The impact of different filter baskets, heights of perforated disc and amount of ground coffee on the extraction of organics acids and the main bioactive compounds in espresso coffee

Green hybrid coagulants for water treatment: An innovative approach using alum and bentonite clay combined with eco-friendly plant materials for batch and column adsorption

Textile industries contribute to water pollution through synthetic dye discharge. This study explores the use of natural bio-coagulants to remove acid dyes from wastewater, investigating factors like pH, coagulant dose, dye concentration, contact time, and temperature for optimal results. The optimum pH and coagulants capabilities of (CAAPP, CAAPH, CBAGL, CBAPP and CBAPH) were 3 (49.6 mg/g), 3 (42.5 mg/g), 3 (38.9 mg/g), 4 (35.7 mg/g), 4 (34.1 mg/g), and 4 (29.4 mg/g) respectively, while treating of selected BRF-221 dyes from water solution. The acidic range (3-4) was found to have the best pH for the maximal coagulation, and the optimal dose were found to be 0.05 g/50 mL. The equilibrium was attained within 45-60 min for all coagulants. After 60 min of shaking, the maximum coagulation capacities (21.9, 21.02, 16.5, 27.9, 25.3, and 23.4 mg/g) of several coagulant composites (CAAGL, CAAPP, CAAPH, CBAGL, CBAPP, CBAPH) were determined. The initial BRF-221 dye concentration in the range of 10-200 mg/L was considered as optimum for gaiting maximum elimination of dye using different coagulants. At a dye value of 100 mg/L of BRF-221, maximal coagulation capacities CAAGL (179.19 mg/g), CAAPP (166.06 mg/g), CAAPH (141.60 mg/g), and CBAGL (126.49 mg/g), CBAPP (113.9 mg/g), CBAPH (93.08 mg/g) were attained. The study found 35 °C to be the optimal temperature for maximum acid dye removal using bio-coagulants. Increasing temperature reduced coagulation capacity, indicating an exothermic process. Freundlich and Langmuir isotherms showed suitability for pseudo-first-order and pseudo-second-order kinetics in biosorption. Thermodynamic parameters were assessed for process feasibility. Effective coagulants demonstrated sensitivity to electrolyte variations. In column studies, adjusting parameters achieved maximum coagulation efficiency for removing BRF-221 dyes. The study successfully applied optimal parameters to remove real textile effluents at a practical scale. SEM, FT-IR, BET and XRD characterized coagulants, providing insights into stability and morphology.

Effect of Extraction Methods on Aroma Profile, Antioxidant Activity and Sensory Acceptability of Specialty Coffee Brews

Specialty coffees from various geographical origins were processed using different extraction methods. Four extraction techniques were employed: cold brew (CB), espresso (ES), French press (FR), and aeropress (AE). The potential health benefits of coffee brews were linked to their antioxidant activity, as determined by the DPPH assay, and total polyphenol content (TPC) measured through the Folin-Ciocalteu reducing-capacity assay. The Columbia (C) espresso coffee type (omni-roasting) exhibited the highest antioxidant activity (86.31 ± 0.70) μmol/100 mL, with a TPC value of (44.41 ± 0.35) mg GAE/g. Quantitative analyses of caffeine and chlorogenic acid were conducted using high-performance liquid chromatography (HPLC). The evaluation of coffee aroma profiles involved the application of headspace solid-phase microextraction/gas chromatography-mass spectrometry (HS-SPME/GC-MS) and was complemented by sensory analysis following the Specialty Coffee Association (SCA) standard protocol. The predominant volatile compounds found in all samples included furans, phenols, pyrazines, and terpenes. The EY espresso type (medium dark roasting) had the highest levels of most coffee volatiles. The C cold brew type (omni-roasting) was rated as the preferred coffee in terms of its sensory characteristics and flavour. In summary, ES and CB were found to be more effective extraction methods for the parameters assessed.

Effect of organic acid-soaking and sonication on the formation of volatile compounds and α-dicarbonyl compounds in Robusta coffee

In this study, the effects of organic acid-soaking (malic, citric, tartaric, and succinic acid) and sonication on the formation of flavor and α-dicarbonyl compounds in Robusta (C. canephora syn. Coffea robusta) green beans were investigated. A total of 20 volatile compounds were identified in Robusta coffee. Furfural and 5-methyl furfural, two dominant volatile compounds in Arabica coffee, increased after organic acid pretreatment. In Robusta coffee processed from 3% malic acid-soaked coffee beans, furfural and 5-methyl furfural increased by 90.99% and 24.92%, respectively, compared to the control. In Robusta coffee processed from 3% malic acid-sonicated (280 W, 1 h) coffee beans, furfural and 5-methyl furfural increased by 236.03% and 114.77%, respectively. α-Dicarbonyls (glyoxal, methylglyoxal, and diacetyl) were significantly (p < 0.05) decreased in all Robusta coffees after organic acid pretreatment. In Robusta coffee processed from coffee beans soaked and sonicated in tartaric acid solution, the α-dicarbonyls decreased by up to 44% and 58%, respectively, compared to the control. This study suggested the pretreatment methods to enhance the flavor substances and reduce the α-DCs in Robusta coffee.

