Predicting best planting location and coffee cup quality from chemical parameters: An evaluation of raw Arabica coffee beans from São Paulo over two harvests.

Arabica coffee is one of the most consumed beverages in the world. The chemical components present in raw Arabica coffee beans (RACB) are directly related to the cup quality of the beverage. Environmental and genetic factors influence the content and profile of these components. Then, this work aimed to evaluate different chemical parameters of RACB from 3 varieties planted in 3 different experimental farms located within the "Alta Mogiana" terroir harvested in 2021 and 2022 to identify a better variety for each farm to produce a high cup quality Arabica coffee. The harvest period had a strong influence on most of the studied parameters because atypical weather conditions occurred in the 2021 harvest. The RACB harvested in 2022 yielded better results and supposedly will produce a beverage of high cup quality. Samples harvested in this period presented mainly average moisture levels closer to optimum (11.02 against 8.56 % in 2021); low total titratable acidity (98.00 against 169.75 mL 0.1 M NaOH/100 g in 2021); high amounts of free amino acids (0.96 against 0.93 g GAE/100 g in 2021), low amounts of CGA (4.27 against 4.85 g/100 g in 2021) and caffeine (1.08 against 1.76 g/100 g in 2021) and high amounts of trigonelline (1.12 against 0.96 g/100 g in 2021). The Rome Sudan variety had the best combination of chemical results, mainly when cultivated in Farm 2 in 2022, presenting high amounts of protein content (15.24 %) and free amino acids (0.96 g GAE/100 g), low total titratable acidity (98.3 mL 0.1 M NaOH/100 g), low amounts of CGA (4.55 g/100 g) and caffeine (1.29 g/100 g) and high amounts of trigonelline (1.11 g/100 g). The analysis of chemical compounds could predict the best farm to cultivate each variety studied and was a guide to foresee a higher cup quality of RACB beverages.

Exploring Microbial Influence on Flavor Development during Coffee Processing in Humid Subtropical Climate through Metagenetic-Metabolomics Analysis.

Research into microbial interactions during coffee processing is essential for developing new methods that adapt to climate change and improve flavor, thus enhancing the resilience and quality of global coffee production. This study aimed to investigate how microbial communities interact and contribute to flavor development in coffee processing within humid subtropical climates. Employing Illumina sequencing for microbial dynamics analysis, and high-performance liquid chromatography (HPLC) integrated with gas chromatography-mass spectrometry (GC-MS) for metabolite assessment, the study revealed intricate microbial diversity and associated metabolic activities. Throughout the fermentation process, dominant microbial species included Enterobacter, Erwinia, Kluyvera, and Pantoea from the prokaryotic group, and Fusarium, Cladosporium, Kurtzmaniella, Leptosphaerulina, Neonectria, and Penicillium from the eukaryotic group. The key metabolites identified were ethanol, and lactic, acetic, and citric acids. Notably, the bacterial community plays a crucial role in flavor development by utilizing metabolic versatility to produce esters and alcohols, while plant-derived metabolites such as caffeine and linalool remain stable throughout the fermentation process. The undirected network analysis revealed 321 interactions among microbial species and key substances during the fermentation process, with Enterobacter, Kluyvera, and Serratia showing strong connections with sugar and various volatile compounds, such as hexanal, benzaldehyde, 3-methylbenzaldehyde, 2-butenal, and 4-heptenal. These interactions, including inhibitory effects by Fusarium and Cladosporium, suggest microbial adaptability to subtropical conditions, potentially influencing fermentation and coffee quality. The sensory analysis showed that the final beverage obtained a score of 80.83 ± 0.39, being classified as a specialty coffee by the Specialty Coffee Association (SCA) metrics. Nonetheless, further enhancements in acidity, body, and aftertaste could lead to a more balanced flavor profile. The findings of this research hold substantial implications for the coffee industry in humid subtropical regions, offering potential strategies to enhance flavor quality and consistency through controlled fermentation practices. Furthermore, this study contributes to the broader understanding of how microbial ecology interplays with environmental factors to influence food and beverage fermentation, a topic of growing interest in the context of climate change and sustainable agriculture.

