Genome-wide identification and expression analysis of the U-box gene family related to biotic and abiotic stresses in Coffea canephora L.

Plant U-box genes play an important role in the regulation of plant hormone signal transduction, stress tolerance, and pathogen resistance; however, their functions in coffee (Coffea canephora L.) remain largely unexplored. In this study, we identified 47 CcPUB genes in the C. canephora L. genome, clustering them into nine groups via phylogenetic tree. The CcPUB genes were unevenly distributed across the 11 chromosomes of C. canephora L., with the majority (11) on chromosome 2 and none on chromosome 8. The cis-acting elements analysis showed that CcPUB genes were involved in abiotic and biotic stresses, phytohormone responsive, and plant growth and development. RNA-seq data revealed diverse expression patterns of CcPUB genes across leaves, stems, and fruits tissues. qRT-PCR analyses under dehydration, low temperature, SA, and Colletotrichum stresses showed significant up-regulation of CcPUB2, CcPUB24, CcPUB34, and CcPUB40 in leaves. Furthermore, subcellular localization showed CcPUB2 and CcPUB34 were located in the plasma membrane and nucleus, and CcPUB24 and CcPUB40 were located in the nucleus. This study provides valuable insights into the roles of PUB genes in stress responses and phytohormone signaling in C. canephora L., and provided basis for functional characterization of PUB genes in C. canephora L.

RGeasy: a reference gene analysis tool for gene expression studies via RT-qPCR.

Gene expression through RT-qPCR can be performed by the relative quantification method, which requires the expression normalization through reference genes. Therefore, it is essential to validate, experimentally, the candidate reference genes. Thus, although there are several studies that are performed to identify the most stable reference genes, most them validate genes for very specific conditions, not exploring the whole potential of the research since not all possible combinations of treatments and/or conditions of the study are explored. For this reason, new experiments must be conducted by researchers that have interest in analyzing gene expression of treatments and/or conditions present, but not explored, in these studies. Here, we present the RGeasy tool, which aims to facilitate the selection of reference genes, allowing the user to choose genes for a greater number of combinations of treatments/conditions, compared to the ones present in the original articles, through just a few clicks. RGeasy was validated with RT-qPCR data from gene expression studies performed in two coffee species, Coffea arabica and Coffea canephora, and it can be used for any animal, plant or microorganism species. In addition to displaying a rank of the most stable reference genes for each condition or treatment, the user also has access to the primer pairs for the selected reference genes.

Immunoexpression of aortic endothelial P-selectin and serum apolipoprotein A-1 levels after administration of arabica (Coffea arabica) and robusta (Coffea canephora) coffee bean extracts: In vivo study in atherosclerosis rat model.

Atherosclerosis is a leading cause of cardiovascular disease-related death worldwide. Some studies suggested that the natural ingredients in coffee may negatively affect cardiovascular diseases, while other studies indicated that coffee contains anti-inflammatory compounds that are beneficial for cardiovascular diseases. The aim of this study was to measure the expression of P-selectin in aortic endothelial cells and the level of serum apolipoprotein A-1 (ApoA-1) in an atherosclerosis rat model after the administration of arabica and robusta coffee bean extracts at mild-moderate and high doses. An experimental study was conducted with a complete randomized design using 36 adult male white rats (Rattus norvegicus) divided into six groups: negative control (NC), positive control (PC), arabica mild-moderate dose (A1), arabica high dose (A2), robusta mild-moderate dose (R1), and robusta high dose (R2). Animals were induced atherosclerosis with atherogenic feed and then were treated with arabica and robusta coffee bean extracts at two different doses for four weeks. The results showed that the expression of P-selectin in the group of rats treated with robusta coffee bean extract was lower than arabica coffee bean extract group. Rats with robusta coffee bean extract mild-moderate dose had the highest ApoA-1 levels compared to other groups significantly (p<0.05). The level of ApoA-1 was higher in both mild-moderate and high dose of robusta coffee groups compared to the negative control group (both with p<0.001). In conclusion, mild-moderate intake of robusta coffee bean extract could reduce aortic P-selectin immunoexpression and increase serum ApoA-1 levels in an atherosclerosis rat model.

Gene isolation and enzymatic characterization of UDP-glycosyltransferases of terpene glucoside biosynthesis involved in linalyl-glycoside accumulation in Coffea arabica.

