Article

Comparative study of polyphenols and caffeine in different coffee varieties affected by the degree of roasting

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Abstract

The bioactive composition of coffee, as one of the most popular beverages in the world, has attracted interest as a potential source of beneficial bioactive compounds, especially polyphenols and caffeine. Since the content of these compounds is affected by the processing conditions, the objective of this study was to determine the content of polyphenolic compounds and caffeine in four different coffee varieties: Minas and Cioccolatato (Coffea arabica), and Cherry and Vietnam (Coffea canephora syn. Coffea robusta), roasted by three varying degrees (light, medium and dark). The content of the polyphenolic compounds and the antioxidant capacity of coffees were determined using UV/Vis spectrophotometric methods, while the content of chlorogenic acid derivatives was determined using HPLC analysis. The caffeine content was determined by means of two spectrophotometric methods, as well as HPLC analysis. Additionally, raw caffeine was also obtained by an isolation procedure with chloroform. Cherry coffee, a variety of C. canephora exhibited the highest overall content of total phenols (42.37mg GAE/g), followed by Minas coffee, while Cioccolatato contained the lowest TPC (33.12mg GAE/g). Cherry coffee also exhibited the highest content of individual classes of polyphenols (flavan-3-ols, procyanidins and tannins), while the highest content of chlorogenic acid (CQA) derivatives was determined in Minas and Cioccolatato coffees (C. arabica). The highest content of total and individual polyphenolic compounds was determined in coffees roasted in both light and medium roasting conditions, which was also observed for the content of CQA derivatives and antioxidant capacity of roasted coffees. The highest caffeine content in the coffee samples was determined by employing the HPLC analysis (0.06–2.55%). Light roasted Cherry coffee contained the highest overall content of caffeine among all coffees, which exhibited a decrease with intensified roasting.

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... The bioactive composition of coffee has received increasing interest, and it is counted among the rich sources of bioactive compounds, particularly phenolics and caffeine (Hečimović, Belščak-Cvitanović, Horžić, & Komes, 2011). However, processing conditions can significantly affect the content of these compounds. ...
... Previous reports suggested that chlorogenic, coumaric, ferulic, and caffeic acids, alkaloids, aromatic compounds, and lard reaction products such as melanoidins were the main bioactive constituents in coffee brews (Muñoz, Hernández, Tolosa, Burillo, & Olalla Herrera, 2020). However, this depends mainly on the species and their origin (Hečimović et al., 2011). It is worth noting that while phenolic acids and their derivatives were the main phenolics in coffee beans, several flavonoids were also identified, although in low concentrations consistent with previous results (Król et al., 2020). ...
... It can be pointed out from the above results that light and medium roasting conditions are more favourable for preserving bioactive composition during coffee roasting as phenolic acids, particularly chlorogenic acids, are more prevalent under milder processing conditions (Hečimović et al., 2011). However, in baobab brews, TPC, TFC, and individual phenolic contents were significantly higher in medium, city, and French brews than in the light samples. ...
Article
The seeds of Africa's majestic baobab are often discarded or poorly utilized. Few studies explored its potential as a coffee substitute, while the key volatile compounds are still unknown. These compounds were hypothesized to be responsible for baobab's sensory acceptance. In this study, the physicochemical, sensory, and key volatile composition of brews from coffee beans and baobab seeds subjected to different roasting conditions were reported. Roasting increases pH while reducing acidity, total soluble solids, lightness (L*), redness/greenness (a*), and yellowness/blueness (b*) in coffee and baobab brews. Phenolic contents increased significantly (p < 0.05) with increased roasting intensity in baobab while degrading in coffee. Significant variability of volatile composition existed among coffee and baobab matrices and the roasting conditions. Nevertheless, the presence of several key coffee odorants in baobab from pyrazines, phenols, and furans chemical families, owing to their odour active value ≥1, likely contributed to its sensory acceptance.
... Both market coffees were very similar in terms of caffeine content. The values of the caffeine level obtained in the study are of the same order of magnitude as the data reported in the literature by various authors (dePaula and Farah, 2019; Dias and Benassi, 2015;Hečimović et al., 2011). Often, the caffeine content is given per portion of the infusion (e.g., a cup), which makes it difficult to compare the data. ...
... This strictly corresponds to the alkaloid content in the samples we tested. The geographic origin of coffee, the conditions of its brewing and processing, and the method of preparing the infusion may also have an impact on the caffeine content (Hečimović et al., 2011;McCusker et al., 2003). There is currently no set acceptable daily intake (ADI) value for caffeine, but the dose of ≤2.5 mg/kg body weight/day has been used in risk assessments (Pollard et al., 2015). ...
... The results obtained were lower in comparison to the HPLC results as a consequence of incomplete analyte recovery. A similar tendency was observed by Hečimović et al. (2011) in the case of using chloroform extraction . Moreover, a great variability between the two methods was observed (by 3-75%), which indicates the problem with gaining full effectiveness of the extraction. ...
Article
Background. The aim of the study was to evaluate the caffeine level and antioxidant activity of brews of specialty grade coffee compared to popular coffee brands. Materials and methods. Ten types of coffee were used, including 7 specialty Arabica, 1 Robusta and 2 popular cheap coffee brands. For caffeine determination, HPLC analysis and the spectrophotometric method were used as reference. The total polyphenol content and antioxidant capacity (DPPH and FRAP methods) were evaluated. For two selected high-quality coffees, the influence of the brewing method on the antioxidant activity and caffeine content in the brews was assayed. Results. Regarding the caffeine content, differences between specialty coffee brews and popular products were not found, and an average level amounted to 56 and 40 mg/ml, respectively. In contrast, the antioxidant capacity of specialty coffee brews was significantly higher than for popular ones, independently of the test used. The highest scavenging ability and total phenolic content was found for S3 specialty coffee (46.15% of DPPH inhibition and 58.7 mg GAE/ml, respectively), whereas the lowest was found for popular coffee (about 35% of DPPH inhibition and about 41 mg/GAE/ml). For two selected high-quality coffees, the influence of the brewing method on the antioxidant activity and caffeine content in the brews was tested. It was found that the use of a dripper (overflow brewing method) provides the brew with the best antioxidant properties but with moderate caffeine levels. Conclusion. It was found that ‘specialty’ quality coffees do not differ from popular brands in terms of caffeine content, but significantly outweigh them in terms of antioxidant activity. This property can be beneficial in the case of a high consumption of coffee, due to antiradical protective effects without the risk of caffeine overdose.
... It is consistent with previous research that the decreased tendency of the total content of phenolic compounds is along with the intensification of roasting (Cho et al., 2014;Król et al., 2020;Somporn et al., 2011). Polyphenolic compounds, especially chlorogenic acids in coffee beans, performing highly thermal instability, could be directly decomposed with a temperature higher than 80°C which cause the TPC reduction after intensive roasting (Hecimovic et al., 2011;Król et al., 2020). Partial bound phenolic compounds existing in the plant matrix could be liberated during thermal processing by disrupting cellulose constituents (Cho et al., 2014;Mehari et al., 2020;Somporn et al., 2011). ...
... When it comes to TFC and TCT, comparing to the bound phenolic, the results of free phenolic compounds exhibited a reverse trend that the free TFC and TCT values increased from 0.97 ± 0.01 mg QE/g and 1.87 ± 0.23 mg CE/g to 1.16 ± 0.04 mg QE/g and 5.46 ± 0.21 mg CE/g with significant differences when roasting degree increased. Similar results were observed by Hecimovic et al. (2011), Odzakovic et al. (2016 and Król et al. (2020) that the content of total flavonoids and tannins was directly proportional to the roasting degree. More and more bound phenolic compounds were released by the increasing roasting temperature, which improved the free TFC and TCT while reduced that of the bound reasonably. ...
... Flavan-3-ol is the monomer of condensed tannins which belongs to flavonoids, whereas gallic acid is a component of hydrolyzable tannins belonging to nonflavonoids (Mehari et al., 2020). Thus, various compounds including flavan-3ols complexes, quinolactones, and gallic acids complexes could be formed via the isomerization and polymerization of polyphenolic compounds and interactions with proteins and sugars during thermal processing, which could induce the increase in TPC and TCT (Farah & Donangelo, 2006;Hecimovic et al., 2011;Kim et al., 2011;Król et al., 2020). ...
Article
Full-text available
Phenolic compounds present in coffee beans could generate flavor and bring benefits to health. This study aimed to evaluate the impacts of commercial roasting levels (light, medium, and dark) on phenolic content and antioxidant potential of Arabica coffee beans (Coffea arabica) comprehensively via antioxidant assays. The phenolic compounds in roasted samples were characterized via liquid chromatography–electrospray ionization quadrupole time‐of‐flight mass spectrometry (LC‐ESI‐QTOF‐MS/MS). Furthermore, the coffee volatile compounds were identified and semi‐quantified by headspace/gas chromatography–mass spectrometry (HS‐SPME‐GC‐MS). Generally, for phenolic and antioxidant potential estimation, light roasted samples exhibited the highest TPC (free: 23.97 ± 0.60 mg GAE/g; bound: 19.32 ± 1.29 mg GAE/g), DPPH, and FRAP. The medium roasted beans performed the second high in all assays but the highest ABTS+ radicals scavenging capacity (free: 102.37 ± 8.10 mg TE/g; bound: 69.51 ± 4.20 mg TE/g). Totally, 23 phenolic compounds were tentatively characterized through LC‐ESI‐QTOF‐MS/MS, which is mainly adopted by 15 phenolic acid and 5 other polyphenols. The majority of phenolic compounds were detected in the medium roasted samples, followed by the light. Regarding GC‐MS, a total of 20 volatile compounds were identified and semi‐quantified which exhibited the highest in the dark followed by the medium. Overall, this study confirmed that phenolic compounds in coffee beans would be reduced with intensive roasting, whereas their antioxidant capacity could be maintained or improved. Commercial medium roasted coffee beans exhibit relatively better nutritional value and organoleptic properties. Our results could narrow down previous conflicts and be practical evidence for coffee manufacturing in food industries. Therefore, this research aimed to assess the impact of commercial roasting degrees (light, medium, and dark) on the content and the composition of phenolic and volatile compounds of coffee beans as well as their antioxidant potential. Total phenolic (TPC), flavonoids (TFC), and condensed tannins (TCT) content, reducing powder (RPA), ferric reducing antioxidant potential (FRAP), and ferrous ion chelating activity (FICA), 2,2′‐diphenyl‐1‐picrylhydrazyl (DPPH), 2,2′‐azinobis‐(3‐ethylbenzothiazoline‐6‐sulfonic acid) (ABTS), and hydroxyl radical scavenging activity (·OH‐RSA) were applied to estimate the antioxidant potential of phenolic compounds with the combination of ultraviolet‐visible spectroscopy. Liquid chromatography–electrospray ionization quadrupole time‐of‐flight mass spectrometry (LC‐ESI‐QTOF‐MS/MS) was used for the characterization and identification of phenolic compounds. Furthermore, headspace/gas chromatography–mass spectrometry (HS‐SPME‐GC‐MS) was applied for the identification and quantification of volatile compounds in the roasted coffee beans.