Potential of rust-resistant arabica coffee cultivars for specialty coffee production

Rust is the main disease affecting Coffea arabica, the most economically important coffee species. The objective of this study was to analyze C. arabicacultivars with different levels of rust resistance, including bean size, raw bean appearance, finalsensory scores (FSS), and aromaand taste nuances of the coffee cup. The experiment was designed in randomized blocks (RBD) with three replications and 20 treatments (cultivars), totaling 60 experimental plots. The rust-susceptible cultivars IPR 100, Rubi MG 1192, and Topázio MG 1190 were compared with 17 rust-resistant cultivars.Cultivars IPR 103, MGS Aranãs, and SaíraII presented the highest percentages of high sieves, highest scores of raw bean appearance, and low percentages of mocha-type beans. All cultivars had FSS above 82 and were classified as specialty coffees. The cultivars with the highest FSS (Arara and Catiguá MG2) showed a greater diversity of coffee cup aroma and flavor nuances. Rust-resistant Arabica coffee cultivars are promising for the physical quality of beans and have potential for the specialty coffee market.

Microbial diversity associated with spontaneous coffee bean fermentation process and specialty coffee production in northern Colombia.

Coffee fermentation involves the action of microorganisms, whose metabolism has a significant influence on the composition of the beans and, consequently, on the beverage's sensory characteristics. In this study, the microbial diversity during the wet fermentation of Coffea arabica L. in the Sierra Nevada of Santa Marta (SNSM) in Colombia was explored by high-throughput sequencing and the resulting cup quality through the standards of the Specialty Coffee Association. The taxonomic assignment of sequence reads showed a high microbial diversity comprised of 695 bacterial and 156 fungal genera. The microbial community was dominated by the Lactic Acid Bacteria (LAB) Leuconostoc, the yeast Kazachstania, and the Acetic Acid Bacteria (AAB) Acetobacter. Co-occurrence relationships suggested synergistic patterns between populations of LAB-AAB, yeasts-AAB, Leuconostoc-Prevotella, LAB-ABB-Selenomonas, and yeasts-fungi-nonLAB-nonAAB, which may result in the production of metabolites that positively impact the sensory attributes of coffee. The beverages produced were classified as specialty coffees, and their score was positively influenced by the fungal richness and the abundance of unclassified Lactobacillales, Pichia, and Pseudomonas. The findings show the richness and microbial diversity of the SNSM and serve as input for future research such as the analysis of microbial-derived metabolites and the establishment of starter cultures in coffee processing that guarantee the generation of high-quality beverages, the standardization of processes, the reduction of economic losses, and the production of value-added products that allow taking advantage of specialty coffee market.

Multivariate classification for the direct determination of cup profile in coffee blends via handheld near-infrared spectroscopy.

Professional cupping is a reliable methodology for the coffee industry and its professionals. However, it faces barriers for its implementation on an industrial scale. To date, no study has determined a coffee cup profile using a handheld near-infrared (NIR) spectrometer. Therefore, the aim of this study was to evaluate directly cup profiles in roasted and ground coffee blends via handheld NIR spectroscopy combined with partial least squares with discriminant analysis (PLS-DA), in an industrial case study. The sensitivity and specificity of the model obtained ranged from 91 to 100%, 84-100%, and 73-95% in the training, prediction, and internal cross-validation sets, respectively. These results are therefore promising for the industrial reality and the methodology could assist coffee professionals in their decisions during cup evaluation in further tests. The proposed method is viable for the direct determination of cup profile at industrial scale since it is portable, fast, simple, robust, and less expensive compared to the benchtops equipment.

Metabolomic Markers for the Early Selection of Coffea canephora Plants with Desirable Cup Quality Traits.

