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.

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.

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.

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.

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.

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.

Determination of synthetic pharmaceutical adulterants in herbal weight gain supplements sold in herb shops, Tehran, Iran.

BACKGROUND: Nowadays with the growing popularity of herbal remedies across the world, large sections of population rely on herbal drug practitioners for their primary care. Therefore there is a need to ensure about the safety of herbal drugs and to detect adulteration with undeclared active pharmaceutical ingredients. Herbal drugs are used as first-line drug therapy in some instances. Unfortunately even if there are claims as to be natural, undeclared active pharmaceutical ingredients have been detected in these supplements. OBJECTIVES: The purpose of the present study was to analyse herbal weight gain drugs collected from herb shops located in Tehran, Iran to detect hidden pharmaceutical ingredients using UHPLC and GC/MS instrumentations. METHODS: Sixty herbal drugs advertised as weight gain supplements were gathered from herb shops Tehran province, Iran. All samples were analysed from analytical toxicology point of view to detect undeclared active pharmaceutical ingredients. Method was validated for quantitative analysis of cyproheptadine and dexamethasone. RESULTS: Method validity parameters showed good results for quantitative analysis of pharmaceutical ingredients. Cyproheptadine, dexamethasone, sildenafil, tramadol, caffeine and acetaminophen were detected in herbal weight gain drugs. Analysed dosage forms contained cyproheptadine and dexamethasone in concentrations higher than therapeutic doses. Quantitative analysis of contaminated drugs showed that the content of pharmacologic ingredients were 0.2-67 and 5.5-10.1 mg/tablet or capsule for cyproheptadine and dexamethasone respectively. CONCLUSIONS: Despite natural supplements producers' claim, herbal weight gain drugs were not natural at all. Undeclared active pharmaceutical ingredients can predispose patients to health problems and even life-threatening situations. Graphical Abstract ᅟ.

Preconcentration and GC-MS determination of caffeine in tea and coffee using homogeneous liquid-liquid microextraction based on solvents volume ratio alteration.

A simple, fast and green homogeneous liquid-liquid microextraction (HLLME) method based on solvents volume ratio alteration (SVRA) combined with gas chromatography-mass spectrometry (GC-MS) was developed for the preconcentration and determination of caffeine in tea and coffee samples. In the proposed HLLME-SVRA method, the primary extraction from solid samples was achieved by a 2:1 ethanol-water mixture. A micro-volume of dichloromethane (DCM) formed a homogeneous solvent with this mixture after choosing an appropriate volume ratio between the three solvents. After vigorous shaking, an extra volume of water was added that resulted in phase separation due to the solvents volume ratio alteration. As a result, complete extraction of caffeine was achieved after centrifugation. The sedimented dichloromethane phase was then injected into GC-MS for the analysis. The influence of a number of parameters influencing the efficiency of the extraction was investigated and optimized. Under the optimal conditions, an enrichment factor of 11, a limit of detection of 0.05 µg mL-1 and a limit of quantification of 0.16 µg mL-1 were obtained for caffeine. A linear dynamic range of 0.16 to 50 µg mL-1 and a determination coefficient (R2) of 0.9980 were achieved. The precision of the method, expressed as relative standard deviation, was 4.8% for six replicated measurements. The method was successfully applied to the determination of caffeine in tea and coffee samples.

A Prospective Randomized, Double-Blind, Two-Period Crossover Pharmacokinetic Trial Comparing Green Coffee Bean Extract-A Botanically Sourced Caffeine-With a Synthetic USP Control.

Coffee is a primary dietary source of the chlorogenic acids (CGAs) of phenolic compounds. Coffee contains caffeine and other phytonutrients, including CGAs. Caffeine on its own has been well characterized and descried pharmacokinetically in the literature, less so for CGAs. The purpose of this double-blind crossover study was to determine the comparative pharmacokinetics of CGAs with caffeine (natural extract) with synthetic caffeine (US Pharmacopeia [USP] standard). Sixteen healthy male subjects were randomly assigned to take 1 dose of product 1, 60 mg of botanically sourced caffeine from 480 mg of green coffee bean extract, or product 2, 60 mg of synthetic USP caffeine, with 5 days between. Blood analysis was done to determine the levels of CGA compounds, more specifically 3-, 4-, and 5-caffeoylquinic acid (CQA), and serum caffeine. The natural caffeine extract exhibited mean peak concentrations (Cmax ) of 3-CQA (11.4 ng/mL), 4-CQA (6.84 ng/mL), and 5-CQA (7.20 ng/mL). The mean systemic 4-hour exposure (AUC0-4 h ) was 3-CQA (27.3 ng·h/mL), 4-CQA (16.1 ng·h/mL), and 5-CQA (15.7 ng·h/mL). The median tmax was 3-CQA (1.00 hour), 4-CQA (1.00 hour), and 5-CQA (1.50 hours). The tmax of caffeine was 0.75 hours (natural extract) and 0.63 hours (synthetic caffeine). Cmax and AUC0-4 h of serum caffeine were statistically equivalent between products. The geometric least-squares mean ratios (GMRs) of Cmax and AUC0-4 h of caffeine were 97.77% (natural extract) and 98.33% (synthetic caffeine). It would appear that CGA compounds from the natural caffeine extract are bioavailable, and 3-CGA may be the compound most absorbed. In addition, caffeine sourced from natural extract versus synthetic were statistically similar for pharmacokinetic parameters. There were no adverse events or safety concerns.

