Gustatory reaction time and time intensity measurements of trehalose and sucrose solutions and their mixtures

Transcription

1 Glmrini, Mr Virgini ; Zmor, Mrí Clr ; Chirife, Jorge Gusttory rection time nd time intensity mesurements of trehlose nd sucrose solutions nd their mixtures Preprint del documento publicdo en Journl of Sensory Studies Vol. 24, 29 Este documento está disponible en l Bibliotec Digitl de l Universidd Ctólic Argentin, repositorio institucionl desrrolldo por l Bibliotec Centrl Sn Benito Abd. Su objetivo es difundir y preservr l producción intelectul de l Institución. L Bibliotec posee l utorizción del utor pr su divulgción en líne. Cómo citr el documento: Glmrini, M. V., Zmor, M. C. nd Chirife, J. (29), Gusttory rection time nd time intensity mesurements of trehlose nd sucrose solutions nd their mixtures [en líne]. Journl of Sensory Studies, 24. doi: /j X x Disponible en: [Fech de consult:...] (Se recomiend indicr fech de consult l finl de l cit. Ej: [Fech de consult: 19 de gosto de 21]).

2 GUSTATORY REACTION TIME AND TIME INTENSITY MEASUREMENTS OF TREHALOSE AND SUCROSE SOLUTIONS AND THEIR MIXTURES. GALMARINI, MARA VIRGINIA * 1,2 ; ZAMORA, MARÍA CLARA 1,2 ; CHIRIFE, JORGE 2 1 Consejo Ncionl de Investigciones Científics y Técnics (CONICET), Av. Rivdvi 1917 (C133AAJ) - Buenos Aires, Argentin. 2 Fcultd de Ciencis Agrris, Pontifici Universidd Ctólic Argentin (UCA), Cp. Grl. Rmón Freire (C1426AVC) - Buenos Aires, Argentin. *Corresponding uthor: Mr Glmrini, TEL/FAX: (54-11) /2721/2724; emil: mglmrini@gmil.com Potentil reviewers: Professor Gordon Birch Dr. John Piggott g.g.birch@reding.c.uk j.r.piggott@strth.c.uk 1

3 ABSTRACT Dynmic sweetness perception of commercil food grde trehlose, sucrose solutions nd their mixtures ws studied for wide rnge of concentrtions. For Gusttory Rection Time (GRT) concentrtions rnged from 2.3 to 13.8% sucrose nd up to 23.% for trehlose. For Time Intensity (T-I) sucrose or trehlose solutions (concentrtion rnge %) nd their combintions (23. nd 36.8% totl solids) were nlyzed. Trehlose hd bigger GRT long the studied rnge. Both sugrs presented similr vlues for persistence nd times of plteu nd to mximum intensity, while significnt difference ws observed in intensity nd GRT t equl concentrtions. Trehlose hd longer persistence thn sucrose in equi-sweet solutions. Overll sweetness profile of some sucrose solutions (i.e. 29.9% sucrose solution nd.6 sucrose/trehlose rtio mixture t 36.8% totl solids) were perceived s similr to mixtures of sucrose/trehlose or single trehlose solutions; which suggests the possibility of sugr replcement without completely modifying sweetness perception. Prcticl Applictions It hs been suggested tht trehlose my be potentil substitute for sucrose nd other sugrs used in food formultion becuse, lthough its chemicl structure is very similr to tht of sucrose, it is more stble t low ph nd high tempertures. It is not involved in crmeliztion nd does not prticipte in Millrd rection with mino cids/proteins. In order to fully estblish the potentil of trehlose s functionl replcement of sucrose we hve determined the sweetness dynmic profile (Gusttory Rection Time nd Time-Intensity curves) of trehlose solutions nd sucrose/trehlose solutions; this spect is needed for dequtely replcing (prtilly or totlly) sucrose in food systems. Key words: Trehlose; sucrose; sweetness; time-intensity; gusttory rection time; sensory nlysis. 2

