Cíntia Sorane Good Kitzberger

Caracterização sensorial de cafés arábica de diferentes cultivares produzidos nas mesmas condições edafoclimáticas

O melhoramento genético de café promove ganhos em produtividade e características de interesse agronômico, mas afeta a composição do produto e consequentemente seus atributos sensoriais. A análise descritiva de Perfil Livre foi empregada para investigar a influência da variabilidade genética sobre as características das bebidas de cafés arábica de diferentes cultivares produzidos nas mesmas condições edafoclimáticas. Foram estudados cultivares tradicionais (Bourbon vermelho, Catuaí vermelho, Icatu amarelo) e os desenvolvidos pelo Instituto Agronômico do Paraná (IAPAR 59, IPR 98, IPR 99 e IPR 103). Os cafés, coletados em estágio cereja e secos ao sol, foram beneficiados e, após eliminação de defeitos, torrados (8 a 11 min, 200 a 210 °C, luminosidade de 28). Empregaram-se 15 provadores e um delineamento de blocos incompletos balanceados para 7 amostras, com 3 repetições. Os dados foram analisados por Análise Procrustes Generalizada. Os provadores mostraram concordância, repetibilidade e adequada discriminação. As duas primeiras dimensões foram responsáveis por 57% da variância observada. A primeira dimensão caracterizou-se principalmente pelos parâmetros cor de café, turbidez, aroma de café, chocolate, caramelo e doce, sabor amargo e textura encorpada (positivamente). A segunda dimensão correlacionou-se positivamente com sabor ácido e verde e transparência. O café Bourbon caracterizou-se como menos encorpado, pela menor intensidade de cor e de sabor amargo. Os cultivares IAPAR 59, IPR 98, Icatu e Catuaí foram descritos como similares e apresentaram comportamento intermediário. Catuaí diferenciou-se pela menor intensidade de sabor ácido e verde. Os cultivares IPR 99 e IPR 103 foram caracterizados como mais encorpados e pela maior intensidade de cor de café, turbidez, aroma de café, chocolate, caramelo e doce. As condições edafoclimáticas da região estudada proporcionaram a formação de atributos positivos para os cultivares oriundos de cruzamentos.

Composição química de cafés árabica de cultivares tradicionais e modernas

O objetivo deste trabalho foi avaliar a influencia da diversidade genetica sobre a composicao quimica de cultivares modernas e tradicionais de cafe arabica brasileiro. Cultivares tradicionais (Bourbon, Catuai e Icatu) e modernas (Iapar 59, IPR 98, IPR 99 e IPR 103) foram cultivadas nas mesmas condicoes edafoclimaticas e submetidas a tratamentos pos-colheita padronizados. Determinaram-se os teores de sacarose, acucares redutores, acidos orgânicos (quinico, malico e citrico), compostos fenolicos totais, acido 5-cafeoilquinico, compostos nitrogenados (proteina, trigonelina e cafeina), lipideos totais, cafestol e caveol. A diversidade genetica confere variabilidade a composicao do cafe e permite a discriminacao entre cultivares tradicionais e modernas. As cultivares modernas apresentam maior teor de acidos malico e 5-cafeoilquinico, lipideos totais, caveol e trigonelina. Os parâmetros caveol e a relacao caveol/cafestol sao propostos como discriminadores entre cultivares modernas e tradicionais, uma vez que a introgressao de genes de Coffea canephora aumenta os teores de caveol e os valores da relacao caveol/cafestol.

