Inhibition of α-glucosidase activity by potential peptides derived from fermented spent coffee grounds.

The control of α-glucosidase activity has been associated with managing diabetes. We previously identified three peptides with high bioactive indices derived from protein hydrolysates of fermented spent coffee grounds. In this study, the peptides YGF, GMCC, and RMYRY were synthesized and tested in vitro for their α-glucosidase inhibition activity, complemented by in silico analyses. Two of the three peptides significantly inhibited α-glucosidase activity, with the more efficient peptides being YGF and GMCC (0.42 mg/mL), resulting in decreased enzymatic activity of 95.31% and 89.79%, respectively. These peptides exhibited binding free energies with the α-glucosidase complex of -8.5 and - 6.6 kcal/mol, respectively, through hydrogen bonds and van der Waals interactions with amino acids from the active site. Pharmacokinetic analysis indicated that YGF and GMCC profiles were unrelated to toxicity. These results underscore the importance of focusing on food waste bioprocessing products to expand the range of alternatives that could aid in diabetes treatment.

Chemical composition and sensory profiling of coffees treated with asparaginase to decrease acrylamide formation during roasting.

Acrylamide is an amide formed in the Maillard reaction, with asparagine as the primary amino acid precursor. The intake of large amounts of acrylamide has induced genotoxic and carcinogenic effects in hormone-sensitive tissues of animals. The enzime asparaginase is one of the most effective methods for lowering the formation of acrylamide in foods such as potatoes. However, the reported sensory outcomes for coffee have been unsatisfactory so far. This study aimed to produce coffees with reduced levels of acrylamide by treating them with asparaginase while retaining their original sensory and bioactive profiles. Three raw samples of Coffea arabica, including two specialty coffees, and one of Coffea canephora were treated with 1000, 2000, and 3000 ASNU of the enzyme. Asparagine and bioactive compounds (chlorogenic acids-CGA, caffeine, and trigonelline) were quantified in raw and roasted beans by HPLC and LC-MS, while the determination of acrylamide and volatile organic compounds was performed in roasted beans by CG-MS. Soluble solids, titratable acidity, and pH were also determined. Professional cupping by Q-graders and consumer sensory tests were also conducted. Results were analyzed by ANOVA-Fisher, MFA, PCA and Cluster analyses, with significance levels set at p ≤ 0.05. Steam treatment alone decreased acrylamide content by 18.4%, on average, and 6.1% in medium roasted arabica and canefora coffees. Average reductions of 32.5-56.0% in acrylamide formation were observed in medium roasted arabica beans when 1000-3000 ASNU were applied. In the canefora sample, 59.4-60.7% reductions were observed. However, steam treatment primarily caused 17.1-26.7% reduction of total CGA and lactones in medium roasted arabica samples and 13.9-22.0% in canefora sample, while changes in trigonelline, caffeine, and other evaluated chemical parameters, including the volatile profiles were minimal. Increasing enzyme loads slightly elevated acidity. The only sensory changes observed by Q-graders and or consumers in treated samples were a modest increase in acidity when 3000 ASNU was used in the sample with lower acidity, loss of mild off-notes in control samples, and increased perception of sensory descriptors. The former was selected given the similarity in chemical outcomes among beans treated with 2000 and 3000 ASNU loads.

Identification of microorganisms in wet coffee fermentation Coffea arabica Var Catimor and Castillo in Jardín, Antioquia-Colombia, using culture-dependent methods / Identificación de microorganismos en fermentación húmeda de café Coffea arabica Var Catimor y Castillo en Jardín, Antioquia-Colombia, usando métodos cultivo-dependientes