Terpenes, one of the secondary metabolites produced by plants, have diverse physiological functions. They are volatile compounds with physiological bioactivities (e.g., insect repellent, attracting enemies, and interacting with other plants). Terpenoids are also essential for flavor and aroma in plant-derived foods. In coffee, its aroma decides the value of coffee beans. Linalool, one of the volatile terpene compounds, is dominant in the coffee aroma. Coffee, with its good flavor and aroma, has high demand worldwide. Because terpenoids generally accumulate as glycosides in plant cells, glycosylation is catalyzed by UDP-glycosyltransferases (UGTs). Two linalyl-diglycosides have been identified: terpenoids reflected as necessary for coffee flavor. However, these UGTs and their action mechanisms are unknown in the Coffea genus. To obtain knowledge of terpene UGTs and elucidate the mechanism of terpene glycosylation in coffee, this study isolated terpene UGT genes and analyzed their functions. In silico screening based on the sequence of UGT85K11, which catalyzes terpene glycosylation from Camellia sinensis, was performed to obtain sequence information on five candidate UGT genes (CaUGT4, CaUGT5, CaUGT10, CaUGT15, and CaUGT20). These genes were isolated by reverse transcription-polymerase chain reaction, and the recombinant enzymes were produced with the Escherichia coli expression system. In functional analysis using radioisotopes, CaUGT4 showed critical activity against linalool, which had a higher affinity for its substrate than that of UGT85A84 from Osmanthus fragrans. Liquid chromatography-tandem mass spectrometry also revealed that CaUGT4 mainly produces linalyl glucoside. In this study, the first linalyl UGT was isolated from coffee. These findings can be used to elucidate the fundamental mechanism of the chemical defense in plants and apply aroma precursors for the plant-derived food industry in the future.

Influence of Fermentation Time and Inoculation of Starter Culture on the Chemical Composition of Fermented Natural Coffee Followed by Depulping.

Fermentation using starter cultures has been considered an alternative and economically viable technology for the production of specialty coffees. This type of technology promotes several benefits, such as increased sensory quality, control over the fermentation process, predictability of the final product and added value. Coffee (Coffea arabica L.) samples for this study were collected in Presidente Olegário - MG (2018/19 crop year) in the Cerrado region of Minas Gerais. The effects of natural fermentation and inoculation of the yeast Torulaspora delbrueckii and duration of fermentation (0, 24, 48, 72 and 96 hours) on the sensory and chemical quality (analysis of bioactive, volatile, and organic compounds and fatty acids) of coffee were evaluated. The objective of this study was to determine the effect of fermentation time and starter culture inoculation on the chemical composition of fermented coffees. Fermentation time significantly influenced the sensory description of the coffee beverage, with notes of honey, brown sugar and almond predominating up to 48 hours, for coffees fermented for 72 and 96 hours the notes described were and fruity, winey notes. The chemical composition was primarily influenced by fermentation time.

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.

Assessing the influence of spontaneous fermentation on consumer emotional responses to roasted arabica coffee in a biometric approach.

Beyond sensory quality, food-evoked emotions play a crucial role in consumers acceptance and willingness to try, which are essential for product development. The link between fermented coffee sensory characteristics and elicited emotional responses from consumers is underexplored. This study aimed to evaluate consumers' acceptability of spontaneously fermented and unfermented roasted coffee through self-reported sensory evaluation and biometrics assessment. Self-reported liking in 15-cm non-structured scale, multiple choice of negative, neutral, and positive emojis, and subconscious emotional responses from 85 regular coffee consumers were analysed. Their relationship with the pattern of volatile aromatic compounds were also investigated. Fermented (F) and unfermented (UF) coffee beans with light- (L), dark- (D), and commercial dark (C) roasting levels were brewed and evaluated along with gas chromatography-mass spectrometry measurement. Multivariate data analysis was conducted to explore the inner relationships among volatile compounds, self-reported liking, and biometrics. Unfermented-dark roasted coffee (UFD) had highest overall consumer liking response ± standard error (8.68 ± 0.40), followed by the fermented-dark roasted (FD) at 7.73 ± 0.43 with no significant differences (p > 0.05). Fermented light-roasted coffee was associated with lower liking scores and negative emotional responses. In contrast, dark roasted coffee, which was linked to positive emojis and emotional responses, exhibited less detected peak area of volatile compounds contributing fruity and vegetative aromas, such as benzaldehyde, furfuryl acetate, 2-acetyl-1-methyl pyrrole, and isovaleric acid, potentially as negative drivers of consumer liking. Findings from this study could guide coffee manufacturers in developing specialty coffee if spontaneous fermentation is offered.

