Coffee flavour precursors: contribution of water nonextractable green bean components to roasted coffee flavour
This study focuses on the changes in aroma generated upon roasting of green coffee beans (Coffea arabica and Coffea canephora) that were previously subjected to extraction with hot water. The combined water extracts were concentrated to _15 litres. The concentrated extract and extracted coffee beans were freeze-dried, and a suspension of the freeze-dried extract was reincorporated into the extracted coffee beans. These treated beans were freeze-dried and finally roasted. The composition of coffee beans was determined before and after treatment, and possible correlations with the aroma profile after roasting were studied. The aroma and flavour profiles of coffee brew samples were also evaluated. Results showed that water extraction followed by roasting resulted in a coffee with strongly reduced key impact odourants (e.g. 2- and 3-methylbutanal, alpha-diketones and guaiacols). Among the sulfur compounds, only furfurylthiol increased significantly. This indicates that its precursors are mainly water-unextractable components. Approximately 90-95 percent of the initial caffeine and caffeoylquinic acids was found after reincorporation of the water extract on the extracted coffee beans. Sensory evaluation of the coffee brews showed a reduction in quality: roasting extracted beans resulted in a significantly lower overall intensity and lower coffee flavour attributes. Results indicate that hot water-extractable green coffee components are important for the intensity and balance of coffee flavour. However, the contribution of water-unextractable components to coffee flavour is not negligible, as key odourants are still generated upon roasting of extracted coffee beans.
| Main Authors: | , , , , , , , |
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| Format: | biblioteca |
| Published: |
Trieste (Italia) ASIC
2001
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| Subjects: | COFFEA, COFFEA ARABICA, COFFEA CANEPHORA, SABOR, CAFEINA, COMPOSICION QUIMICA, ACIDO CLOROGENICO, CAFE, GUAYACOL, TOSTADO, ANALISIS ORGANOLEPTICO, TIOLES, COMPUESTO VOLATIL, |
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