4 INTRODUCTION Trehlose is non reducing discchride composed of two glucose molecules linked by n α, α -1,1 glycosidic bond. It is nturlly found in mushrooms, yests, certin spores (Crowe et l. 1988) nd even insects hemolymph (Lee, 198). In the pst yers it hs been studied due to its physicl, chemicl nd biologicl properties. It hs become incresingly vilble for food ppliction s produced by the Hyshibr method (Crgill, 24) being considered generlly recognized s sfe (GRAS) multipurpose ingredient for ll uses in food in ccordnce with current good mnufcturing prctices. Even though its chemicl structure is very similr to tht of sucrose, trehlose hs n extrordinry chemicl stbility which mkes it prticulrly interesting s functionl food dditive. It is more stble thn sucrose t low ph conditions nd high tempertures. It is hrdly involved in crmeliztion nd does not result in Millrd rection with mino cids nd proteins, thus preserving the nturl color of the product. In queous solutions it presents wter ctivity ( w ) lowering behvior identicl to tht of sucrose t the sme concentrtions (Glmrini et l. 28). This llows its use in combintion with sucrose to optimize sweetness without ltering the w which is relted to microbil stbility. Trehlose hs mild sweetness equivlent to 45% of sucrose (Americn Dietetic Assocition, 24; Birch et l. 197) but little work hs been reported on its dynmic profile, which is known to give closer description to ctul perception during ingestion. For this purpose the two min tools usully utilized to describe sweetness dynmic profile re, T-I curves nd GRT. T-I curves quntify the continuous perceptul chnges tht occur in specified ttribute, providing temporl informtion bout perceived senstions, from onset through extinction. They cn be chrcterized by severl prmeters including, mximum intensity (I mx ), time to mximum intensity (T mx ), totl durtion of sweet tste (T dur ), time for sweetness intensity to decline to hlf its mximum vlue (T 5mx ), re under curve (AUC), rte of increse 3

5 (R inc ), rte of decrese (R dec ) nd plteu time (T plt ). Portmnn nd Birch (1995) described sweet tste of trehlose only in terms of intensity nd persistence by SMURF (Sensory Mesuring Unit for Recording Flux) technique. However, they did not evlute other importnt prmeters tht describe chnges in sweetness long time which cn be obtined by T-I records. It is to be noted tht their evlutions were crried out long smll concentrtion rnge (2.3 to 9.2%) nd lso the trehlose used t tht time ws not commercil product, s the one currently used by the food industry (Hyshibr, Crgill, 24). Gusttory Rection Time (GRT) is defined s the minimum time required by subject to report ny tste chnges fter onset of tste stimultion t low concentrtion levels; being this the scope in which T-I hs smller sensitivity (Zmor et l. 1998). This kind of study contributes to explining the dynmic behvior of substnces ner threshold nd up to ner hlf suprumbrl rnge (i.e. 15% in sucrose solutions, Zmor et l 1998). No previous work ws found in literture describing GRT for trehlose. The im of the present work ws to chrcterize sweetness perception for trehlose nd sucrose solutions s well s their mixtures using dynmic methods such s GRT nd T-I; wide rnge of solid concentrtions ws considered. MATERIALS AND METHODS Preprtion of solutions All tested solutions were prepred with commercil food grde crystlline trehlose (dihydrte) provided by Crgill Inc., Wyzt MN, U.S.A., commercil sucrose from Ledesm S.A., Argentin nd distilled wter. Solution concentrtions tested by GRT technique were, 2.3%; 4.6%; 9.2% nd 13.8 % for sucrose; nd, 2.3%; 4.6%; 9.2%; 13.8%; 16.1% nd 23.% for trehlose. These concentrtions were selected bsed on previous work by Zmor et. l (1998) which showed tht the greter vrition of GRT is found ner threshold concentrtion becoming constnt t 4

