The multiple role of polyphenol chemistry in coffee associated with quality attributes 24 th ASIC Conference, Costa Rica, 13.11.2012 Arne Glabasnia, Imre Blank, Federico Mora, Valérie Leloup, Josef Kerler Nestlé PTC rbe
AGENDA Introduction Coffee polyphenols as quality markers for green coffee Coffee Polyphenols and aroma Coffee Polyphenols and taste Coffee Polyphenols and health Conclusion PTC rbe-science&nutrition / AGL / 13.11.2012
The family tree of (poly)phenols Antioxidants Phenolic acids (e.g ferulic acid, caffeic acid, chlorogenic acids) Ellagic acid/ellagitannins (Poly)phenols Flavonoids thers (BHT, Vit C) Isoflavones (genistein, daidzein) Flavonols (e.g. quercetin) Flavanones e.g. hesperidin Flavanols Anthocyanins Catechins Pro(antho)cyanidins PTC rbe-science&nutrition / AGL / 13.11.2012
Chlorogenic acids are the major phenols in coffee H H H H R H R Quinic acid Intermediate from the shikimic acid cycle H H H R H R H R Cinnamic acids Common metabolites in plants Chlorogenic acids Esters of quinic acid with hydroxycinnamic acids PTC rbe-science&nutrition / AGL / 13.11.2012
Diversity of chlorogenic acids in coffee H H H H H H 3-caffeoyl quinic acid 4-caffeoyl quinic acid 5-caffeoyl quinic acid H H H CH 3 H CH 3 H 3 C H 3-feruoyl quinic acid 4-feruoyl quinic acid 5-feruoyl quinic acid R R CH 3 R CH 3 R CH 3 CH 3 CH 3 CH 3 CH 3 coumaric acid dimethoxycaffeic acid trimethoxycaffeic acid sinapic acid PTC rbe-science&nutrition / AGL / 13.11.2012
Diversity further increased by presence of diesters H H H H H 3,4-dicaffeoyl quinic acid 3,5-dicaffeoyl quinic acid 4,5-dicaffeoyl quinic acid Di-Caffeoylquinic acids 1C,3CQA 1C,4CQA 1C,5CQA 1F,3FQA 1F,4FQA 1F,5FQA 3F,4FQA 3F,5FQA 4F,5FQA 1C,3FQA 1C,4FQA 1C,5FQA 3C,4FQA 3C,5FQA 4C,5FQA 1F,3CQA 1F,4CQA 1F,5CQA 3F,4CQA 3F,5CQA 4F,5CQA + all homo- and heterodiesters containing - coumaric acid - dimethoxycaffeic acid - trimethoxycaffeic acid - sinapic acid More than 100 different Di-Chlorogenic acid PTC rbe-science&nutrition / AGL / 13.11.2012
Coffee phenols as quality markers for green coffee PTC rbe-science&nutrition / AGL / 13.11.2012
Chlorogenic acids as quality markers for blend To differentiate between Robusta and Arabica To calculate blend of unknown samples LC-DAD (Mullen et al. 2011) by NIR (Haiduc et al.) by NMR (Wei et al. 2010) by LC/MS direct infusion (Garrett et al. 2012) Arabica Robusta PTC rbe-science&nutrition / AGL / 13.11.2012 Haiduc et al, unpublished Garrett et al, 2012
Chlorogenic acids as markers for coffee origin CGA used in as indicator of origin (Alonso-Salces et al, 2009) - to classify Robusta coffees from Cameroon, Indonesia, Vietnam - to classify Arabicas from America and Africa Robusta Arabica Alonso-Salces, 2009 Alonso-Salces, 2009 No effect for origin for Robusta from Africa (Ky et al 2001) PTC rbe-science&nutrition / AGL / 13.11.2012
Differentiation of cultivar by CGA content Differentiation of cultivars by CGA profile sometimes possible Crop to crop variety for one cultivar bigger than from cultivar to cultivar Monteiro et al (2012) PTC rbe-science&nutrition / AGL / 13.11.2012
5-CQA [mg/100g] Chlorogenic acids as quality markers for post-harvest treatment 17 brazilians cultivars analysed for CGAs, trigonelline, caffeine and sucrose In average higher CGA content in wet-processed coffee compared to semi-dry Trigonelline higher as well, sucrose lower, no effect on caffeine semi-dry wet 6000 5000 4000 3000 2000 1000 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 (adapted from Duarte et al, 2010) PTC rbe-science&nutrition / AGL / 13.11.2012