... Kopi mengandung senyawa polifenol antioksidan yang tinggi yang berasal dari asam fenolik seperti kafein, asam klorogenat, kumarin, ferulik dan asam sinapik (Hečimović et al., 2011;Tamilmani, et al., 2015). Kualitas biji kopi dan aktivitas antioksidan ditentukan oleh komposisi polifenol dalam biji kopi (Belay et al., 2009;Hečimović et al., 2011;Tamilmani et al., 2015). ...
... Kopi mengandung senyawa polifenol antioksidan yang tinggi yang berasal dari asam fenolik seperti kafein, asam klorogenat, kumarin, ferulik dan asam sinapik (Hečimović et al., 2011;Tamilmani, et al., 2015). Kualitas biji kopi dan aktivitas antioksidan ditentukan oleh komposisi polifenol dalam biji kopi (Belay et al., 2009;Hečimović et al., 2011;Tamilmani et al., 2015). Komposisi polifenol dipengaruhi oleh jenis, cara pengolahan biji kopi dan letak geografis. ...
... Proses sangrai umumnya dilakukan pada suhu 200-240 o C dan menghasilkan biji kopi yang berwarna cokelat disertai pelepasan aroma yang khas. Selama proses sangrai terjadi perubahan komposisi senyawa bioaktif, termasuk senyawa polifenol yang berperan sebagai antioksida akibat terdegradasinya asam klorogenat, kafein, trigonelin dan senyawa bioaktif lainnya (Hečimović et al., 2011). Semakin tinggi suhu proses sangrai, aktivitas antioksidannya semakin berkurang (Cammerer et al., 2006). ...
Article
Coffee bean are rich of secondary metabolits that able to inhibit free radical compounds. This antioxidant activity may reduce many diseases correlated with it. The aims of this study were to determined the phytochemical content and antioxidant activity of roasted coffee bean from Wamena and Moenemani regency, Papua. Roasted coffee beans were extracted by maceration for 24 hr with methanol. Harborne standard method was used for the phytochemical analysis and DPPH assay was used to determine the antioxidant activity. IC50 was measured by spectrophotometric assay using spectrophotometer Uv-Vis at 517 nm wavelenghth. Result showed that both Arabica roasted coffee beans from Wamena and Moanemany had the capacity to inhibit free radical at 61,71% and 69,7% with IC50 at 107,97 and 100,91 ppm, respectively . Phytochemical investigation revealed that the bioactive compounds from Moanemani and Wamena coffee beans were similar, which composed of alkaloids, flavonoids, terpenoids, saponins, and tanins. In conclusion, the methanolic extract of roasted Arabica coffee beans from Wamena and Moanemani can be used as the source of natural antioxidant.Keywords: Arabica roasted coffee beans; phytochemical; antioxidant; DPPH method.
... In general, during the roasting process, a substantial decrease in the caffeine concentrations of the sample coffee beans was found. Similar work was also carried out by certain researchers [113,114,115]. Sidama coffee lost up to 60% of its caffeine content, while Yirgacheffe and Harar coffees lost an average of 53% and 40% of their caffeine content, respectively. ...
... Caffeine is moderately heat-stable during coffee roasting. However, due to sublimation loss at higher roast temperatures, caffeine concentration in dark-roast coffee tends to be lower than in lighter roasts [113]. ...
... In general, during the roasting process, a substantial decrease in the caffeine concentrations of the sample coffee beans was found. Similar work was also carried out by certain researchers [113][114][115]. Sidama coffee lost up to 60% of its caffeine content, while Yirgacheffe and Harar coffees lost an average of 53% and 40% of their caffeine content, respectively. ...
Article
Full-text available
Coffee is consumed not just for its flavor, but also for its health advantages. The quality of coffee beverages is affected by a number of elements and a series of processes, including: the environment, cultivation, post-harvest, fermentation, storage, roasting, and brewing to produce a cup of coffee. The chemical components of coffee beans alter throughout this procedure. The purpose of this article is to present information about changes in chemical components and bioactive compounds in coffee during preharvest and postharvest. The selection of the appropriate cherry maturity level is the first step in the coffee manufacturing process. The coffee cherry has specific flavor-precursor components and other chemical components that become raw materials in the fermentation process. During the fermentation process, there are not many changes in the phenolic or other bioactive components of coffee. Metabolites fermented by microbes diffuse into the seeds, which improves their quality. A germination process occurs during wet processing, which increases the quantity of amino acids, while the dry process induces an increase in non-protein amino acid γ-aminobutyric acid (GABA). In the roasting process, there is a change in the aroma precursors from the phenolic compounds, especially chlorogenic acid, amino acids, and sugars found in coffee beans, to produce a distinctive coffee taste.
... Moreover, the increase in the brewing time for the infusion method caused a decrease in the total phenolic contents, and also the highest amounts for Colombia, Peru, and Brazil coffees were obtained after infusion for 1 min. It was reported that high temperature (> 80 °C) can cause decomposition of phenolic compounds, which are highly thermolabile compounds [26]; Especially, chlorogenic acids were degraded to hydroxycinnamates and quinic acid during the roasting process [14]. The reduction in the total phenolic contents of coffee brews may probably be caused by hydrolysis of chlorogenic acids during infusion. ...
... mg TAE/g [25]. According to the study of Hečimović et al. [26], the roasting degree caused differences in the tannin contents of coffee. In the current study, coffee brews obtained with Peru beans had higher tannin content in comparison to Colombia and Brazil. ...
Article
Full-text available
This study was performed to compare the effects of brewing method (decoction and infusion), time (1–5 min), and also origin of coffee beans on antioxidant activity using DPPH, ABTS, FRAP methods, caffeine content and phenolic compounds by HPLC. Principal component analysis was used to determine the effective treatments on bioactive properties. Coffee brews prepared with decoction method contained higher contents of total phenolic, total flavonoid, and total tannin as compared to the infusion method. On the other hand, antioxidant activity of coffee brews by DPPH and ABTS radical methods showed an opposite trend. Similar to antioxidant activity, infusion method was better to obtain higher amounts of catechin, caffeic acid and quercetin in coffee brews. The brewing method did not cause a significant difference in caffeine and rutin contents. Brewing time had major effects on several bioactive compounds, and their amounts showed an increase after extending the time of brewing.
... It is a natural methylxanthine alkaloid found in more than 60 plants, including coffee beans, tea leaves, cola nuts, and cocoa pods [11]. The quantity of CAF is greatly affected by the roasting level and decreases with the intensity of roasting [12,13]. ...
... CAF content was similar in both the COL and NIC coffees but increased with roasting time. Lightly roasted coffees contain more CAF, which decreases with more intense roasting due to the release of CAF from the cell walls of the roasted beans and/or as the beans lose weight from the degradation of other organic substances [13,27]. Similarly, CAF content varies substantially depending on the origin of the coffee and the method of roasting and beverage preparation. ...
Article
Full-text available
The aim of this study was to determine the effect of roasting on the contents of polyphenols (PPH), acrylamide (AA), and caffeine (CAF) and to analyze heavy metals in specialty coffee beans from Colombia (COL) and Nicaragua (NIC). Samples of NIC were naturally processed and COL was fermented anaerobically. Green beans from COL (COL-GR) and NIC (NIC-GR) were roasted at two levels, light roasting (COL-LIGHT and NIC-LIGHT) and darker roasting (COL-DARK and NIC-DARK), at final temperatures of 210 °C (10 min) and 215 °C (12 min), respectively. Quantitative analyses of PPH identified caffeoylquinic acids (CQA), feruloylquinic acids, and dicaffeoylquinic acids. Isomer 5-CQA was present at the highest levels and reached 60.8 and 57.7% in COL-GR and NIC-GR, 23.4 and 29.3% in COL-LIGHT and NIC-LIGHT, and 18 and 24.2% in COL-DARK and NIC-DARK, respectively, of the total PPH. The total PPH contents were highest in COL-GR (59.76 mg/g dry matter, DM). Roasting affected the contents of PPH, CAF, and AA (p < 0.001, p < 0.011 and p < 0.001, respectively). Nickel and cadmium contents were significantly higher in the COL-GR than in the NIC-GR beans. Darker roasting decreased AA content, but light roasting maintained similar amounts of CAF and total PPH.
... The worldwide importance of coffee is mainly due to the unique properties of coffee brews. Coffee beverages are known for their stimulating and refreshing effects on humans, their antioxidant activity and unique, pleasant flavour [2]. ...
