Biochemical composition of green and roasted coffee beans and their association with coffee quality from different districts of southwest Ethiopia

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.

Molecular Insights on Coffee Components as Chemical Antioxidants

Coffee is not only a delicious beverage but also an important dietary source of natural antioxidants. We live in a world where it is impossible to avoid pollution, stress, food additives, radiation, and other sources of oxidants that eventually lead to severe health disorders. Fortunately, there are chemicals in our diet that counteract the hazards posed by the reactive species that trigger oxidative stress. They are usually referred to as antioxidants; some of them can be versatile compounds that exert such a role in many ways. This review summarizes, from a chemical point of view, the antioxidant effects of relevant molecules found in coffee. Their mechanisms of action, trends in activity, and the influence of media and pH in aqueous solutions, are analyzed. Structure-activity relationships are discussed, and the protective roles of these compounds are examined. A particular section is devoted to derivatives of some coffee components, and another one to their bioactivity. The data used in the analysis come from theoretical and computational protocols, which have been proven to be very useful in this context. Hopefully, the information provided here will pro-mote further investigations into the amazing chemistry contained in our morning coffee cup.   Resumen. El café no solo es una bebida deliciosa, sino también una importante fuente dietética de antioxidantes naturales. Vivimos en un mundo donde es imposible evitar la contaminación, el estrés, los aditivos alimentarios, la radiación y otras fuentes de oxidantes que eventualmente conducen a trastornos de salud graves. Afortunadamente, existen sustancias químicas en nuestra dieta que contrarrestan los peligros planteados por las especies reactivas que desencadenan el estrés oxidativo. Por lo general, se les denomina antioxidantes; algunos de ellos pueden ser compuestos versátiles que ejercen dicho papel de muchas maneras. Este artículo de revisión resume, desde un punto de vista químico, los efectos antioxidantes de moléculas relevantes encontradas en el café. Se analizan sus mecanismos de acción, tendencias en la actividad y la influencia del medio y el pH en soluciones acuosas. Se discuten las relaciones estructura-actividad, y se examinan los roles protectores de estos compuestos. Se dedica una sección particular a los derivados de algunos componentes del café, y otra a su bioactividad. Los datos utilizados en el análisis provienen de protocolos teóricos y computacionales, que han demostrado ser muy útiles en este contexto. Se espera que la información proporcionada aquí promueva investigaciones futuras sobre la química contenida en nuestra taza de café matutina.

Evaluation of physical and chemical characteristics of bean and cup quality of arabica coffee genotypes grown in Southern Ethiopia

The study aimed to investigate physical characteristics, cup quality, and biochemical content variability among thirty South Ethiopian Arabica coffee genotypes over three locations. The results revealed the existence of statistically significant variation among genotype, location, and GEI effects for all studied traits. The overall coffee quality score for most of the tested genotypes in three locations was above 80 %. Therefore, in terms of quality, most of the tested genotypes can be used to produce specialty coffee in the study areas. A wider range of caffeine (0.52 % dwb to 1.53 % dwb) was recorded among the studied genotypes. Accordingly, the low caffeine contenting genotypes could be a promising candidate for the development of low caffeine varieties through selection and hybridization. Cluster analysis grouped genotypes into different clusters based on quality trait variation and similarity among genotypes. According to the PCA, caffeine content (0.35), chlorogenic acid (0.34), aromatic quality (0.31), trigonelline (0.29), acidity (0.28), astringency (0.28), color (0.27) in the first PCA, flavor (-0.48), and screen size (0.46) in the second PCA were the important variables contributing more to the variation, and these traits could be considered for effective parent selection in quality improvement programs. Genotype AW9648 achieved the highest score in overall quality attributes at all three locations and could be promoted as a promising candidate and best parent for hybridization in terms of quality. Hence, genotype by environment interaction was significant, the coffee quality improvement program should give due attention to incorporating genetic and environmental influences by using a multi-locational selection strategy.

