fisher s LSD for rnk sums were lulte n multiple omprison proeure ws performe to etermine the signifine of ifferenes etween itterness of smples evlute y rnking test. The signifine of ifferenes in the se of the tringle test ws etermine y the omprison of results with ritil numer of orret responses (Meilgr, Civille, & Crr, 1999). Differenes mong results otine y quntittive esriptive nlysis, s well s those relte to onentrtions of voltile ompouns, were teste y one-wy nlysis of vrine t 5% signifine level. The homogeneity of vrine ws teste y Levene s test n the men vlues were ompre y the Tukey s honest signifint ifferene test. Person liner orreltion ws pplie to relte the onentrtion of voltile ompouns to the onentrtion of e PL. All sttistil nlyses were performe using the softwre pkge Sttisti 7.1 (SttSoft In., Tuls, USA). 3. Results n isussion 3.1. Effiieny of PL in itterness ttenution of VOO Extr VOO use in the experiment ws hosen on the sis of its strong itter tste, evlute y quntittive esriptive sensory nlysis. This property ws itionlly heke y itterness inex etermine t 225 nm tht ws (Tle 1). Sine Gutiérrez Rosles et l. (1992) hve reporte tht K 225 vlue of the orer orrespons to quite itter oils, whih re rejete y mny onsumers, this result onfirme the suitility of the smple for the purpose of the stuy. For preliminry estimtion of the possiility of itterness ttenution, pure VOO smple (0 g/kg of e PL) n smples with PL onentrtions similr to those present in Tle 1 Bitterness inex (K 225 ) n overll sensory gring of VOO with phospholipis (PL) ition in rnge from 0.0 to 10.0 g/kg PL onentrtion (g/kg) K 225 Overll sensory gring e Results re the mens of three replitions SD; the mens within the olumn lelle y ifferent letters re signifintly ifferent (Tukey s test, p 0.01). Sle from 1 (lowest qulity) to 9 (est qulity), results re the mens of vlues otine y single etermintion from eight ssessors SD; the mens within the olumn lelle y ifferent letters re signifintly ifferent (Tukey s test, p 0.05). see oils (10, 20 n 30 g/kg) were nlyze y simple rnking test. The results in Fig. 1 show tht there were sttistilly signifint ifferenes etween pure VOO n ll smples enrihe with PL, s well s etween smples with 10 n 30 g/kg of PL. This onfirms the effetiveness of PL issolve in oil mtrix s possile ittermsking sustne. However, ifferenes etween 10 n 20 g/kg, s well s etween 20 n 30 g/kg, were not sttistilly signifint t the level of 95%, initing tht in this rnge the reltion etween two prmeters (oil itterness n PL onentrtion) ws not liner for the hosen VOO. Nevertheless, the results of rnking test showe tht the minimum PL onentrtion effetive in itterness ttenution of hosen VOO ws lower thn or equl to 10 g/ kg. In orer to selet n pproprite onentrtion sle to stuy the influene of PL ition on the tste, oor n voltiles omposition of VOO, the effiieny of onentrtion positione in the mile of intervl etween 0 n 10 g/kg ws verifie y the tringle ifferene test. Two pirs of onentrtions (0 vs. 5 g/kg n 5 vs. 10 g/kg) were teste n 24 responses were otine for eh pir. No sttistilly signifint ifferene ws foun etween 5 n 10 g/kg (ssessors were orret t 10 out of 24 trils, p 0.40), ut it ws etween 0 n 5 g/kg of PL (21 orret nswers out of 24 trils, p 0.001). Assuming tht vlues lower thn 5 g/kg of PL oul hve impt not only to itterness ut s well to the other sensory hrteristis of oil, five-point onentrtion sle with 2.5 g/kg s the lest istne in the rnge from 0 to 10 g/kg ws hosen. Fig. 2 shows sensory profiles of oil smples, otine y quntittive esriptive nlysis. Besie strong itter tste, pure VOO smple ws hrterize y strong pungeny n sre to light sweetness. It is evient tht pungeny ws the tste property lest influene y PL ition, with no sttistilly signifint ifferenes of intensity etween the smples. A signifint erese of Rnk sum PL onentrtion (g/kg) Fig. 1. Results of simple rnking test relte to itterness of oil smples ontining 0, 10, 20 n 30 g/kg of e phospholipis (PL); t re rnk sums of 16 responses; olumns lelle y ifferent letters re signifintly ifferent (p 0.05).

