ADVANCED ANALYTICAL SENSORY CORRELATION TOWARDS A BETTER MOLECULAR UNDERSTANDING OF COFFEE FLAVOUR 23/09/2011 J. KERLER, J. BAGGENSTOSS, M. MOSER, A. RYTZ, E. THOMAS, A. GLABASNIA, L. POISSON, B. FOLMER, I. BLANK
Can we predict in-cup sensory profiles by analytical data? 01 THE CHALLENGE SENSORY ANALYTICAL CORRELATION STATE OF THE ART 02 THE APPROACH MONADIC SENSORY PROFILING TARGETED GC/MS ANALYSIS ADVANCED STATISTICS 03 THE SOLUTION RELIABLE PREDICTIVE TOOL P2
01 THE CHALLENGE SENSORY ANALYTICAL CORRELATION
Aroma Value Concept: a comprehensive approach to evaluate coffee aroma P4
The coffee melodie fundamentally different nature of sensory & analytical data SENSORY PROFILING Listen to the orchestra Describe specific instruments/tonalities Evaluate their intensities AROMA ANALYTICS (targeted) Identification of the key players/instruments Evaluation of their concentrations & impact Reconstitute melodie P5
Outline & Objectives of study 12 coffee blends (25 ml, 40 ml, 110 ml) Instrumental analysis (42 odorants, 12 taste compounds) Targeted approach Predictive analyticalsensory correlation model Sensory analysis (12 panelists, 9 sensory descriptors) Profiling OBJECTIVES Develop mathematical model to predict coffee in-cup sensory profiles Identify well correlated marker compounds for sensory descriptors P6
02 THE APPROACH MONADIC SENSORY PROFILING TARGETED GC/MS ANALYSIS ADVANCED STATISTICS P7
Sensory profiling was carried out with an expert panel (n=12) THE BASIC ATTRIBUTES... roasty bitter acid... describe the basic properties of an Espresso coffee The subtle aroma descriptors... fruity-floral red fruits, lemon, jasmine green-vegetal herbs, fresh vegetables dry-vegetal wood, malt, cereal vegetal-humus earthy, mushroom cocoa roasted, cacao, dark chocolate sweet vanilla, caramel, honey... describe the signature aroma of an Espresso coffee... are grouped based on olfactive similarity P8
In-cup concentrations of 54 aroma and taste compounds were determined substance flavor quality substance flavor quality 1 methanethiol sulfur, garlic 28 2-acetylthiazole roasty, popcorn 2 dimethyl sulfide cabbage, sulfur 29 furfural grass, almond 3 dimethyl trisulfide sulfur, cabbage 30 furfuryl acetate - 4 furfurylthiol sulfur, roast 31 2,3,5-trimethylpyrazine roasty 5 3-mercapto-3-methylbutylformate catty 32 2-ethyl-3,6-dimethylpyrazine roasty, earthy 6 methional potato 33 2-ethyl-3,5-dimethylpyrazine roasty, earthy 7 3-methyl-2-butenethiol sulfur, amine 34 2-ethenyl-3,5-dimethylpyrazine roasty, earthy 8 2-methyl-3-furanthiol meat 35 2,3-diethyl-5-methylpyrazine roasty, earthy 9 acetaldehyde pungent, fruity 36 2-acetylpyrazine roasty 10 propanal solvent, pungent, fruity 37 2-isopropyl-3-methoxypyrazine pea, earthy 11 2-methylpropanal fruity, pungent 38 2-isobutyl-3-methoxypyrazine pea, earthy 12 