Skip to Content
Merck
  • Use of gas chromatography-olfactometry to identify key odorant compounds in dark chocolate. Comparison of samples before and after conching.

Use of gas chromatography-olfactometry to identify key odorant compounds in dark chocolate. Comparison of samples before and after conching.

Journal of agricultural and food chemistry (2002-04-04)
Christine Counet, Delphine Callemien, Caroline Ouwerx, Sonia Collin
ABSTRACT

After vacuum distillation and liquid-liquid extraction, the volatile fractions of dark chocolates were analyzed by gas chromatography-olfactometry and gas chromatography-mass spectrometry. Aroma extract dilution analysis revealed the presence of 33 potent odorants in the neutral/basic fraction. Three of these had a strong chocolate flavor: 2-methylpropanal, 2-methylbutanal, and 3-methylbutanal. Many others were characterized by cocoa/praline-flavored/nutty/coffee notes: 2,3-dimethylpyrazine, trimethylpyrazine, tetramethylpyrazine, 3(or 2),5-dimethyl-2(or 3)-ethylpyrazine, 3,5(or 6)-diethyl-2-methylpyrazine, and furfurylpyrrole. Comparisons carried out before and after conching indicate that although no new key odorant is synthesized during the heating process, levels of 2-phenyl-5-methyl-2-hexenal, Furaneol, and branched pyrazines are significantly increased while most Strecker aldehydes are lost by evaporation.

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
Isobutyraldehyde, dry, 98%
Sigma-Aldrich
Isobutyraldehyde, natural, 96%, FG
Sigma-Aldrich
Isobutyraldehyde, 98%
Sigma-Aldrich
Isobutyraldehyde, redistilled, ≥99.5%
Sigma-Aldrich
Isobutyraldehyde, ≥99%
Sigma-Aldrich
Isobutyraldehyde, ≥98%, FG