... Due to the complex chemical composition of green coffee beans, an intricate set of concurring chemical reactions lead to the formation and decomposition of many bioactive compounds. As a result, changes in the physical and sensory properties as well as the bioactive compounds profile occur [2,4,5]. The roasting process is responsible for the degradation of polysaccharides [6] and phenolic compounds due to their low thermal stability [7], and the formation of Maillard reaction products that darken the colour of the bean and contribute to its overall antioxidant activity [8]. ...
Article
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The chemical composition of green coffee beans depends on the number of parameters, such as coffee cherry processing methods, used. The quality of roasted coffee is related to the certain substances that developed during the roasting process and that are responsible for the organoleptic properties. The main objective of this study was an investigation of the thermal behaviour and the fatty acids profile of green and roasted Brazilian Santos coffee beans. The glass transition temperature was measured using modulated differential scanning calorimetry (MDSC). The thermal behaviour of coffee samples was evaluated by means of thermogravimetry (TG) and first derivative thermogravimetry (DTG). The oxidative stability and kinetic parameters were characterized with the use of differential scanning calorimetry (DSC). According to the TG and DTG curves, coffee samples showed different behaviour of thermal degradation in the atmosphere of oxygen and nitrogen. Our research shows that the thermal properties and fatty acids profile did not change during the roasting process.
... TPC and TFC of light roasted beans from both soxhlet and infusion extractions were found to be significantly (p < 0.05) the highest, and the TPC and TFC of coffee beans have declined with the increasing roasting degrees. The results obtained were literally in accordance with the fact that phenolic compounds are highly thermolabile and are readily decomposed under the influence of high temperature (above 80 °C) [29]. Green beans extracts from both soxhlet and infusion methods possessed high phenolic content. ...
... It was discovered that roasting process affects both flavonoid and phenolic content, but light roasted beans preserved most of these valuable compounds. The results attained in the present study were in agreement with the study conducted by Hečimović et al. [29] that compared the effects of coffee varieties and roasting degrees on polyphenols content, which concluded that TPC and TFC were the highest in coffees roasted at light and medium roasting conditions. The DPPH scavenging assay showed a comparable result with ascorbic acid that all Coffea liberica beans extracts have demonstrated a higher antioxidant activity than that of ascorbic acid. ...
Article
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Coffee consumption has been associated with many health benefits, that the naturally occurring phytochemicals in coffee are believed to have anti-cancer properties. Unfortunately, established phytochemicals study are scarce. Hence, the present study aimed to evaluate the antioxidant and anti-angiogenic activities of Coffea liberica as influenced by different roasting degrees. Green and roasted (light, medium, dark) Coffea liberica beans were extracted using soxhlet extraction and cold infusion. Preliminary screening showed that roasting did not affect the phytochemicals qualitatively. Light roasted coffee infusion extract had the highest total phenolic content (366.72 ± 1.54 µg/mL) and percentage scavenging; light roasted coffee soxhlet extract had the highest total flavonoid content (324.67 ± 1.19 µg/mL), and green beans soxhlet extract exhibited the highest anti-angiogenic activity with an average score of 1.33. In conclusion, these findings endorse further investigations to determine the active principles and their mode of actions for potential preventative therapies against angiogenesis-related diseases.
... The contents of caffeine in arabica CS (0.80 ± 0.002 g/100 g) and CS pellets (0.76 ± 0.01 g/100 g) were comparable whereas canephora CS had higher values (0.86 ± 0.03 g/100 g). The caffeine content in coffee is approximately 1-2 g/100 g with the values being influenced by the degree of roasting and species [71]. Additionally, Coffea canephora coffee beans were found to contain more caffeine than Coffea arabica, with caffeine contents decreasing with increasing degree of roast [70,71]. ...
... The caffeine content in coffee is approximately 1-2 g/100 g with the values being influenced by the degree of roasting and species [71]. Additionally, Coffea canephora coffee beans were found to contain more caffeine than Coffea arabica, with caffeine contents decreasing with increasing degree of roast [70,71]. Thus, the caffeine contents of CS are lower as compared to coffee beans. ...
Article
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Coffee silver skin is produced in large amounts as a by-product during the coffee roasting process. In this study, coffee silver skin of the species Coffea arabica L. and Coffea canephora Pierre ex A. Froehner as well as silver skin pellets produced in the coffee industry were characterized with respect to both nutritional value and potential heat-induced contaminants. Enzymatic-gravimetric/chromatographic determination of the dietary fiber content showed values ranging from 59 to 67 g/100 g with a comparably high portion of soluble fiber, whereas low molecular weight soluble fiber was not detected. Compositional and methylation analysis indicated the presence of cellulose and xylans in the insoluble dietary fiber fraction, whereas pectic polysaccharides dominate the soluble dietary fiber fraction. The protein content as determined by the Kjeldahl method was in the range of 18 to 22 g/100 g, and all essential amino acids were present in coffee silver skin; whereas fat contents were low, high ash contents were determined. Elemental analysis by inductively coupled plasma mass spectrometry (ICP-MS) showed the presence of macroelements in large amounts, whereas toxic mineral elements were only detected in trace amounts or being absent. Acrylamide was quantified with levels of 24–161 µg/kg. Although 5-hydroxymethylfurfural was detected, its concentration was below the limit of determination. Furfuryl alcohol was not detected.
... Coffee contains mineral intake, including providing up to 8% of the daily requirement of Cr, and is an important source of Mg, which is 63.7 mg/cup (100 mL). Coffee is also an important source of polyphenols, including caffeine, chlorogenic acid, coumaric acid, ferulic acid, and synaptic acid [1]. ...
Conference Paper
Coffee is a very promising commodity. Besides being consumed as a famous drink with high caffeine content, coffee also has many compounds that can act as antioxidants. One part of the coffee plant that acts as an antioxidant is the leaf. Robusta coffee (Coffea canephora) is one species of the genus Coffee. The aims of this study were to determined the phytochemical and antioxidant activity on Robusta coffee leaves as seen based on differences in the ecology of the highlands on Alor Island – East Nusa Tenggara. Robusta coffee leaves were extracted by maceration for 24 hours with methanol. DPPH assay was used to determine the antioxidant activity. The result showed that Robusta coffee leaves from Alor Island give the antioxidant activity with IC50 56,337 ppm. Phytochemical analysis revealed that the bioactive compound from Robusta coffee leaves is composed of alkaloids, flavonoids, terpenoids, and phenolic.
... In their study, higher antioxidant activity evaluated using FRAP and ABTS methods was found for roasted bean infusions as compared with infusions prepared from green coffee beans. Hečimović et al. [24] also confirmed our observations, that both factors-coffee variety and the roasting degree-affect the antioxidant activity. In their study, similarly to ours, infusions prepared from unroasted beans showed a lower potential than extracts from roasted beans. ...
Article
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Coffee is one of the most often consumed beverages almost all over the world. The multiplicity of beans, as well as the methods and parameters used to brew, encourages the optimization of the brewing process. The study aimed to analyze the effect of roasting beans, the brewing technique, and its parameters (time and water temperature) on antioxidant activity (determined using several in vitro methods), total polyphenols, flavonoids, and caffeine content. The infusions of unroasted and roasted Arabica beans from Brazil, Colombia, India, Peru, and Rwanda were analyzed. In general, infusions prepared from roasted beans had higher antioxidant activity and the content of above-mentioned compounds. The hot brew method was used to obtain infusions with a higher antioxidant activity, while the cold brew with higher caffeine content. The phenolic compound content in infusions prepared using both techniques depended on the roasting process. Moreover, the bean’s origin, roasting process, and brewing technique had a significant effect on the tested properties, in contrary to brewing time and water temperature (below and above 90 °C), which had less impact. The results confirm the importance of coffee brewing optimization.
... Popularitas dan daya tarik kopi di seluruh dunia berasal dari cita rasanya yang unik, sehingga menjadi salah-satu minuman yang paling diinginkan dan sering dikonsumsi. Lebih lanjut, Hečimović et al. (2011) menyatakan bahwa kopi memiliki kepentingan sejarah, budaya, sosial dan ekonomi yang kuat. ...
... Coffea robusta. Traditionally, C. canephora, primarily from African origins, was the dominant component in most coffee blends available in Belgium/Luxemburg, France, Portugal, and the UK, while most blends available in Scandinavia, Austria, Switzerland, Germany, Italy, and Spain incorporated a much higher proportion of C. Arabica [2]. ...
Article
Coffea is considered as a large genus (with more than 90 species) of flowering plants belongs in the family Rubiaceae. However, coffee ranks as one of the major commodity crops in the world and is the essential export product of some countries. Moreover, coffee beans found on the market are produced from two different species of the Coffea genus such as Coffea arabica and Coffea canephora syn. Coffea robusta. Nowadays, due to its pleasant taste, aroma, stimulant effect, and health benefits, coffee is one among the most widely consumed beverages throughout the world includes Rwanda country. Both species of coffee present a rich source of biologically active compounds such as caffeine. Caffeine is defined as a xanthine alkaloid compound that acts as a stimulant in humans. It is normally found in the leaves and beans of the coffee plant. In addition to that, caffeine is widely used to enhance alertness and improve performance as it acts as psychostimulant. Consequently, the strong pharmacological effects of caffeine have led to consumer demand for caffeine-free coffee beverages. Due to the high consumption rate of caffeine and its potential physiological effects, both health professionals and consumers need to know the exact caffeine content in food. The way to assess their content to find a more precise relationship between the amounts of consumed caffeine and it's physiological effects ,it is therefore important to precisely determine the caffeine content in different coffee types. The research's objective was to determine Caffeine content in coffee growing in different Regions of Rwanda in order to identify the coffee region that contains the highest amount of caffeine. The Coffee samples presenting four growing regions of Rwanda have been taken from NAEB and brought to the College of Science and Technology (CST) chemistry department Laboratory. Quantitative analysis of Caffeine was performed by using a UV-Visible spectrometer (UV-Vis spectrometer) at 650 nm. The results showed that the highest caffeine concentration was obtained from coffee grown in the Western province region presented by GASHONGA Coffee (RUSIZI District) with 9.4±1.962 ppm of caffeine concentration. This was followed by coffee grown in the Southern province region presented by MARABA Coffee (HUYE District) which contains 7.5333±0.8885 ppm of caffeine concentration. The third coffee in caffeine concentration was MUSASA Coffee (GAKENKE District) grown in the Northern Province region which contains 3.8±1.270ppm of caffeine. The last caffeine concentration was obtained in coffee from Eastern province, presented by HUMURE Coffee (GATSIBO District) with 3.2667± 1.578ppm of caffeine Western province region presented by GASHONGA Coffee (RUSIZI district).