Fermentation of coffee fruit with sequential inoculation of Lactiplantibacillus plantarum and Saccharomyces cerevisiae: effect on sensory attributes and chemical composition of the beans

This study has innovative aspects related to the use of sequential inoculation technique in the coffee bean fermentation process: the inoculation of Lactiplantibacillus plantarum followed by Saccharomyces cerevisiae, in the fermentation of coffee fruit for the production of specialty natural coffees. The objective was to evaluate the effect of this technique and of the total fermentation time on the sensory attributes of the coffee beverage and on the organic acid profile, bioactive compounds, and fatty acid profile of the beans. The fermentation of coffee fruit with sequential inoculation resulted in greater acidity of the beverage and contributed to increases of up to 2 points in coffee fermented. The total fermentation time was directly related to the organic acid content, and the longer the total fermentation time was, the greater the organic acid content. The fatty acid content and bioactive compound content showed little variation among treatments.

A Comprehensive View on the Impact of Chlorogenic Acids on Colorectal Cancer

Chlorogenic acids are plant secondary metabolites, chemically-polyphenols with similar biological activity, formed through the esterification of quinic acid and hydrocinnamic acid moieties. They are best known for their high concentration in coffee and other dietary sources and the antioxidant properties that they exhibit. Both chlorogenic acids and plant extracts containing significant amounts of the compounds show promising in vitro activity against colorectal cancer. With coffee being the most popular drink in the world, and colorectal cancer at an unfortunate peak in incidence and mortality, the mechanisms through which the anti-tumorigenic effect of chlorogenic acids could be functionalized for CRC prevention seem appealing to study. Therefore, this review aims to enable a better understanding of the modes of action of chlorogenic acids in combating carcinogenesis, with a focus on cell cycle arrest, the induction of apoptosis, and the modulation of Wnt, Pi3K/Akt, and MAPK signal transduction pathways, alongside the reduction in the number of inflammatory cytokines and chemokines and the counterintuitive beneficial elevation of oxidative stress.

Quality of Arabica coffee grown in Brazilian Savannah and impact of potassium sources

Located in Brazil's Central Plateau, the Cerrado Savannah is an emerging coffee-growing region with significant potential for the national coffee market. This study investigated the impact of potassium fertilization on Arabica coffee quality in the Cerrado, using three potassium sources (K2SO4, KCl, and KNO3) and five cultivars (Arara, Aranãs, IPR103, Catiguá and Topázio) across two consecutive harvests. We focused on productivity, granulometry, chemical composition, and sensory characteristics. No significant difference in productivity across the cultivars studied or potassium sources as isolated factors were observed. Regarding chemical parameters, potassium sources only affected NO3- and SO42- levels in the grains. Cultivar-specific differences were noted in caffeine (CAF), citric acid (CA), and sucrose (SUC), highlighting a strong genetic influence. K2SO4 improved productivity in Arara (15 %) and IPR103 (11 %), while KNO3 reduced flat grain percentage to 70 % in Catiguá. Sensory evaluation showed that all potassium sources and cultivars produced specialty coffees, with the Arara cultivar treated with K2SO4 achieving the highest SCA score (83.3) while IPR 103 treated with KCl scored the lowest at 78. Only three treatments were below but very close to the threshold (80). Multivariate analysis indicated a trend where specific treatments correlated with higher productivity and quality. Despite the subtle differences in productivity and quality among potassium sources, a cost-benefit analysis may favor KCl due to its affordability, suggesting its viability as a potassium fertilization option in coffee cultivation. Future research is needed to confirm these trends and optimize potassium source selection to enhance coffee quality in the Cerrado.

Changes in biochemical composition of Ethiopian Coffee arabica with growing region and traditional roasting

Updating the biochemical composition of coffee beans across the years is necessary. This is important to understand the vulnerability of coffee toward climate adaptation longitudinally. Accordingly, in this study the influence of growing area and traditional roasting on the biochemical composition of five common Ethiopian Arabica coffee beans collected in the harvest year of 2021/22 were investigated. With an average of 11.34 g/100 g, the Hararge and Jimma coffee beans had the highest crude fat content (p < 0.05). The crude protein content of the five varieties was in the range of 13-15 g/100 g, with respective highest and lowest contents in the (Hararge and Nekemte) and (Sidama and Yirgachefe) coffee beans (p < 0.05). The total phenolic content (TPC) of the coffee beans was in the order of Jimma (46.52) > Nekemte (44.55) > Sidama (44.31) > Hararge (39.02) > Yirgachefe (34.25) mg GAE/100 g. The 50% inhibitory concentration (IC50) of ascorbic acid, coffee bean extract from Jimma and Hararge against 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical was 19.86, 20.22 and 20.02 μg/mL, respectively. The respective highest and lowest caffeine concentration was obtained in the Yirgachefe (10.38) and Hararge (7.55 g/100 g) coffee beans (p < 0.05). The Jimma, Sidama, and Nekemte coffee varieties had the highest chlorogenic acid content of 45 g/100 g (p > 0.05); whereas the lowest content was in Hararge coffee (36.78 g/100 g). While the caffeine concentration did not show significant (p > 0.05) difference, with all the coffee beans the roasting has reduced significantly the TPC, trigonelline and mainly the chlorogenic acid (p < 0.05). These data can update the existing facts on biochemical diversity of coffee beans in the country which can be used for evidence based innovations of climate adaptation in predicting the quality of coffee. Further recommendation of optimizing the traditional coffee processing method is supported from this study.