Background: Mild Colombian coffees are recognized worldwide for their high-quality coffee cup. However, there have been some failures in post-harvest practices, such as coffee grain fermentation. These failures could occasionally lead to defects and inconsistencies in quality products and economic losses for coffee farmers. In Colombia, one of the fermentation methods most used by coffee growers is wet fermentation, conducted by submerging the de-pulped coffee beans for enough time in water tanks to remove the mucilage. Objectives: We evaluated the effect of the water (g)/de-pulped coffee (g) ratio (I: 0/25, II: 10/25, III: 20/25) and final fermentation time (24, 48, and 72 hours) on the total number of microbial groups. We also identified microorganisms of interest as starter cultures. Methods: We used a completely randomized experimental design with two factors; the effect of the water (g)/de-pulped coffee (g) ratio (I: 0/25, II: 10/25, III: 20/25) and final fermentation time (24, 48, and 72 hours), for 9 treatments with two replicates. During the coffee fermentation (1,950 g), the pH and °Brix were monitored. Total counts of different microbial groups (mesophiles, coliforms, lactic-acid bacteria, acetic-acid bacteria, and yeasts) were performed. Various isolates of microorganisms of interest as starter cultures (lactic-acid bacteria and yeasts) were identified using molecular sequencing techniques. Results: 21 lactic-acid bacteria (LAB) isolates and 22 yeasts were obtained from the different mini-batch fermentation systems. The most abundant lactic-acid bacteria species found were Lactiplantibacillus plantarum (46%) and Levilactobacillus brevis (31%). Pichia kluivery (39%) and Torulaspora delbrueckii (22%) were the most abundant yeast species. Conclusion The studied factors did not have effect over the microorganism's development. The identified bacterial and yeasts species have potential as starter cultures for better-quality coffees and in fermentation-related applications.

Antecedentes: Los cafés suaves lavados colombianos son reconocidos a nivel mundial por su buena puntuación sensorial; sin embargo, se han detectado fallas en las prácticas de postcosecha, como lo es la fermentación de los granos de café. Dichas fallas pueden causar defectos y carecer de consistencia en la calidad del producto, ocasionando pérdidas económicas para los caficultores. En Colombia, uno de los métodos más usados por los caficultores es la fermentación húmeda, la cual consiste en sumergir los granos de café despulpado en tanques con agua por un período de tiempo que permita la remoción del mucílago. Objetivos: La presente investigación evaluó la incidencia que tienen la proporción agua/granos despulpados de café (I: 0/25, II: 10/25, III: 20/25) y el tiempo final de fermentación (24, 48 y 72 horas) en el recuento final de grupos microbianos. Por otra parte, se identificaron taxonómicamente microorganismos de interés para su uso como cultivos iniciadores. Métodos: Mini-lotes consistieron en café despulpado (1950 g) puesto en recipientes de plástico abiertos y sumergidos en agua. Se aplicó un diseño experimental completamente aleatorizado de dos factores (proporción agua/ granos de café despulpado y tiempo) a tres niveles, para un total de nueve tratamientos con dos replicas. Durante las fermentaciones de café (1,950 g), el pH y los grados ºBrix, fueron monitoreados. Se realizaron los recuentos totales de los diferentes grupos microbianos: mesófilos, coliformes, bacterias ácido-lácticas, bacterias ácido-acéticas y levaduras. Se identificaron molecularmente diferentes aislados con potencial para ser usados como cultivos iniciadores (bacterias ácido-lácticas y levaduras). Resultados: Los resultados obtenidos mostraron que no hubo diferencia estádisticamente significativa entre los tratamientos aplicados y el recuento final de microorganismos. Un total de 21 aislados de bacterias ácido-lácticas (BAL) y 22 levaduras lograron obtenerse a partir de los diferentes sistemas de fermentación en mini-lote. Las especies de bacterias ácido-lácticas con mayor porcentaje acorde a su identificación taxonómica, corresponden a Lactiplantibacillus plantarum (46%), Levilactobacillus brevis (31%). Las especies de levaduras con mayor porcentaje acorde a su identificación taxonómica corresponden a Pichia kluivery (39%) y Torulaspora delbrueckii (22%). Conclusión Los factores estudiados no afectaron el crecimiento de ninguno de los grupos microbianos presentes en la fermentacion del café. Las especies de microorganismos identificados tienen potencial para se usados como cultivos starter o en aplicaciones dentro de las ciencias de fermentación.

Transcriptomic Analysis of Alternative Splicing Events during Different Fruit Ripening Stages of Coffea arabica L.

