Trends in Understanding the Science & Technology of Cocoa, Coffee, and Tea

Transcription

1 Trends in Understanding the Science & Technology of Cocoa, Coffee, and Tea 2 nd CoCoTea Conference, Naples, ctober 9-11, 2013 Imre Blank, Arne Glabasnia, and Andrew Scott Nestlé R&D

2 Technical challenges to meet consumers expectations Raw material quality, sourcing Mild processing Desirable vs undesirable effects Industrial efficiency Products in various formats (powder, liquid) Product properties (e.g. wettability, flowability) Shelf life, freshness All five senses are key for consumer preference Products with multiple benefits: Aroma, taste, colour, health benefits, powder properties 2

3 Global consumer mega-trends contributing to quality of life Convenience Pleasure Health Lifestyle Redefiniton No time to sit down but want the experience Easier, Faster and Disposable Leave more time for work or leisure Less hassle, no mess Men and Women roles mixed Slow Cooking made fast and easy Satisfying the Senses Guilt-free indulgence Emotional compensation for stress Mass - Luxury Individualism - Homing Worldly tastes Increased willingness to experiment with ethnic Artisanal varieties Well-being matters Achieve better performance To look good Get and keep balance To stay free of diseases Minimize the effect of ageing / prevent Less fat, sugar, salt The green season (Source: Datamonitor, Reuters) 3

4 Chemic al composition of Cocoa, Coffee, and Tea Average composition of green coffee Composition of fermented cocoa beans Content (% db) Arabica Robusta Polysaccharides Sucrose Lipids Trigonelline rganic acids Proteins Caffeine Chlorogenic acids Ash Green tea leaf (Graham, 1992) Component Content [% db] Carbohydrates 25 Polyphenol 30 Protein 15 Amino acids 4 Methylxanthines 3.5 Lipids 2 rganic acids 1.5 Ash 5 Similarities: Polyphenols, methylxanthines Differences: Trigonellin (coffee), theanin (tea) 4

5 The family tree of (poly)phenols Phenolic acids (e.g ferulic acid, caffeic acid, chlorogenic acids) Ellagic acid/ellagitannins (Poly)phenols Flavonoids Multiple role of polyphenols in coffee, cocoa, and tea driving quality attributes: Aroma, taste, colour, health benefits, texture Isoflavones (genistein, daidzein) Flavonols (e.g. quercetin) Flavanones e.g. hesperidin Flavanols Anthocyanins Catechins Pro(antho)cyanidins 5

6 Diversity of chlorogenic acids in CFFEE H H H H H H H H H H H H H H H H H H 3-caffeoyl quinic acid 4-caffeoyl quinic acid 5-caffeoyl quinic acid H H H H H H H CH 3 H H CH 3 H H H H 3 C H H H 3-feruoyl quinic acid 4-feruoyl quinic acid 5-feruoyl quinic acid R R CH 3 R CH 3 R CH 3 H CH 3 CH 3 CH 3 CH 3 H coumaric acid dimethoxycaffeic acid trimethoxycaffeic acid sinapic acid 6

7 Chlorogenic acids as quality markers for green coffee To differentiate between Robusta and Arabica To calculate blend of unknown samples by NIR (Haiduc et al.) by NMR (Wei et al. 2010) by LC/MS direct infusion (Garrett et al. 2012) Blend Post harvest Cultivar Crop Arabica Robusta (Haiduc et al, unpublished) (Garrett et al, 2012) 7

8 Transformation of raw materials: Chemical & physical changes upon roasting of green coffee beans Amino acids & Proteins Sugar - Carbohydrates NRC Nestlé Research Center Arabinogalactan-Protein Structure H H H CH 2 H H H CH 2 H H H H H CH 2 H CH 2 H H H H 2 C H H CH 2 H H H H Protein H CH 2 H H CH 2 H H Arabinogalactan H H 2 C H H H NRC/dpt - name/ yyyy-mm-dd 12 Roasting Key reactions: Maillard reaction Lipid oxidation Radical induced conversion of phenols Aroma, Taste, Colour, Health benefits Lipids Polyphenols (CAs) % degraded Sucrose Roasting losses (%) 3- Proteins Polysaccharides 2- CAs Trigonelline 8 20

9 Chlorogenic acids as aroma precursors upon roasting 9

10 Formation of coffee aroma compounds upon roasting phenolic aroma compounds Robusta green beans (9.2%) contain more chlorogenic acids than Arabica (7.2%) Kinetics of degradation of precursors (amino acids) and formation of aroma compounds correspond quite well (Wocheslander et al, unpublished) 10

11 Rel% Formation of bitter tastants upon coffee roasting 120 Caffeine CQL DKP Phenylindane Bitter precursor content depends on blend caffeine-like Bitter compound formation depends on roasting degree 60 metallic coffee-like Kinetics are different for different chemical classes 40 Bitter quality also different 20 harsh Compound class Threshold for bitterness (μmol/l) 0 green Roast degree Caffeine 750 Lactones DKPs Phenylindanes Benzenediols (Frank et al, ) H H 11

12 Sensory-analytical correlation: 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 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) 12

13 Bitterness prediction model from aroma compounds including those derived from CQA is very good (Baggenstoss et al, ASIC 2010) 13