Potential of Coffee Cherry Pulp Extract against Polycyclic Aromatic Hydrocarbons in Air Pollution Induced Inflammation and Oxidative Stress for Topical Applications.

Airborne particulate matter (PM) contains polycyclic aromatic hydrocarbons (PAHs) as primary toxic components, causing oxidative damage and being associated with various inflammatory skin pathologies such as premature aging, atopic dermatitis, and psoriasis. Coffee cherry pulp (CCS) extract, rich in chlorogenic acid, caffeine, and theophylline, has demonstrated strong antioxidant properties. However, its specific anti-inflammatory effects and ability to protect macrophages against PAH-induced inflammation remain unexplored. Thus, this study aimed to evaluate the anti-inflammatory properties of CCS extract on RAW 264.7 macrophage cells exposed to atmospheric PAHs, compared to chlorogenic acid (CGA), caffeine (CAF), and theophylline (THP) standards. The CCS extract was assessed for its impact on the production of nitric oxide (NO) and expression of tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), inducible nitric oxide synthase (iNOS), and cyclooxygenase-2 (COX-2). Results showed that CCS extract exhibited significant antioxidant activities and effectively inhibited protease and lipoxygenase (LOX) activities. The PAH induced the increase in intracellular reactive oxygen species, NO, TNF-α, IL-6, iNOS, and COX-2, which were markedly suppressed by CCS extract in a dose-dependent manner, comparable to the effects of chlorogenic acid, caffeine, and theophylline. In conclusion, CCS extract inhibits PAH-induced inflammation by reducing pro-inflammatory cytokines and reactive oxygen species (ROS) production in RAW 264.7 cells. This effect is likely due to the synergistic effects of its bioactive compounds. Chlorogenic acid showed strong antioxidant and anti-inflammatory activities, while caffeine and theophylline enhanced anti-inflammatory activity. CCS extract did not irritate the hen's egg chorioallantoic membrane. Therefore, CCS extract shows its potential as a promising cosmeceutical ingredient for safely alleviating inflammatory skin diseases caused by air pollution.

The Influence of Maceration and Flavoring on the Composition and Health-Promoting Properties of Roasted Coffee.

Over the years, many methods of refining green beans have been developed, including maceration aimed at enriching the coffee aroma and improving the overall quality. This study aimed to evaluate the influence of different methods of maceration (fruit and wine) and the addition of food flavors to coffee beans on antioxidant activity, caffeine, phenolic and organic acid content, as well as health-promoting properties. This research showed that the use of the maceration in melon and apple fruit pulp (100 g of fruit pulp per 100 g of green coffee, incubated for 24 h, coffee roasting at 230 °C, control trial roasted coffee) ensured the highest polyphenol (hydroxycinnamic acids and their esters-chlorogenic acids) content (in melon pulp-13.56 g/100 g d.b. (dry bean); in apple pulp-13.22 g/100 g d.b., p < 0.05 (one-way ANOVA)) and antioxidant activity. Melon (92.11%, IC50 = 3.80 mg/mL extract) and apple (84.55%, IC50 = 4.14 mg/mL) showed the highest α-amylase (enzyme concentration 10 µmol/mL) inhibition activity (0.5 mg/mL for both fruits). The addition of food flavors reduced the total content of chlorogenic acids to the range of 4.64 to 6.48 g/100 g d.b. and increased the content of acrylamide and 5-HMF, which positively correlated with a low antioxidant potential compared to the macerated samples and the control. Studies have shown that coffee macerated in the pulp of melon and apple fruit, due to its great potential to inhibit α-amylase in vivo, may have a preventive effect on type II diabetes. This study complements the current knowledge on the potential health-promoting properties of coffee flavored using different methods; further research should include more advanced models for testing these health-promoting properties. Statistical analysis was based on the determination of the average values of six measurements and their standard deviation, as well as on the one-way ANOVA (analysis of variation) and the Pearson correlation coefficient, using Statistic 10.0 software. The significance was defined at p ≤ 0.05.

An overview on the Brazilian Coffea canephora scenario and the current chemometrics-based spectroscopic research.

