Browsing by Author "Felix Frauendorfer"

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    Changes in Key Aroma Compounds of Criollo Cocoa Beans During Roasting
    (2008) Felix Frauendorfer; Peter Schieberle
    Application of a comparative aroma extraction dilution analysis on unroasted and roasted Criollo cocoa beans revealed 42 aroma compounds in the flavor dilution (FD) factor range of 1-4096 for the unroasted and 4-8192 for the roasted cocoa beans. While tne same compounds were present in the unroasted and roasted cocoa beans, respectively, these clearly differed in their intensity. For example, 2- and 3-methylbutanoic acid (rancid) and acetic acid (sour) showed the highest FD factors in the unroasted beans, while 3-methylbutanal (malty), 4-hydroxy-2,5-dimethy1-3{2H)-furanone (caramel-like), and 2- and 3-methylbutanoic acid (sweaty) were detected with the nighest FD factors in the roasted seeds. Quantitatton of 30 odorants by means of stable isotope dilution assays followed by a calcuiation of odor activity values (ratio of the concentration/odor threshold) revealed concentrations above the odor threshold for 22 compound^ in the unroasted and 27 compounds in the roasted cocoa beans, respectively. In particular, a strong increase in the concentrations of the Strecker aldehydes 3-methylbutana! and phenylacetaldehyde as well as 4-hydroxy-2,5-dimethyl-3(2H)-furanone was measured, suggesting that these odorants should contribute most to the chanyes in the overall aroma after roasting. Various compounds contributing to the aroma of roasted cocoa beans, such as 3-methylbutanoic acid, ethyl 2-methylbutanoate, and 2-phenylethanol, were already present in unroasted, fermented cocoa beans and were not increased during roasting.
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    Changes in key aroma compounds of Criollo cocoa beans during roasting
    (2008) Felix Frauendorfer; Peter Schieberle