Diterpenes biochemical profile and transcriptional analysis of cytochrome P450s genes in leaves, roots, flowers, and during #Coffea arabica# L. fruit development

Lipids are among the major chemical compounds present in coffee beans, and they affect the flavor and aroma of the coffee beverage. Coffee oil is rich in kaurene diterpene compounds, mainly cafestol (CAF) and kahweol (KAH), which are related to plant defense mechanisms and to nutraceutical and sensorial beverage characteristics. Despite their importance, the final steps of coffee diterpenes biosynthesis remain unknown. To understand the molecular basis of coffee diterpenes biosynthesis, we report the content dynamics of CAF and KAH in several Coffea arabica tissues and the transcriptional analysis of cytochrome P450 genes (P450). We measured CAF and KAH concentrations in leaves, roots, flower buds, flowers and fruit tissues at seven developmental stages (30-240 days after flowering - DAF) using HPLC. Higher CAF levels were detected in flower buds and flowers when compared to fruits. In contrast, KAH concentration increased along fruit development, peaking at 120 DAF. We did not detect CAF or KAH in leaves, and higher amounts of KAH than CAF were detected in roots. Using P450 candidate genes from a coffee EST database, we performed RT-qPCR transcriptional analysis of leaves, flowers and fruits at three developmental stages (90, 120 and 150 DAF). Three P450 genes (CaCYP76C4, CaCYP82C2 and CaCYP74A1) had transcriptional patterns similar to CAF concentration and two P450 genes (CaCYP71A25 and CaCYP701A3) have transcript accumulation similar to KAH concentration. These data warrant further investigation of these P450s as potential candidate genes involved in the final stages of the CAF and KAH biosynthetic pathways.

Application of near infrared spectroscopy for green coffee biochemical phenotyping

Accessions resulting from surveys in Ethiopia (the centre of origin of Arabica coffee) can be used as a source of genetic variability in breeding coffee plants. They may contain some genes of interest for coffee breeding, specifically in relation to beverage quality. Near infrared (NIR) spectroscopy was used to develop models for predicting the major coffee constituents related to quality beverage (proteins, caffeine, lipids, chlorogenic acids, phenolic compounds, total sugars and sucrose). We selected coffee samples listed in a database containing data of chemical contents from samples of traditional and modern cultivars and of Ethiopian accessions to construct models to predict these compounds. Spectra were collected between 1100 nm and 2500 nm, and mathematical pretreatments were applied. The number of samples for the calibration step for each compound was set so as to be representative of distribution values. Cross-validation was performed on the total set of samples to select the optimal number of terms for the prediction models of each component. The prediction models were developed employing a modified partial least-squares regression. The total set of samples for each component was divided randomly into two subsets: one for developing the prediction model and the other to evaluate the predicted values. The best prediction models obtained were for chlorogenic acids (r2 = 0.94, RPD = 4.16), proteins (r2 = 0.94, RPD = 4.09) and caffeine (r2 = 0.92, RPD = 4.16). Models for lipids and phenolic compounds were not as accurate (r2 = 0.87, RPD = 2.77 and r2 = 0.86, RPD = 2.62, respectively), while models for sucrose (r2 = 0.84, RPD = 2.44) and total sugars (r2 = 0.85, RPD = 2.55) were even less accurate. All these models can be used for identifying coffee lines with more desirable traits in breeding programmes. The models were effective in discriminating Ethiopian coffee accessions from modern cultivars of coffee. Additionally, the NIR technique will make it possible to analyse a large number of samples in breeding programmes and may be used as a high-throughput analysis for green coffee phenotyping.

Genome-wide association study reveals candidate genes influencing lipids and diterpenes contents in Coffea arabica L

Lipids, including the diterpenes cafestol and kahweol, are key compounds that contribute to the quality of coffee beverages. We determined total lipid content and cafestol and kahweol concentrations in green beans and genotyped 107 Coffea arabica accessions, including wild genotypes from the historical FAO collection from Ethiopia. A genome-wide association study was performed to identify genomic regions associated with lipid, cafestol and kahweol contents and cafestol/kahweol ratio. Using the diploid Coffea canephora genome as a reference, we identified 6,696 SNPs. Population structure analyses suggested the presence of two to three groups (K = 2 and K = 3) corresponding to the east and west sides of the Great Rift Valley and an additional group formed by wild accessions collected in western forests. We identified 5 SNPs associated with lipid content, 4 with cafestol, 3 with kahweol and 9 with cafestol/kahweol ratio. Most of these SNPs are located inside or near candidate genes related to metabolic pathways of these chemical compounds in coffee beans. In addition, three trait-associated SNPs showed evidence of directional selection among cultivated and wild coffee accessions. Our results also confirm a great allelic richness in wild accessions from Ethiopia, especially in accessions originating from forests in the west side of the Great Rift Valley.

