Ultrasound combined with microwave hydrodiffusion and gravity for enhancement of caffeine extraction from guarana powder.

The extraction of valuable compounds from dried fruits and vegetables by microwave hydrodiffusion and gravity (MHG) requires previous hydration of the plant material. In this work, ultrasound was used to speed up the hydration of guarana powder before MHG extraction and increase caffeine recovery. The humidification step was speeded up with ultrasound taking only 15 min over 60 min without ultrasound. Water and 50% (v/v) ethanol were evaluated as green solvents for humidification, with a higher concentration of caffeine obtained for the hydroalcoholic solution. Ultrasound pretreatment allowed guarana extracts from MHG with two times more caffeine for both solvents evaluated. Therefore, ultrasound can be used in the hydration step before MHG extraction to reduce time and increase caffeine recovery from guarana powder.

Electrochemical Oxidation of Different Therapeutic Classes of Pharmaceuticals Using Graphite-PVC Composite Electrode.

This study reports electrochemical treatment of different therapeutic classes of pharmaceuticals (caffeine, prazosin, enalapril, carbamazepine, nifedipine, levonorgestrel, and simvastatin) in a mixture. The electrochemical process was investigated using graphite-PVC anode at different applied voltages (3, 5, and 12 V), initial concentrations of studied pharmaceuticals in aqueous solution (5 and 10 mg/L), and concentrations of sodium chloride (1 and 2 g/L). The % removal of pharmaceuticals increased with the applied voltage, and was found higher than 98% after 50 min of electrolysis at 5 V. Energy consumption ranged between 0.760 and 3.300 Wh/mg using 12 V being the highest value compared to 3 and 5 V. The formation of chlorinated by-products from four selected pharmaceuticals, simvastatin (C11H13Cl3O5, and C10H12Cl4O3), prazosin (C13H12Cl3N5O3 and C10H11Cl4N2O2), carbamazepine and caffeine (C15H11N2O2Cl and C8H9N4O2Cl) was identified and elucidated using liquid chromatography-time of flight mass spectrometry (LC-TOF/MS).

Process characterization and optimization of cold brew coffee: effect of pressure, temperature, time and solvent volume on yield, caffeine and phenol content.

BACKGROUND: Cold brew coffee, based on cold extraction, is rapidly attracting consumers' preference worldwide. Low total solids yield and long extraction times (up to 24 h) are the main drawbacks of this process. Five different treatments were investigated: the traditional cold extraction method, freezing, lyophilization of coffee beans, use of chaotropic salt and reduced pressure extraction. The latter was optimized by applying a Box-Behnken design. Pressure, vacuum cycles, duration of each cycle and mass of ground coffee to water ratio were the optimization parameters. Yield, caffeine and phenol concentration were the response variables. RESULTS: Caffeine concentration and yield were significantly affected by vacuum cycles and by the combination of vacuum cycles and duration of each cycle. Validation of the derived quadratic models for each response variable was performed. Optimum values for highest extraction yield (22%) and phenol concentration as well as mass transfer coefficients of phenol and caffeine were also determined. CONCLUSIONS: Extraction under reduced pressure might be the best treatment for the acceleration of cold brew coffee extraction. © 2021 Society of Chemical Industry.

Coffee in cancer chemoprevention: an updated review.

INTRODUCTION: Chemoprevention of cancer refers to the use of natural or synthetic compounds to abolish or perturb a variety of steps in tumor initiation, promotion, and progression. This can be realized through different mechanisms, including activation of free radical scavenging enzymes, control of chronic inflammation, and downregulation of specific signaling pathways. AREAS COVERED: The goal of this article is to critically review recent evidence on association between coffee and prevention of different types of cancer, with particular emphasis on the molecular mechanisms and the bioactive compounds involved in its anticancer activity. EXPERT OPINION: Coffee is a mixture of different compounds able to decrease the risk of many types of cancer. However, its potential anticancer activity is not completely understood. Hundreds of biologically active components such as caffeine, chlorogenic acid, diterpenes are contained in coffee. Further research is needed to fully elucidate the molecular mechanisms underlying the anticancer effects of coffee and fully understand the role of different confounding factors playing a role in its reported anticancer activity.