Effect of processing methods on physicochemical and cup quality of coffee at Jimma, Ethiopia

Coffee quality is a complex attribute influenced by a variety of factors, including postharvest processing methods. The goal of this study was to investigate the impact of coffee processing methods on coffee quality (raw, cup, and biochemical makeup) in Jimma, which represents the midland areas. Coffee samples were collected for Jimma agricultural research center and processed with three methods (washed, Semi-washed and dry process). The result indicated that washed coffee beans scored significantly the highest color (13.43) and odor [10] score than the other processing methods. The statistically best raw quality score (35.57 %) was therefore reported for washed coffee in Jimma. Cup quality attributes however were not significantly affected by processing methods. Among chemical composition studied, lipid was significantly affected by processing methods and highest lipid 13.74 and 13.17 g/100g was reported for semi-washed and washed coffee beans respectively. Generally, washed and semi-washed coffee were preferable in terms of bean color and odor quality. Correlations were found among cup quality attributes and chemical compositions. However, further research into the accessibility and economics of coffee processing methods in the area is necessary.

Sensitising natural wool with green and brown coffee using a facile extraction method to optimise dye process parameters

Green coffee powder is the raw powder of coffee cherries and all coffee's potential components are held within this green powder. A new natural colourant was extracted from Green Coffee using water as an extractant. To obtain a green-colored solution, a specific amount of green coffee was mixed with distilled water and left for 24 h at room temperature. Furthermore, the colouring performance of extracted colour has been studied using the conventional exhaust dyeing method on wool fabric. Different parameters viz. concentration of Green coffee powder, the temperature of the dye bath, the period for immersion, and solution pH were made to set to obtain a fine tone of green colour. The dyeing parameters (amount of the coffee: 2 g, 100 °C, 70 min & 6.7 pH) were optimised and selected to draw a comparison with the conventional Brown coffee powder. In experiments on wool, this potential solution of Green coffee offered rich green hues with good tonal variation. In addition, the colour fastness to washing was found superior in the case of both Green and Brown coffee and colour fastness to light, rubbing as well as perspiration also showed good performance. In this study, our main focus was to obtain the true and fast green tone of the fabric using Green Coffee and compare it with brown coffee using the same conditions used for dyeing with green coffee. The application of these dyes as natural dyes results in obtaining innovative natural fast colour with remarkable dyeing properties and a new inclusion to the existing commercial spectra of natural dyes.

Evaluation of spontaneous fermentation impact on the physicochemical properties and sensory profile of green and roasted arabica coffee by digital technologies

There is a growing demand for specialty coffee with more pleasant and uniform sensory perception. Wet fermentation could modulate and confer additional aroma notes to final roasted coffee brew. This study aimed to assess differences in volatile compounds and the intensities of sensory descriptors between unfermented and spontaneously fermented coffee using digital technologies. Fermented (F) and unfermented (UF) coffee samples, harvested from two Australia local farms Mountain Top Estate (T) and Kahawa Estate (K), with four roasting levels (green, light-, medium-, and dark-) were analysed using near-infrared spectrometry (NIR), and a low-cost electronic nose (e-nose) along with some ground truth measurements such as headspace/gas chromatography-mass spectrometry (HS-SPME-GC-MS), and quantitative descriptive analysis (QDA ®). Regression machine learning (ML) modelling based on artificial neural networks (ANN) was conducted to predict volatile aromatic compounds and intensity of sensory descriptors using NIR and e-nose data as inputs. Green fermented coffee had significant perception of hay aroma and flavor. Roasted fermented coffee had higher intensities of coffee liquid color, crema height and color, aftertaste, aroma and flavor of dark chocolate and roasted, and butter flavor (p < 0.05). According to GC-MS detection, volatile aromatic compounds, including methylpyrazine, 2-ethyl-5-methylpyrazine, and 2-ethyl-6-methylpyrazine, were observed to discriminate fermented and unfermented roasted coffee. The four ML models developed using the NIR absorbance values and e-nose measurements as inputs were highly accurate in predicting (i) the peak area of volatile aromatic compounds (Model 1, R = 0.98; Model 3, R = 0.87) and (ii) intensities of sensory descriptors (Model 2 and Model 4; R = 0.91), respectively. The proposed efficient, reliable, and affordable method may potentially be used in the coffee industry and smallholders in the differentiation and development of specialty coffee, as well as in process monitoring and sensory quality assurance.