... However, there was variation in the activity depending on the extraction temperature. In a previous study, the highest polyphenolic content appeared in both light and medium roasting conditions (28). The highest antioxidant activity was found in the medium-roasted coffee by the ABTS radical scavenging, whereas the maximum activity was found in the light-roasted coffee by the DPPH radical scavenging (30). ...
Article
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Ultrasound-assisted extraction (UAE) is an effective tool for the extraction of natural antioxidants. Thus, differentially roasted Arabica-coffee beans known as light (LC), medium (MC), and dark coffee (DC) were prepared and extracted under the influence of UAE. Following that, they were examined specifically on theirs physicochemical and biological characteristics: nutritional values, pH, °Brix, antioxidant activities, polyphenol content, caffeine, and chlorogenic-acid levels. Various parameters, such as extraction temperatures (20, 40, and 80°C) and extraction time periods (5, 10, and 20 min), were examined. DC extract was less acidic than those on MC and LC extracts. LC showed higher moisture content than the MC and DC (1.56, 1.3, and 0.92%, respectively). MC displayed the highest polyphenol content and potent antioxidant activity. Caffeine and chlorogenic acid contents trend to decrease during roasting. The maximum caffeine level was found in MC at 80°C for 5 min (27.65 mg/g extract). The highest chlorogenic acid content was in LC at 80°C for 10 min (16.67 mg/g extract). The caffeine and chlorogenic acid contents were related to the polyphenol content and depended on the roasting and extraction conditions. These results suggest that the UAE at various temperature and extraction time period may alter the physicochemical and biological characteristics of different coffee roasts.
... This is because naturally, Robusta coffee has 40-50% higher caffeine than Arabica (Song et al., 2018). The longer it is roasted the caffeine content increases, but then the caffeine decreases due to the sublimation process (Hečimović et al., 2011). Robusta coffee chlorogenic acid is higher (6.64 g/100g) than Arabica (4.37 g/100g). ...
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Coffee is one of Indonesia's leading plantation commodities, which is ranked third in the world. Currently, coffee-based drinks have become a lifestyle in the millennial era. The high interest in coffee affects the economy of the community. Various efforts were made to further encourage the level of coffee consumption, especially in the form of beverages. On the other hand, it is necessary to diversify the product by highlighting the technology side, such as making effervescent which is easier, more practical, and can be enjoyed directly with cold water. Effervescent is known as a product that can cause gas bubbles as a result of the reaction of acids and bases when dissolved in water. The resulting gas bubbles are carbon dioxide which gives a sparkling effect (a taste sensation like sparkling water). The use of coffee as an effervescent raw material is related to its taste, bioactive compounds, and antioxidants. Coffee extract powder can be made from robusta and arabica coffee roasted at medium level with low-temperature crystallization, spray drying, freeze drying, and vacuum drying. Other materials that need to be added such as acid sources, bases, fillers, and binders can affect the effervescent characteristics such as tablet hardness, moisture content, hygroscopicity, and dissolution time. The recommended composition is citric acid, sodium bicarbonate, dextrin, and PVP (Polyvinilpyrrolydone).
... As expected, no significant changes in the concentration of caffeine were recorded (Table 5). This might be justified by the loss of water and organic matter and the sublimation of a fraction of caffeine during roasting (Illy & Viani, 2005); reversely, concentration defers among different coffee lots due to variety and origin variability (He cimovi c et al., 2011). ...
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Specialty Coffee (SC) has been showing an increasing interest from the consumers which appreciate its traceability and the peculiar flavours from each single Origin. Additionally, the processes to which coffee fruits underwent to get green coffee characterize the beans in terms of macromolecules acting as substrates during the roasting. This work evaluates via sensory analysed eight SC, roasted at light, medium, and dark level, submitted to Italian espresso extraction, to assess how different roasting levels exalt the expected cup profile obtained by the suppliers via cupping in origin countries. Finally, roasted beans were characterized for physicochemical features (pH, titratable acidity, caffeine, melanoidins, polyphenols and acrylamide). Sensory analysis demonstrated that the intermediate roasting level and espresso extraction matches better attributes from in‐Origin cupping. Melanoidins (mmol/g coffee d.b.) was able to discriminate among roasting levels (light 0,12±0,01; medium 0,13±0,003; dark 0,14±0,01; α=0,05). Acrylamide analyses assured the compliance with the food safety standard (light 301,9±37,2 ppb; medium 126,1±19ppb; dark 107,9±22,5ppb). Physicochemical features were able to cluster samples from different Origin within the same roasting level (α=0,05). Results shown correlations (α=0,01) between sensory analysis and physicochemical values: direct for caffeine and astringency, reverse for perceived acidity in relation to astringency, roasted, dried fruits and nuts notes.
... Coffee is one of the most popular beverages in the world that are commercially cultivated [22]. They are considered a rich source of biologically active compounds, especially polyphenols [23]. Its seeds (i.e., coffee beans) contain two types of alkaloids, caffeine and trigonelline, as major components. ...
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Silver nanoparticles (AgNPs) were extensively used in different fields worldwide. There is a continued increase in their productions to fulfill various uses. Biological and chemical AgNP syntheses were the most popular mechanisms in this field. Agrowastes are rich in proteins, phenolics, and flavonoids that could act as bioreductant agents in AgNP biological synthesis. The present study was aimed at synthesizing AgNPs via chemical and biological methods using trisodium citrate, pomegranate fruit peel, and coffee ground waste extracts. Moreover, silver nanoparticles were monitored by UV-vis spectroscopy and characterized using zeta potential, size distribution mean, scanning electron microscope (SEM), X-ray diffractometer (XRD), and Fourier transforms infrared spectroscopy (FTIR). Four pathogenic bacterial strains (Enterobacter aerogenes, Klebsiella pneumoniae, Pseudomonas aeruginosa, and MRSA) were used to assess the antimicrobial effect of the synthesized AgNPs (2, 4, and 8 mg/ml). Results report the successful formation of silver nanoparticles chemically (AgNPs_Chem) and biologically by using pomegranate peel extract (AgNPs_PPE) and coffee ground waste extract (AgNPs_CE) due to the change of color to dark brown that is confirmed by UV-vis sharp absorption spectra at specific wavelengths. Characterization using SEM and XRD revealed their crystalline shape with a mean size of AgNPs_Chem=62.75, AgNPs_CE=273.7 nm, and AgNPs_PPE=591.9 nm. AgNPs_Chem show higher negativity of zeta potential (−46.7 mV) than AgNPs_CE (−12.6 mV), followed by AgNPs_PPE (−7.98 mV), which had the least stability. All the synthesized AgNPs show antimicrobial potential on all selected strains. However, 8 mg/ml shows the most effective concentration and has more efficiency on K. pneumoniae than others. Overall, the results highlight that the use of agrowastes could be an ecofriendly way to synthesize AgNPs biologically that have the same antimicrobial effect as the chemically synthesized AgNPs.
... A few studies reported a higher CC in brewed coffee made with medium roast coffees compared to those made with medium-dark roast which was in accordance with our study. [51,52] Others reported that, since caffeine was thermostable, it was not affected by roasting. [53] A third group even reported lower CC in light roasted coffee compared to darker roasted. ...
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Objectives: The global population’s primary intake of caffeine comes from the consumption of coffee. Arabic coffee is traditionally brewed and served using a unique process. The objective of this study was to examine the plausibility of two widespread myths regarding Arabic coffee; that the longer the cooking time, and/or the more roasted the coffee, the higher is the amount of caffeine extracted per kilo‑gram of raw coffee (CE). Materials and Methods: A total of 12 different samples of traditionally brewed Arabic coffee (with correction of lost volume due to evaporation) were directly analyzed for their caffeine concentration using the ultra‑high performance liquid chromatography. The amount of caffeine extracted per kilogram of raw coffee (CE) where then calculated. Comparisons were then made between the CE from three types of raw coffee beans; Yemeni Bari, Yemeni Kulani, and Ethiopian Harrari. They were each roasted to two different grades (light vs. medium‑dark) and each grade was cooked for a different duration of time (15 min vs. 30 min). Results: The type of coffee bean used was shown to significantly affect the amount of CE from raw coffee (P = 0.011). The highest amount of caffeine was extracted from raw Ethiopian Harrari coffee bean, followed by the Yemeni Kulani bean (P = 0.020 and P = 0.027, respectively). A longer cooking time significantly decreased the amount of CE from raw coffee as compared to a shorter time (P = 0.041). Medium‑dark roasting was observed to cause a slight but nonsignificant decrease in amount of CE compared to light roasting (P = 0.178). Conclusions: The type of coffee bean used in brewing Arabic coffee is the main determinant of the amount of caffeine extracted from raw coffee. Longer cooking time and a darker roast both decrease the amount of extracted caffeine in the final brew, rendering the old myths nonplausible.