Chlorogenic acids in correlation with cup quality Correlation of CGA content with cup quality (Farah et al, 2006) The higher the CGA content the lower the cup quality Cup quality PTC rbe-science&nutrition / AGL / 13.11.2012 Farah et al (2006)
Coffee phenols and their role in coffee aroma PTC rbe-science&nutrition / AGL / 13.11.2012
Chlorogenic acids as aroma precursors upon roasting PTC rbe-science&nutrition / AGL / 13.11.2012
Important aroma compounds in roasted coffee Dose-over threshold Compound Arabica Robusta (E)-beta-damescenone 260000 270000 furfurylthiol 110000 170000 MMBF 37000 33000 MBT 27300 27700 3-isobutyl-2-methoxypyrazin 16600 2400 homofuraneol 15000 12000 furaneol 11000 5700 2,3-butandione 3390 3190 4-vinylguaiacol 3200 8900 guaiacol 1700 11000 2,3-pentandione 1320 660 methional 1200 500 vanillin 192 644 2-ethyl-3,5-dimethylpyrazin 165 470 2,3-diethyl-5-methylpyrazin 95 310 sotolon 74 32 4-ethylguaiacol 32 362 abhexon 21 11 Semmelroch et al. (1995) Phenolic impact compounds guaiacol CH 2 CH 3 4-vinylguaiacol CH 3 CH 3 CH 3 CH 3 4-ethylguaiacol vanillin PTC rbe-science&nutrition / AGL / 13.11.2012
Relative headspace concentration (%) Role of chlorogenic acids in aroma staling Significant losses in headspace concentration of e.g. thiols, pyrroles occur within hours Losses in headspace concentration of FFT occur within minutes 100 80 60 40 DMS Ethanethiol FFT MMBF N-Methylpyrrole 2,3-Pentanedione 20 0 0 10 20 Time (hours) Mueller et al, 2007 Are chlorogenic acids involved in that degradation? PTC rbe-science&nutrition / AGL / 13.11.2012
Trapping of key odorants (thiols) by polyphenols via oxidative coupling hydroxyhydroquinone (HHQ) (Müller et al, 2007) The loss of 2-furfurylthiol during coffee storage is mainly due to the oxidative coupling of the odorant to hydroxyhydroquinone (2), giving rise to the conjugates 9 and 10. PTC rbe-science&nutrition / AGL / 13.11.2012
Reaction possible for intact CGAs but not found in coffee Formed in model experiments Found in coffee brew H S H S catechol adduct H 3 C S caffeic acid adduct H S H S CQA adduct PTC rbe-science&nutrition / AGL / 13.11.2012 (Mueller et al, 2007)
Chlorogenic acids involved in coffee staling but not exclusively Munro et al. (2003) R SH oxidation - direct or radical induced (S-radical) S S R N S Milo et al. (unpublished ) radical induced oxidation (C-radical) reaction with aldehydes/ heterocycles? Müller & Hofmann (2005) H H S S H H nucleophilic addition at chlorogenic acid derivatives SH nucleophilic addition at melanoidins R N +. N R S R N N R R N N R + + S Hofmann & Schieberle (2002) PTC rbe-science&nutrition / AGL / 13.11.2012
Coffee phenols and their role in coffee taste PTC rbe-science&nutrition / AGL / 13.11.2012
CGAs as precursors for tastants: lactones Lactone formation well known (Farah et al, 2005) Lactones have been identified as bitter compounds in coffee (Frank et al. 2006) giving pleasant coffee-like bitter taste Bitter threshold Compound mg/l umol/l 3--caffeoyl-γ-quinide (2a) 13.4 40 4--caffeoyl-γ- quinide (3a) 12.1 36 5--caffeoyl-epi-δ-qunide (4a) 60.5 180 4--caffeoyl-muco-γ- quinide (5a) 11.2 30 5--caffeoyl-muco-γ- quinide (6a) 9.7 29 3--feruoyl-γ-quinide (2b) 13.7 39 4--feruoyl-γ- quinide (3b) 13.7 39 3,4--dicaffeoyl-γ-quinide 4.8 9.8 3,5--dicaffeoyl-epi-δ-quinide 24.9 50 4,5--dicaffeoyl-muco-γ- quinide (3a) 4.8 9.8 Frank et al., 2006 PTC rbe-science&nutrition / AGL / 13.11.2012 Frank et al., 2006
