Identification of the key aroma compounds in cocoa powder based on molecular sensory correlations.

Isolation of the volatile fraction from cocoa powder (50 g; 20% fat content) by a careful extraction/distillation process followed by application of an aroma extract dilution analysis revealed 35 odor-active constituents in the flavor dilution (FD) factor range of 8-4096. Among them, 4-hydroxy-2,5-dimethyl-3(2H)-furanone (caramel-like), 2- and 3-methylbutanoic acid (sweaty, rancid), dimethyl trisulfide (cooked cabbage), 2-ethyl-3,5-dimethylpyrazine (potato-chip-like), and phenylacetaldehyde (honey-like) showed the highest FD factors. Quantitation of 31 key odorants by means of stable isotope dilution assays, followed by a calculation of their odor activity values (OAVs) (ratio of concentration to odor threshold) revealed OAVs>100 for the five odorants acetic acid (sour), 3-methylbutanal (malty), 3-methylbutanoic acid, phenylacetaldehyde, and 2-methylbutanal (malty). In addition, another 19 aroma compounds showed OAVs>1. To establish their contribution to the overall aroma of the cocoa powder, these 24 compounds were added to a reconstructed cocoa matrix in exactly the same concentrations as they occurred in the cocoa powder. The matrix was prepared from deodorized cocoa powder, which was adjusted to 20% fat content using deodorized cocoa butter. The overall sensory evaluation of this aroma recombinate versus the cocoa powder clearly indicated that the 24 compounds represented the typical sweet, cocoa-like odor of the real sample.

[1]  D. Reymond,et al.  Sur la composition de l'ar?me de cacao , 1965 .

[2]  O. Vitzthum,et al.  VOLATILE COMPONENTS OF ROASTED COCOA: BASIC FRACTION , 1975 .

[3]  P. Schieberle,et al.  Quantitative Studies on the Formation of Key Odorants in Thermally Treated Yeast Extracts Using Stable Isotope Dilution Assays , 1998 .

[4]  P. Schieberle,et al.  Character Impact Odour Compounds of Different Kinds of Butter , 1993 .

[5]  P. Schieberle,et al.  Quantitative determination of 2,5-dimethyl-4-hydroxy-3(2H)-furanone and its methyl ether using a stable isotope dilution assay , 1991 .

[6]  L. Fay,et al.  Determination and Origin of the Aroma Impact Compounds of Yogurt Flavor , 1997 .

[7]  P. Schieberle,et al.  Changes in the concentrations of potent crust odourants during storage of white bread , 1992 .

[8]  Peter Schieberle,et al.  Solvent assisted flavour evaporation – a new and versatile technique for the careful and direct isolation of aroma compounds from complex food matrices , 1999 .

[9]  S. H. Davies,et al.  CCXXXI.—The essential oil of cocoa , 1912 .

[10]  P. Schieberle,et al.  Evaluation of the character impact odorants in fresh strawberry juice by quantitative measurements and sensory studies on model mixtures , 1997 .

[11]  Werner Grosch,et al.  Evaluation of Key Odorants of the Neutral Volatiles of Emmentaler Cheese by the Calculation of Odour Activity Values , 1994 .

[12]  Terry E. Acree,et al.  A Procedure for the Sensory Analysis of Gas Chromatographic Effluents , 1984 .

[13]  J. Sevcík.  Detectors in gas chromatography , 1976 .

[14]  P. Schieberle,et al.  Evaluation of Key Odorants in Milk Chocolate and Cocoa Mass by Aroma Extract Dilution Analyses , 1997 .

[15]  R. Buttery.  2-Acetyl-1-pyrroline : An important aroma component of cooked rice , 1982 .

[16]  W. Grosch,et al.  Potent odorants of raw Arabica coffee. Their changes during roasting. , 2000, Journal of agricultural and food chemistry.

[17]  W. Grosch,et al.  Identification of the Character Impact Odorants of Stewed Beef Juice by Instrumental Analyses and Sensory Studies , 1994 .

[18]  M. V. Praag,et al.  Steam volatile aroma constituents of roasted cocoa beans , 1968 .

[19]  S. Issanchou,et al.  Odor intensity evaluation in gas chromatography-olfactometry by finger span method. , 1999, Journal of agricultural and food chemistry.

[20]  P. Schieberle,et al.  Quantitative analysis of aroma compounds in wheat and rye bread crusts using a stable isotope dilution assay , 1987 .

[21]  M. Schneider,et al.  Enzyme assisted synthesis of enantiomerically pure δ-lactones , 1993 .

[22]  W. Grosch,et al.  Quantification of character-impact odour compounds of roasted beef , 1993 .

[23]  B. Willhalm,et al.  Recherches sur les arǒmes. 16e communication [1]. Sur l'arǒme du cacao III , 1967 .

[24]  P. Schieberle,et al.  Quantitative determination of .beta.-damascenone in foods using a stable isotope dilution assay , 1991 .

[25]  Nancy J. Micheals,et al.  Pinot noir aroma: a sensory/gas chromatographic approach , 1990 .

[26]  W. Grosch,et al.  Deterioration of soya-bean oil: quantification of primary flavour compounds using a stable isotope dilution assay. , 1990 .