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Analysis of volatile compounds released during the grinding of roasted coffee beans using solid-phase microextraction
Masayuki Akiyama1, Kazuya Murakami, Noboru Ohtani
1Food Research & Development Laboratory, Morinaga Milk Industry Co., Ltd., 5-1-83 Higashihara, Zama, Kanagawa, 228-8583 Japan. m_akiyam@morinagamilk.co.jp
Journal of Agricultural and Food Chemistry
|March 20, 2003
Summary
A new dynamic solid-phase microextraction (SPME) method captures fresh coffee headspace volatiles during grinding. This technique enhances the detection of nutty and smoky aromas, offering a more authentic profile of roasted coffee.
Area of Science:
- Food Chemistry
- Analytical Chemistry
- Sensory Science
Background:
- Traditional methods for analyzing coffee volatiles often use ground coffee, which may not fully represent the aroma profile released during the grinding process.
- Understanding the volatile compounds released during coffee grinding is crucial for characterizing fresh roast aroma and quality.
Purpose of the Study:
- To develop and validate a dynamic solid-phase microextraction (SPME) method for sampling fresh headspace volatile compounds released during the grinding of roasted coffee beans.
- To compare the volatile profiles obtained by dynamic SPME with conventional static SPME methods using ground coffee.
- To characterize the aroma profile, particularly nutty and smoke-roast notes, generated during coffee bean grinding.
Main Methods:
- Dynamic solid-phase microextraction (SPME) using a poly(dimethylsiloxane)/divinylbenzene (PDMS/DVB) fiber was employed to capture volatiles from the headspace of freshly ground roasted coffee beans.
- Volatiles were sampled by exposing the SPME fiber to nitrogen gas purging through a sealed grinding vessel for 8 minutes.
- Analysis of the captured volatile compounds was performed using gas chromatography/mass spectrometry (GC/MS) and gas chromatography/olfactometry (GC/O).
Main Results:
- The dynamic SPME method demonstrated high reproducibility, with peak areas of 47 typical coffee volatile compounds showing coefficients of variation less than 5% (n=3).
- The gas chromatographic profile obtained by dynamic SPME was comparable to solvent extracts of ground coffee, with notable differences for highly volatile compounds.
- Volatile compounds generated during grinding were found to be significantly richer in nutty and smoke-roast aromas compared to static headspace analysis of ground coffee.
Conclusions:
- Dynamic SPME is an effective method for sampling fresh headspace volatiles released during coffee grinding, providing a more representative aroma profile.
- The grinding process itself contributes unique volatile compounds, enhancing nutty and smoke-roast characteristics crucial for coffee aroma.
- This method offers improved accuracy for analyzing the dynamic aroma release of roasted coffee.