2-methylbutanal fruity, cocoa 39 β-damascenone rose, honey 13 3-methylbutanal malty 40 sotolon maggi, curry 14 phenylacetaldehyde honey 41 furaneol caramel 15 hexanal grass 42 maltol caramel 16 2,3-butanedione buttery 43 3-CQA - 17 2,3-pentanedione buttery 44 5-CQA - 18 vanilline vanilla 45 4-CQA - 19 ethyl 2-methylbutanoate fruity 46 5-CQL bitter 20 ethyl 3-methylbutanoate fruity 47 4-CQL bitter 21 p-cresol medicinal, phenolic, smoke 48 5-FQA - 22 guaiacol smoke, medicine 49 4-FQA - 23 4-ethylguaiacol spice, clove 50 cyclo-val-pro bitter 24 4-vinylguaiacol spice, clove 51 cyclo-ala-pro bitter 25 N-methylpyrrole - 52 cyclo-pro-leu bitter 26 pyridine - 53 cyclo-phe-pro bitter 27 2-acetylpyridine popcorn 54 caffeine bitter P9
In-cup quantification was carried out using state-of-the-art methods ABSOLUTE QUANTITATIVE DATA 42 aroma compounds (isotope dilution assay) a. SPME-GC-MS b. SPME-GCxGC-TOF MS c. SPE-GC-MS 12 taste compounds (external standardisation) a. HPLC-DAD b. LC-MS/MS P10
Comprehensive GCxGC-TOF MS to quantify high impact trace odorants Analysis of methional Counts RT: 0.00-33.66 23000 22000 21000 20000 19000 18000 17000 16000 15000 14000 13000 12000 11000 10000 9000 8000 7000 6000 5000 4000 3000 2000 1000 0 RT: 1.35 AA: 10422 RT: 5.60 AA: 20990 RT: 5.67 AA: 4261 RT: 8.61 AA: 4626 RT: 11.44 AA: 40188? RT: 13.08 AA: 41504 Methional peak hidden behind other peaks Resolved by deconvolution and 2-dimensional techniques 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 Time (min) NL: 2.32E4 FID Analog ICIS 42GC6-101 P11
Preprocessing of analytical & sensory data key to perform multivariate statistics Sensory data Normalize Subtract (instrumental) pseudo-conc. Correlation of the two datasets X = Y + P Use of PCA & PCR Subtract pseudo-conc. Normalize Log 10 (conc.) Fechner s law: perception ~ k log (concentration) Instrumental Data (C. Lindinger et al., 2008) P12
Normalisation & transformation of analytical data Log 10 (conc.) Pseudo-concentration Pseudo-composition methanethiol dimethyl sulfide dimethyl trisulfide furfurylthiol 3-mercapto-3-methylbutylformate R1 2.67 1.92 0.42 2.24 1.32 3.73 3.36 3.50 3.48 3.39 E1 2.56 1.80-0.11 2.10 1.10 3.49 3.14 3.36 3.25 3.13 E5 2.64 1.63 0.11 2.08 1.35 3.62 3.18 3.41 3.30 3.21 L1 2.20 1.64-0.13 1.66 0.73 3.38 2.95 3.12 3.07 2.97 L2 2.25 1.41 0.13 1.85 0.97 3.31 3.05 3.28 3.11 2.99 R2 2.92 1.79 0.39 2.27 1.23 3.77 3.42 3.61 3.53 3.41 R3 2.88 1.63 0.30 2.24 1.33 3.66 3.35 3.70 3.43 3.31 E4 2.66 1.81 0.21 2.14 1.20 3.56 3.19 3.41 3.38 3.28 E2 2.90 2.40 0.11 2.13 1.56 3.68 3.27 3.46 3.40 3.34 E6 2.65 2.08 0.22 1.84 1.39 3.47 3.16 3.52 3.44 3.27 L3 2.17 1.56 0.08 1.85 1.14 3.28 2.95 3.19 3.08 3.01 E3 2.45 1.69 0.06 2.01 0.91 3.57 3.11 3.29 3.21 3.11 Mean 2.60 1.83 0.18 2.03 1.22 3.55 3.17 3.42 3.28 3.18 SD 0.25 0.28 0.17 0.18 0.23 0.15 0.14 