Influence of processing on the generation of γ-aminobutyric acid in green coffee beans
ABSTRACT A determination of the concentrations of free amino acids in differently processed green coffees indicated the nonprotein amino acid -aminobutyric acid (GABA), a well-known plant stress metabolite, to be present in raw coffee beans (Coffea arabica L.) in significantly varying amounts. The GABA content of unwashed Arabica beans (green coffee produced by the dry processing method) was always markedly higher than that of washed Arabicas (wet processing method) as well as that of untreated seeds. This result underlined the assumption that during postharvest treatment a significant metabolism occurs within coffee seeds. A putative relation between drought stress of the coffee seeds and postharvest treatment methods is discussed. The GABA content of green coffee beans may serve as a potent tool to characterize the type of postharvest treatment applied in coffee processing.
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ABSTRACT: Seeds from different coffee species and coffee from different continents or countries have very distinct chemical compositions. However, the differences between genotypes grown at micro-regional levels with similar geographical characteristics are still unclear. In this study, we highlighted the need of using metabolite profiling instead of the usual targeted analysis as a more powerful tool to describe the slight differences between coffees of the same species grown in close origins. Thus, our study focused on finding potential metabolite markers to describe differences of Coffea arabica L. genotypes (Mundo Novo and Bourbons) grown in Brazilian coffee producing municipalities (Lavras, Santo Antônio do Amparo-SAA, and São Sebastião da Grama-SSG). Using the metabolomics approach, 44 metabolites were identified, and some showed great potential for origin and genotype differentiation. The Partial Least Square Discriminant Analysis- PLS-DA model showed that the SAA coffee samples had the most differentiated metabolite profile (approximately 95% accuracy) compared to the other municipalities. The samples from Lavras and SGG had similar profiles (model accuracy of approximately 50%). Potential metabolite markers for the SAA samples included, galactinol, fructose, malic acid, oxalic acid, D-glucose, D-sorbitol, galactinol, and myo-inositol. The model used to differentiate the bourbon genotypes and the MN showed 100% accuracy indicating very different metabolite profiles. The features that were most influential in differentiating genotype were: bourbon (5-CQA, oxalic acid, galactinol, nicotinic acid, caffeine, and caffeic acid) and MN (myo-inositol, quinic acid, malic acid, fructose, and D- glucose). Enhancing subtle differences in the data by combining information from GC-Q/MS and multivariate analysis resulted in the identification of coffee origins and genotypes as well as the identification of potential markers.Food Research International 07/2014; 61:75-82. · 3.05 Impact Factor
- Brazilian Journal of Botany 12/2011; 35(4):357-376. · 1.39 Impact Factor
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ABSTRACT: Coffee is one of the most frequently consumed drinks in the world. Coffee silverskin (CS) is the only by-product produced during the coffee beans roasting process, and large amounts of CS are produced by roasters in coffee-consuming countries. However, methods for the effective utilization of CS have not been developed. Reuse of CS, which is the primary residues from the coffee industry, is important for the environment and economy. Recently, there have been some attempts to reuse CS for biological materials and as a nutrient source for solid-state fermentation. The purpose of this review is to provide an overview about CS, its chemical composition, biological activity, and attempts at its reuse of CS.Food Research International 07/2014; · 3.05 Impact Factor