... [16] Information in the literature on the total polyphenol content of green coffee beans is generally scarce, although some data is available mainly for roasted [23] and soluble [24] coffees. From the limited literature sources, the data reported by Hecimovic et al. [25] on the total soluble polyphenol contents of green beans from two Arabica coffee varieties (Cioccolatato, 21 mg GAE g −1 and Minas, 31 mg GAE g −1 ), lies within the range of concentrations found in this study. The total amount of soluble polyphenols determined in the coffee beans is about 2-4 times higher than that present bound to the cell wall. ...
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The knowledge of the levels of polyphenols present in green coffee beans from different geographical origins is important to identify beans that can provide better coffee quality. The aim of this study was to determine the concentrations of both soluble and cell wall-bound polyphenols in green coffee beans (Coffea arbica L.) from different cultivation regions of Ethiopia. A total of 100 samples were collected from four geographical regions (East, West, South, Northwest) and comprised eight commercial types of coffee (Harar, Jimma, Kaffa, Wollega, Sidama, Yirgacheffe, Finoteselam and Benishangul). The total concentrations of soluble and cell wall-bound poly-phenols and flavonoids in the sample extracts were determined using the Folin-Ciocalteu and aluminum chloride reagent methods, respectively. Qualitative analysis was also performed by using high performance thin layer chromatography (HPTLC). Results revealed that chlorogenic acids as the predominant constituents of the phenolic fraction of the green coffee beans. The total soluble polyphenol, cell wall-bound polyphenol and flavo-noid contents of the green coffee beans were in the range of 21.8-43.6 milligrams of gallic acid equivalents per gram (mg GAE g −1), 8.6-15.3 mg GAE g −1 and 3.3-6.2 milligrams of (+)-catechin equivalents per gram (mg CE g −1) of dry mass, respectively. Cell wall-bound polyphenols were found to contribute significantly (21.0-32.5%) to the total polyphenol contents (TPC) of the green coffee beans. The polyphenol contents of green coffee beans have been found to vary with geographical origins. Harar coffee contained significantly (p < 0.05) lower amounts of both total soluble and cell wall-bound polyphenols than the other regional coffee types. Furthermore, the contribution of cell wall-bound phenolic to the TPC should not be overlooked. ARTICLE HISTORY
... The content of condensed tannins was determined as reported by Hecimovic et al. [15]. A volume of 500 μL of methanolic extract (80%, v/v) of the seed oils was added with 3 mL of butanol-HCl (95:5, v/v) and 100 μL of the ferric reagent (2% ferric ammonium sulfate in 2 M HCl). ...
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Cucurbita species are delicious, nutritious, and delightful products. Cucurbita seeds remain in large quantities as a waste product that could be valorized since they are excellent sources of oil. The aim of this study was to compare the seed oil of two Cucurbita species ( Cucurbita pepo and Cucurbita moschata ) harvested in Bejaia (Algeria). The oil quality was evaluated by the determination of some physicochemical parameters, and the content of phenolic compounds. The antiradical capacity of the antioxidants present in the oils was also assessed using two methods. The oil yield was 42.85% and 40.47% from the seeds of Cucurbita pepo and Cucurbita moschata , respectively. The determined physicochemical parameters were close to those defined by the international standards. The phenolic contents of the methanolic extracts of both oils were 5.53 and 4.45 mg GAE/100 g for Cucurbita moschata and Cucurbita pepo , respectively. The best anti-DPPH power was attributed to the oil of Cucurbita moschata (44.7%), while the methanolic extract of the seed oil of Cucurbita pepo showed the highest percentage (41.02%) of the ABTS•+ radical inhibition. By this study we confirmed that the Cucurbita seeds oil are highly nutritious and offer some medicinal benefits.
... The investigation of different sources of coffee beans under different roasting degrees showed that the caffeine slightly increased after roasting, showing a similar tendency to that reported in Hecimovic et al. [41], Moon et al. [4], and Ludwig et al. [42] ( Figure 1A). However, the content of chlorogenic acid showed the opposite trend: with a higher roasting degree, the chlorogenic acid content decreased ( Figure 1B), similar to Moon et al. [4] and Ludwig et al. [42]. ...
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Coffee is one of the main economic crops in the world and is now widely grown throughout Taiwan. The process of roasting coffee begins with the heating and smooth expansion of raw beans, which leads to changes in appearance and color while affecting the flavor and taste of coffee. So far, most coffee manufacturers have used visual inspection or colorimeter methods to identify differences in coffee quality. Moreover, there is no literature discussing the correlation of roasted bean color with caffeine and chlorogenic acid content. Therefore, the purpose of this experiment was to analyze the chlorogenic acid and caffeine content and their correlation with bean color under different roasting degrees and from different sources to establish basic data for the rapid identification of coffee quality in the future. In this experiment, the coffee Coffea arabica typica from Dongshan, Gukeng, and Sumatra’s Indonesian rainforest was used, and the beans were roasted into four degrees: raw bean, light, medium, and dark roast, to investigate the appearance of the coffee beans and its correlation with caffeine and chlorogenic acid content. The results showed that with a higher roasting degree, caffeine content increased gradually, except for Indonesian beans, but the chlorogenic acid content in all samples showed a declining trend with the increase in roasting degree. The correlation between the chlorogenic acid content and the color space value of the coffee bean color shows that L*, a*, and h° in both ground and unground coffee are highly correlated. The C* value of the ground and unground coffee showed a correlation coefficient of r = 0.159 ns and 0.299 ns, respectively. The correlation between the caffeine content and the color space value of the unground coffee bean shows that the a*, b*, and C* value is highly correlated with the caffeine content. The color space values of ground coffee beans show no correlation with caffeine.
... The applicant determined the concentrations of total polyphenols, tannins, chlorogenic acid, caffeine, oxalic acid and catechol in the NF (Table 7). The reported values in the NF are lower or comparable to the occurrence levels of these compounds in other foodstuffs (Charrier et al., 2002;He cimovi c et al., 2011;Kopjar et al., 2015;Kr ol et al., 2019). The safety of caffeine has been previously assessed by EFSA (EFSA NDA Panel, 2015) and it was concluded that the estimated habitual intake of caffeine from all sources, i.e. 400 mg/day for adults other than pregnant and lactating women, did not raise safety concerns. ...
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Abstract Following a request from the European Commission, the EFSA Panel on Nutrition, Novel Foods and Food Allergens (NDA) was asked to deliver an opinion on dried coffee husk (cascara) from Coffea arabica L. as a novel food (NF) pursuant to Regulation (EU) 2015/2283. The NF comprises the skin (exocarp), pulp (mesocarp), mucilage (pectin), parchment (endocarp) and a portion of the silver skin of the coffee fruit, and consists mainly of digestible carbohydrates, dietary fibre and water. The Panel considers that there are no safety concerns regarding the stability of the NF if the NF complies with the proposed specification limits during its entire shelf‐life. The NF as such will not be consumed, instead, beverages produced with the infusion of the NF in water will be available to consumers. Considering an 100% extraction of caffeine from the NF to the beverage, the specification limit set for caffeine and the proposed use levels, the maximum concentration of caffeine in infusions produced using the NF could be up to 600 mg/L of drink, a concentration comparable to those in coffee beverages. The Panel notes that consumption of beverages produced using the NF will add significantly to the total dietary intake of caffeine of the general population. The consumption of beverages containing caffeine is not recommended for children, pregnant or breast‐feeding women if the caffeine content exceeds 150 mg/L. Taking into account the nature of the NF, the history of use of the NF as food and the proposed uses and use levels, the Panel considers that no toxicological studies are required on the NF. The risk of allergic reactions to the NF is considered low. The Panel concludes that the NF, dried husk of the fruit of Coffea arabica L., is safe under the proposed conditions of use.
... It was stated that medium-roasting at 220 °C for 12 min was the best for coffee beans, above which the antioxidant capacity decreased. In similar studies using different antioxidant capacity methods, Arabica and Robusta coffee beans showed different antioxidant capacity results according to the region where they were grown [35,36]. In the present study, in which similar results were obtained with the literature results, significant differences were found between the antioxidant capacity analysis results according to the coffee species and growing region. ...
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In this study, 7 Arabica (A) and 3 Robusto (R) green coffee beans (GCB) grown in different countries were used. These beans were roasted (RCB), and their coffee silverskin (CSS) produced during roasting was separated. The objective of the study was to determine the total phenolic contents, antioxidant capacities and bioaccessibility of green coffee beans and roasted coffee beans and their coffee silverskin. Three different antioxidant capacity determination methods (ABTS, CUPRAC, FRAP) were used for the determination of the antioxidant capacity; the Folin–Ciocalteau method was employed for the determination of the total phenol content (TPC); and the in-vitro enzymatic extraction method was applied for the determination of the bioaccessibility. The average bioaccessibility values of the TPCs of the GCB and RCB and their coffee silverskin were determined to be 50.05%, 41.45%, and 39.18%, respectively. The highest % bioaccessibiliy results for CSS were determined in the Ethiopia coffee for Arabica species and in the Indonesia-grown coffee for Robusta species. The highest % bioaccessibiliy in the green and roasted coffee beans of Arabica species was determined in the Kenya and Costa Rica coffees, while in Robusta species, it was determined in the India coffee. In general, although the total phenolic content and antioxidant capacity of the coffee beans were found to be higher in the Robusta, the Arabica was found to be higher in terms of % bioaccessibility results. As a result, it is recommended to use GCB and RCB and their CSS in the development of foods and beverages with functional properties.
... Due to high potential health benefits of coffee, coffee is considered as a functio na l beverage (Cheong, et al., 2013;Farah & Lima, 2019). Rich source of bioactive compounds with determined antioxidant capacity of coffee and coffee beverages arising from compounds in both its natural structure and formed after processing (Dybkowska, et al., 2017;Heĉimović , Belščak-Cvitanović , Horžic , & Draženka, 2011;Kitzberger, Scholz, & Benassi, 2014). Diversity of phenolic components provide potential health benefits and phenols play an important role in the formation of coffee flavor. ...