To date, genomic and transcriptomic data on Coffea arabica L. in public databases are very limited, and there has been no comprehensive integrated investigation conducted on alternative splicing (AS). Previously, we have constructed and sequenced eighteen RNA-seq libraries of C. arabica at different ripening stages of fruit development. From this dataset, a total of 3824, 2445, 2564, 2990, and 3162 DSGs were identified in a comparison of different fruit ripening stages. The largest proportion of DSGs, approximately 65%, were of the skipped exon (SE) type. Biologically, 9 and 29 differentially expressed DSGs in the spliceosome pathway and carbon metabolism pathway, respectively, were identified. These DSGs exhibited significant variations, primarily in S1 vs. S2 and S5 vs. S6, and they involve many aspects of organ development, hormone transduction, and the synthesis of flavor components. Through the examination of research findings regarding the biological functions and biochemical pathways associated with DSGs and DEGs, it was observed that six DSGs significantly enriched in ABC transporters, namely, LOC113712394, LOC113726618, LOC113739972, LOC113725240, LOC113730214, and LOC113707447, were continually down-regulated at the fruit ripening stage. In contrast, a total of four genes, which were LOC113732777, LOC113727880, LOC113690566, and LOC113711936, including those enriched in the cysteine and methionine metabolism, were continually up-regulated. Collectively, our findings may contribute to the exploration of alternative splicing mechanisms for focused investigations of potential genes associated with the ripening of fruits in C. arabica.

The genome and population genomics of allopolyploid Coffea arabica reveal the diversification history of modern coffee cultivars.

Coffea arabica, an allotetraploid hybrid of Coffea eugenioides and Coffea canephora, is the source of approximately 60% of coffee products worldwide, and its cultivated accessions have undergone several population bottlenecks. We present chromosome-level assemblies of a di-haploid C. arabica accession and modern representatives of its diploid progenitors, C. eugenioides and C. canephora. The three species exhibit largely conserved genome structures between diploid parents and descendant subgenomes, with no obvious global subgenome dominance. We find evidence for a founding polyploidy event 350,000-610,000 years ago, followed by several pre-domestication bottlenecks, resulting in narrow genetic variation. A split between wild accessions and cultivar progenitors occurred ~30.5 thousand years ago, followed by a period of migration between the two populations. Analysis of modern varieties, including lines historically introgressed with C. canephora, highlights their breeding histories and loci that may contribute to pathogen resistance, laying the groundwork for future genomics-based breeding of C. arabica.

Optimization and validation of high throughput methods for the determination of 132 organic contaminants in green and roasted coffee using GC-QqQ-MS/MS and LC-QqQ-MS/MS.

Recently some major safety concerns have been raised on organic contaminants in widely consumed plants such as coffee. Hence, this study aimed to develop specifically optimized methods for determining organic contaminants, such as pesticides and polychlorinated biphenyls (PCBs), in coffee using GC-MS/MS and LC-MS/MS. QuEChERS method was used as a base extraction method, and 27 experiments were studied using design of experiments with categorical variables (extraction buffers, cleanup sorbents, and coffee roasting degree) to find the optimum method for each matrix type. The optimum method for green coffee was acetate buffer and chitosan for clean-up, while no-buffer extraction and the PSA + C18 method were ideal for light and dark-roasted coffee. The optimized methods were validated in accordance with SANTE/11312/2021. Furthermore, ten real samples (4 green, and 6 roasted) from the markets were analysed; ortho-phenylphenol was found in all the roasted coffee samples, and carbendazim was found in one green coffee sample.

Combined sensory, volatilome and transcriptome analyses identify a limonene terpene synthase as a major contributor to the characteristic aroma of a Coffea arabica L. specialty coffee.

