Factorial design fingerprint discrimination of Coffea arabica beans under elevated carbon dioxide and limited water conditions

Abstract

Coffee is one of the most important commodities, showing sensitivity to environmental variations. The main effects and their interaction for two levels of atmospheric CO₂ concentrations and two water regimes of a factorial design were investigated for the metabolic profiles of Coffea arabica raw beans using UV fingerprint analysis from a mixture design. UV fingerprint results obtained from pure ethanol and binary ethanol-dichloromethane mixtures showed the largest metabolic discriminations between CO₂ levels and their extracts were investigated in detail. The biosynthesis of major metabolites, chlorogenic acids, cafestol, kahweol and caffeine were altered owing to environmental conditions. Higher amounts of chlorogenic acids and kahweol were observed in beans from unirrigated plants grown with enriched CO₂ and irrigated ones at the current CO₂ level. Water availability and CO₂ concentration interaction affects the metabolite amounts. Besides a significant CO₂ atmospheric effect water availability was a limiting factor for metabolite content only at current CO₂ level, suggesting the successful metabolic coping of CO₂ enriched Arabic coffee beans suffering future droughts.

Keywords: Arabica coffee; Drought; Elevated CO(2); Metabolic modification; UV fingerprint.