14 4-Vinylcatechol oligomers Effect of roasting conditions on taste formation Percolation of roast & ground coffee with hot water 4-Vinylcatechol oligomers Strong retention to the coffee material (Blumberg et al, 2010) (260 C) 14

15 What matters in CCA powder? Flavour Appearance Health Benefits Taste & Texture Colour Appearance Healthy growth Balanced nutrition ne of the most complex flavours known to mankind Up to 20 chemical classes involved (Schieberle et al, Hofmann et al) Increasing number of scientific publication on cocoa covering a large range of health benefits smokey astringent bitter cocoa acid roasted fruity Wettability Fibres: Cellulose Pectin CVD Cognition Skin Health Metabolic Health Immune function 15

16 Polyphenols in Cocoa (Ferruzzi et al., 2012) 16

17 Impact of processing on bioactive compounds and colour formation More red 5.E+07 4.E+07 3.E+07 Theobromine 2.E+07 More dark 1.E+07 0.E+00 4.E+05 3.E+05 Pro-Val 3.E+05 2.E+05 2.E+05 1.E+05 5.E+04 0.E+00 1.E+06 1.E+06 8.E+05 Tyrosin 2.E+06 1.E+06 1.E+06 1.E+06 catechin 6.E+05 8.E+05 4.E+05 2.E+05 6.E+05 4.E+05 2.E+05 0.E+00 0.E+00 17

18 Is ph related to the chemical diversity of cocoa powders? TotalCocoa_Chained-Filters.M3 (PCA-X), t[comp. 1]/t[Comp. 2] Colored according to bs ID (ph range) DP 11 Impact-AL DP t[2] D11RB D11MA DCP 10 R 1 D11SB D11S D11DQ GT 150 DR74 JB DP 11 GT78 SR4 D11 N11N VB DSR SR8 Marquise R MR 10 DPDF DZA SR7 D11A D11 CE D11CA AJ11MV DB82 11-D-040 Valencia AJ11V D102C JB JB DP 11 GT50 SR5 DR DP11 DF RB DE Samara Samara DF700-11BR No ID < 0 ph 6.0 (natural cocoa) 1 3pH ph ph ph > ph t[1] R2X[1] = R2X[2] = ph (alkali Ellipse: concentration) Hotelling T2 (0.95) does not explain alone SIMCA-P :27:08 (UTC+1) chemical diversity. Additional parameter may be: Roasting Bean origin

19 Caking of cocoa powder: Water a major food plasticizer Total Energy (g.mm) Failure test (force vs. distance) 1.E+05 Texture Analyser distance= 10mm, speed= 0.1 mm/s 1.E+04 1.E+03 1.E+02 1.E+01 Ref 10% 30% 19

20 Consumer trend: Reduced-fat chocolate Chocolate is considered to be an indulgent product and consumers not willing to sacrifice taste. Effect of Fat content on Consumer preference Euromonitor valued the global reduced fat chocolate market at $440m in 2012 and it is forecasting 13.4% growth this year (US: 80%) 20

21 Fat reduction significantly increases chocolate viscosity Fat plays an important role in the chocolate mouthfeel The way fat melts in mouth has profound impact in mouthfeel of chocolate Understand processes and driving factors controlling in-mouth texture of chocolate to achieve enjoyment at lower levels of fat Viscosity increases as fat content is reduced from 35% fat suspension Chocolate viscosity increases significantly below 28% fat. The rheological properties of molten chocolate influence the eating experience of chocolate 21 1 Do, T-A L et al, J Food Sci, 72(9), , 2007

22 Viscosity reduction by lowering inter-particle interaction, aggregation during flow Surfactants play important role in achieving desired flow properties of chocolate (Do et al, 2010) Limonene Triglyceride Limonene mixes with and within the cocoa butter TAGs, diluting the fat and leading to a decrease in overall fat viscosity (EP ) Effect of limonene on viscosity of reduced-fat chocolate (25%fat) 22

23 Polyphenols in TEA 23 Andrew Scott

24 Polyphenol composition and tea processing White tea Buds & young leaves Sun & air dried Dried Green tea Buds & young / mature leaves Withered Steam or Pan-fried (oxidase inactived) Dried Catechins olong tea Buds & young / mature leaves Black tea Buds & young / mature leaves Withered Withered Bruised Rolled / Cut, tea & curl) Partially oxidised (fermented) Extensively oxidised (fermented) Pan-fried ven dried / fired Dried Dried Theaflavins & thearubigens ΔT / ox. ΔT / ox. oxidation (fermentation) oxidation (fermentation) 24

25 % dmb Tea polyphenols: Composition, Taste and Brewing 16 Average content of selected compounds in green and black tea min aq brews vs total Black teabags green black % (Engelhard et al., 2000) Astringency (molar base) Polyphenol Taste Flavan-3-ols astringent Theaflavins Mouth-drying, rough Flavonol glycosides Velvety, silky astringent mouth-coating Threshold (μmol; water) Compound Rutin (Scharbert et al., 2004) 25

26 Conclusions Composition of the raw material is key to product quality, along with (mild) processing conditions Polyphenol chemistry is to be better understood to achieve multiple benefits in the final product Targeted and holistic approaches are equally important (systemic approach for multiple benefits), requires interdisciplinary thinking! pportunities to leverage knowledge across product categories to be explored more 26