0.16 0.16 0.15 acetaldehyde propanal 2-methylpropanal 2-methylbutanal 3-methylbutanal methanethiol dimethyl sulfide dimethyl trisulfide furfurylthiol 3-mercapto-3-methylbutylformate R1 0.31 0.29 1.40 1.18 0.43 1.20 1.32 0.54 1.23 1.35 E1-0.17-0.13-1.63 0.42-0.50-0.42-0.21-0.35-0.23-0.34 E5 0.18-0.72-0.41 0.28 0.57 0.45 0.06-0.05 0.08 0.20 L1-1.60-0.68-1.78-2.03-2.12-1.15-1.59-1.87-1.37-1.43 L2-1.39-1.54-0.26-0.98-1.05-1.62-0.86-0.84-1.12-1.25 R2 1.29-0.17 1.23 1.38 0.04 1.44 1.75 1.21 1.57 1.52 R3 1.15-0.72 0.71 1.19 0.46 0.70 1.26 1.79 0.93 0.85 E4 0.24-0.10 0.18 0.64-0.08 0.04 0.16-0.03 0.60 0.65 E2 1.21 2.02-0.40 0.59 1.44 0.88 0.69 0.24 0.69 1.01 E6 0.20 0.89 0.25-1.05 0.72-0.53-0.10 0.62 0.99 0.54 L3-1.74-0.99-0.56-0.97-0.35-1.82-1.53-1.44-1.28-1.16 E3-0.60-0.52-0.67-0.10-1.31 0.10-0.44-0.80-0.48-0.47 acetaldehyde propanal 2-methylpropanal 2-methylbutanal 3-methylbutanal Pseudo-conc. 0.95-0.25 0.22-1.53-0.76 1.14 0.91 0.21 0.24 0.13-1.09-0.18 methanethiol dimethyl sulfide dimethyl trisulfide furfurylthiol 3-mercapto-3-methylbutylformate R1-0.64-0.65 0.46 0.23-0.51 0.26 0.37-0.41 0.28 0.40 E1 0.08 0.13-1.38 0.67-0.25-0.17 0.04-0.10 0.02-0.09 E5-0.04-0.94-0.63 0.06 0.35 0.23-0.16-0.27-0.14-0.02 L1-0.07 0.85-0.25-0.50-0.59 0.38-0.06-0.34 0.16 0.10 L2-0.63-0.77 0.50-0.22-0.29-0.86-0.09-0.07-0.36-0.48 R2 0.15-1.31 0.09 0.24-1.10 0.30 0.61 0.07 0.43 0.38 R3 0.24-1.64-0.20 0.27-0.46-0.21 0.34 0.88 0.02-0.06 E4 0.03-0.31-0.04 0.43-0.29-0.17-0.06-0.24 0.39 0.43 E2 0.97 1.79-0.63 0.35 1.20 0.64 0.45 0.00 0.46 0.77 E6 0.07 0.76 0.12-1.17 0.59-0.66-0.22 0.49 0.86 0.42 L3-0.65 0.10 0.53 0.12 0.74-0.73-0.44-0.35-0.19-0.08 E3-0.42-0.34-0.49 0.08-1.13 0.28-0.26-0.62-0.30-0.29 acetaldehyde propanal 2-methylpropanal 2-methylbutanal 3-methylbutanal Standardize weight of each compound across coffees Y1 = (X1 mean) / SD Substract pseudo-concentration as per coffee Y2 = Y1 mean conc. P13
Approach used by Lindinger et al. (2008) achieved prediction of coffee headspace profiles by PTR-MS analysis M41 M45 M57 M61 M68 M69 M73 M75 M81 M82 M83 M87 M89 M97 M101 M111 Espresso n 1 145 3392 74 750 165 747 1374 786 1021 254 376 1081 58 311 285 240 Espresso n 2 127 3074 70 855 108 640 1237 647 781 171 299 936 49 328 284 229 Espresso n 3 129 3485 73 1080 82 671 1291 618 821 147 287 957 55 471 328 299 Espresso n 4 135 3502 72 961 91 733 1359 643 781 164 359 1006 51 415 323 269 Espresso n 5 162 3324 67 794 115 870 1434 689 994 186 364 1100 56 393 289 290 Espresso n 6 158 3822 70 947 80 855 1425 581 833 140 370 1061 51 509 314 307 Espresso n 7 125 3950 81 1268 81 600 1191 729 740 142 238 899 57 600 370 327 Espresso n 8 108 2618 63 766 122 561 1079 706 898 180 262 806 49 264 228 215 Espresso n 9 135 2828 80 864 164 707 1340 1128 1026 236 391 1030 65 302 280 229 Espresso n 10 96 2473 64 719 106 493 945 571 815 162 