5 Author's personl opy O. Koprivnjk et l. / LWT - Foo Siene n Tehnology 42 (2009) intensity of pereption itter pungent sweet olive fruity ripe fruits green (tste properties) (oor properties) Fig. 2. Sensory profiles of oil smples enrihe with 0.0 ( ), 2.5 ( ), 5.0 ( ), 7.5 ( ) n 10.0 ( ) g/kg of phospholipis. Intensity of pereption ws quntifie using six-point orinl rting sle from 0 (no pereption) to 5 (extreme); results re the mens of vlues otine y single etermintion from eight ssessors SD; the mens within eh sensory ttriute lelle y ifferent letters re signifintly ifferent (Tukey s test, p 0.05). itterness with respet to pure VOO ws otine strting from 5 g/ kg of e PL. However, no signifint ifferenes were foun mong smples in the rnge from 5 to 10 g/kg, whih is in orne with the results of tringle tests. The opposite tren is evient for sweetness of oil. Despite neutrl tste of use grnulr leithin, ition of PL t levels of 7.5 n 10 g/kg use signifint ifferenes with regr to pure VOO. The K 225 vlues etermine on methnol extrt of oil y UVspetrosopy (Tle 1) lso emonstrte remrkle itternessmsking potentil of PL issolve in VOO. This property oul e srie to the ipolr hrter of PL, whih re known s emulsifiers. Shwrz et l. (2000) hve reporte tht some ommeril emulsifiers e to the ulk oil (Tegore 215 n Tegore 450) form lmellr strutures visile y trnseletron mirosopy. Polr groups of those moleules oul entrp hyrophili sustnes within the lyers n similr ehvior might e expete from PL. Sine the min itter-tsting sustnes in VOOs re hyrophili phenols, it is most likely tht PL in suh wy hiners their ontt with itter-tste reeptors lote on tste us Effet of PL on oor properties n voltile sustnes As regrs the oor properties, pure VOO ws hrterize y mile to strong olive fruity, light to mile green grss or lefs n sre ripe fruits oor intensity. In ll smples enrihe with PL, intensities of olive fruity s well s green grss or lefs oor notes showe eresing tren with respet to pure VOO. On the other hn, those smples h more pronoune ripe fruits notes tht ontriute to the rihness of oil rom. Although these hnges were not sttistilly signifint t the level of 95% (exept for olive fruity in smple with 10 g/kg of PL), their onsisteny implies tht PL oul hve some impt on the relese of voltile ompouns from oil. This ws heke y the nlysis of the oil hespe voltile omposition fter SPME. Twenty sustnes with known green, sweet or rni (ftty, oxiize) oor esriptors (Klu et l., 2007) were tken into onsiertion (Tle 2). In orer to otin more informtion out the effet of PL ition, the onentrtion rnge of PL ws extene up to 20 g/kg. The min ompoun in the hespe of pure VOO smple ws E-2-hexenl, followe y 1-hexnol, E-2-hexen-1-ol n Z-3-hexen-1-ol (t not shown), the ompouns tht re hrteristi for oils otine from green or prtly ripe olives (Klu et l., 2007). Fig. 3A shows tht PL ition use signifint n lmost liner erese of the totl onentrtion of 20 voltiles tken into onsiertion (slope 0.056; r ¼ ) (Tle 2), suggesting their retention ue to intertions etween PL n voltile ompouns. This is to the highest extent linke to the erese of the E-2-hexenl onentrtion tht ws hrterize y similr liner regression slope (0.048) n orreltion oeffiient (r ¼ ) s of totl Tle 2 Oor esriptors n results of liner regression nlysis etween voltile ompoun onentrtion (mg/kg) n phospholipis onentrtion (g/kg) in VOO smples Voltile ompoun Oor esriptors Slope Correltion oeffiient r Green voltile sustnes 1-Hexnol Green, fruity, tomto Penten-3-on Green Butyl ette Green, fruity E-2-hexen-1-ol Green, grss, leves E-2-hexenl Green, pple, lmon E-2-penten-1-ol þ Green Z-3-hexenyl ette E-2-pentenl Green, pple, lmon E-3-hexen-1-ol Green Hexnl Green Hexyl ette Green, fruity Z-2-penten-1-ol Green, nn, lmon Z-3-hexen-1-ol Green Totl other green sustnes Sweet-fruity voltile sustnes 3-Methylutn-1-l Mlty, sweet Methylutyl ette Sweet, nn Ethyl-2-methylutyrte Fruity Pentn-3-on Sweet Totl sweet-fruity sustnes Other voltile sustnes Otnl Rni (ftty, oxiize) Z-2-hexen-1-ol þ E-2-otenl Totl of 20 voltile sustnes Klu et l. (2007). Sustnes tht oul not hve een seprte y GC nlysis. Sum of green voltile sustnes exluing E-2-hexenl.