Article
In this study, we determined how roasting levels (light, medium, dark) of Arabica coffee seed and three brewing techniques – decoction methods (Turkish coffee), infusion method (filter coffee) and pressure methods (Espresso) – affect total antioxidant capacity in a cup of coffee beverage by electrochemical methods such as square wave stripping voltammetry (SWSV), differential pulse stripping voltammetry (DPSV) and cyclic voltammetry (CV). The highest antioxidant capacity was found in espresso coffee prepared with light roasted coffee seeds as equivalent the rutin and caffeic at 9.4 ± 0.2 g/L and 19.7 ± 0.7 g/L, respectively with SWSV on a carbon paste electrode (CPE). The antioxidant capacity of coffee beverages was influenced by roasting degree, extraction time and brewing methods significantly. SWSV, DPSV and CV voltammetric methods, fast, reliable, fully validated and without any pretreatment are alternative to conventional analytical methods to evaluation antioxidant values in coffee brews.
... The total polyphenols and total flavonoids contents in the aqueous extracts our sample (EAGTCc) were determined to be 81.67 mg EAG / g and 293.33 mg EQ / g respectively (Table 1). The total polyphenol content (81.67) determined in the aqueous extracts of roasted bean seeds of Coffea c. was seen to be higher than that reported from previous research done on aqueous extracts of roasted beans of coffee robusta (47.85 ± 0.077 mg EAG / g and 7 mg EAG / g to 42.37 mg EAG / g [21,22]. The only research that has reported higher values of total polyphenol content (561.91) ...
... Third, caffeine contents of products were estimated based on standardized values of each type of caffeinated product. Specific products can differ in caffeine content [29,[98][99][100]. Fourth, the questionnaire used in this study was not validated against other measures of caffeine consumption such as plasma caffeine levels or beverage records. ...
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Background Although representative data on caffeine intake in Americans are available, these data do not include US service members (SMs). The few previous investigations in military personnel largely involve convenience samples. This cross-sectional study examined prevalence of caffeine consumers, daily caffeine consumption, and factors associated with caffeine use among United States active duty military service members (SMs). Methods A stratified random sample of SMs were asked to complete an on-line questionnaire on their personal characteristics and consumption of caffeinated products (exclusive of dietary supplements). Eighteen percent ( n = 26,680) of successfully contacted SMs ( n = 146,365) completed the questionnaire. Results Overall, 87% reported consuming caffeinated products ≥1 time/week. Mean ± standard error per-capita consumption (all participants) was 218 ± 2 and 167 ± 3 mg/day for men and women, respectively. Caffeine consumers ingested 243 ± 2 mg/day (251 ± 2 mg/day men, 195 ± 3 mg/day women). On a body-weight basis, men and women consumed respectively similar caffeine amounts (2.93 vs 2.85 mg/day/kg; p = 0.12). Among individual caffeinated products, coffee had the highest use (68%), followed by sodas (42%), teas (29%), energy drinks (29%) and gums/candy/medications (4%). In multivariable logistic regression, characteristics independently associated with caffeine use (≥1 time/week) included female gender, older age, white race/ethnicity, higher body mass index, tobacco use or former use, greater alcohol intake, and higher enlisted or officer rank. Conclusion Compared to National Health and Nutrition Examination Survey data, daily caffeine consumption (mg/day) by SMs was higher, perhaps reflecting higher mental and physical occupational demands on SMs.
... Moreover, trigonelline may indirectly affect hypoglycaemia and hypolipidaemia 14 . Various studies have also indicated that coffee has high concentrations of polyphenols [15][16][17] . The most studied phenolic compounds in coffee are chlorogenic acids. ...
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Currently, there is no technology for the storage of green coffee (GrC), that results in obtaining high-quality roasted coffee (RC). The aim of this study was to evaluate the effects of storage temperature (− 10, 5, 10, 18, 20 °C), postharvest treatment method (natural (N), washed (W)) and type of packaging material (GrainPro (G), jute (J) bags) on the content of chlorogenic acids (CQAs), caffeine and trigonelline as well as the sensory profile of RC from the specialty sector after 12 months of regulated storage. Sensory analysis showed that natural coffees have better taste and higher quality than washed coffees after 12 months of storage. The highest total scores were obtained from the natural coffee stored in a GrainPro bag at − 10 °C followed by coffee stored in a jute bag at 10 °C which had the smallest decreases compared to the initial recorded values. No notable differences among CQA contents in washed coffees stored in either type of bag was seen but natural coffees stored in jute bags at 10 °C and 18 °C displayed the lowest drops relative to the initial values.
... Weight loss of light, medium and dark roasted coffee is 14, 15, and 19%, respectively. Roasting temperature significantly affected weight loss; wheather it is below 200 o C reduces the weight loss faster due to water vapour [29,30]. The lightness intensity of roasted coffee decreased as roasted coffee degree increase as well. ...
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Due to its chemical compounds, coffee has a good taste, pleasant aroma, stimulant effect, and health benefits. Roasting is a critical process to develop a good flavor and cup quality of the coffee brew. This article reviews the coffee chemical reaction proceeds during roasting, evaluates the roasted degree by physic and chemical approach and biochemical changes. The articles were compiled from ScienceDirect, SpringerLink, ResearchGate, and Google Scholar. Out of all of the collected papers, 40 articles were covered in this paper. The initial process of roasting is water content evaporating and continuously is followed by roasting phase including pyrolysis, Maillard reaction and caramelization. The roasted coffee degree is determined by visual, weight loss, acidity, and pop beans sound. The bioactive compounds of coffee such as chlorogenic acids, caffeine, and trigonelline affect brewed coffee’s cup quality. Chlorogenic acid and trigonelline significantly decrease during the roasting process. However, caffein is quite stable during roasting. The roasted coffee performs a function in the consumers’ health since in vitro and in vivo analysis present that bronze roasted espresso has the most powerful activity as anti-inflammatory and antioxidant.
... Therefore, there are a lot of types of coffee beverages such as espresso, cappuccino, Turkish coffee, Ireland coffee, etc. (Desem, 2000). Differences in coffee bean varieties, post-harvest processing conditions (drying, storage, grinding and roasting) and extraction procedures result in a great chemical diversity of the coffee beverages (Hečimović et al., 2011). Recent scientific studies declare considerable evidence of positive health effects of moderate coffee consumption that is 3-4 cups of coffee per day for adults. ...
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Abstract Mırra is a coffee beverage widely consumed in Syria and Turkey, and often produced from roasted and ground coffee beans. Recently, it is prepared from classical instant coffee. In this study, some physicochemical, bioactive and sensory properties of Mırra samples were determined. The average viscosity, °Brix, HMF, total phenolic content, DPPH and ABTS values were 1.36 cP, 3.70, 71.60 mg/L, 3431.55 mg GA eq./L, 6.24 mmol Trol. eq./mL and 35.23 mmol Trol. eq./mL for Mırra samples made by traditional process, and 4.85 cP, 16.36, 303.3 mg/L, 11276.47 mg GA eq./L, 23.89 mmol Trol. eq./mL and 89.70 mmol Trol. eq./mL for Mırra samples made with classic instant coffee, respectively. All Mırra samples also contained high levels of caffeine (1416.93 - 4347.46 mg/L). Chlorogenic acid, 4-O-caffeoylquinic acid and trans-5-O-caffeoylquinic acid were identified in Mırra samples. Total chlorogenic acid contents of Mırra samples were ranged from 1097.85 to 5283.21 mg/L. In all sensory parameters, Mırras with °Brix value over 5.75 had high scores. Results show that Mırra has high antioxidant activity. However, Mırra consumption may have negative health effects for risk groups due to the high caffeine content.
... 2. Using lighter rather than darker roasts in order to ensure pronouncing of the natural flavours of the beans rather than burned aroma and having higher caffeine content, thus higher anti-inflammatory properties (Hečimović et al. 2011). ...
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Caffeination can open tired eyes and enhance focus. Over-caffeination, furthermore, can lead to errors but also to unexpected discoveries that might not have happened without 30 hours of sleep deprivation and 500mg of caffeine in our bodies. This paper presents exactly such a discovery. Upon much staring into our coffee cups, empty anew, the thought struck us: coffee in space. Caffeine may not be the only key. HL Tau, Taurus, bull... Taurine! We grinded some red bourbon for a new pour-over, and developed the new, coffee-groundsbreaking Large Astrocomical Taurine Tester Experiment (LATTE) in just 1/4 of a day. We felt bull-ish about our chances of making a great discovery! We installed LATTE, aimed it at the well-known young star HL Tau, and there it was: an abundance of taurine gas beautifully outlining a cup of cosmic flat white, with the ring structure of HL Tau turning out to be latte art performed by a skillful cosmic barista. The first Robusta discovery of coffee in space. Speaking of coffee, we hope you have a nice hot cup with you, and we encourage you to pun-tinue all the way to the end of this bean-grinding paper.
... Due to the high potential health benefits of coffee, it is considered as a functional beverage (Cheong et al., 2013;Farah & de Paula Lima, 2019). Rich source of bioactive compounds of coffee beverages with antioxidant capacity arising from both its natural structure and formed compounds after processing (Dybkowska et al., 2017;Heĉimović et al., 2011;Kitzberger et al., 2014). The diversity of phenolic components provides potential health benefits, and phenols play an important role in the formation of coffee flavor. ...
... Additionally, while some of these questionnaires inquire about the amount of coffee consumed, they do not consider the type of coffee roast (i.e., light, medium, or dark) [48]. Future studies should consider this as coffee roasting affects caffeine content and, therefore, habitual caffeine intake [49]. ...