Use of asparaginase for acrylamide mitigation in coffee and its influence on the content of caffeine, chlorogenic acid, and caffeic acid.

A factorial design with a duplicate in the central point was used to investigate the effect of treating arabica coffee beans with asparaginase. The investigated factors were enzymatic load (1000 and 5000 ASNU/Kg), water percentage (30 and 90%), and hydrolysis time (1 and 3 h). The acrylamide content was determined by UPLC-MS/MS, and the caffeic acid, chlorogenic acid and caffeine concentrations were determined by HPLC-DAD. The statistical analysis was carried out in the R platform using RStudio graphical interface. The results indicated the importance of coffee bean pretreatment with steam, and that the enzyme load reduced the acrylamide content to 65 mg/kg in coffee beans. The predicted reduction was obtained with hydrolysis time of 2 h, water content of 90%, and asparaginase load of 5000 ASNU/kg. The asparaginase treatment did not influence the major bioactive compounds in coffee.

Hierarchical zeolitic imidazolate framework-67 derived from in-situ synthesized CO-Al layered double hydroxide embedded within porous-anodized aluminum foil for thin film microextraction of caffeine followed by its high performance liquid chromatography-ultraviolet detection.

In this study, the in-situ conversion of the synthesized Co-Al layered double hydroxide (Co-Al LDH) nanosheets to three dimensional hierarchical zeolitic imidazolate framework-67 (3D HZIF-67) was presented as a cost-effective, highly efficient, flexible and robust sorbent to carry out the microextraction process. In the first stage, the anodized aluminum foil was prepared electrochemically. Then, the Co-Al LDH precursor was constructed on the surface of the previously-prepared anodized Al foil applying in-situ formation approach. The procedure is followed by the conversion of the prepared Co-Al LDH film to 3D HZIF-67 film via a facile solvothermal method without adding cobalt salt. The in-situ prepared 3D HZIF-67-anodized Al was used for the thin film microextraction (TFME) of caffeine. The effective factors in TFME procedure were investigated and optimized through applying Central Composite Design (CCD). In the obtained optimal condition, the calibration curves for TFME-HPLC-UV of caffeine were linear in the range of 1-200 µg L-1 with the coefficient of determination (r2) higher than 0.9915. The limits of detection were 0.33 and 0.38 µg L-1, in water and urine matrices, respectively. Moreover, the enrichment factors (EFs) and absolute recoveries (%AR) were also calculated as 173-198 and 57.1%-65.3%, respectively. The inter-day relative standard deviations (RSDs) were evaluated as the method precision for 20 and 200 µg L-1 of spiked sample and were between 4.9-6.1%. The repeatability of the preparation step was investigated as batch-to-batch reproducibility and it was found to be 4.9%; as a result, the reproducibility of the presented film was approved. Finally, the proposed method was utilized to determine caffeine (as the model analyte) from different types of real samples including urine, coffee, beverage (Pepsi) and shampoo. The obtained recoveries (higher than 88%) confirmed the capability of the method for real sample analysis.

Antidepressant Effect of Shaded White Leaf Tea Containing High Levels of Caffeine and Amino Acids.

The young leaves of green tea become lighter in color than usual when protected from sunlight by a shading net for about two weeks while growing. These leaves are called "shaded white leaf tea" or SWLT. In the eluate of SWLT, the amount of amino acids (361 mg/L) was significantly higher than that in regular tea (53.5 mg/L). Since theanine and arginine, the first and second most abundant amino acids in SWLT, have significant antistress effects, we examined the antistress effect of SWLT on humans. SWLT or placebo green tea (3 g) was eluted with room-temperature water (500 mL). Participants consumed the tea for one week prior to pharmacy practice and continued for 10 days in the practice period. The state-trait anxiety inventory, an anxiety questionnaire, tended to be scored lower in the SWLT group than the placebo, but other stress markers showed no differences. The effect of the difference in SWLT components examined with mice showed that aspartic acid and asparagine, which are abundant in SWLT, counteracted the antistress effects of theanine and arginine. Large amounts of caffeine also interfered with SWLT's antistress effect. Thus, SWLT, which is high in caffeine and amino acids, suppressed depressant behavior in mice.