BACKGROUND: The fruity aromatic bouquet of coffee has attracted recent interest to differentiate high value market produce as specialty coffee. Although the volatile compounds present in green and roasted coffee beans have been extensively described, no study has yet linked varietal molecular differences to the greater abundance of specific substances and support the aroma specificity of specialty coffees. RESULTS: This study compared four Arabica genotypes including one, Geisha Especial, suggested to generate specialty coffee. Formal sensory evaluations of coffee beverages stressed the importance of coffee genotype in aroma perception and that Geisha Especial-made coffee stood out by having fine fruity, and floral, aromas and a more balanced acidity. Comparative SPME-GC-MS analyses of green and roasted bean volatile compounds indicated that those of Geisha Especial differed by having greater amounts of limonene and 3-methylbutanoic acid in agreement with the coffee cup aroma perception. A search for gene ontology differences of ripening beans transcriptomes of the four varieties revealed that they differed by metabolic processes linked to terpene biosynthesis due to the greater gene expression of prenyl-pyrophosphate biosynthetic genes and terpene synthases. Only one terpene synthase (CaTPS10-like) had an expression pattern that paralleled limonene loss during the final stage of berry ripening and limonene content in the studied four varieties beans. Its functional expression in tobacco leaves confirmed its functioning as a limonene synthase. CONCLUSIONS: Taken together, these data indicate that coffee variety genotypic specificities may influence ripe berry chemotype and final coffee aroma unicity. For the specialty coffee variety Geisha Especial, greater expression of terpene biosynthetic genes including CaTPS10-like, a limonene synthase, resulted in the greater abundance of limonene in green beans, roasted beans and a unique citrus note of the coffee drink.

Carboxymethyl cellulose-based multifunctional film integrated with polyphenol-rich extract and carbon dots from coffee husk waste for active food packaging applications.

Sustainable carboxymethyl cellulose (CMC)-based active composite films were developed through the addition of polyphenol-rich extract from coffee husk (CHE) and carbon dots (CDs) prepared using the biowaste residue of CHE extraction. The influences of various CDs contents on the physicochemical and functional characteristics of composite films have been researched. The 6% (w/w) CHE and 3% (w/w) CDs were uniformly dispersed within the CMC matrix to produce a homogenous film with enhanced mechanical properties. The CMC/CHE/CDs3% film exhibited outstanding UV-light blocking, improved water and gas barriers, potent antioxidant activity with above 95% DPPH and ABTS scavenging rates, and effective antibacterial capabilities against L. monocytogenes and E. coli. The food packaging experiment demonstrated that this active composite film slowed the rotting of fresh-cut apples and extended their shelf-life to 7 days at 4 °C storage. Therefore, the obtained multifunctional film showed promise as an environmentally friendly food packaging material.

Characterization and bioactivities of coffee husks extract encapsulated with polyvinylpyrrolidone.

Coffee processing generates large amounts of residues of which a portion still has bioactive properties due to their richness in phenolic compounds. This study aimed to obtain a coffee husks extract (CHE) and to encapsulate it (ECHE) with polyvinylpyrrolidone using a one-step procedure of solid dispersion. The extraction and encapsulation yields were 9.1% and 92%, respectively. Thermal analyses revealed that the encapsulation increased the thermal stability of CHE and dynamic light scattering analyses showed a bimodal distribution of size with 81% of the ECHE particles measuring approximately 711 nm. Trigonelline and caffeine were the main alkaloids and quercetin the main phenolic compound in CHE, and the encapsulation tripled quercetin extraction. The total phenolics content and the antioxidant activity of ECHE, assayed with three different procedures, were higher than those of CHE. The antioxidant activity and the bioaccessibility of the phenolic compounds of ECHE were also higher than those of CHE following simulated gastrointestinal digestion (SGID). Both CHE and ECHE were not toxic against Alliumcepa cells and showed similar capacities for inhibiting the pancreatic α-amylase in vitro. After SGID, however, ECHE became a 1.9-times stronger inhibitor of the α-amylase activity in vitro (IC50 = 8.5 mg/mL) when compared to CHE. Kinetic analysis revealed a non-competitive mechanism of inhibition and in silico docking simulation suggests that quercetin could be contributing significantly to the inhibitory action of both ECHE and CHE. In addition, ECHE (400 mg/kg) was able to delay by 50% the increases of blood glucose in vivo after oral administration of starch to rats. This finding shows that ECHE may be a candidate ingredient in dietary supplements used as an adjuvant for the treatment of diabetes.

Antioxidant, antimicrobial and healing properties of an extract from coffee pulp for the development of a phytocosmetic.

