Evaluation of Key Odorants in Milk Chocolate and Cocoa Mass by Aroma Extract Dilution Analyses

Application of an aroma extract dilution analysis (AEDA) on the volatiles of a commercial milk chocolate revealed 51 odor-active compounds in the flavor dilution (FD) factor range 8−1024, 44 of which could be identified. The following 13 odorants contributed with the highest FD factors to the overall chocolate flavor: 3-methylbutanal (malty); 2-ethyl-3,5-dimethylpyrazine (potato chip-like); 2- and 3-methylbutanoic acid (sweaty); 5-methyl-( E )-2-hepten-4-one (hazelnut-like); 1-octen-3-one (mushroom-like); 2-ethyl-3,6-dimethylpyrazine (nutty, earthy); 2,3-diethyl-5-methylpyrazine (potato chip-like); ( Z )-2-nonenal (green, tallowy); ( E, E )-2,4-decadienal (fatty, waxy); ( E, E )-2,4-nonadienal (fatty); R -δ-decalactone (sweet, peach-like); and 2-methyl-3-(methyldithio)furan. Application of the AEDA on the cocoa mass used in the production of the milk chocolate led to the identification of 37 odorants, seven of which were sensorially not detected in the chocolate. By contrast, 11 odorants were present in the milk chocolate but were not sensorially relevant in cocoa mass, e.g., R -δ-decalactone and 5-methyl-( E )-2-hepten-4-one.