CGAs as precursors for tastants: phenylindanes Phenylindanes another class of bitter compounds formed from CQA degradation H R 1 H C H phenylbutanes phenylbutanes H H quinic acid H H H + Interm. R 1 H phenylbutenes phenylbutenes HC H 3 C H phenylindanes phenylindanes 5-Chlorogenic acid 4-vinyl 5-CQA caffeic acid vinylcatechol R 1 Bitter threshold Compound mg/l µmol/l H H H H Phenylbutanes 6 23 Phenylbutenes 39 145 Phenylindanes 9-40 32-148 H 3 C H H H 3 C Diphenylindanes 15-27 37-67 Frank et al., 2007 PTC rbe-science&nutrition / AGL / 13.11.2012 R 1 diphenylindanes diphenylindanes R 1 Frank et al., 2007
CGA as precursors for tastants: furan benzene diols Benzene diols are formed from catechols and furan derivatives in model roast experiments (Kreppenhofer et al. 2010) furfuryl alcohol H H+ - H 2 0 H H + CH 2 R + CH 2 + R H 4-(furan-2-ylmethyl)benzene-1,2-diol 4-CQA catechol H H CH 3 TC: 9.6 mg/l TC: 6.5 mg/l H H H CH 3 PTC rbe-science&nutrition / AGL / 13.11.2012 TC: 5.7 mg/l Kreppenhofer et al, 2007 TC: 7.5 mg/l
Rel% Formation of bitter tastants upon roasting 120 100 Roasting Caffeine CQL DKP Phenylindane Bitter precursor content depends on blend caffeine-like 80 coffee-like Bitter compound formation depends on roasting degree 60 40 metallic harsh Kinetics are different for different chemical classes 20 Bitter quality also different 0 green 110 90 70 50 Roast degree Compound class Threshold for bitterness (umol/l) Caffeine 750 Lactones 30-200 DKPs 190-4000 Phenylindanes 30-150 Benzenediols 100-800 PTC rbe-science&nutrition / AGL / 13.11.2012
Sensory analytical correlation 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 cacao roasted, cacao, dark chocolate sweet vanilla, caramel, honey... describe the signature aroma of an Espresso coffee... are grouped based on olfactive similarity PTC rbe-science&nutrition / AGL / 13.11.2012 Baggenstoss et al, ASIC 2010
54 aroma and taste compounds were analyzed for the present study 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 PTC rbe-science&nutrition / AGL / 13.11.2012 Baggenstoss et al, ASIC 2010
Comp2 Around 30 compounds exhibit strong correlation to aroma quality -1.0-0.5 0.0 0.5 1.0 25mL (Ristretto) 40mL (Espresso) 110mL (Lungo) E1 dimethyl sulfide sotolon furaneol CTn methional furfural E6 E2 acetaldehyde 2,3-pentanedione 2,3-butanedione methanethiol fruity-flowery acid green-vegetal E3 L1 2,3,5-trimethylpyrazine furfurylthiol pyridine furfuryl acetate 2-acetylpyridine E4 E5 R2 R1 3-methyl-2- butene-1-thiol N-methylpyrrole 2-isopropyl-3- methoxypyrazine L2 2-methyl-3-furanthiol 2-methylbutanal 4-vinylguaiacol 4-ethylguaiacol dimethyl trisulfide guaiacol 2-acetylthiazole vanilline 2,3-diethyl-5-methylpyrazine 2-isobutyl-3-methoxypyrazine 2-methylpropanal hexanal R3 p-cresol L3 vegetal-humus sweet phenylacetaldehyde roasty dry-vegetal cocoa bitter No correlation with lactones found for bitterness perception -1.0-0.5 0.0 0.5 1.0 PTC rbe-science&nutrition / AGL / 13.11.2012 Comp1 Baggenstoss et al, ASIC 2010