6 higher concentrtions, i.e. 15% for sucrose. The studied rnge for trehlose ws extended due to its lower sweetness intensity t equl concentrtions. The T-I method ws used to evlute pure scchride solutions (sucrose or trehlose) s well s their mixtures; in this cse concentrtions were, 2.3%; 9.2%; 16.1%; 23.%; 29.9% nd 36.8%, for sucrose nd trehlose. These were chosen bsed on previous work from Portmnn nd Birch (1995). Regrding sucrose/trehlose mixtures they hd totl solid content of 23. nd 36.8 %, nd were prepred by replcing different mounts of sucrose by trehlose obtining mixtures rnging between pure sucrose to pure trehlose with the following sucrose/trehlose (s/t) rtio, 15.; 4.3; 3.; 1.7; 1.3;.8;.6;.3;.2;.6 t totl concentrtions of 23. nd 36.8%. In order to find the significntly different mixture solutions within mixtures compositions, ll blends were nlyzed by pired comprison. All solutions were kept t 4ºC nd tested t 18±2 ºC. Gusttory Rection Time (GRT) GRT of sucrose nd trehlose solutions ws evluted using computerized system developed by Guiro nd Zmor (1999). This equipment consisted of pumping system, computerized interfce nd push button. The pumping system delivered stndrdized mount of chosen solution directly into the mouth of the ssessor. The softwre commnded this pumping system llowing to control the durtion of stimuli presenttion (4 milliseconds) nd interstimuli intervls (3 milliseconds). Once the stimuli ws delivered, the subject hd to press the push button s soon s something different from wter ws identified ( go no go procedure). This response ws registered by the softwre recording the time (in milliseconds) elpsed between pumping nd button pressing. For this prt of the experiment nine ssessors (ll femles, 22 to 5 yers old) students nd stff from Fcultd de Ciencis Agrris, Pontifici Universidd Ctólic Argentin were recruited. They were first trined in the technique nd use of the equipment with distilled wter long two sessions of 15 minutes ech. During these trining sessions judges hd to press the button s soon s they felt wter (Touch Rection Time) on the tongue surfce. In this wy they got cquinted with the technique whilst their individul Touch Rection Time (TRT) ws 5

7 obtined. Sugr solutions were evluted over 1 sessions of 15 minutes in individul booths under dy light (65 K). An mount of 4 ml of smple ws pumped directly into the mouth of the ssessor, solutions were presented in rndom order nd rinsing with distilled wter between smples ws mndtory. Pired comprison A pnel of 12 ssessors (3 men, 9 women; 16-5 yers old; students nd stff from Fcultd de Ciencis Agrris, Pontifici Universidd Ctólic Argentin) evluted ll the solutions mentioned in Preprtion of Solution (sucrose/trehlose mixtures with totl solid content of 23. nd 36.8 %, rnging between pure sucrose to pure trehlose with the s/t rtio, 15.; 4.3; 3.; 1.7; 1.3;.8;.6;.3;.2;.6 ) by forced choice pired comprison (ASTM, 1977). Evlution ws performed in duplicte obtining totl of 24 nswers. Ech ssessor received two smples (1 ml) presented in three digit coded plstic cups nd they hd to choose the sweetest one. Rinsing between smples with distilled wter ws llowed. The first two pirs tested were the pure sucrose solutions (23.% nd 36.8%) ginst 15. sucrose/trehlose rtio mixture t both totl solids content. Assessors hd to choose the sweetest one. If this comprison proved significntly different then the next tested pir ws 15. s/t rtio mixtures ginst 4. s/t rtio mixtures, if not 4. s/t rtio mixtures were testes ginst pure sucrose solutions. Time-Intensity (T-I) Mesurements Sweetness evolution over time ws studied ccording to ISO TC 34/SC 12 N 385 (1999) using computer softwre specilly designed for this purpose. Assessors used mouse to move cursor long 5 pixel line which represented 2cm unstructured line scle on the monitor. For ech smple nd ssessor dt were utomticlly recorded every.35 seconds. The softwre provided the T-I curve s well s eight prmeters which described it; mximum intensity reched (I mx ), time elpsed to mximum intensity (T mx ), totl durtion of sweet tste (T dur ), time for sweetness intensity to decline to hlf its mximum vlue (T 5mx ), re under curve (AUC), rte of increse of sweet tste (R inc ), rte of decrese of sweet tste (R dec ) nd plteu time (time during which tste intensity remined constnt) (T plt ). Assessors were 6