238 752 47 283 241 212 Espresso n 11 116 3150 69 834 110 564 1110 620 820 169 252 831 49 351 289 245 min 96 2473 63 719 80 493 945 571 740 140 238 752 47 264 228 212 M41 M45 M57 M61 M68 M69 M73 M75 M81 M82 M83 M87 M89 M97 M101 M111 Conc Espresso n 1 1.50 1.37 1.17 1.04 2.07 1.51 1.45 1.38 1.38 1.81 1.58 1.44 1.23 1.18 1.25 1.13 1.41 Espresso n 2 1.32 1.24 1.12 1.19 1.35 1.30 1.31 1.13 1.06 1.22 1.26 1.25 1.05 1.24 1.25 1.08 1.21 Espresso n 3 1.34 1.41 1.16 1.50 1.02 1.36 1.37 1.08 1.11 1.05 1.21 1.27 1.16 1.78 1.44 1.41 1.29 Espresso n 4 1.40 1.42 1.14 1.34 1.14 1.48 1.44 1.13 1.06 1.17 1.51 1.34 1.09 1.57 1.42 1.27 1.31 Espresso n 5 1.68 1.34 1.07 1.10 1.45 1.76 1.52 1.21 1.34 1.33 1.53 1.46 1.19 1.49 1.27 1.37 1.38 Espresso n 6 1.64 1.55 1.11 1.32 1.00 1.73 1.51 1.02 1.13 1.00 1.55 1.41 1.09 1.93 1.38 1.45 1.36 Espresso n 7 1.29 1.60 1.29 1.76 1.02 1.22 1.26 1.28 1.00 1.01 1.00 1.20 1.21 2.27 1.63 1.54 1.35 Espresso n 8 1.12 1.06 1.00 1.07 1.53 1.14 1.14 1.24 1.21 1.28 1.10 1.07 1.03 1.00 1.00 1.01 1.13 Espresso n 9 1.39 1.14 1.27 1.20 2.06 1.43 1.42 1.97 1.39 1.68 1.65 1.37 1.39 1.14 1.23 1.08 1.43 Espresso n 10 1.00 1.00 1.02 1.00 1.33 1.00 1.00 1.00 1.10 1.16 1.00 1.00 1.00 1.07 1.06 1.00 1.05 Espresso n 11 1.20 1.27 1.10 1.16 1.38 1.14 1.17 1.08 1.11 1.21 1.06 1.11 1.04 1.33 1.27 1.16 1.17 M41 M45 M57 M61 M68 M69 M73 M75 M81 M82 M83 M87 M89 M97 M101 M111 Espresso n 1 107 98 83 74 147 108 103 98 98 129 112 102 87 84 89 80 Espresso n 2 109 103 92 98 112 107 108 94 87 101 104 103 86 103 103 90 Espresso n 3 104 109 90 116 79 105 106 84 86 81 93 99 90 138 111 109 Espresso n 4 107 108 87 102 87 114 110 86 81 90 115 102 84 120 109 97 Espresso n 5 122 97 77 80 105 128 110 87 97 96 111 106 86 108 92 99 Espresso n 6 120 113 81 97 73 127 111 75 83 73 114 104 80 141 101 106 Espresso n 7 96 118 95 131 76 90 93 95 74 75 74 89 90 168 121 114 Espresso n 8 100 94 89 95 136 101 101 110 108 114 98 95 92 89 89 90 Espresso n 9 98 80 89 84 144 100 99 138 97 118 115 96 98 80 86 76 Espresso n 10 96 96 98 96 127 96 96 96 105 110 96 96 96 102 101 96 Espresso n 11 102 108 94 99 117 97 100 92 94 103 90 94 88 113 108 99 Espresso n 7 Standardize weight of each mass X 1 = X 0/min Pseudo-concentration Mean over all masses Pseudo-composition X 2 = X 1/Conc (x 100%) Flowery Winey Citrus Acid Comp2 (18%) Espresso n 3 Espresso n 4 Espresso n 6 Espresso n 11 Espresso n Coffee 1 Bitter Cocoa Espresso n 10 Espresso n 8 Espresso n 9 Espresso n 5 Roasted Woody Analytical data ButterToffee Cereal Espresso n 2 Sensory profile Comp1 (72%) Espresso n 7 Espresso n 9 Espresso n 11 Flow ery Winey Coffee Bitter Cocoa Flow ery Winey Coffee Bitter Cocoa Flow ery Winey Coffee Bitter Cocoa Citrus Roasted Citrus Roasted Citrus Roasted Acid Woody Cereal ButterToffee Acid Woody Cereal ButterToffee Acid Woody Cereal ButterToffee Sensory profile: by expert Predicted sensory profile P14