Long-Term Coffee Consumption is Associated with Fecal Microbial Composition in Humans.

Coffee consumption has been related to a preventive effect against several non-transmissible pathologies. Due to the content of this beverage in phytochemicals and minerals, it has been proposed that its impact on health may partly depend on gut microbiota modulation. Our aim was to explore the interaction among gut microbiota, fecal short chain fatty acids, and health-related parameters in 147 healthy subjects classified according to coffee consumption, to deepen the association of the role of the (poly)phenol and alkaloid content of this beverage. Food daily intake was assessed by an annual food frequency questionnaire (FFQ). Coffee consumption was categorized into three groups: non-coffee-consumers (0-3 mL/day), moderate consumers (3-45 mL/day) and high-coffee consumers (45-500 mL/day). Some relevant groups of the gut microbiota were determined by qPCR, and concentration of fecal short chain fatty acids by gas chromatography. Serum health related biomarkers were determined by standardized methods. Interestingly, a higher level of Bacteroides-Prevotella-Porphyromonas was observed in the high consumers of coffee, who also had lower levels of lipoperoxidation. Two groups of coffee-derived (poly)phenol, methoxyphenols and alkylphenols, and caffeine, among alkaloids, were directly associated with Bacteroides group levels. Thus, regular consumption of coffee appears to be associated with changes in some intestinal microbiota groups in which dietary (poly)phenol and caffeine may play a role.

Poultry Farms as a Potential Source of Environmental Pollution by Pharmaceuticals.

Industrial poultry breeding is associated with the need to increase productivity while maintaining low meat prices. Little is known about its impact on the environment of soil pollution by pharmaceuticals. Breeders routinely use veterinary pharmaceuticals for therapeutic and preventive purposes. The aim of this work was to determine the influence of mass breeding of hens on the soil contamination with 26 pharmaceuticals and caffeine. During two seasons-winter and summer 2019-15 soil samples were collected. Liquid extraction was used to isolate analytes from samples. Extracts were analyzed using ultra-high performance liquid chromatography coupled with tandem mass spectrometry detection (UPLC-MS/MS). The results showed the seasonal changes in pharmaceutical presence in analyzed soil samples. Ten pharmaceuticals (metoclopramide, sulphanilamide, salicic acid, metoprolol, sulphamethazine, nimesulide, carbamazepine, trimethoprim, propranolol, and paracetamol) and caffeine were determined in soil samples collected in March, and five pharmaceuticals (metoclopramide, sulphanilamide, sulphamethazine, carbamazepine, sulfanilamid) in soil samples collected in July. The highest concentrations were observed for sulphanilamide, in a range from 746.57 ± 15.61 ng/g d.w to 3518.22 ± 146.05 ng/g d.w. The level of bacterial resistance to antibiotics did not differ between samples coming from intensive breeding farm surroundings and the reference area, based on antibiotic resistance of 85 random bacterial isolates.

Fluorescence Sensing of Caffeine in Tea Beverages with 3,5-diaminobenzoic Acid.

A rapid, selective and sensitive method for the detection of caffeine in tea infusion and tea beverages are proposed by using 3,5-diaminobenzoic acid as a fluorescent probe. The 3,5-diaminobenzoic acid emits strong fluorescence around 410 nm under the excitation of light at 280 nm. Both the molecular electrostatic potential analysis and fluorescent lifetime measurement proved that the existence of caffeine can quench the fluorescence of 3,5-diaminobenzoic acid. Under the optimal experimental parameters, the 3,5-diaminobenzoic acid was used as a fluorescent probe to detect the caffeine aqueous solution. There exists a good linear relationship between the fluorescence quenching of the fluorescent probe and the concentration of caffeine in the range of 0.1-100 µM, with recovery within 96.0 to 106.2%, while the limit of detection of caffeine is 0.03 µM. This method shows a high selectivity for caffeine. The caffeine content in different tea infusions and tea beverages has been determined and compared with the results from HPLC measurement.