8 prompted by the computer to expectorte the smple t 1 seconds while continully recording perceived intensity until sweet flvor reched extinction. Only the ssessors who prticipted in both the GRT evlutions nd the pired comprison experiment crried out the T-I test (femles, 22 to 5 yers old). For this prt of the experiment ssessors were trined in order to minimize individul differences nd stndrdize T-I curves long intensity nd time xes. For this purpose three sucrose concentrtions within the rnge used in this study were used s stndrds, 2.3; 23.; 36.8%. These were given the following I mx reference vlues on -1 scle: 5-15 (low concentrtion); 5 6 (medium concentrtion); 9-1 (high concentrtion). Tking these reference vlues into ccount, the nine ssessors performed the T-I curves of ech stndrd solution in duplicte. These were nlyzed obtining T dur for ech stndrd by eliminting extremely long nd short times nd clculting the mode vlue of this prmeter. Afterwrds, ssessors re-did their evlution of the stndrds but now with reference vlue for I mx nd T dur. Once ssessors replicted the curves for the stndrd solutions, they could begin testing unknown solutions. The number of trining sessions depended on lerning skills of ech ssessor, rnging from four to six of 15 minutes ech. A blnced design ws used so tht ll concentrtions could be compred ginst ech other. At the beginning of ech session nd before nlyzing unknown smples, judges evluted the stndrd solutions. These were lso included s unknown smples for control. Trined ssessors evluted smples in triplicte long ten sessions of 4 minutes ech in individul booths under dy light (65 K). Dt Anlysis Averge TRT vlues of ech ssessor were subtrcted from their GRT vlues, in order to evlute only gusttory response dismissing motor nd cognitive individul differences. Ten vlues were obtined per ssessor for every solution; medi, stndrd devition nd rnge were clculted. Finl verge vlues presented highly significnt differences mong stndrd devitions (p<.1, Brtlett s test) even fter mthemticl 7

9 trnsformtion, therefore the non prmetric Kruskl Wllis test nd subsequent Connover s test were used. The grdients of the curves (GRT vs. concentrtion) obtined for ech ssessor for sucrose nd trehlose were compred by t- test for two pired smples. Significnce level of pired comprison test ws clculted by binomil test bsed on the number of correct nswers. The T-I dt for triplictes of the 18 tretments were nlyzed seprtely using noncentered Principl Component Anlysis (PCA) (Dijksterhuis et l. 1994; Piggott et l. 2). Chrcteristic prmeters were clculted for ech of these new curves obtined by non-centered PCA (in triplicte for ech studied solution) nd were nlyzed by n Anlysis of Vrince (ANOVA) nd Student Neumn-Keuls (SNK) using replictes nd solutions s fctors. These prmeters were then verged in order to perform PCA nd non hierrchicl k mens cluster nlysis. Anlyses were crried out with SPSS v. 13. (Inc. Chicgo, IL), Unscrumbler v. 9.7 (CAMO ASA, N-115 Oslo, Norwy) nd Infostt v. 27 (Universidd Ncionl de Córdob, Argentin). RESULTS AND DISCUSSION Gusttory Rection Time (GRT) For both sugrs (trehlose or sucrose) GRT decresed with the increse of concentrtion, s shown in Fig. 1. At ny concentrtion sucrose ws detected erlier thn trehlose, i.e. smller GRT; for exmple 4.6% sucrose solution hd lmost the sme GRT s 13.8% trehlose solution. As noted in Fig. 1 trehlose t 2.3% solution hs reltively lrge stndrd devition s compred to other dt. This my be ttributed to the fct tht 2.3% is close to threshold concentrtion of trehlose (Lee nd Birch, 1975). For both sugrs, GRT my be fitted to power function of concentrtion, following Pieron s Lw (Pieron, 1914, 192, 1952), 8

10 (GRT) -t o = kc -α where GRT is Gusttory Rection Time, t o n symptotic RT reched t higher stimulus intensities, k the rnge of chnges between t o vlue nd the mximum RT determined t threshold, C the concentrtion of the stimulus nd α the exponent of the function. The verge empiricl exponents of 1 ssessors (α± SD) were found to be -.52 ±.5 for sucrose nd -.37 ±.5 for trehlose, this vlues being significntly different (t- test for two pired smples, p<.1). Even though GRT did not rech constnt vlue, the behvior of the curve seems to be symptotic t high concentrtion vlues. Present results show tht trehlose hs longer tste detection time thn sucrose. This phenomenon could be explined by the good fitting between the equtoril disposition of hydroxyl groups nd the structure of wter. The stereochemicl comptibility (wter trehlose) prevents the AH-B bonding to the receptor (Portmnn nd Birch, 1995) which results not only in lower sweetness intensity but lso in greter GRT. Pired Comprison Both pure sucrose solutions t 23. nd 36.8% were not perceived s different from 15.; 4.3 nd 3. s/t rtio mixtures but were both perceived s significntly different (p<.5 nd p<.1 respectively) from mixtures with 1.7 s/t rtio. These significntly different binry solutions of 1.7 s/t rtio t 23. nd 36.8% totl solids were lso perceived s different from mixtures.6 s/t rtio t 23. nd 36.8% (p<.1 for both cses). These.6 s/t rtio solutions were lso found different from.2 s/t rtio solutions for both totl solids content with p<.1 for 23.% nd p<.1 for 36.8%. For 36.8% totl solids, the.2 s/t mixture ws found different from pure trehlose solution (p<.5) but in terms of 23.% totl solids solutions it ws found different from pure trehlose solution (p<.1) nd from.6 s/t rtio solution (p<.1). This ws the only cse in which the differences did not remin constnt between the two totl solid contents. 9