Systematic investigation for extraction and separation of polyphenols in tea leaves by magnetic ionic liquids.

BACKGROUND: Magnetic separation has become a mature industrial technique in many fields and its application in the food and agricultural fields is expected for further extension. Furthermore, there has been little application of magnetic ionic liquids in the preparation of bioactive products. In the present study, 0.8 mol L-1 C3 MIMFeCl4 in its aqueous solution was found to be ideal for the extraction of active constituents from tea leaves. After extraction, polyphenols, caffeine and ionic liquid were also satisfactorily separated from the crude extract by various easy operations. RESULTS: The average extraction efficiency of tea polyphenols could reach up to 185.38 g kg-1 and the recovery percent of the magnetic ionic liquid was 99.8% through an external magnetic field. The extraction process was more consistent with a pseudo-second order kinetic model. Moreover, C3 MIMFeCl4 had no effect on the stability of tea polyphenols, which was very different from ordinary ferric salt. The presence of magnetic ionic liquid had a positive effect on the antioxidant activity of the product. CONCLUSION: The developed method had a good performance for selective extraction together with separation of tea polyphenols and caffeine, which is expected in the preparation of more similar active components from food and agricultural resources as a useful multifunctional solvent. © 2018 Society of Chemical Industry.

Caffeine - rich infusion from Cola nitida (kola nut) inhibits major carbohydrate catabolic enzymes; abates redox imbalance; and modulates oxidative dysregulated metabolic pathways and metabolites in Fe2+-induced hepatic toxicity.

The antioxidative and antidiabetic effects and toxicity of caffeine-rich infusion of Cola nitida were investigated using in vitro, ex vivo and in silico models. C. nitida was infused in boiling water and allowed to cool before concentrating at <50°C. HPLC analysis of the infusion revealed a caffeine content of 80.08%. The infusion showed potent in vitro antioxidant activity by significantly (p<0.05) scavenging 2,2'-diphenyl-1-picrylhydrazyl (DPPH). It significantly (p<0.05) inhibited α-glucosidase and α-amylase activities. Treatment of Fe2+ induced oxidative hepatic tissues with the infusion led to increase Superoxide Dismutase (SOD) and catalase activities, and glutathione (GSH) level as well as decreased malondialdehyde (MDA) level. FTIR spectroscopy of hepatic metabolite revealed restoration of oxidative-induced depleted functional groups by the infusion. LC-MS analysis of the metabolite also revealed restoration of most depleted metabolites with concomitant generation of 4-O-Methylgallic, (-)-Epicatechin sulfate, L-Arginine, L-tyrosine, Citric acid and Decanoic acid in infusion-treated tissues. Pathway analysis of the identified metabolites revealed the presence of 21 metabolic pathways involved in normal hepatic tissues, 12 in oxidative injured tissues and 17 in the treated tissues. Treatment with the infusion restored 4 metabolic pathways common to the normal tissue and further activated 4 additional pathways. Prediction of oral toxicity of caffeine showed it to belong to class 3, with a LD50 of 127mg/kg. Its toxicity target was predicted as Adenosine Receptor A2a. It was also predicted to be an inhibitor of CYP1A2. These results suggest the antioxidative and antidiabetic properties of C. nitida infusion, with caffeine as the major constituent.

Evaluation of New Cleanup Agents for Analysis of Pesticide Residues in Tea.

We evaluated the effectiveness of new cleanup agents (S-NH2 and S-Si) compared with other previously reported cleanup agents (octadecylsilane, graphitized carbon, aminopropyl and silica gel) for removal of interfering substances such as catechin and caffeine prior to analysis of pesticide residues in tea. S-NH2 and S-Si were highly efficient in removal of catechin and caffeine, respectively. Recoveries of 80 pesticides using S-NH2 and S-Si were tested, and more than 70% of pesticides showed recovery greater than 70%. These results indicate that S-NH2 and S-Si agents will be useful for analysis of pesticide residues in tea.

Caffeine adsorption of montmorillonite in coffee extracts.

The growth in health-conscious consumers continues to drive the demand for a wide variety of decaffeinated beverages. We previously developed a new technology using montmorillonite (MMT) in selective decaffeination of tea extract. This study evaluated and compared decaffeination of coffee extract using MMT and activated carbon (AC). MMT adsorbed caffeine without significant adsorption of caffeoylquinic acids (CQAs), feruloylquinic acids (FQAs), dicaffeoylquinic acids (di-CQAs), or caffeoylquinic lactones (CQLs). AC adsorbed caffeine, chlorogenic acids (CGAs) and CQLs simultaneously. The results suggested that the adsorption selectivity for caffeine in coffee extract is higher in MMT than AC. The caffeine adsorption isotherms of MMT in coffee extract fitted well to the Langmuir adsorption model. The adsorption properties in coffee extracts from the same species were comparable, regardless of roasting level and locality of growth. Our findings suggest that MMT is a useful adsorbent in the decaffeination of a wide range of coffee extracts.