Consumer demand for natural, chemical-free products has grown. Food industry residues, like coffee pulp, rich in caffeine, chlorogenic acid and phenolic compounds, offer potential for pharmaceutical and cosmetic applications due to their antioxidant, anti-inflammatory, and antibacterial properties. Therefore, the objective of this work was to develop a phytocosmetic only with natural products containing coffee pulp extract as active pharmaceutical ingredient with antioxidant, antimicrobial and healing activity. Eight samples from Coffea arabica and Coffea canephora Pierre were analyzed for caffeine, chlorogenic acid, phenolic compounds, tannins, flavonoids, cytotoxicity, antibacterial activity, and healing potential. The Robusta IAC-extract had the greatest prominence with 192.92 µg/mL of chlorogenic acid, 58.98 ± 2.88 mg GAE/g sample in the FRAP test, 79.53 ± 5.61 mg GAE/g sample in the test of total phenolics, was not cytotoxic, and MIC 3 mg/mL against Staphylococcus aureus. This extract was incorporated into a stable formulation and preferred by 88% of volunteers. At last, a scratch assay exhibited the formulation promoted cell migration after 24 h, therefore, increased scratch retraction. In this way, it was possible to develop a phytocosmetic with the coffee pulp that showed desirable antioxidant, antimicrobial and healing properties.

Functioning of Saccharomyces cerevisiae in honey coffee (Coffea canephora) and their effect on metabolites, volatiles and flavor profiles.

Post-harvesting and microbial activity of coffee play a critical role in the metabolites and the sensory quality of the brew. The pulped natural/honey coffee process is an improvised semi-dry technique consisting of prolonged fermentation of depulped coffee beans excluding washing steps. The starter culture application in coffee industry plays an important role to enhance the cup quality. This work focuses on the fermentation of pulped natural/honey Robusta coffee with a starter culture (Saccharomyces cerevisiae MTCC 173) and the identification of fermentation patterns through 1H NMR, microbial ecology, volatomics and organoleptics of brew. Fermentation was accelerated by yeast populace (10 cfu log/mL) for 192 h. Principal compound analysis performed on 1H NMR led to the investigation of metabolites such as sugars, alkaloids, alcohols, organic acids and amino acids. Detection of some sugars and organic acids represented that the starter cultures imparted few metabolic changes during the process. A major activity of sugars in fermentation with 83.3 % variance in PC 1 and 16.7 % in PC 2 was observed. The chemical characteristics such as carbohydrates (41.88 ± 0.77 mg/g), polyphenols (34.16 ± 0.79 mg/g), proteins (58.54 ± 0.66 mg/g), caffeine (26.54 ± 0.06 mg/g), and CGA (21.83 ± 0.04 mg/g) were also evaluated. The heatmap-based visualization of GC-MS accorded characterization of additional 5 compounds in treated (T) coffee contributing to sweet, fruity and caramelly odor notes compared to untreated (UT). The sensory outlines 72.5 in T and 70.5 in UT scores. Preparation of honey coffee with Saccharomyces cerevisiae is the first report, which modulated the flavor and quality of coffee.

Inhibition of pancreatic lipase by coffee leaves-derived polyphenols: A mechanistic study.

The suppression of pancreatic lipase has been employed to mitigate obesity. This study explored the mechanism of coffee leaf extracts to inhibit pancreatic lipase. The ethyl acetate fraction derived from coffee leaves (EAC) exhibited the highest inhibitory capacity with a half-maximal inhibitory concentration (IC50) of 0.469 mg/mL and an inhibitor constant (Ki) of 0.185 mg/mL. This fraction was enriched with 3,5-dicaffeoylquinic acid (3,5-diCQA, 146.50 mg/g), epicatechin (87.51 mg/g), and isoquercetin (48.29 mg/g). EAC inhibited lipase in a reversible and competitive manner, and quenched its intrinsic fluorescence through a static mechanism. Molecular docking revealed that bioactive compounds in EAC bind to key amino acid residues (HIS-263, PHE-77, and SER-152) located within the active cavity of lipase. Catechin derivatives play a key role in the lipase inhibitory activity within EAC. Overall, our findings highlight the promising potential of coffee leaf extract as a functional ingredient for alleviating obesity through inhibition of lipase.

Fractional extraction of lignin from coffee beans with low cytotoxicity, excellent anticancer and antioxidant activities.