11 The dt obtined could be extrpolted to other sucrose/trehlose mixtures with different mount of totl solids within the given rnge (23.%-36.8% of totl solid content), knowing tht in order to perceive difference in sweetness intensity in mixture, the sucrose/trehlose should be of 1.7 or less. Sweetness dynmic profile Results of ANOVA for T-I prmeters showed tht sources of vrition were type of sugr (trehlose vs. sucrose) nd their concentrtions; however repliction nd repliction*concentrtion were not significnt supporting the interprettion tht the ssessors were consistent with their evlutions. Fig. 2 shows the vlues obtined for I mx (), T dur (b), T pl (c), T5 mx (d), R inc (e), TI mx (f), R dec (g) nd AUC (h) in terms of concentrtion for both sugrs nd their mixtures (18 tretments). I mx ws the prmeter tht showed the highest vrition mong concentrtions nd sugrs; ll pure solutions were significntly different t p<.5. I mx vlues nd concentrtions were relted by power function (See Fig. 2; being r 2 =.98 nd.99 for sucrose nd trehlose respectively). Exponent (β) of power function ws.79 for sucrose nd 1.32 for trehlose. According to Guiro (198) there is positive correltion between bsolute threshold vlues nd β: the higher the threshold of given substnce the bigger the vlue of β. This suggestion grees with the experimentl fct tht trehlose hs much bigger threshold vlue thn sucrose (1.5 g/1 ml for trehlose nd.65 g/1ml for sucrose; Lee nd Birch, 1975). Birch et l. (197), stted tht sucrose is 4-45% sweeter thn trehlose. In present work the I mx vlues of both sugrs were compred t ech concentrtion observing tht their sweetness rtio (trehlose/sucrose) vried from.32 to.51 (men.44) in the rnge studied. It is to be noted tht present results were obtined by extrpolting prmeters from dynmic technique which is not specilly designed for this purpose. Binry solutions were perceived s different (see Fig. 2) from ech other nd from pure solutions with the sme totl solid content (p<.5); however there were some similrities with 1

12 pure solutions t other concentrtions. A mixture of 23.% totl sugr with.2 s/t rtio ws perceived like pure sucrose t 16.1%; while 23.% mixture of.6 s/t rtio ws similr to pure trehlose t 36.8%. In order to evlute if there ws synergic, dditive or suppressive behvior between the studied sugrs, perceived nd expected sweetness intensity were compred. This dt is presented in Tble 1. Perceived sweetness intensity ws given by the I mx vlues obtined (Fig. 2 br grph) while expected sweetness intensity ws clculted by dding sweetness intensity of pure sugr solutions t their concentrtion in the mixture by mens of the equtions presented in Fig. 2. Even though the proportion perceived/expected sweetness intensity rnged from 1. to 1.3, these results were not sttisticlly significnt (t- test for two pired smples, p>.5). In sensory evlution sme qulity interctions re often predicted by sigmoidel shped psychophysicl function, with expnsive, liner or compressive phses (Kest nd Breslin, 23). The liner region is in the middle of the function nd should result in intensity dditivity when two concentrtions from this region re dded together nd hve β close to 1. The mixtures studied belong to this region (liner) nd their β is ner the mentioned vlue, which explins why n dditive behviour, except of synergism, ws found. This is lso suggesting tht both sugrs interct with the sme receptors given tht if two sweet compounds ct vi the sme mechnism, mixtures of two should behve in n dditive mnner (Hyes 28). Fig 2b presents the obtined results for T dur. For sucrose this prmeter ws described s liner function of concentrtion in the rnge studied (r 2 =.97) but for trehlose the sme behvior ws observed only up to concentrtion of 29.9% (r 2 =.99); fter tht vlue the prmeter remined constnt. Pure solutions t equl concentrtions presented no significnt differences except t 36.8% where sucrose showed much higher persistence thn trehlose (p<.5). In this wy, equl concentrtions showed significnt differences for I mx but not for T dur. When compring the vlues of T dur for equi-sweet concentrtions by mens of the equtions presented in Fig 2, the rtio trehlose/sucrose obtined is 1.5 for the liner studied rnge. This shows tht in eqully 11