Acids in coffee: A review of sensory measurements and meta-analysis of chemical composition

Coffee contains a variety of organic acids (OAs) and chlorogenic acids (CGAs) that contribute to overall sensory properties. Large variations in preparation and measurement methodology across the literature complicate interpretation of general trends. Here, we perform a systematic review and meta-analysis of the published literature to elucidate the concentrations of OAs and CGAs in both Coffea arabica (arabica) and Coffea canephora (robusta), for both green coffee and roasted coffee at multiple roast levels. A total of 129 publications were found to report acid concentration measurements, yielding 8,634 distinct data points. Analysis of the full data set reveals several trends. First, roasted robusta has considerably more acidic compounds than arabica with 2 to 5 times as much total OAs, and much larger amounts of formic and acetic acid. As for CGAs, in both arabica and robusta 5-CQA is the major component, and progressive roasting decreases the concentration of all CGAs. The total amount of CGA present was more dependent on roast level than the type of coffee (arabica vs. robusta). Overall, this meta-analysis suggests that the increases in certain OAs with roast level might play more of a role in the sensory profile of dark roast coffees than previously suspected.

Analysis of Phytosterols Content in Italian-Standard Espresso Coffee

This study aims to assess for the first time the content of phytosterols (PS) in espresso coffee (EC) to deepen the knowledge about the phytochemicals and health potentials of coffee brews. PS were extracted by hot saponification from 14 EC samples produced with coffee originating from 13 coffee-producing countries. PS were identified and quantified by high-performance liquid chromatography (HPLC) after derivatization. Among the detected PS, β-sitosterol (4.1–18.2 mg/L) was the most abundant followed by stigmasterol (1.1–4.9 mg/L), campesterol (0.9–4.7 mg/L), and cycloartenol (0.3–2.0 mg/L). Total PS fraction ranged from 6.5 mg/L to 30.0 mg/L with an average level of 15.7 ± 5.8 mg/L. Therefore, a standard cup of EC (25 mL) could provide 0.4 ± 0.1 mg of PS.

Characterization of the Aroma Profile and Main Key Odorants of Espresso Coffee

Espresso coffee (EC) is a common coffee preparation technique that nowadays is broadly widespread all over the globe. Its popularity is in part attributed to the intense aroma and pleasant flavor. Many researchers have studied and reviewed the aroma of the coffee, but there is a lack of specific review focused on EC aroma profile even if it is intensively investigated. Thus, the objective of the current review was to summarize the aroma profile of EC and how different preparation variables can affect EC flavor. Moreover, a collection of diverse analytical procedures for volatile analysis was also reported. The findings of this survey showed that the volatile fraction of EC is extremely complex, but just some compounds are responsible for the characteristic aroma of the coffee, such as some aldehyde, ketones, furanones, furans, sulfur compounds, pyrazines, etc. In addition, during preparation, some variables, e.g., temperature and pressure of water, granulometry of the coffee particle, and brew ratio, can also modify the aroma profile of this beverage, and therefore its quality. A better understanding of the aroma fraction of EC and how the preparation variables should be adjusted according to desired EC would assist coffee workers in obtaining a higher quality product.

Anti-Platelet Aggregation and Anti-Cyclooxygenase Activities for a Range of Coffee Extracts (Coffea arabica)

Coffee is rich in caffeine (CF), chlorogenic acid (CGA) and phenolics. Differing types of coffee beverages and brewing procedures may result in differences in total phenolic contents (TPC) and biological activities. Inflammation and increases of platelet activation and aggregation can lead to thrombosis. We focused on determining the chemical composition, antioxidant activity and inhibitory effects on agonist-induced platelet aggregation and cyclooxygenase (COX) of coffee beverages in relation to their preparation method. We prepared instant coffee and brewed coffee beverages using drip, espresso, and boiling techniques. Coffee extracts were assayed for their CF and CGA contents using HPLC, TPC using colorimetry, platelet aggregation with an aggregometer, and COX activity using ELISA. The findings have shown all coffee extracts, except the decaffeinated types, contained nearly equal amounts of CF, CGA, and TPC. Inhibitory effects of coffee extracts on platelet aggregation differed depending on the activation pathways induced by different agonists. All espresso, drip and boiled coffee extracts caused dose dependent inhibition of platelet aggregation induced by ADP, collagen, epinephrine, and arachidonic acid (ARA). The most marked inhibition was seen at low doses of collagen or ARA. Espresso and drip extracts inhibited collagen-induced platelet aggregation more than purified caffeine or CGA. Espresso, boiled and drip coffee extracts were also a more potent inhibitors of COX-1 and COX-2 than purified caffeine or CGA. We conclude that inhibition of platelet aggregation and COX-1 and COX-2 may contribute to anti-platelet and anti-inflammatory effects of espresso and drip coffee extracts.