Genetic improvement of coffee plants represents a great challenge for breeders. Conventional breeding takes a too long time for responding timely to market demands, climatic variations and new biological threads. The correlation of genetic markers with the plant phenotype and final product quality is usually poor. Additionally, the creation and use of genetically modified organisms (GMOs) are often legally restricted and rejected by customers that demand natural products. Therefore, we developed a non-targeted metabolomics approach to accelerate conventional breeding. Our main idea was to identify highly heritable metabolites in Coffea canephora seedlings, which are linked to coffee cup quality. We employed a maternal half-sibs approach to estimate the metabolites heritability in open-pollinated plants in both leaves and fruits at an early plant development stage. We evaluated the cup quality of roasted beans and correlated highly heritable metabolites with sensory quality traits of the coffee beverage. Our results provide new insights about the heritability of metabolites of C. canephora plants. Furthermore, we found strong correlations between highly heritable metabolites and sensory traits of coffee beverage. We revealed metabolites that serve as predictive metabolite markers at an early development stage of coffee plants. Informed decisions can be made on plants of six months old, compared to 3.5 to 5 years using conventional selection methods. The metabolome-wide association study (MWAS) drastically accelerates the selection of C. canephora plants with desirable characteristics and represents a novel approach for the focused breeding of crops.

Mid infrared spectroscopy and chemometrics as tools for the classification of roasted coffees by cup quality.

Sensory (cup) analysis is a reliable methodology for green coffee quality evaluation, but faces barriers when applied to commercial roasted coffees due to lack of information on roasting conditions. The aim of this study was to examine the potential of mid-infrared spectroscopy for predicting cup quality of arabica coffees of different roasting degrees. PCA analysis showed separation of arabica and robusta. A two-level PLS-DA Hierarchical strategy was employed, with coffee being classified as high or low quality in the first level and then separated according to cup quality in the second level. Validation results showed that the second level models exhibited 100% sensitivity and specificity in the training sets. For the test set, sensitivity ranged from 67% (rio zona) to 100% (soft) while specificity ranged from 71% (rio) to 100% (rioysh, hard). Thus, the proposed method can be used for the quality evaluation of arabica coffees regardless of roasting conditions.

Mapping the potential beverage quality of coffee produced in the Zona da Mata, Minas Gerais, Brazil.

BACKGROUND: Detailed knowledge of coffee production systems enables optimization of crop management, harvesting and post-harvest techniques. In this study, coffee quality is mapped as a function of coffee variety, altitude and terrain aspect attributes. The work was performed in the Zona da Mata, Minas Gerais, Brazil. RESULTS: A large range of coffee quality grades was observed for the Red Catuai variety. For the Yellow Catuai variety, no quality grades lower than 70 were observed. Regarding the terrain aspect, samples from the southeast-facing slope (SEFS) and the northwest-facing slope (NWFS) exhibited distinct behaviors. The SEFS samples had a greater range of quality grades than did the NWFS samples. The highest grade was obtained from an NWFS point. The lowest quality values and the largest range of grades were observed at lower altitudes. The extracts from the highest-altitude samples did not produce any low-quality coffee. CONCLUSIONS: The production site's position and altitude are the primary variables that influenced the coffee quality. The study area has micro-regions with grades ranging from 80 to 94. These areas have the potential for producing specialty coffees. © 2015 Society of Chemical Industry.

New approaches on the analyses of thermolabile coffee diterpenes by gas chromatography and its relationship with cup quality.

A new gas chromatography method using pulsed split injector (PS-GC) was validated to quantify thermolabile diterpenes cafestol, kahweol and isokahweol in methanolysed Arabica coffee oils. Linearity was 0.99 from 8 to 69mgmL(-1), recovery ranged from 99% to 101% and precision of less than 4% was obtained. Besides, Soxhlet extraction time was evaluated and Tukey׳s test indicated that the mass of diterpenes obtained in 4h is equivalent to a 16h period, which represents a space-time yield four times higher. The microwave assisted methanolysis proved to be efficient to quantitatively convert the natural diterpene esters in their respective alcohols and fatty acid methyl esters, accompanied by PS-GC. Also, the intact diterpene esters were analyzed by GC for the first time by the comparison between cold on-column (COC) and PS injection techniques. In all these stages, the molecular integrity of the thermolabile furokaurane diterpenes was maintained. The methanolysed oils from 13 samples of green Brazilian Arabica coffees were analyzed by PS-GC and the diterpenes composition varied from 8 to 12% w/w in oil and 0.7-1% in coffee beans. The ratio between cafestol and kahweol was successfully used to predict the quality of coffee even before the roasting and brewing processes.