13 intense solutions trehlose is much more persistent thn sucrose. In previous work Portmnn nd Birch (1995) reported tht trehlose presented greter persistence thn sucrose t equl concentrtions while the findings of this work revel tht this bigger persistence is found for equi-sweet concentrtions. Among binry solutions with 36.8% totl solids significnt differences were found, being the solution with greter proportion of trehlose similr to pure 36.8% trehlose solution nd less persistent thn the other two mixtures (p<.5). For the prmeter T pl (Fig 2c) 36.8% pure sucrose ws the only solution which ws perceived s significntly different (p<.5) from every other solution, showing the highest vlue. Fig 2d shows tht both sugrs presented similr liner functions of T5 mx in terms of concentrtion. The greter differences mong pure solutions were observed for concentrtions, 16.1%; 23.% nd 36.8%. In binry solutions of 36.8% totl solids, the one with the lest trehlose content presented greter T5 mx thn the other two mixtures with the sme totl sugrs. Both sugrs presented R inc tht followed liner function in terms of concentrtion (Fig 2 e), hving sucrose greter grdient s consequence of its higher intensity. Mixtures t 23.% presented the sme vlues s the pure solutions t the sme concentrtion except for 1.7 s/t rtio solution which ws different only from pure trehlose solution. On the other hnd, 36.8% binry solutions with 1.7 nd.6 s/t rtio hd R inc equivlent to tht of pure sucrose solution t 36.8% nd different from pure trehlose t the sme concentrtion while.2 s/t ws different from pure sucrose but not from pure trehlose solution. TI mx (Fig 2 f) ws similr for both sugrs nd their mixtures long the studied concentrtion rnge. These results gree with those obtined for T dur nd T pl which did not present big vritions. The R dec (Fig. 2 g) for sucrose ws lmost constnt long the concentrtion rnge here studied, while for trehlose this prmeter showed positive liner dependency on concentrtion (r 2 =.98). These results show tht n increse in perceived intensity is 12

14 ccompnied by n increse in persistence for sucrose but not for trehlose. For this prmeter, mixtures t 23.% were ll significntly different (p<.5) from trehlose pure solution t the sme concentrtion but not from sucrose. The AUC (Fig. 2 h) showed significnt differences (p<.5) mong sucrose solutions t different concentrtions except for 2.3 nd 9.2%. Trehlose solutions did not show differences between 9.2 nd 16.1% nd between 29.9 nd 36.8%. All binry solutions t 36.8% totl solids were different from pure sucrose nd trehlose solutions. In order to summrize T-I responses of ll tested solutions, the obtined prmeters for the three replictes of ech solution were verged nd Principl Component Anlysis ws performed (Fig. 3) using the correltion mtrix. The first Principl Component (PC1) ws responsible for 83.1% of the totl vrition nd ws the only component with n eigenvlue greter thn one (6.65), being the only fctor necessry to explin vrition mong solutions. Six groups of smples were formed by non hierrchicl k mens cluster nlysis. The 36.8% pure sucrose solution ws not relted to ny other solution nd the sme ws observed for the mixture of 36.8% totl solid with 1.7 s/t rtio. Sucrose solution t 29.9% ws pired with the mixture of 36.8% totl solids with.6 s/t rtio. This shows tht even though these two solutions hd different mounts of solid contents, their mximum intensities were perceived s different but the sweetness profiles (i.e., T dur, T pl, T 5mx, T Imx ) were very similr. Another group ws conformed by five solutions, sucrose 23.%; trehlose 36.8%; 23.% solids mixtures with 1.7 nd.6 s/t rtio nd the 36.8% binry solution with.2 s/t rtio. In this wy, considering sweetness profile perception 23.% sucrose solution could be replced by different binry mixtures or even by pure trehlose solution of higher concentrtion. The fifth cluster included 29.9% nd 23.% trehlose, 16.1% sucrose solutions nd the binry 23.% solids solutions with.2 nd.6 s/t rtio. This is nother exmple of group of scchrides solutions which cn be exchnged ccording to technologicl needs without ltering sweetness 13