Berry distributions on coffee trees cultivated under high densities modulate the chemical composition of respective coffee beans during one biannual cycle

ABSTRACT Coffee trees show the fluctuation in production related to biannual phenological development. We aimed to quantify the berry distribution over the vertical profile and relate the chemical composition of coffee beans during few subsequent harvests in each of two production years (PY). The analyzed coffee productions followed severe pruning of plants grown in different planting designs. In the second PY, coffee plants loaded roughly fourfold more berries than the first PY. In the first PY, berry distribution in zones of plagiotropic axes that passed all physiological phases was characterized by random maturation over three harvests, while in the second PY, berry maturation over the orthotropic and plagiotropic axes differed between two harvests, suggesting higher impact of local light microclimate and, consequently, local source–sink relations. Proteins, sucrose, and lipids were the most sensitive studied chemical components when modifications in coffee beans composition were analyzed, considering the impacts of PY, harvest time, planting design, and berry position. Sucrose content increased in latter harvests, indicating better berry maturation compared to the first harvest in both PY. Protein and caffeine contents increased and lipids decreased in higher density and low plant layer during the second PY, suggesting that deposition of those components was modified by self-shading and maturation time related to the berry position over the plant profile.

Dynamics of sensory perceptions in arabica coffee brews with different roasting degrees

ABSTRACT Temporal Dominance of Sensations (TDS) technique was used to assess the temporal aspects of the sensory perception of coffee brew attributes. Two arabica coffees with differences in the composition were roasted to two different roasting degrees (medium-light and dark). The medium-light roast process induced to higher differences in brews composition that were related to more diversity in TDS profiles. The bitter taste and roasted flavor were the dominant attributes in dark roasted coffee brews, while in the medium-light roasted, the sour taste was highlighted. In general, high acidity and high caffeine content favored the dominance of astringent and sour taste in the brews, while a high content of chlorogenic acids favored the dominance of the bitter taste.

The typicity of coffees from different terroirs determined by groups of physico-chemical and sensory variables and multiple factor analysis

Coffee production is the result of the relationship between local environmental conditions and coffee cultivars that grow in this place. Coffee plants develop original physico-chemical and sensory characteristics that together with the agricultural techniques practiced by growers define the terroir. The objective of this study was to describe the typicity of coffee prepared by coffee growers from seven coffee terroirs in Paraná, Brazil. The terroir categorization was based on the local latitude, longitude, altitude and annual average temperature. Coffee samples were prepared by the coffee growers according to their agricultural techniques. A multiple factor analysis (MFA) was applied to the groups of variables of the green and roasted coffee bean physico-chemical and sensory attributes. The variability in environmental conditions was sufficient to modify the green and roasted coffee bean characteristics and sensory attributes. The terroir description obtained with MFA description compared to that obtained with individual groups of variables was different among terroirs. Roasted coffee variables and sensory attributes caused the greatest differences. The individual use of these groups of variables may result in non-representative descriptions of coffee from different terroirs. Mandaguari and Ivaiporã terroirs were associated with high nitrogenous compounds content, high expansion volume and low density of roasted coffees, and the beverages showed a high turbidity and intense body. Apucarana, São Jerônimo da Serra and Ribeirão do Pinhal terroirs were associated with low lipids content, high density and low volume expansion roasted coffee, and the beverage showed intense coffee and sweet aromas and a low turbidity and body texture. In coffee from the Londrina terroir, medium nitrogenous compounds content and high sucrose and lipids contents were found. Their beverage showed a high turbidity and intense body as well as a grassy green taste and astringency. Coffee from Ribeirão Claro terroir presented high lipids and sucrose contents and low caffeine and phenolic compounds contents, and the main sensory attributes were a coffee aroma and sweet and sour tastes. In conclusion, a terroir formed by environmental conditions and agricultural techniques can produce coffee with a set of physico-chemical and sensory characteristics that define its typicity.