Solvent and temperature effect of accelerated solvent extraction (ASE) coupled with ultra-high-pressure liquid chromatography (UHPLC-PDA) for the determination of methyl xanthines in commercial tea and coffee.

BACKGROUND: Methyl xanthines (MX), known for its psychostimulant effect, occurs mostly in tea and coffee samples. However most of the market available products does not mention the proper amount and quality of MX present where, its consumption in high amount may pose health risks. AIM OF THE STUDY: To develop and validate a fast, efficient and reliable method of MX extraction along with a sensitive, rapid and precise method for simultaneous analysis of MX i.e. Theobromine (TB), Theophylline (TH) and Caffeine (C), with application in commercial tea and coffee samples. MATERIALS AND METHODS: Accelerated Solvent Extraction (ASE) was utilized for the first time to extract MX, whereas UHPLC-DAD was applied in order to quantify MX. RESULTS: ASE resulted a high extract yield (940.22 ± 192.28 mg/g) with optimized conditions of temperature (100 °C) and solvent (MeOH). UHPLC-DAD showed retention time (min) of 1.51 (TB), 1.81 (TH), 2.30 (C) with r2 values (0.980-0.988). Average MX (µg/mL) was as; TB (14.73 ± 20.9), TH (32.05 ± 55.5), C (121.87 ± 32.3). The method application in commercial samples showed a high extract yield with MX concentration (mg/g) as; TB (0.13-0.38), TH (0-0.55), C (7.14-11.20). Temperature and solvent variation showed important correlation with samples in terms of extraction yield. CONCLUSION: ASE-UHPLC/DAD revealed a fast and sensitive method of MX extraction, quantification and quality determination in market available tea and coffee samples.

Modeling of two semi-continuous methods in liquid-liquid chromatography: Comparing conventional and closed-loop recycling modes.

Two high throughput steady-state methods of counter-current chromatography separations: conventional (SS CCC) and closed-loop recycling (SS CLR CCC) are proposed, evaluated and compared. The methods are based on the application of semi-continuous sample loading technique: the CCC setup includes two mobile phase tanks - one with the pure mobile phase and the second - with the sample solution in the mobile phase. The mobile phase pump is periodically switching from one tank to another. The sample solution is continuously loaded into the CCC column over a constant time with the constant volumetric rate equal to the flow rate of the pure mobile phase. Analytical expressions are developed to describe the SS CCC and SS CLR CCC separations with semi-continuous sample loading. Examples of separation of binary and multicomponent mixtures are discussed. The SS CLR CCC has been shown to provide a multiple increase in the performance and effectiveness of CCC devices. Several examples of simulation of SS CLR CCC separation with semi-continuous sample loading are presented in "Mathcad" program. For the experimental verification of the theory, the separation of the binary mixture caffeine/ coumarin was studied. The biphasic solvent system hexane/isopropanol/water (1:1:1), was used. The comparison of experimental and simulated separations demonstrated a reasonable agreement between theory and experiment.

Seven-day Green Tea Supplementation Revamps Gut Microbiome and Caecum/Skin Metabolome in Mice from Stress.

Green tea supplementation has beneficial health effects. However, its underlying mechanisms, such as effects on modulating the intestinal microbiome and endogenous metabolome, particularly following short-term supplementation, are largely unclear. We conducted an integrative metabolomics study to evaluate the effects of short-term (7-day) supplementation of green tea extract (GTE) or its components, epigallocatechin gallate, caffeine, and theanine, on the caecum microbiota and caecum/skin metabolome in mice. Further, we established an integrative metabolome-microbiome model for correlating gut and skin findings. The effects of short-term supplementation with dietary compounds were evaluated with respect to UV stress response, with GTE showing the most remarkable effects. Biplot analysis revealed that Bifidobacteria and Lactobacillus spp. were considerably influenced by short-term GTE supplementation, while Clostridium butyricum was significantly increased by UV stress without supplementation. GTE supplementation helped the skin metabolome defend against UV stress. Interestingly, a significant positive correlation was observed between caecum bacteria (Bifidobacteria, Lactobacillus spp.) and metabolites including skin barrier function-related skin metabolites, caecal fatty acids, and caecal amino acids. Overall, 7-day GTE supplementation was sufficient to alter the gut microbiota and endogenous caecum/skin metabolome, with positive effects on UV stress response, providing insight into the mechanism of the prebiotic effects of GTE supplementation.