15 profile sensory perception. The lst group ws composed of the four lest concentrted solutions, 2.3% nd 9.2% sucrose nd 9.2% nd 16.1% trehlose. CONCLUSION When compring sucrose to trehlose t equl concentrtions, trehlose presented lesser sweetness, bigger GRT nd the sme persistence. However, in terms of equi-sweet solutions trehlose presented greter persistence thn sucrose. This found chrcteristic could be of gret use in products were sweetness persistence is desired, such s chewing gums nd cndy. The similrities observed in this work for both sugrs in Time-Intensity prmeters such s T dur, T pl, T 5mx nd T Imx reveled tht trehlose nd sucrose showed similr sweetness profiles. In this wy, trehlose could be of much use in those products were mjor chemicl stbility is desired, obtining higher qulity product without ltering sensory perception; i.e. sweet foodstuffs in which Millrd rection is not desired. 14

16 ACKNOWLEDGEMENTS The uthors would like to thnk the finncil support from Agenci Ncionl de Promoción Científic y Tecnológic (PICT 31951), to the sensory pnel for their coopertion nd to Crgill Inc. for donting the trehlose. 15

17 REFERENCES AMERICAN DIETETIC ASSOCIATION ASTM Mnul on Sensory Testing nd Methods, STP 434, pp, 16-19, Americn Society for Testing nd Mterils, Phildelphi, PA. BIRCH, G., COWELL, N.D. nd EYTON, D A quntittive investigtion of Shllenberger's sweetness hypothesis. Journl of Food Technology. 5, CARGILL FOODS. 24. Specilty Food Ingredients, Crgill Inc., Wyzt, MN, USA. CROWE, J.H., CROWE, L. M., CARPENTER, J.F., RUDOLPH, A.S., AURELL WISTROM, C., SPARGO, B.J., ANCHORDOGUY, T.J Interctions of Sugrs with membrnes. Biochim Biophys Act. 769, DIJKSTERHUIS, G.B., FLIPSEN, M. nd PUNTER, P.H Pricipl component nlysis of time-intensity dt: three methods compred. Food Qulity nd Preference. 5, GALMARINI, M.V., CHIRIFE, J., ZAMORA, M.C. nd PEREZ, A. 28. Determintion nd correltion of wter ctivity of unsturted, supersturted nd sturted trehlose solutions. LWT Food Science nd Technology. 41, GUIRAO, M Los sentidos, bses de l percepción, p 68, Alhmbr, Espñ. GUIRAO, M. nd ZAMORA, M.C A computerized system for controlling nd mesuring gusttory rection times. Journl of Sensory Studies. 15, HAYES, J.E. 28. Trnsdisciplinry Perspectives on Sweetness. Chemicl Perception. DOI 1.17/s z ISO TC 34/ SC 12 N Sensory nlysis guide for the chrcteriztion of the evolution of the intensity of sensory ttribute during the time. Genev, Switzerlnd. KEAST, R.S.J. nd BRESLIN, P.A.S. 23. An overview of binry tste-tste interctions. Food Qulity nd Preference. 14, LEE, C. K Developments in Food crbohydrte 2, ed. pp Lee, C,K, Applied Science Publishers Ltd, Londres, UK. 16

18 LEE, C.K. nd BIRCH, G Structurl functions of tste in the sugr series: binding chrcteristics of discchrides. J. Sci. Fd. Agric. 26, PIERON, H Recherches sur les lois de vrition des temps de ltence sensorielle en function des intensités excittrices. Ann. Psychol.2, PIERON, H Nouvelles recherches sur l nlyse dy temps de ltence sensorielle en fonction des intensités excittrices. Ann. Psychol.22, PIERON, H The senstions. New Heven, CT : Yle University Press. PIGGOTT, J.R., HUNTER, E. A., MARGOMENAU, L. 2. Comprison of methods of nlysis of time-intensity dt: ppliction to Scotch mlt whisky. Food Chemistry. 71, PORTMANN, M. O. nd BIRCH, G Sweet tste nd solution properties of α, α- trehlose. Journl of the Science of Food nd Agriculture. 69, ZAMORA, M.C., BURATTI, F.M., OTERO-LOSADA, M.E Temporl study of sucrose nd fructose reltive sweetness. Journl of Sensory Studies. 13,