This review explores the historical, botanical, sensory, and quality aspects of Coffea canephora, with a focus on Brazil's rise as a producer of specialty canephora coffees in the Amazon region, Espírito Santo, and Bahia. Brazil has gained global recognition through the first geographical indications for canephora: Matas de Rondônia for robusta amazônico coffee and Espírito Santo for conilon coffee. Despite this, comprehensive insights into how variety, terroir, environmental conditions, and cultivation practices influence the chemical and sensory attributes of Brazilian canephora remain underdeveloped compared to well-studied arabica coffee. Producers and researchers are working to elevate canephora coffees to higher market levels, despite technological, production, and perception challenges stemming from its historical reputation for poor quality. Ensuring the sustainability of Amazonian canephora coffee without deforestation is particularly challenging due to the need to verify practices across numerous small-scale farms. There is also a critical need for standardized production and tasting protocols for Brazilian canephora, leveraging local expertise and professional cuppers to ensure consistent quality and reliable sustainability claims. Significant opportunities exist in valuing the production chain of geographically unique canephora coffees, which could increase specialty exports, enhance economic prospects for local farmers, and support Amazon preservation. Recognizing and marketing these coffees as premium products with unique flavor profiles can boost their global appeal. Another challenge lies in establishing new specialty standards for soluble coffee from specialty canephora to meet consumer demands for convenience without compromising taste or ethical standards. In such a scenario, several analytical methods have been suggested to identify high-quality variants, combating their stigmatization. The potential of spectroscopy techniques and chemometrics-based data science is highlighted in confirming coffee quality, authenticity, traceability, and geographical origin, enhancing model interpretation and predictive accuracy through synergistic and complementary information. Non-targeted spectroscopic analyses, providing comprehensive spectral fingerprints, are contrasted with targeted analyses. Overall, this review offers valuable insights for the coffee scientific community, exporters, importers, roasters, and consumers in recognizing the potential of Brazilian canephora coffees.

Fabrication of smart nanogel based on carrageenan and green coffee extract as a long-term antifouling agent to improve biofilm prevention in food production.

This study investigates the extract of the bioactive compounds from green coffee extract (GCE) and the loading of two different concentrations of GCE (1% and 2%) onto carrageenan nanogels (CAR NGs) to compare their antibacterial and antibiofilm effects with unloaded nanogels (NGs). The bioactive compounds of GCE were characterized using GC-MS analysis. The GCE1 and GCE2 were successfully deposited onto the surface of CAR NGs. The antibacterial and antibiofilm potential of prepared NGs were conducted against some foodborne pathogens (E. coli O157, Salmonella enterica, Staphylococcus aureus, and Listeria monocytogenes). The results of GC-MS analysis indicated that there were identified 16 bioactive compounds in GCE, including caffeine (36.27%), Dodemorph (9.04%), and D-Glycero-d-ido-heptose (2.44%), contributing to its antimicrobial properties. The antibacterial coatings demonstrated a notable antimicrobial effect, showing zone of inhibition (ZOI) diameters of up to 37 mm for GCE2 loaded CAR NGs. The minimum inhibitory concentration (MIC) values for GCE2 loaded CAR NGs were 80 ppm for E. coli O157, and 120 ppm for S. enterica, S. aureus, and L. monocytogenes, achieving complete bacterial inactivation within 10-15 min of exposure. Both GCE1 and GCE2 loaded CAR NGs significantly reduced biofilm cell densities on stainless steel (SS) materials for E. coli O157, S. enterica, S. aureus, and L. monocytogenes, with reductions ranging from 60% to 95%. Specifically, biofilm densities were reduced by up to 95% for E. coli O157, 89% for S. enterica, 85% for S. aureus, and 80% for L. monocytogenes. Results of the toxicity evaluation indicated that the NGs were non-toxic and biocompatible, with predicted EC50 values proved their biocompatibility and safety. These results recommended that GCE loaded CAR NGs are promising as natural antimicrobial agents for enhancing food safety and extending shelf life. Further, the study concluded that incorporating GCE into CAR NGs is an effective strategy for developing sustainable antimicrobial coatings for the food industry and manufacturing.

Evaluation of the effect of roasting and digestion on biological activity of compounds of coffee extracts - in vitro assessment of the bioavailability, cytoprotective properties and modulation of inflammatory response.