Lignin, a biopolymer generated from renewable resources, is widely present in terrestrial plants and possesses notable biosafety characteristics. The objective of this work was to assess the edible safety, in vitro antioxidant, and anti-cancer properties of various lignin fractions isolated from commercially available coffee beans often used for coffee preparation. The findings suggest that the phenolic hydroxyl content increased from 3.26 mmol/g (ED70L) to 5.81 mmol/g (ED0L) with decreasing molecular weight, which resulted in more significant antioxidant properties of the low molecular weight lignin fraction. The findings of the study indicate that the viability of RAW 264.7 and HaCaT cells decreased as the quantity of lignin fractions increased. It was observed that concentrations below 200 µg/mL did not exhibit any harmful effects on normal cells. The results of the study demonstrated a significant reduction of cancer cell growth (specifically A375 cells) at a concentration of 800 µg/mL for all lignin fractions, with an observed inhibition rate of 95 %. The results of this study indicate that the lignin extracts derived from coffee beans exhibit significant potential in mitigating diseases resulting from excessive radical production. Furthermore, these extracts show promise as natural antioxidants and anti-cancer agents.

Gas chromatography-mass spectrometry analysis of fatty acids in healthy and Aspergillus niger MH078571.1-infected Arabica coffee beans.

The organic composition of Arabica coffee beans, particularly fatty acids, significantly influences their overall quality. After measuring its composition of fatty acids, it contained a high percentage of saturated fatty acids (SFA), including caprylic, lauric, myristic, palmitic, margaric, fat, and orchid. Moreover, the sample contained unsaturated fatty acids (USFA), namely palmitoleic acid (C16:1), oleic acid (C18:1), linoleic acid (C18:2), and alpha-linoleic acid (C18:3). Coffee beans are susceptible to infection by fungi during storage, the development of which has adverse effects on the beans. The present study aimed to examine the impact of Aspergillus niger MH078571.1 infection on the diversity and abundance of fatty acids in green Arabica coffee beans. The impact of Aspergillus niger on the consumption of fatty acids in Arabica coffee beans was assessed. The findings of the study indicate that the duration of storage had a significant impact on the levels of fatty acids, specifically miristic (C14:0), margaric (C17:0), and stearic (C18:0), which increased as the storage period and temperature increased. Conversely, the percentage of oleic acid decreased under these conditions. This trend was observed across different storage temperatures (0, 8, and 25°C) in untreated coffee beans affected by fungal activity.

Unveiling the bioactivity and bioaccessibility of phenolic compounds from organic coffee husks using an in vitro digestion model.

BACKGROUND: The large quantities of by-products generated in the coffee industry are a problem. Studies related to the biological potential of organic coffee husks are still limited. The aim of this work was to investigate the occurrence of phenolic compounds in organic coffee husks and to evaluate their potential as a source of bioactive dietary components. RESULTS: To achieve this objective, three extracts were prepared, namely extractable polyphenols (EPs), hydrolyzable non-extractable polyphenols (H-NEPs), and non-extractable polyphenols (NEPs). These extracts were characterized and evaluated for their bioactive properties after simulated gastrointestinal digestion. The results show that the extraction process affected the occurrence of phenols from coffee peels, especially for caffeic acid, gallic acid, and chlorogenic acid. The free and bound polyphenols found in the extracts and digests not only showed antioxidant properties against 2,2'-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), ferric reducing antioxidant power (FRAP), and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicals but were also strongly bioavailable and had good anticoagulant potential. CONCLUSION: These results highlight the potential health benefits of phytochemicals from coffee husks and open new perspectives for the use of such compounds in dietary supplements. © 2023 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Using underutilized residues of coffee to obtain valuable dietary and antioxidant bioactive compounds.

