New aspects of coffee processing: How do the different post harvest treatments influence the formation of potential flavour precursors?

Citation
G. Bytof et al., New aspects of coffee processing: How do the different post harvest treatments influence the formation of potential flavour precursors?, J APPL BOT, 74(3-4), 2000, pp. 131-136
Citations number
36
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Plant Sciences
Journal title
JOURNAL OF APPLIED BOTANY-ANGEWANDTE BOTANIK
ISSN journal
0949-5460 → ACNP
Volume
74
Issue
3-4
Year of publication
2000
Pages
131 - 136
Database
ISI
SICI code
0949-5460(200009)74:3-4<131:NAOCPH>2.0.ZU;2-8
Abstract
This paper represents a brief overview on coffee processing with special em phasis on the physiology and biochemistry of the coffee beans. Green coffee is obtained by submitting the harvested coffee cherries to either wet or d ry processing. It is well accepted that wet processed coffees evolve much b etter quality. The decisive quality criterion of coffee as a beverage is it s aroma, being composed of more than 800 compounds. Surprisingly, only abou t 30 of these contribute significantly to the specific coffee aroma. These aroma impact compounds are suitable indicators to estimate objectively the aroma differences resulting from different processing. Up to now, the reaso ns for the quality differences of technologically distinctively produced co ffees are unknown. In this context, the biochemical and physiological proce sses which occur in the living coffee bean during post harvest processing, and which are related to quality, must be taken into consideration. The coffee plant reveals some particularities which are relevant for the ge neration of aroma components but which, so far, hardly any attention has be en paid to: the coffee bean stands intermediately between recalcitrant and orthodox seeds. It does not undergo a resting period induced by maturation drying, and seed germination is initiated while the fruit is still in the f inal stages of development. In consequence, coffee beans that are submitted to processing do not represent resting seeds but rather developing seedlin gs. Substantial features of a seed in state of germination are an increasin g rate of respiration and the mobilization of storage compounds. These phys iological processes must have an impact on the concentration of aroma precu rsors in green coffee beans and thus on coffee quality. Accordingly, the re ported discrepancies between differently processed coffees appear to be the consequence of distinct developmental stages in the course of the coffee s eed germination, since the different processing procedures (dry or wet) are suitable to favour germination to an unequal extent.