Coffee is the most consumed beverage in the world. Consumption of phenolic compounds present in coffee protects the body against oxidative stress generation, inflammatory response, and cancer development. The aim of the study was evaluation of biological activity of coffee extracts (obtained from green, as well as light and dark roasted Robusta and Arabica beans) and isolated fractions on human colon adenocarcinoma Caco-2 cells, which are used as a cellular model of intestinal barrier in bioavailability studies. Additionally, impact of coffee phenolics on oxidative stress level and anti-inflammatory activity has been studied with RAW 264.7 macrophages used in immunomodulatory research. It was demonstrated that the coffee constituents protection against oxidative stress, lipotoxicity and secretion of proinflammatory mediators is correlated with the presence of mono- and dichlorogenic acids and roasting process. It was demonstrated that coffee phytochemicals can decrease cells proliferation and bind to topoisomerase IIα being a dietary tool in cancer prevention.

Neem-Extract Formulation on Hypothenemus hampei Preference and Performance in Arabica Coffee Fruits and Artificial Diet.

Coffee berry borer (CBB) Hypothenemus hampei is a major biotic threat to coffee production worldwide. Studies have reported negative effects on CBB by oil-based formulations of neem (Azadirachta indica), but little information is available for other neem-extract formulations. This study evaluated CBB preference and performance in arabica coffee fruits and artificial diet treated with a neem-extract formulation (Openeem Plus®) in the field and laboratory conditions. Field experiments were performed using CBB females artificially infested in cherry or green coffee fruits confined in voile-fabric cages tied to branches of neem-treated and control plants, recording the adult mortality and offspring production. Dual-choice and no-choice bioassays assessed CBB preference and development in fruits and artificial diet treated with the neem extract compared to controls in the laboratory, respectively. As main results obtained in the field and laboratory experiments, the neem extract significantly reduced CBB oviposition in both cherry and green fruits, as well as in artificial diet compared to controls. However, the botanical product did not affect CBB adult survival and preference in the laboratory bioassays. The neem extract is promising for use in pest management strategies in sustainable arabica coffee crops by reducing CBB oviposition and offspring. These effects can contribute to lowering the pest population buildup along the crop cycle and damage potential to coffee production.

Insights into acrylamide and furanic compounds in coffee with a focus on roasting methods and additives.

Roasting is necessary for bringing out the aroma and flavor of coffee beans, making coffee one of the most consumed beverages. However, this process also generates a series of toxic compounds, including acrylamide and furanic compounds (5-hydroxymethylfurfural, furan, 2-methylfuran, 3-methylfuran, 2,3-dimethylfuran, and 2,5-dimethylfuran). Furthermore, not much is known about the formation of these compounds in emerging coffee formulations containing alcohol and sugars. Therefore, this study investigated the effect of roasting time and degree on levels of acrylamide and furanic compounds in arabica coffee using fast and slow roasting methods. The fast and slow roasting methods took 5.62 min and 9.65 min, respectively, and reached a maximum of 210 °C to achieve a light roast. For the very dark roast, the coffee beans were roasted for 10.5 min and the maximum temperature reached 245 °C. Our findings showed that the levels of acrylamide (375 ± 2.52 µg kg-1) and 5-HMF (194 ± 11.7 mg kg-1) in the slow-roasted coffee were 35.0 % and 17.4 % lower than in fast-roasted coffee. Furthermore, light roast coffee had significantly lower concentrations of acrylamide and 5-HMF than very dark roast, with values of 93.7 ± 7.51 µg kg-1 and 21.3 ± 10.3 mg kg-1, respectively. However, the levels of furan and alkylfurans increased with increasing roasting time and degree. In this study, we also examined the concentrations of these pollutants in new coffee formulations consisting of alcohol-, sugar-, and honey-infused coffee beans. Formulations with honey and sugar resulted in higher concentrations of 5-HMF, but no clear trend was observed for acrylamide. On the other hand, formulations with honey had higher concentrations of furan and alkylfurans. These results indicate that optimizing roasting time and temperature might not achieve the simultaneous reduction of all the pollutants. Additionally, sugar- and honey-infused coffee beans are bound to have higher furanic compounds, posing a higher health risk.

Organic arabic coffee husk: Antioxidant and cytoprotective properties and potential impacts on selected human intestinal bacterial populations of individuals with diabetes.