Efeito do tempo de formação do grão de café (Coffea sp) na qualidade da bebida / Effect of time on coffe bean (Coffea sp) grouth in cup quality

O café (Coffea sp) é uma das culturas mais tradicionais da agricultura brasileira e a qualidade de sua bebida tem sido alvo de diversas pesquisas. A qualidade da bebida depende das operações anteriores ao beneficiamento, tais como tipo de colheita, estádio de maturação dos grãos, preparo e secagem do café. No cafeeiro a qualidade do grão depende da quantidade de fotoassimilados disponíveis, principalmente na fase de crescimento ou enchimento de grãos. Fatores como crescimento de grão, taxa de crescimento da cultura, tempo de crescimento e a capacidade de armazenamento de grão podem ser limitantes a produção da cultura e a qualidade da bebida. O sabor e aroma do café são parâmetros complexos que fazem parte da qualidade da bebida. Estes parâmetros por sua vez dependem da composição química do grão. O acúmulo de fotossintatos durante o crescimento de frutos também torna-se um fator importante na qualidade da bebida, pois no momento que o período de crescimento de grão é encurtado, há um menor acúmulo de fotossintatos e assim, uma menor qualidade de bebida.

Coffee (Coffea sp) is one of the most traditional crops of Brazilian agriculture and its cup quality has been the subject of several studies. The cup quality depends on the pre-processing operations, such as type of crop, stage of maturation of the grain, preparation and drying of coffee. In the coffee tree, the quality of grain depends on the amount of photoassimilates available, mainly in the growth phase or grain filling. Factors such as grain growth, the growth rate of culture, time of growth and grain storage capacity may be limiting the production of culture and the cup quality. The taste and aroma of coffee are complex parameters that are part of the cup quality. These parameters in turn depend on the chemical composition of grain. The accumulation of fotossintatos during the growth of fruit also becomes an important factor in the cup quality, because when the period of grain growth is reduced, a smaller accumulation of fotossintatos and thus a lower quality of drink.

Altered expression of the caffeine synthase gene in a naturally caffeine-free mutant of Coffea arabica.

In this work, we studied the biosynthesis of caffeine by examining the expression of genes involved in this biosynthetic pathway in coffee fruits containing normal or low levels of this substance. The amplification of gene-specific transcripts during fruit development revealed that low-caffeine fruits had a lower expression of the theobromine synthase and caffeine synthase genes and also contained an extra transcript of the caffeine synthase gene. This extra transcript contained only part of exon 1 and all of exon 3. The sequence of the mutant caffeine synthase gene revealed the substitution of isoleucine for valine in the enzyme active site that probably interfered with enzymatic activity. These findings indicate that the absence of caffeine in these mutants probably resulted from a combination of transcriptional regulation and the presence of mutations in the caffeine synthase amino acid sequence.

Altered expression of the caffeine synthase gene in a naturally caffeine-free mutant of Coffea arabica

In this work, we studied the biosynthesis of caffeine by examining the expression of genes involved in this biosynthetic pathway in coffee fruits containing normal or low levels of this substance. The amplification of gene-specific transcripts during fruit development revealed that low-caffeine fruits had a lower expression of the theobromine synthase and caffeine synthase genes and also contained an extra transcript of the caffeine synthase gene. This extra transcript contained only part of exon 1 and all of exon 3. The sequence of the mutant caffeine synthase gene revealed the substitution of isoleucine for valine in the enzyme active site that probably interfered with enzymatic activity. These findings indicate that the absence of caffeine in these mutants probably resulted from a combination of transcriptional regulation and the presence of mutations in the caffeine synthase amino acid sequence.