Transient occurrence of seed germination processes during coffee post-harvest treatment.
OBJECTIVE
The chemical composition of green coffee and thus the final coffee quality are specifically determined by the mode of post-harvest treatment, i.e. the wet and dry processing. Recently, it was shown that metabolic processes, i.e. germination and, a slightly delayed stress-related metabolism are executed during the course of processing. The specific ambient conditions of either post-harvest treatment may influence differentially the extent and time course of these metabolic reactions; therefore, the incidence and intensity of germination processes in coffee seeds were analysed during processing.


METHODS
Expression of the germination-specific isocitrate lyase was monitored using competitive RT-PCRs analyses. Resumption of cell cycle activity and cell division were determined by flow cytometry, as well as by the abundance of beta-tubulin quantified by Western blot analyses.


RESULTS
The extent and the time courses of germination processes in coffee seeds differed significantly between wet and dry processed beans. The highest germination activity occurred 2 d after the onset of wet processing, whereas the corresponding maximum in the course of dry processing appeared about 1 week after the start of post harvest treatment.


CONCLUSIONS
As recently shown, there are specific differences in the chemical composition of differentially processed coffee beans. It is concluded that these substantial differences are the consequence of the differential expression of germination processes, i.e. they are the result of differences in the corresponding metabolic activities. The coherence of germination-related metabolism and of expression-specific coffee qualities establishes the basis for a novel approach in coffee research.
Bytof
Gerhard
G
Institute for Plant Biology, Technical University Braunschweig, Mendelssohnstrasse 4, 38106 Braunschweig, Germany.
Knopp
Sven-Erik
SE
Kramer
Daniela
D
Breitenstein
Björn
B
Bergervoet
Jan H W
JH
Groot
Steven P C
SP
Selmar
Dirk
D
D002453:Cell Cycle / Q000502:physiology; D040503:Coffea / Q000196:embryology*; D005434:Flow Cytometry; D018525:Germination; D007522:Isocitrate Lyase / Q000378:metabolism; D010940:Plant Proteins / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012639:Seeds / Q000254:growth & development*; D014404:Tubulin / Q000378:metabolism
D010940:Plant Proteins; D014404:Tubulin; D007522:Isocitrate Lyase