03 THE SOLUTION RELIABLE PREDICTIVE TOOL FOR IN-CUP SENSORY PROFILES P15
Coffees are widely distributed over sensory space Comp2-1.0-0.5 0.0 0.5 1.0 25mL (Ristretto) 40mL (Espresso) 110mL (Lungo) fruity-floral acid E1 green-vegetal CTn E6 E2 E3 L1 E4 E5 R2 R1 R3 L3 L2 vegetal-humus sweet roasty dry-vegetal cocoa bitter PCA from Sensory data (substracted intensity effect ) -1.0-0.5 0.0 0.5 1.0 P16
Combination of sensory & analytical spaces using PCA Comp2-1.0-0.5 0.0 0.5 1.0 25mL (Ristretto) 40mL (Espresso) 110mL (Lungo) fruity-flowery 2,3-pentanedione acid E6 hexanal E2 acetaldehyde 2,3,5-trimethylpyrazine furfurylthiol E4 E5 dimethyl trisulfide 2,3-diethyl-5-methylpyrazine guaiacol R3 2-acetylpyridine furfuryl acetate phenylacetaldehyde 2,3-butanedione methanethiol propanal E1 cyclo-val-pro cyclo-pro-leu caffeine dimethyl sulfide 3-methylbutanal 3-methyl-2-butene-1-thiol N-methylpyrrole E3 R2 cyclo-ala-pro 2-ethyl-3,6-dimethylpyrazine sotolon 2-acetylpyrazine cyclo-phe-pro ethyl 3-methylbutanoate 2-isopropyl-3-methoxypyrazine cocoa furaneol 3-mercapto-3-methylbutylformate?-damascenone R1 methional CTn maltol 2-methyl-3-furanthiol L1 L2 bitter furfural ethyl 2-methylbutanoate L3 2-methylbutanal 2-ethenyl-3,5-dimethylpyrazine 2-ethyl-3,5-dimethylpyrazine 4-vinylguaiacol 4-ethylguaiacol green-vegetal vanilline 2-acetylthiazole 2-isobutyl-3-methoxypyrazine 2-methylpropanal 5-CQA 4-CQL 5-FQA 4-FQA 4-CQA 3-CQA 5-CQL p-cresol vegetal-humus sweet roasty dry-vegetal Correlated arrows are close to each other The longer an arrow, the better its representation in sensory space -1.0-0.5 0.0 0.5 1.0 Comp1 P17
30 compounds exhibit strong correlation to the sensory descriptors 2,3,5-trimethylpyrazine 2-furfurylthiol acetaldehyde methanethiol 2,3-butanedione 2,3-pentanedione dimethyl sulfide sotolon furaneol 2-acetylpyridine pyridine sweet furfuryl acetate phenylacetaldehyde roasty dry vegetal 3-methyl-2-butene-thiol N-methylpyrrole methional furfural 2-methylbutanal acid green vegetal cocoa bitter vegetalhumus fruityflowery 2-isopropyl-3-methoxypyrazine 2-methyl-3-furanthiol vanilline 2-acetylthiazole hexanal 2-isobutyl-3-methoxypyrazine 2-methylpropanal p-cresol 4-ethylguaiacol guaiacol 4-vinylguaiacol dimethyl trisulfide 2,3-diethyl-5-methylpyrazine P18
The robust statistical model allows a reliable prediction of the sensory profile, i.e. 101 out of 106 data are below LSD R1 R2 R3 E1 E2 E3 E4 E5 E6 L1 L2 L3 P19
CONCLUSIONS A mathematical model has been developed which allows predicting the sensory in-cup profiles of Nespresso blends Deeper understanding of link between sensory descriptors and aroma markers Useful tool to support development of Nespresso blends with new taste experiences P20
Thank you for your attention! ANY QUESTIONS?