Effect of different extraction methods on the recovery of chlorogenic acids,caffeine and Maillard reaction products in coffee beans |
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Authors: | Gra?yna Budryn Ewa Nebesny Anna Pods?dek Dorota ?y?elewicz Ma?gorzata Materska Stefan Jankowski Bogdan Janda |
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Affiliation: | Gra?yna Budryn, Ewa Nebesny, Anna Pods?dek, Dorota ?y?elewicz, Ma?gorzata Materska, Stefan Jankowski and Bogdan Janda |
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Abstract: | Water and ethanolic extracts were obtained from green and roasted (3 different roast degrees) Arabica and Robusta coffee beans.
Three types of water extracts were prepared from the examined, finely ground material through: (a) brewing with boiling water,
(b) boiling in water, and (c) boiling in water under elevated pressure. All these extracts were lyophilized. Two types of
ethanolic extracts were derived from the examined material through (a) extraction of the finely ground coffee beans and (b)
extraction of the solid residue that remained after boiling the coffee beans in water under elevated pressure. These ethanolic
extracts were dried. Both water and ethanolic extracts were analyzed for concentration of potential antioxidants such as chlorogenic
acids and caffeine (by HPLC) and Maillard reaction products (measurements of absorbance at 420 nm). Concentration of chlorogenic
acids in Robusta extracts varied between 0.4 and 36.0 g × 100 g−1 dry extract weight (db.), while in Arabica extracts it ranged from 0.1 to 22.4 g × 100 g−1 db. Extracts of dark roasted Arabica contained more chlorogenic acids than those of Robusta. Concentration of caffeine, which
in green and roasted coffee beans is maintained at the similar level, tended to increase in Robusta extracts with the roast
degree and temperature of extraction with water, while in case of Arabica extracts there was no noticeable tendency. Caffeine
concentrations varied between 0.12 and 8.41 g × 100 g−1 db. and between 0.03 and 6.53 g × 100 g−1 db. in Robusta and Arabica extracts, respectively. Ethanolic extracts were characterized by relatively higher caffeine concentrations
and lower contents of brown pigments and chlorogenic acids as compared to water extracts. The richest in antioxidants were
extracts of green Robusta coffee beans derived through boiling in water under elevated pressure. |
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Keywords: | Coffee Coffee processing Chlorogenic acids Caffeine Maillard reaction products HPLC |
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