Enhancing Bioactivity and Conjugation in Green Coffee Bean (Coffea arabica) Extract through Cold Plasma Treatment: Insights into Antioxidant Activity and Phenolic-Protein Conjugates

Cold plasma technology is gaining attention as a promising approach to enhancing the bioactivity of plant extracts. However, its impact on green coffee bean extracts (GCBEs) still needs to be explored. In this study, an innovative underwater plasma jet system was employed to investigate the effects of cold plasma on Coffea arabica GCBEs, focusing on the conjugation reflected by the change in composition and bioactivity. The DPPH radical scavenging antioxidant activity exhibited a gradual increase with plasma treatment up to 35 min, followed by a decline. Remarkably, at 35 min, the plasma treatment resulted in a significant 66% increase in the DPPH radical scavenging activity of the GCBE. The total phenolic compound content also displayed a similar increasing trend to the DPPH radical scavenging activity. However, the phenolic profile analysis indicated a significant decrease in chlorogenic acids and caffeine. Furthermore, the chemical composition analysis revealed a decrease in free amino acids, while sucrose remained unchanged. Additionally, the SDS-PAGE results suggested a slight increase in protein size. The observed enhancement in antioxidant activity, despite the reduction in the two major antioxidants in the GCBE, along with the increase in protein size, might suggest the occurrence of conjugation processes induced by plasma, particularly involving proteins and phenolic compounds. Notably, the plasma treatment exhibited no adverse effects on the extract's safety, as confirmed by the MTT assay. These findings indicate that cold plasma treatment holds significant promise in improving the functional properties of GCBE while ensuring its safety. Incorporating cold plasma technology into the processing of natural extracts may offer exciting opportunities for developing novel and potent antioxidant-rich products.

Coffee bean processing: Emerging methods and their effects on chemical, biological and sensory properties

Emerging processing methods have been applied in coffee bean processing for improved sensory quality. The processes focus on optimizing the fermentation process of the coffee cherries and beans. This involves various pathways, including the formation of volatiles, flavor precursors and organic acids and the reduction in the concentrations of bioactive compounds. Comprehensive information regarding the effect of these emerging processes on the chemical, biological and sensory properties of the coffee beans is summarized. Emerging processes affected the coffee bean to various degrees depending on the raw material and the method used. The emerging methods promoted the reduction of bioactives such as caffeine and phenolics in coffee beans. Substantial improvement of these processes is needed to obtain coffee beans with improved biological activities. Effort to simplify the methods and optimize the post-fermentation process is crucial for the methods to be easily accessible by the producers and to produce defect-free coffee beans.

Exploring correlations between green coffee bean components and thermal contaminants in roasted coffee beans

This study evaluated chemical compositions of green coffee beans from multi-production regions and correlated this information with thermal contaminants in roasted coffee. Using multivariate statistical techniques, formation of 5-hydroxymethylfurfural (5-HMF), furan, 2- and 3-methylfuran were positively correlated with lipid, sucrose, glutamic acid, phenylalanine, margaric acid, linolenic acid and trigonelline in green coffee beans. Moreover, significant positive correlations between acrylamide (AA) levels with aspartic acid, serine, alanine, histidine, asparagine, protein, and caffeine was found in green beans. Despite this, 5-HMF, furan, 2- and 3-methylfuran showed negative correlations with active constitutes (neochlorogenic acid, cryptochlorogenic acid, caffeine, total phenolics (TPC) and total flavonoids contents (TFC)), and several amino acids, and there were slight negative relationships between AA and myristic acid, palmitic acid, chlorogenic acid, sucrose, lipid, TPC and TFC. This study provides valuable enlightenment for the selection of proper coffee beans for production of coffee with high nutrition and low chemical hazardous risks.