Coffee husks are the main by-product of the coffee industry and have been traditionally discarded in the environment or used as fertilizers. However, recent studies have shown that coffee husks have bioactive compounds, such as phenolics and fiber-bound macro antioxidants, offering a range of potential health benefits. This study evaluated the antioxidant capacity, cytoprotective/cytotoxic properties, and stimulatory effects on the relative abundance of selected intestinal bacterial populations of individuals with diabetes of organic coffee husks. Organic coffee husk had good antioxidant capacity, maintained under simulated gastric conditions, with more than 50% of antioxidant capacity remaining. Organic coffee husk exerted cytoprotective properties in Caco-2 cells, indicating that cellular functions were not disturbed, besides not inducing oxidation. Overall, organic coffee husk promoted positive effects on the abundance of distinct intestinal bacterial groups of individuals with diabetes during in vitro colonic fermentation, with a higher relative abundance of Bifidobacterium spp., indicating the availability of components able to reach the colon to be fermented by intestinal microbiota. Organic coffee husk could be a circular material to develop new safe and pesticide-free functional ingredients with antioxidant and potential beneficial effects on human intestinal microbiota.

Microbiota of arabica coffee: insights from soil to fruit.

Studies have shown that a diverse and metabolically active microbiota exists throughout different stages of coffee processing, from pre- to post-harvest. This microbiota originates from both the cultivation and processing environments. Additionally, microorganisms from the soil can be found on the fruit due to the transfer between them. This study reviews the microbiota present in Arabica coffee fruits and the soils where the plants are grown. It examines how microbial profiles are related to coffee variety, altitude, cultivation region, and processing method, and establishes a connection between the microbiota in soil and fruit. A diverse microbiota was observed in both coffee fruits and soils, with similar microorganisms identified across different growing regions, processing methods, and coffee varieties. However, exclusive detections of some microorganisms were also observed. These differences highlight the influence of terroir on coffee's microbial composition, confirming that environmental conditions, genetic factors, and processing methods shape coffee microbiota. Since microbial development during coffee fermentation can affect the beverage's quality, the data presented in this review offer valuable insights for researchers and producers. Understanding the influence of processing methods, coffee varieties, and cultivation regions on coffee microbiota enables the selection of specific fermentation conditions or starter cultures to enhance terroir characteristics or adjust microbial populations to favor or introduce microorganisms beneficial for coffee quality.

Spent coffee waste-derived biochar improves physical properties, water retention, and maize (Zea mays L.) growth in sandy soil.

Adding organic soil amendments can improve the physical and hydrological properties of soil, subsequently enhancing fertility for better crop production. In this study, spent Arabica and Columbian coffee wastes and their respective biochars were evaluated as soil amendments to improve the physical and hydrological properties of loamy sand soil and enhance maize (Zea mays L.) crop growth. Spent Arabica coffee (AC) and Columbian coffee (CC) wastes were collected and transformed into biochar through pyrolysis process at 550 °C with a residence time of 3 h and pyrolysis rate of 5 °C per minute. The AC and CC derived biochar were termed as ABC and CBC, respectively. The produced soil amendments were applied to soil at 0% (control), 1%, 3%, and 5% in a column setup. The moisture characteristics, including water infiltration, evaporation, and water retention, were investigated. Thereafter, the prepared amendments were applied to loamy sand soils at 0% (control), 1%, 3%, and 5% (w/w) application rates. Maize growth was then observed for a period of 30 days under greenhouse conditions. Results of the column trials showed that ABC and CBC applied at 5% reduced the cumulative water evaporation by 57%-66% and cumulative infiltration by 124%-181% compared to control. Likewise, 5% application of ABC and CBC resulted in 101 to 130% higher water retention in loamy sand soil. Results of the greenhouse experiment showed that 5% application of ABC and CBC amendments resulted in root biomass of 2.12 and 2.38 g, respectively, as compared to 0.51 g in control treatment. Similar treatments resulted in shoot biomass of 9.70 and 9.93 g respectively, as compared to 7.37 g in control. Likewise, 5% application of CBC and ABC increase plant height from 15.71 to 30.94 cm in ABC and 33.23 cm in CBC. Overall, 5% application of coffee waste-derived biochars significantly reduced water evaporation and infiltration, while increasing soil water retention and maize plant height, root biomass, and shoot biomass. Therefore, spent coffee waste-derived biochar could effectively be employed to improve physical and hydrological properties of loamy sand soils for better crop productivity.

Actinomycetes isolated from rhizosphere of wild Coffea arabica L. showed strong biocontrol activities against coffee wilt disease.