Around 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 vegetalhumus fruityflowery 3-methyl-2-butenethiol N-methylpyrrole methional furfural 2-methylbutanal acid green vegetal vanilline 2-acetylthiazole hexanal 2-isobutyl-3-methoxypyrazine 2-methylpropanal PTC rbe-science&nutrition / AGL / 13.11.2012 p-cresol bitter cocoa 2-isopropyl-3-methoxypyrazine 2-methyl-3-furanthiol 4-ethylguaiacol guaiacol 4-vinylguaiacol dimethyl trisulfide 2,3-diethyl-5-methylpyrazine Correlation found for aroma compounds derived from CQA breakdown with bitterness perception Baggenstoss et al, ASIC 2010
Bitterness prediction model from aroma compounds including those derived from CQA is very good Baggenstoss et al, ASIC 2010 PTC rbe-science&nutrition / AGL / 13.11.2012
Coffee phenols and their role for health PTC rbe-science&nutrition / AGL / 13.11.2012
Polyphenols/flavonoids have been considered to have an effect on health for many years 1936 Albert von Szent- Györgyi Nobel Prize in Physiology or Medicine (1937) 1957 PTC rbe-science&nutrition / AGL / 13.11.2012
The importance of coffee polyphenols in human diet pear black tea apricot pecan black grape nectarine red wine dessert apple broad bean peach raspberry grapefruit strawberry green tea infusion orange juice cider apple plum highbush blueberry blackberry dark chocolate 0 40 80 120 160 (mg/100g fresh weight) epicatechin catechin procyanidin B2 procyanidin B3 procyanidin B1 procyanidin C1 procyanidin EEC EGC EGCG cyanidin delphinidin malvidin pelargonidin petunidin quercetin hesperidin naringenin Coffee 36. place in mg/100g 6. place per serving 1. place for daily consumption (3-4 cups per day) PTC rbe-science&nutrition / AGL / 13.11.2012 Scalbert et al, 2010
CQAs most contributors to polyphenol intake in French adults Scalbert et al, 2011 PTC rbe-science&nutrition / AGL / 13.11.2012
More and more reports on positive effects on health for a moderate coffee consumption Robust inverse relation between regular coffee consumption, including decaffeinated, and risk of type 2 diabetes based on meta-analyses of epidemiological studies (van Dam 2006; van Dam and Hu 2005) Coffee, decaffeinated coffee, and tea consumption in relation to incident type 2 diabetes mellitus: a systematic review with meta-analysis. (Huxley et al 2009) The use of green coffee extract as a weight loss supplement: a systematic review and meta-analysis of randomised clinical trials. (nakpoya et al 2011) Lipophilic antioxidants more neuroprotective than hydrophilic (e.g. lactones (Chu et al 2009) High CQA coffees prevent oxidative damage (Hoelzl et al 2010) Antioxidant rich coffee reduces DNA damage (Bakuradze et al, 2011) CGA rich coffee induce chemopreventive phase II enzymes (Boettler et al. 2011) Coffee has positive effects to reduce cognitive decline (Abreu et al, 2011) ASIC session yesterday PTC rbe-science&nutrition / AGL / 13.11.2012
Antioxidant activity of green coffee comes mainly from CGAs 80% of the total antioxidant activity in green coffee comes from the 9 main chlorogenic acid H H H Total Antioxidant Activity by folin in% H CH 3 H CQA FQA di-cqa More than 100 coffee polyphenols have been already reported in the literature by the scientific community (Clifford & Kuhnert ) PTC rbe-science&nutrition / AGL / 13.11.2012
Antioxidant activity in roasted coffee stays at high level but is less explained by CGAs Total polyphenols (µmol 3CQA /g green coffee d.b.) Antioxidant capacity (µmol 3CQA /g green coffee d.b.) Total polyphenols (µmol 3CQA /g green coffee d.b.) Antioxidant capacity (µmol 3CQA /g green coffee d.b.) 400 400 350 350 300 300 250 250 a)total polyphenols by FLIN 200 150 200 150 100 100 50 50 From 9 CGAs 0 GC Light Medium Dark 0 GC From melanoidins 400 400 350 350 300 300 250 250 b) Antioxidant capacity by ABTS 200 200 150 150 100 100 50 50 0 GC Light Medium Dark 0 GC Leloup et al, ASIC 2010 PTC rbe-science&nutrition / AGL / 13.11.2012