BACKGROUND: Coffee cultivation and agroindustry generate residues that are rich in several metabolites. These compounds, such as phenolic compounds and alkaloids, are known for their antioxidant activity and are usually consumed as nutraceuticals. The purpose of this study was to evaluate the occurrence of chemical and antioxidant components of low-pruned coffee stems under different fertilizer regimes. Extractives and lignin composition, histochemical, chromatographic, and antioxidant analyses were performed. RESULTS: Multiple compounds were found to accumulate in the stems of coffee trees. Furthermore, the presence of phenolic compounds such as chlorogenic acid, vanillin, resveratrol, and the alkaloids caffeine and trigonelline varied depending on the type of fertilization. In all samples examined, optimal performance was observed at the highest tested concentration (500 µg mL-1 ). All samples analyzed presented a great performance at the highest concentration tested (500 µg mL-1 ), with the dose 70% and the dose 100%, which is the recommended for the culture, showing the highest values for most of the concentrations and the best half-maximal inhibitory concentration (IC50 ) when compared with the other samples tested. CONCLUSION: As shown in the results, the reuse of stem residues as antioxidant material, with the potential to be profitable, and has the added benefit of providing a sustainable destination for material that until now has been underutilized. © 2023 Society of Chemical Industry.

Influence of Post-Harvest Processing on Functional Properties of Coffee (Coffea arabica L.).

Coffee is one of the most popular beverages worldwide, valued for its sensory properties as well as for its psychoactive effects that are associated with caffeine content. Nevertheless, coffee also contains antioxidant substances. Therefore, it can be considered a functional beverage. The aim of this study is to evaluate the influence of four selected post-harvest coffee fruit treatments (natural, full washed, washed-extended fermentation, and anaerobic) on the antioxidant and psychoactive properties of Arabica coffee. Additionally, the impact of coffee processing on the selected quality parameters was checked. For this purpose, results for caffeine content, total phenolic content (TPC), DPPH assay, pH, titratable acidity, and water content were determined. The results show that natural and anaerobic processing allow the highest caffeine concentration to be retained. The selection of the processing method does not have a significant influence on the TPC or antiradical activity of coffee. The identified differences concerning water content and pH along with lack of significant discrepancies in titratable acidity may have an influence on the sensory profile of coffee.

Coffee Leaf Tea Extracts Improve Hyperuricemia Nephropathy and Its Associated Negative Effect in Gut Microbiota and Amino Acid Metabolism in Rats.

Hyperuricemia nephropathy (HN) is a metabolic disease characterized by tubular damage, tubulointerstitial fibrosis, and uric acid kidney stones and has been demonstrated to be associated with hyperuricemia. Coffee leaf tea is drunk as a functional beverage. However, its prevention effects on HN remain to be explored. This study showed that coffee leaf tea extracts (TE) contain 19 polyphenols, with a total content of 550.15 ± 27.58 mg GAE/g. TE decreased serum uric acid levels via inhibiting XOD activities and modulating the expression of urate transporters (GLUT9, OAT3, and ABCG2) in HN rats. TE prevented HN-induced liver and kidney damage and attenuated renal fibrosis. Moreover, it upregulated the abundance of SCFA-producing bacteria (Phascolarctobacterium, Alloprevotella, and Butyricicoccus) in the gut and reversed the amino acid-related metabolism disorder caused by HN. TE also decreased the circulating LPS and d-lactate levels and increased the fecal SCFA levels. This study supported the preliminary and indicative effect of coffee leaf tea in the prevention of hyperuricemia and HN.

High-Density Chitosan Induces a Biochemical and Molecular Response in Coffea arabica during Infection with Hemileia vastatrix.

The coffee industry faces coffee leaf rust caused by Hemileia vastratix, which is considered the most devastating disease of the crop, as it reduces the photosynthetic rate and limits productivity. The use of plant resistance inducers, such as chitosan, is an alternative for the control of the disease by inducing the synthesis of phytoalexins, as well as the activation of resistance genes. Previously, the effect of chitosan from different sources and physicochemical properties was studied; however, its mechanisms of action have not been fully elucidated. In this work, the ability of food-grade high-density chitosan (0.01% and 0.05%) to control the infection caused by the pathogen was evaluated. Subsequently, the effect of high-density chitosan (0.05%) on the induction of pathogenesis-related gene expression (GLUC, POX, PAL, NPR1, and CAT), the enzymatic activity of pathogenesis-related proteins (GLUC, POX, SOD, PPO, and APX), and phytoalexin production were evaluated. The results showed that 0.05% chitosan increased the activity and gene expression of ß-1,3 glucanases and induced a differentiated response in enzymes related to the antioxidant system of plants. In addition, a correlation was observed between the activities of polyphenol oxidase and the production of phytoalexin, which allowed an effective defense response in coffee plants.