Karakteristik Fisikokimia dan Kapasitas Antioksidan Kopi Liberika dari Kabupaten Tanjung Jabung Barat, Jambi

Liberica coffee is one of the coffee species in commercial trade in Indonesia. The coffee is produced in Tanjung Jabung Barat Regency, Jambi, Indonesia which distributed into 5 sub-districts (Betara, Bram Itam, Kuala Betara, Pengabuan, Senyerang). Information about liberica coffee from Jambi is still limited, thus more exploration is needed. The objectives of this study were to characterize the morphology of the leaf and fruit, the physicochemical characteristics which include the dimension (length, width, thickness), mass, bulk density, colour (L*, a*, b*), moisture contents, TSS (total soluble solids), pH, and antioxidant capacity (DPPH IC50, FRAP) of green and roasted (commercial level) liberica coffee from the above 5 sub-districts. The studies showed that liberica coffee from 5 sub-districts in Tanjung Jabung Barat Rgency, Jambi had various leaf and fruit appearances which were characterized by various size and colour of coffee cherries. Green coffee from different sub-districts owned various physicochemical (width, volume, mass, bulk density, moisture content, TSS) and antioxidant capacity of green coffee. Green coffee from Betara and Pengabuan were associated with high TSS, L* and b* value, while green coffee from Bram Itam and Senyerang were associated with high mass, moisture content and a* value. The highest anti-oxidant capacity was produced by green coffee from Betara and Kuala Betara (DPPH IC50). Meanwhile, roasted coffee produced from green coffee from the 5 sub-districts with similar roasting level (similar L*) produced similar a*, b* value, mass and TSS. However, physicochemical characteristics (length, width, volume, bulk density, moisture content) and antioxidant capacity of these roasted beans varied.

Comparative Analysis of Selected Chemical Parameters of Coffea arabica, from Cascara to Silverskin

Nowadays, there is an increased interest in coffee derivatives (green beans, roasted beans, and coffee by-products (Cascara and Silverskin)) due to their particular chemical composition. This study aimed to compare the content of dry matter, total fat, fatty acids, and fiber (ADF, NDF) of coffee by-products (Cascara and Silverskin) and coffee beans (green and roasted under different conditions). Coffee beans and their by-products were obtained from 100% C. arabica coffee cherries from Panama by dry process. The lowest concentrations of fat corresponded to Cascara 4.24 g·kg-1 and Silverskin 23.70 g·kg-1, respectively. The major fatty acids detected in all samples were palmitic, stearic, oleic, and linoleic acids, the latter two being essential fatty acids. LDA showed that 89.01% of the variability between beans and by-products was explained by lignoceric, myristic, behenic, tricosanoic, arachidic, and heneicosanoic acids. Silverskin appeared to be a good source of lignoceric, myristic, and behenic acids and had a higher concentration of dietary fiber (314.95 g·kg-1) than Cascara (160.03 g·kg-1). Coffee by-products (Silverskin and Cascara) are low-fat products enriched in dietary fiber. Their incorporation, after adjustment, into the global diet may contribute to nutrition security, the sustainability of the coffee sector, and human health.

Green coffee: economic relevance and a systematic review of the effects on human health

Coffee is probably the most popular beverage after water and is an important component in diet and health since its consumption is high worldwide. Globally, it is the most relevant food commodity being just behind crude oil. Besides its pleasant flavor, it is an antioxidant source due to polyphenols, which are protective compounds against several diseases. This study aimed to evaluate the economic relevance and perform a systematic review of green coffee's effects on human health. Databases such as MEDLINE-PubMed, EMBASE, COCHRANE, and GOOGLE SCHOLAR were searched, and PRISMA guidelines were followed. Green coffee is considered a novel food product because consumers usually consume only roasted coffee. It can be marketed as such or as an extract. Due to the content of bioactive compounds, which are partially lost during the roasting process, the extracts are usually marketed concerning the potential regarding health effects. Green coffee can be used as dietary supplements, cosmetics, and pharmaceuticals, as a source of antioxidants. It can benefit human health, such as improvement in blood pressure, plasma lipids, and body weight (thus contributing to the improvement of risk components of Metabolic Syndrome). Moreover, benefits for cognitive functions may also be included.