Analysis of free amino acids in green coffee beans. II. Changes of the amino acid content in arabica coffees in connection with post-harvest model treatment.
Arnold, U.; Ludwig, E.;
Zeitschrift fur Lebensmittel-Untersuchung und -Forschung Year: 1996 Vol: 203 Issue: 4 Pages: 379-384 Ref: 9 ref.
1996
บทคัดย่อ
Amino acid concentrations were determined in 7 samples of freshly harvested seeds (extracted from green fruits) and after drying (at 80 deg C or modelled on solar drying), fermentation (in water) or storage (in cotton bags at room temperature). Compared with fresh seeds, 'solar drying' (alternating temperatures of 20 and 40 deg for 12 h at each temperature) induced considerable changes in the concentrations of individual amino acids. The concentration of glutamic acid increased by about 50% (mean of 500 mg/kg dry matter) and that of aspartic acid decreased by 110-780 mg/kg following solar drying. In most samples, solar drying significantly increased the concentrations of valine, phenylalanine, isoleucine and leucine. Changes in the quantities of other amino acids were non-uniform and insignificant. Minor concentration changes were observed following drying at 80 deg . Modelled fermentation had no significant effect on the concentrations of individual amino acids. Storage of seeds for 4 weeks did
not alter amino acid concentrations further. It was concluded that different postharvest treatments may influence the amount of aroma precursor compounds in coffee seeds.