Article
Objectives: Caffeine ingestion has well-established ergogenic effects for resistance exercise performance. However, the concept of a minimum effective caffeine dose has not yet been thoroughly examined in the literature. Therefore, this review aimed to explore the minimum ergogenic dose of caffeine on resistance exercise outcomes, such as muscular strength, endurance, and velocity, using a meta-analytic approach. Methods: The search for eligible studies was performed through six databases. The methodological quality of the included studies was assessed using the PEDro checklist. A random-effects meta-analysis was performed for data analysis. Twelve studies that provided caffeine supplementation in doses from 0.9 to 2 mg/kg were included. The studies were classified as being of good or excellent methodological quality. Results: The results revealed an ergogenic effect of caffeine for muscular strength (Cohen d: 0.17; 95% confidence interval [CI], 0.03-0.31; P = 0.02), muscular endurance (Cohen d: 0.21; 95% CI, 0.07-0.35; P = 0.003), and mean velocity (Cohen d: 0.56; 95% CI, 0.12-1.01; P = 0.01). Conclusions: This review demonstrated an ergogenic effect of very low doses of caffeine on resistance exercise performance. The magnitude of these effects was similar to that previously reported with higher caffeine doses. These findings highlight that the minimal ergogenic doses of caffeine are even lower than previously suggested. Such doses of caffeine can be consumed through a regular diet, because for most individuals, a dose of approximately 1 to 2 mg/kg is equivalent to a dose of caffeine in one to two cups of coffee.
Article
Old preserved radish (OPR), a traditional pickled-food of Asia, contains the healthy bioactive compounds, such as phenols and flavonoids. To preserve the phenols levels in radish by thermal treatment, which are decreased due to the polyphenol oxidase activity during long storage. Range of thermal processing evaluated to retain the maximum phenols level in the radish while processed at temperatures of 70 °C, 80 °C and 90 °C for 30 days. In this study, the bioactive compounds and antioxidant activity of thermal processing radish (TPR) were evaluated and compared with commercial products of OPR. Results showed the best condition of thermal processing, 80°C for 30 days, could increase the values of phenols, flavonoids and antioxidant activity that were 2.27, 2.74 and 2.89 times, respectively. When comparing the thermally processed radish or TPR with OPR, TPR has a higher content of phenols and flavonoids, indicating that the thermal processing was effective to increase the content of functional compounds in radish and significantly improved its nutritional values.
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Coffee comprises of numerous bioactive compounds, and has recently been cultivated in temperate regions. We investigated the morphological and phytochemical changes in beans of Coffea arabica cvs. Catuai, Caturra, and Geisha cultivated in the Republic of Korea, at three roasting stages: green bean, 1st crack, and 2nd crack. Morphological changes were estimated by considering the size parameters and weights. Total polyphenols were determined using spectrophotometry, and caffeine and chlorogenic acid were quantified using high-performance liquid chromatography with the appropriate standards. Increased volume and decreased weight were observed in the beans of all three cultivars after roasting. The content of total polyphenols was about 13.74 mg gallic acid equivalent/g dry weight. The analysis of variance revealed that the contents of total polyphenols was insignificant among the cultivars and there was no significant change in the roasting stages. Compared to green bean, decreased contents of caffeine were obtained in the 1st crack and 2nd crack of ‘Catuai’. Chlorogenic acid contents were dramatically decreased in the 1st and 2nd crack of all three cultivars, as compared to green bean. Among the cultivars, ‘Geisha’ showed maximum decrease in chlorogenic acid (about 96%, 1.87 mg/mL) at 2nd crack, compared to the green bean (44.72 mg/mL). These results provide information about the characteristics of various coffee cultivars grown in the Republic of Korea during roasting. © 2022 The Korean Society of Food Science and Nutrition. This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (https://creativecommons.org/lice nses/by-nc/4.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
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Background: Polyphenols and flavonoid-rich foods help in arresting reactive oxygen species development and protecting DNA from oxidative damage. Coffee peel (CP) preparations are consumed as beverages, and their total polyphenol or flavonoid content and their effect on oxidative stress–induced human mesenchymal stem cells (hMSCs) are poorly understood. Method: We prepared hot water extracts of CP (CPE) and quantified the amount of total polyphenol and flavonoid using HPLC analysis. In addition, CPE have been studied for their α-amylase inhibitory effect and beneficial effects in oxidative stress–induced hMSCs. Results: The obtained results show that the availability of chlorogenic acid, vanillin, and salicylic acid levels in CPE is more favorable for enhancing cell growth, nuclear integrity, and mitochondrial efficiency which is confirmed by propidium iodide staining and JC-1 staining. CPE treatment to hMSCs for 48 h reduced oxidative stress by decreasing mRNA expression levels of LPO and NOX-4 and in increasing antioxidant CYP1A, GSH, GSK-3β, and GPX mRNA expressions. Decreased pro-inflammatory (TNF-α, NF-κβ, IL-1β, TLR-4) and increased tumor suppressor genes (except Bcl-2) such as Cdkn2A, p53 expressions have been observed. Conclusions: The availability of CGA in CPs effectively reduced mitochondrial oxidative stress, reduced pro-inflammatory cytokines, and increased tumor suppressor genes.
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This study evaluated the effects of high temperature (100 & 180 °C), irradiation of gamma (10 & 20 kGy), and microwave (100 & 180 W) on the antioxidant activity of the ethanolic (96% w/v) extract of Avicennia marina (A. marina) leaves, as well as the soybean oil containing different concentrations of this extract by DPPH˙ radical inhibition, β-carotene bleaching assay, ferric reducing power (FRP), and the total phenolic content. Statistical results showed that the antioxidant activity of the extract decreased by increasing the temperature from 100 to 180 °C in comparison with the control sample (without any extract). On the other hand, gamma irradiation increased the phenolic compounds and the antioxidant power of the extract by increasing the dose from 10 to 20 kGy. Based on the findings, the highest antioxidant activity was related to the extract treated with microwave irradiation (180 W). The EC50 value of the DPPH• radical inhibitory test and FRP were also better than control samples in the treated samples. Simultaneously, the presence of the A. marina leaf extract could lead to a decrease in the oxidation rate of crude soybean oil containing this extract during the preservation processes (e.g., high temperature, gamma, and microwave irradiations) of foodstuff.
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Torrefaction of coffee beans is a practicable way of producing various coffee products. Considering the fact that the variation of atmosphere media in biomass torrefaction results in changes in its characteristics, therefore, it is expected that atmosphere variations during torrefaction of coffee beans would also impact the characteristics and taste of the coffee products. Based on this, the purpose of this study was to determine the effect of atmosphere variations on the temperature and mass of torrefacted coffee beans. The study involved conducting a thermogravimetric test on Arabica coffee beans with atmosphere variations using argon, nitrogen and air at temperature rates of 10 and 20 °C/min. The data obtained were tabulated and statistically analyzed using the Kruskal-Wallis method at a temperature range of ≤250 °C. Results with both temperature rates showed the p values for the temperature were 0.308 and 0.311 while the p values for each coffee mass were 0.000. In conclusion, there was no significant effect of the atmosphere variation on the temperature but had a significant effect on the mass reduction of coffee beans torrefacted in argon, nitrogen and air media.
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Tlie effect of different degrees of roasting on the oxidative reaction of coffee bean oli was studied. The oxidation state of oil fractions extracted from coffee beans having different degrees of roasting were assessed both before and after removal of the lipid-soluble coloured compounds. The stability of coffee oil increased with the degree of roasting, while it decreased as the coloured fractions were removed.
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Different methods are proposed for spectrophotometric analysis of polyphenols in white and red wines. In particular, it is possible to determine different classes of polyphenols: total phenolics (Folin index), total flavonoids, total and free anthocyanins, proanthocyanins, flavans reactive to vanilline and flavans reactive to p-dimethylamino-cinnamaldehyde.
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The aim of this work was to evaluate the effect of processing and roasting on the antioxidant activity of coffee brews. Brews prepared with light, medium and dark roasted coffees were analyzed. The pH, total solids content, polyphenols content, reducing substances and chlorogenic acids content were determined. The antioxidant activity of aqueous extracts, the guaicol decolorizing and the capacity to inhibit lipid peroxidation were also analyzed. The antioxidant activity of coffee brews were concentration-dependent. A progressive antioxidant activity and polyphenols content was observed decreasing with roasting. The light roasted coffee showed the highest antioxidant activity and dark roasted coffee showed the lowest antioxidant activity. The results indicate that the ingestion of coffee brews prepared with light and medium roasted coffees might protect cells from oxidative stress damages.O objetivo deste trabalho foi avaliar o efeito do processamento e grau de torração sobre a atividade antioxidante da bebida de café. Foram analisadas bebidas preparadas com café nos graus de torração claro, médio e escuro. Foram determinados o pH, o conteúdo de sólidos totais, o conteúdo de polifenóis, o conteúdo de substâncias redutoras e o conteúdo de ácidos clorogênicos. Além disto, foram analisadas a atividade antioxidante dos extratos aquosos, a descoloração do guaiacol e a capacidade de inibição da formação de peróxidos lipídicos. A atividade antioxidante mostrou ser dependente da concentração da bebida de café. Foi observada redução progressiva da atividade antioxidante e de compostos fenólicos com o grau de torração. O café submetido à torra clara apresentou atividade antioxidante máxima e o café com maior grau de torra apresentou a menor atividade antioxidante. Os resultados indicam que a ingestão de bebidas preparadas com cafés de torras clara e média pode proteger a célula contra os efeitos do estresse oxidativo.