Identification and Characterization of the Tyrosinase Inhibitory Activity of Caffeine from Camellia Pollen.

Tyrosinase inhibitors are important in cosmetic, medical, and food industries due to their regulation of melanin production. A tyrosinase inhibitor was purified from Camellia pollen using high-speed countercurrent chromatography and preparative high-performance liquid chromatography and was identified as caffeine by NMR and mass spectrometry. It showed strong mushroom tyrosinase inhibitory activity with an IC50 of 18.5 ± 2.31 µg/mL in a noncompetitive model. The caffeine did not interact with copper ions in the active center of the enzyme but could quench fluorescence intensity and change the secondary conformation of this tyrosinase. A molecular dynamics simulation showed that caffeine bound this tyrosinase via Lys379, Lys 376, Asp357, Glu356, Thr308, Gln307, Asp312, and Trp358, thus changing the binding sites of l-tyrosine and the loop conformation adjacent to the active center. In vitro cell model analysis revealed that caffeine exhibited significant inhibitory effects on both intracellular tyrosinase activity and melanin production of B16-F10 melanoma cells in a concentration-dependent manner. These comprehensive results suggest that caffeine is a strong tyrosinase inhibitor that has the potential to be developed as skin-whitening agents in the cosmetics and pharmaceutical industries or as antibrowning agents in the food industry.

Rapid one-step cleanup method to minimize matrix effects for residue analysis of alkaline pesticides in tea using liquid chromatography-high resolution mass spectrometry.

Matrix effects in complex tea matrices remains a great challenge to rapid quantitative analysis of multi-residue pesticides by analysis of mass spectrometry. Herein, a mixed-mode polymer cationic exchange based dispersive solid-phase extraction (DSPE) procedure was established to eliminate matrix effects of tea for a rapid target alkaline multi-residue pesticides analysis. One-step DSPE procedure can eliminate matrix interferences from the tea extract without additional dilution or tedious cleanup operations. Liquid chromatography-high resolution mass spectrometry using pre-column dilution injection mode was used as the detection technique, while eliminating solvent effects of target analytes and improving the detection sensitivity. Based on this effective analytical method, the results of absolute matrix effects were within 0.77-1.08 for quantitation of the 68 alkaline pesticides, and superior relative matrix effects were also achieved with RSD values below 9.8%. Finally, this method was validated and applied to the alkaline pesticides analysis of the 123 tea samples.

Polypyrrole nanotubes for electrochemically controlled extraction of atrazine, caffeine and progesterone.

Polypyrrole (PPy) was electrochemically synthesized with charge control on the surface of a steel mesh. Two different morphologies (globular and nanotubular) were created and characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The modified electrodes were used as extraction phases in solid-phase extraction (SPE) and electrochemically controlled solid-phase extraction (EC-SPE) of atrazine, caffeine and progesterone. Raman spectroscopy was employed for the structural characterization of PPy after long exposure to the analytes. The electrochemical behavior was studied by cyclic voltammetry which revealed the higher capacitive behavior of polypyrrole nanotubes because of the huge superficial area, also no electrocatalytical behavior was observed evidencing the strong adsorption of the analytes on the PPy surface. The effects of the PPy oxidation state on the extraction performance were evaluated by in-situ electrochemical sorption experiments. The sorption capacity was evaluated by gas chromatography coupled to mass spectrometry (GC-MS). The method displays good stability, repeatability and reproducibility. The limits of detection range between 1.7-16.7 µg L-1. Following the extraction of river water samples, it was possible to identify the presence of other endogenous organic compounds besides the analytes of interest. This indicates the potential of the method and material developed in this work. Graphical abstract Schematic representation of a steel mesh electrode covered with polypyrrole nanotubes used as extraction phase for separation of contaminants from aqueous samples. The oxidation level of polypyrrole was electrochemically tuned by which the adsorption of analytes is deeply affected.