Antioxidant activity of roasted coffee derives from small new peaks but mainly from a unresolved hump Absorption Absorption 500 400 5mg/mL 325nm ABTS 300 200 100 CQAs FQAs dicqas 0 0 10 20 30 40 50 60 70 80-100 -200 retention time (min) 150 100 5mg/mL 325nm ABTS 50 0 0 10 20 30 40 50 60 70 80-50 -100-150 retention time (min) Leloup et al, ASIC 2010 PTC rbe-science&nutrition / AGL / 13.11.2012
Intensity * * * Precursor ion scan by LC/MS of a roasted coffee to detect precursors of caffeic acid moiety CQA CafTrp * Lactones * Caffeic acid moiety di-cqa 5 10 15 20 25 30 35 40 45 50 Leloup et al, ASIC 2010 Retention time (min) Caffeic acid moiety largely present in unresolved hump PTC rbe-science&nutrition / AGL / 13.11.2012
Incorporation of chlorogenic acids into coffee melanoidins PTC rbe-science&nutrition / AGL / 13.11.2012 Bekedam et al, 2007
g/100g 15000 Model roasting of 5-CQA at 200 C in dry state 20000 10000 4.76 U n 8 Degradation of 5-CQA and Folin of reaction mixture 5000 0 3.17 11.11 14.76 15.90 3.36 2.62 16.48 17.45 28.75 6.38 12.68 HPLC chromatogram from final reaction mixture 120 100 80 60 40 20 CQA content Folin response -5000 20000 15000 10000 5000 0-5000 4.74 3.13 11.15 14.75 6.37 2.53 12.81 lactones RT: 15.98 MA: 905098 17.55 24.76 28.47 28.89 N 2 C U n 8 0 0 10 20 30 heating time in minutes 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 Time (min) 5-CQA is rapidly degraded in model roast mix at 200 C TPP by Folin of reaction mixture remains almost constant Lactones are formed but cannot explain loss of 5-CQA and Folin values A lot of minor peaks are detectable Chromatographic tools suitable? PTC rbe-science&nutrition / AGL / 13.11.2012
C:\Xcalibur\data\Kaffee\111208c 09.12.2011 17:05:03 CQA + Sucrose 30 min 111208c #10 RT: 0.27 AV: 1 NL: 4.23E7 T: - c ESI Full ms [ 150.00-2000.00] 100 95 90 85 80 75 70 Direct infusion into LC/MS of model roast of 5-CQA Polymerization of CQA can be observed 689.12 +174 QA-H2 H H H H H H 65 60 55 50 45 40 35 30 25 20 15 10 5 0 191.12 255.19 CQA CQL 352.93 DiCQA Di-CQL 497.07 515.10 671.08 707.18 +162 CA-H2 833.09 851.15 +174 QA-H2 1007.11 1025.15 +162 CA-H2 863.15 1187.20 1169.15 200 400 600 800 1000 1200 1400 1600 1800 2000 m/z 1343.17 1361.14 1523.14 1697.08 1043.16 651.15 995.17 1679.25 1859.27 471.10 807.06 881.11 1143.12 561.06 1223.29 1736.08 1996.90 PTC rbe-science&nutrition / AGL / 13.11.2012 +174 QA-H2 H H H H H H H H polymers
H Possible transformations of CGA and the effect on AX properties H AX property H H C H 2 x 2 Chlorogenic acid Polymerization CH 3 Nucl. H H H H H H H H H H H H S PTC rbe-science&nutrition / AGL / 13.11.2012
Conclusions Chlorogenic acids can be used to evaluate green coffee quality with regards to variety, origin and post-harvest treatment Chlorogenic acids play a crucial role in the formation and degradation of important coffee aroma compounds Chlorogenic acids are the main precursors of several bitter compounds in coffee Chlorogenic acids are converted into various compounds upon thermal treatment whilst maintaining the antioxidant activity PTC rbe-science&nutrition / AGL / 13.11.2012
But one thing is sure... Coffee is the most pleasurable hot beverage in the world PTC rbe-science&nutrition / AGL / 13.11.2012