19 TABLE 1. COMPARISON BETWEEN PERCEIVED AND EXPECTED SWEETNESS INTENSITY IN BINARY SUCROSE/TREHALOSE MIXTURES. Sucrose/ trehlose rtio Totl sugr content Perceived sweetness intensity Excpected sweetness intensity Perceived/expected sweetness intensity (I mx vlue, Fig. 2 br grph) = = = = = = = vlues were obtined by dding expected sweetness intensity of pure sucrose in the concentrtion given in the mixture to expected sweetness intensity of pure trehlose in the concentrtion given in the mixture. For this purpose equtions from regressions line (Fig. 2 ) were used. sucrose trehlose 18

20 Figure cptions Figure 1. Gusttory Rection Time (Msec) s function of concentrtion for sucrose nd trehlose. Different lower cse letters represent significnt differences (p<.5) mong solutions ccording to Student Neumn-Keuls. Figure 2. Time-Intensity prmeters s function of concentrtion. Different lower cse letters on the br grph represent significnt differences (p<.5) mong solutions ccording to Student Neumn-Keuls. Figure 3. Principl Component Anlysis of sweetness Time-Intensity dt. Projection of Time- Intensity prmeters lodings (vectors) nd smple fctor scores on principl components 1 nd 2. Clusters re delimitted. Numbers 1-6 refer to sucrose 36.8%, 29.9%, 23.%, 16.1%, 9.2%, 2.3% respectively; 7-11 to trehlose 36.8%, 29.9%, 23.%, 16.1%, 9.2%, respectively; to 36.8% totl solids solutions t 1.7;.6 nd.2 s/t rtio respectively nd to 23.% totl solids solutions t 1.7;.6,.2 nd.6 s/t rtio respectively. 19

21 Time (msec) 25 2 g f f d Sucrose y = x (-.53) ; r 2 =.99 e b Trehlose y = x (-.37) ; r 2 =.99 d c b Concentrtion (% w/v) Figure 1. 2

22 Imx sucrose mixture 1.7 s/t rtio mixture.2 s/t rtio trehlose mixture.6 s/t rtio mixture.6 s/t rtio m p o n Imx 3 25 Sucrose y = 12.92x.79 ) b d h c k e j i h f g i l 2 R 2 = Trehlose 5 y = 1.8x 1.32 R 2 = Totl solid content (%) Totl solid content (%) Tdur i b) b b cde bc fg cdef cd bc gh efg def h gh def Tdur Sucrose y = 3.12x R 2 =.97 Trehlos y = 2.6x R 2 = Totl solid content (%) Totl solid content (%) Tpl b c) Tpl Totl solid content (%) Totl solid content (%) T5mx cd b efg ef efg de cd bc fg efg j i h gh efg T5mx Sucrose y =.92x R 2 =.97 d) Trehlose y =.76x R 2 = Totl solid content (%) Totl solid content (%) 21

23 Rinc 25 2 sucrose mixture 1.7 s/t rtio mixture.2 s/t rtio trehlose mixture.6 s/t rtio mixture.6 s/t rtio ef f f f e) bc cde b def cde cde bcd cde bc bcd bcd cde Rinc Sucrose y =.42x R 2 =.99 Trehlose y =.25x +.73 R 2 = Totl solid content (%) Totl solid content (%) TImx bc b bc b bc bc bc b bc bc c bc bc bc Timx Sucrose y = 8.69e.2x R 2 =.87 f) Trehlose y = 6.57e.2x R 2 = Totl solid content (%) Totl solid content (%) Rdec 3 3 d d cd cd cd cd cd d d d d cd cd g) 2 2 bc b bc Rdec Sucrose y =.2x R 2 = b Trehlose y =.4x +.27 R 2 = Totl solid content (%) Totl solid content (%) 18 h) AUC 16 l 14 k 12 1 i j AUC 2 16 Sucrose y = e.1x R 2 = h g fg fg ef def cd de b bc Trehlose y = e.9x R 2 = Totl solid content (%) Totl solid content (%) Figure 2 22

24 Figure 3 23