Development of a chemometric-assisted deep eutectic solvent-based microextraction procedure for extraction of caffeine in foods and beverages.

In this research article, a novel and green deep eutectic solvent-based microextraction (DES-ME) procedure based on chemometric-assisted (CA) optimization was developed for the extraction of caffeine in foods and beverages prior to its spectrophotometric determination. Ultrasound was used to accelerate the extraction of caffeine. Deep eutectic solvents (DES), prepared in an ultrasonic bath at 20-60 min for 60-80°C, were used as extraction solvents. The important experimental variables (pH, DES amount, temperature, sonication time and metal concentration) were modelled and optimized using response surface methodology (RSM) based on central composite design (CCD). Under the optimum conditions, the proposed method allowed the determination of caffeine with limits of detection (LOD, 3sblank/m) and quantification (LOQ, 3sblank/m) of 7.5 and 25.0 µg L-1, respectively. For 40 µg L-1 and 100 µg L-1 of caffeine (n = 5), relative standard deviations (RSDs%) and recoveries% were 1.2-1.6% and 96.7-98.2%, respectively. Validation studies (accuracy, precision, trueness, reliability and selectivity) of the method were performed before the analysis of real samples. The results showed that the combination of the CCD with the DES-ME can be considered as a new perspective for the extraction and determination of caffeine in foods and beverages.

Multi-Spheres Adsorptive Microextraction (MSAµE)-Application of a Novel Analytical Approach for Monitoring Chemical Anthropogenic Markers in Environmental Water Matrices.

Multi-spheres adsorptive microextraction using powdered activated carbons (ACs) was studied as a novel enrichment approach, followed by liquid desorption and high-performance liquid chromatography with diode array detection (MSAµE(AC)-LD/HPLC-DAD) to monitor caffeine (CAF) and acetaminophen (ACF) traces in environmental matrices. In this study, commercial activated carbons (N, NOX, and R) were tested, with the latter showing a much better performance for the analysis of both anthropogenic drugs. The main parameters affecting the efficiency of the proposed methodology are fully discussed using commercial AC(R). Textural and surface chemistry properties of the ACs sample were correlated with the analytical results. Assays performed on 30 mL of water samples spiked at 10 µg L-1 under optimized experimental conditions, yielding recoveries of 75.3% for ACF and 82.6% for CAF. The methodology also showed excellent linear dynamic ranges for both drugs with determination coefficients higher than 0.9976, limits of detection and quantification of 0.8⁻1.2 µg L-1 and 2.8⁻4.0 µg L-1, respectively, and suitable precision (RSD < 13.8%). By using the standard addition method, the application of the present method to environmental matrices, including superficial, sea, and wastewater samples, allowed very good performance at the trace level. The proposed methodology proved to be a feasible alternative for polar compound analysis, showing to be easy to implement, reliable, and sensitive, with the possibility to reuse and store the analytical devices loaded with the target compounds for later analysis.

Effects of ultrasonication, agitation and stirring extraction techniques on the physicochemical properties, health-promoting phytochemicals and structure of cold-brewed coffee.

BACKGROUND: Ultrasonication, agitation and stirring or a combination of ultrasonication, agitation and stirring extraction techniques were applied to observe their effects on the physicochemical properties, health-promoting phytochemicals, and structure of cold brewed coffee. RESULTS: All the extraction techniques led to significant (P < 0.05) increases in the color values, total soluble solids, antioxidant activities and most organic acids, while a combination of extraction techniques increased the chlorogenic acid and caffeine content significantly (P < 0.05) compared with that by conventional methods. Fourier transform infrared spectroscopy allowed us to identify the different compounds in the cold-brewed coffee extract rapidly. The partial least square regression model presented good predictability because experimental and predicted values were close to each other. Principal component analysis revealed that levels of all phytochemicals correlated with the use of non-conventional methods. CONCLUSION: The combination of ultrasonication and agitation might be the best option to enhance the various phytochemicals in cold-brewed coffee. © 2018 Society of Chemical Industry.