6 Author's personl opy 54 O. Koprivnjk et l. / LWT - Foo Siene n Tehnology 42 (2009) A voltiles onentrtion ( g/kg) B voltiles onentrtion ( g/kg) C voltiles onentrtion ( g/kg) e e PL onentrtion (g/kg) PL onentrtion (g/kg) voltiles. Totl other green sustnes onentrtion, i.e. the sum of green sustnes exluing E-2-hexenl, erese s well (r ¼ ), lthough to muh less extent thn E-2-hexenl (liner regression slope 0.008). Insie this group of ompouns, only the onentrtion of hexnl, up to 7.5 g/kg of PL, showe positive tren (Fig. 3B). Hexnl is known s oil oxition mrker tht is proue y rekown of linolete 13-hyroperoxie (Morles, Rios, & Apriio, 1997; Vihi, Pizzle, Conte, Buxers, & Lopez-Tmmes, 2003). Sine soyen leithin nturlly ontins onsierle mounts of linolei i, it oul e iret soure of hexnl in oil smples enrihe with PL. On the other hn, the e PL onentrtion (g/kg) Fig. 3. Effet of phospholipis on onentrtion of totl voltiles (:), E-2-hexenl (C), other green ompouns (-), hexnl (6), otnl (B) n sweet-fruity ompouns (,) in oil hespe, etermine y SPME GC nlysis. Results re the mens of three replitions SD; the mens (mrks) of the sme urve lelle y ifferent letters re signifintly ifferent (Tukey s test, p 0.05). e f e f g onentrtion of otnl, the prout of olete 11-hyroperoxie rekown, i not hnge signifintly upon the PL ition. This suggests tht use grnulr leithin i not use ny prooxint tivity on oil mtrix, ompose preominntly of olei i. As regrs sweet-fruity ompouns (Fig. 3C), the totl onentrtion of these sustnes showe poor liner orreltion with e PL (r ¼ ). Among them, only 3-methylutyl ette (Tle 2) h positive liner tren (r ¼ ). As whole, the results of SPME GC nlysis of the oil hespe voltile omposition re in orne with slightly reue sensory pereption of green oor notes in the smples with e PL. A likely reson for suh PL influene oul e its ipolr hrter. The polr moieties of its moleules n mke ons with funtionl groups of lehyes, lohols or ketones issolve in VOO, reuing their voltility. Some orne with this hypothesis oul e foun in the results of Tsoutsi, Konstntinou, Hel, n Alnis (2006). They hve reporte tht inresing onentrtion of free ftty is n sterols in olive oil spike with orgnophosphorus insetiies reues the relese of those insetiies from oil mtrix into the hespe. Nevertheless, ompring overll sensory qulity gring of oil smples (Tle 1), tht tkes into ount not only the intensity ut lso equilirium of oor n tste hrteristis, it is evient tht the ition of PL h no unesirle impt. Differenes mong smples were not sttistilly signifint n ll oils h vlues higher thn 6.5 tht inite the sene of ny uneptle sensory hrteristis. It seems tht slight reution of green oor notes ws reompense y higher intensities of ripe fruity notes n, thnks to the lower itterness n higher sweetness, muh greele tste of oils enrihe with PL. Despite promising results onerning itterness ttenution n oor evlution, it is noteworthy to remin tht suh oils nnot e lelle n mrkete s VOO, ut only s kin of funtionl foo. Besies, PL present in onentrtions higher thn nturlly ourring in VOOs oul influene the shelf life performne n this will e the ojetive of our further reserh. Aknowlegement The presente results re erive from the sientifi projets Biotive n voltile ompouns of virgin olive oil in proessing n finishing ( ) n Stility of oil n iotive ompouns in oil uring proessing n storge ( ) supporte y Ministry of Siene, Eution n Sports of Repuli of Croti. We re grteful to Durvk Štruelj for vlule suggestions relte to the topi n to the sensory ssessors for their reful work uring test sessions. Referenes Bernrini, E. (1983). Oilsees, oils n fts, Vol. I. Rome: Oil Pulishing House. pp Binello, A., Crvotto, G., Nno, G. M., & Spgliri, P. (2004). Synthesis of hitosn yloextrin uts n evlution of their itter-msking properties. Flvour n Frgrne Journl, 19, Coex Alimentrius. (1981). Stnr for olive oils n olive pome oils (Rev ). Rome: FAO WHO. Drewnowski, A., & Gomez-Crneros, C. (2000). Bitter tste, phytonutrients, n the onsumer: review. Amerin Journl of Clinil Nutrition, 72, Europen Communities. (1991). Regultion no on the hrteristis of olive n olive-resiue oil n the relevnt methos of nlysis. Annex XII: orgnolepti ssessment of virgin olive oil. Offiil Journl of the Europen Communities, L24, Gutiérrez Rosles, F., Periquero, S., Gutiérrez, R., & Olis, M. J. (1992). Evlution of the itter tste in virgin olive oil. Journl of the Amerin Oil Chemists Soiety, 69, Klu, C. M., Allen, M. S., Begoo, D. R., Jr., Bishop, A. G., Prenzler, P. D., & Rors, K. (2007). Olive oil voltile ompouns, flvour evelopment n qulity: ritil review. Foo Chemistry, 100,

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