Coffee, the second most traded commodity globally after petroleum and is the most exported cash crop of Ethiopia. However, coffee cultivation faces challenges due to fungal diseases, resulting in significant yield losses. The primary fungal diseases affecting coffee production include coffee berry disease, wilt disease (caused by Gibberella xylarioides), and coffee leaf rust. In this study, we aimed to isolate potentially antagonistic actinomycetes from the root rhizosphere of wild Coffea arabica plants in the Yayo coffee forest biosphere in southwestern Ethiopia. Soil samples were collected from the rhizosphere, and actinomycetes were selectively isolated and identified to the genus level by morphological, physiological, and biochemical characterization. These pure isolates were screened for their antagonistic activity against Gibberella xylarioides in vitro using a dual culturing method. Promising isolates demonstrating strong inhibition of fungal mycelial growth were further investigated through in vivo experiments using coffee seedlings. A total of 82 rhizobacteria were isolated. These isolates' inhibition of fungal mycelial growth varied from 0% to 83.3%. Among them, four isolates MUA26, MUA13, MUA52, and MUA14 demonstrated the highest percentage inhibition of fungal mycelial growth: 83.3%, 80%, 76.67%, and 73.3%, respectively. Seedlings inoculated with MUA13, MUA14, and MUA26 during the challenge inoculations (Rhizobacteria + Gibberella xylarioides) exhibited the lowest disease incidence compared to the infected fungi (P < 0.05). Notably, the seedlings inoculated with MUA26 demonstrated the highest disease control efficiency, reaching 83% (P < 0.05). MUA26 was found to produce extracellular enzymes, including chitinase, protease, and lipase, which acted as inhibitors. In summary, this study highlights that MUA26, among the actinomycete isolates, exhibited significant antagonistic activity against Gibberella xylarioides f.sp. coffea. Its efficacy in controlling coffee wilt disease, both in vitro and in vivo, positions it as a potential bioinoculant for managing coffee wilt disease.

Inhibition of Aspergillus spp. growth and ochratoxin A production in Conilon and Arabica coffees based-medium by Saccharomyces cerevisiae.

Saccharomyces cerevisiae CCMA 0159 is reported as a promising biocontrol agent against ochratoxin A (OTA)-producing fungi in coffee. Coffea arabica and Coffea canephora (var. Conilon or Robusta) are the most widely consumed coffee species around the world, cultivated in tropical and subtropical regions, each exhibiting distinct physicochemical and sensory characteristics. The objective of this study was to compare the growth and OTA production by Aspergillus carbonarius, A. ochraceus, and A. westerdijkiae in C. arabica and C. canephora, along with assessing the efficiency of S. cerevisiae CCMA 0159 in biocontrolling ochratoxigenic fungi in both coffee varieties. A. carbonarius exhibited a higher growth rate and OTA production in both coffee varieties, with C. canephora showing particular susceptibility. Conversely, A. ochraceus and A. westerdijkiae demonstrated lower growth and OTA production. S. cerevisiae was effective in biocontrolling the fungal isolates, inhibiting over 80 % of A. carbonarius growth in both coffee varieties. Among the mechanisms of action of the biological control agent, the production of volatile organic compounds stands out. The results of this study confirm the significant potential of S. cerevisiae CCMA 0159 as a biocontrol agent against Aspergillus for application in coffee-producing areas.

Quantification of two derivatives of malic acid first-time discovered in coffee: Influence of postharvest processing method.

This study quantified, for the first time, 2-isopropylmalic and 3-isopropylmalic acids, in green, roasted and espresso coffee by UHPLC-MS/MS. Moreover, it reports the influence of postharvest processing methods (natural, washed and honey) on their content. New extraction techniques were developed and validated from three coffee matrices (green, roasted and espresso). Honey coffee exhibited levels substantially higher of 2-isopropylmalic acid than those processed by natural and washed methods (p < 0.05). Specifically, 2-isopropylmalic acid levels in honey green, roasted and espresso coffee samples were 48.24 ± 7.31 ng/g, 168.8 ± 10.88 ng/g and 177.5 ± 9.49 ng/g, respectively. This research highlights the significant impact of processing methods on the chemical profile of coffee and introduces 2-isopropylmalic and 3-isopropylmalic acids as potential quality indicators. Moreover, it suggests that the fermentation stage during processing may play a crucial role in their formation, laying the foundation for optimizing coffee processing to enhance quality.