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The total antioxidant activity of coffee beverages was measured with stabilized radical EPR spectroscopy. Depending on which stabilized radical is used, Fremy's salt (potassium nitrosodisulphonate) or 2,2,6,6-tetramethyl-1-piperidin-1-oxyl (TEMPO) values can differ significantly. For the determination of antioxidant activity of Maillard reaction products in coffee, TEMPO appears to be the better radical marker. Thus the contribution of both main antioxidant active compounds (polyphenols, melanoidins) whose ratio varies with roasting conditions could be estimated. During storage experiments of coffees brews changes in antioxidant action are found to be time dependent. The content of chlorogenic acids increased significantly at higher storage temperatures, probably caused by a release from polymer structures. Additional antioxidant capacity of coffee melanoidins seems to be strongly influenced by atmospheric oxygen. The higher roasted sample is less vulnerable than medium or light roasted coffee. Investigations with model systems showed that among all coffee constituents the carbohydrates are mainly responsible for the formation of oxygen scavenging substances.
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In this research work using UV/vis spectrophotometer the molar decadic absorption coefficients and transitional dipole moment of pure caffeine in water and dichloromethane were obtained at 272 and 274.7 nm. The molar decadic absorption coefficients of caffeine in water and dichloromethane at these wavelengths are 1115 and 1010 m2 mol−1, respectively. The calculated values for the transitional dipole moment of caffeine in water and in dichloromethane are 10.40 × 10−30 and 10.80 × 10−30 C m, respectively. After characterizing caffeine in water and dichloromethane, fast and simple methods were developed that enable to quantify the content of caffeine in coffee beans. The methods helped in extracting caffeine from coffee dissolved in water by dichloromethane, and Gaussian fit was applied to eliminate the possible interference with the caffeine spectra.
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Chlorogenic acid, an ester of caffeic acid and quinic acid, is a major phenolic compound in coffee; daily intake in coffee drinkers is 0.5-1 g. Chlorogenic acid and caffeic acid are antioxidants in vitro and might therefore contribute to the prevention of cardiovascular disease. However, data on the absorption of chlorogenic acid and caffeic acid in humans are lacking. We determined the absorption of chlorogenic acid and caffeic acid in a cross-over study with 4 female and 3 male healthy ileostomy subjects. In such subjects, degradation by the colonic microflora is minimal and absorption can be calculated as the amount ingested minus the amount excreted in ileostomy effluent. The ileostomy subjects ingested 2.8 mmol chlorogenic acid and 2.8 mmol caffeic acid on separate days in random order and subsequently collected ileostomy fluid and urine for 24 h. Absorption of chlorogenic acid was 33 +/- 17% (mean +/- SD) and of caffeic acid 95 +/- 4%. Traces of the ingested chlorogenic acid and 11% of the ingested caffeic acid were excreted in urine. Thus, one third of chlorogenic acid and almost all of the caffeic acid were absorbed in the small intestine of humans. This implies that part of chlorogenic acid from foods will enter into the blood circulation, but most will reach the colon.
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Coffee is basically consumed for the pleasure given by its taste and aroma, that is, the quality and acceptance of the coffee beverage are directly related to its sensorial characteristics. Thus, nowadays coffee quality is basically evaluated by sensorial analysis. However, together with this kind of analysis, it should be important to have available more objective chemical methods to assess coffee quality. One possible approach could be based on the analysis of chlorogenic acids (CGA), since they are considered precursors of coffee flavour and pigments during roasting. In the present work, high performance liquid chromatography (HPLC) analysis of chlorogenic acids was applied to six different Brazilian arabica green coffee samples which were previously characterised by sensorial analysis. The results showed the potential to correlate the chemical data, evaluated by the Principal Components Analysis (PCA) statistical method, with sensorial analysis in order to discriminate the quality of the samples. It was observed that the 3,4-dicaffeoylquinic (3,4-diCQA) and 3,5-dicaffeoylquinic (3,5-diCQA) isomers are very important for grouping the coffees into good and bad samples.
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Caffeine is the world's most widely consumed drug with its main source found in coffee. We evaluated the caffeine content of caffeinated and decaffeinated specialty coffee samples obtained from coffee shops. Caffeine was isolated from the coffee by liquid-liquid extraction and analyzed by gas chromatography with nitrogen-phosphorus detection. In this study, the coffees sold as decaffeinated were found to have caffeine concentrations less than 17.7 mg/dose. There was a wide range in caffeine content present in caffeinated coffees ranging from 58 to 259 mg/dose. The mean (SD) caffeine content of the brewed specialty coffees was 188 (36) mg for a 16-oz cup. Another notable find is the wide range of caffeine concentrations (259–564 mg/dose) in the same coffee beverage obtained from the same outlet on six consecutive days.
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1 A History of Coffee.- 2 Botanical Classification of Coffee.- 3 Coffee Selection and Breeding.- 4 Climate and Soil.- 5 Physiology of the Coffee Crop.- 6 Mineral Nutrition and Fertiliser Needs.- 7 Cultural Methods.- 8 Pest Control.- 9 Control of Coffee Diseases.- 10 Green Coffee Processing.- 11 World Coffee Trade.- 12 The Microscopic Structure of the Coffee Bean.- 13 Chemical and Physical Aspects of Green Coffee and Coffee Products.- 14 The Technology of Converting Green Coffee into the Beverage.- 15 The Physiological Effects of Coffee Consumption.
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The objective of this study was to analyze the volatile profiles of both green and roasted coffee beans, for assessment of roasting degrees under two different processing temperatures. Volatiles extraction and concentration were performed by solid phase micro-extraction (SPME) of the ground coffee headspace and analysis of the volatiles profile was performed by GC–MS. Four SPME fibers were evaluated, with the one that extracted the highest amount of substances (DVB/CAR/PDMS) being selected. Statistical analysis of the data by principal components (PCA/clusters) showed that the volatile components profile provided separation of green and roasted coffees and also separation according to roasting degree and roasting temperature. Results also indicate that color and weight loss measurements alone are not reliable for roasting degree assessment.
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The objective of this work was to study the putative interactions between flavour compounds and coffee melanoidins. After extraction, melanoidins were freeze-dried and several flavour compounds from different chemical classes were tested in aqueous solution. The retention of flavour compounds by melanoidins was found to be different in function of the method or time of freeze-drying. Thus, for the same freeze-drying method, the retention capacity of melanoidins increased when the aliphatic chain length of a homologous series of flavour compounds increased. This observation seems to favour the hydrophobic nature of the interactions between melanoidins and flavour molecules. Moreover, for the same aroma compound, the retention capacity of coffee melanoidins was found to vary in function of the freeze-drying method used. Freeze-drying could therefore be involved in the modification of the surface properties of melanoidins or in their denaturation, modifying their retention ability towards volatile flavour compounds. At last, retention by coffee melanoidins decreased with the roasting degree of coffee.
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Die Methode zur Bestimmung von Gerbstoffen mit Milcheiweiß wird durch Verwendung von Casein anstelle des nativen Proteins abgewandelt und auf ihre Selektivität zur Erfassung der therapeutisch wirksamen Gerbstoffe in Drogen geprüft. Gepufferte Verdünnungen von Drogenauszügen (pH 5,0), die eine Stunde mit Casein geschüttelt werden, ergeben geringfügig höhere Gerbstoffwerte und etwas größere mittlere Abweichungen als Vergleichsansätze mit nativem Milcheiweiß. Die Untersuchung von 5 Gerbstoffdrogen ergibt, daß Casein hydrolysierbare und kondensierte Gerbstoffe in gleicher Weise absorbiert wie chromiertes Hautpulver. Oxydationsprodukte von Catechingerbstoffen (Phlobaphene) werden dagegen nicht in dem Ausmaß wie vom Hautpulver gebunden. Aus der Differenz zwischen dem Casein-Gerbstoffwert und dem Hautpulver-Gerbstoffwert kann der Phlobaphengehalt einer Droge abgeschätzt werden. Determination of Tannins with Casein The determination of tanning agents with milk protein is changed by using casein instead of the native protein. Further, the special selectivity of the method is tested in registering the tanning agents of therapeutical effect in drugs. Buffered dilutions of drug extracts (pH 5.0), after shaking with casein for one hour, show slightly higher tannin values and average deviations than comparable experiments with the native milk protein. The analysis of 5 tanning plants shows that casein absorbs tanning agents, both condensed and hydrolizable, in the same way as chromed hide powder does. In contrast to this, the oxidation products of catechin tanning agents (phlobaphenes) are not as strongly absorbed as by hide powder. The amount of phlobaphenes in drugs can be estimated from the difference between the tannin value measured with casein and with hide powder.
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The mulberry (Morus alba L.) leaf is a promising dietary source of antioxidants such as quercetin due to its relatively high content of that compound. We investigated effects of an air-drying process on the antioxidant capacity and stability of antioxidant polyphenolic compounds in mulberry leaves. Main compounds playing a central role in antioxidant activities in mulberry leaves are quercetin glycosides and chlorogenic acid. Raw mulberry leaves were air-dried at various temperatures, and antioxidant activity using DPPH radical scavenging assay and levels of antioxidant compounds were measured. DPPH radical scavenging activity and levels of polyphenolic compounds in mulberry leaves air-dried at 60°C or below were not significantly different from those of freeze-dried mulberry leaves, whereas both values in mulberry leaves air-dried at 70°C and over decreased significantly. These results indicate that strict temperature control is important in the production of mulberry leaf products to maintain antioxidant activity and levels of polyphenolic compounds.
Article
The effect of drying temperature (60, 100, and 140 °C) on the polyphenols' content and antioxidant activity of red grape pomace peels was studied. Freeze-dried samples were used as reference. Differences on the CIE-LAB color, total extractable polyphenols, condensed tannins, UV−vis spectra, and antioxidant activity were evaluated. When drying temperature was 100 and 140 °C, a significant reduction in both total extractable polyphenols (18.6 and 32.6%) and condensed tannins (11.1 and 16.6%) was observed, as well as a decrease of 28 and 50% in the antioxidant activity of the samples, respectively. Hue angle and total color difference in the sample dried at 140 °C were significantly higher than in the freeze-dried reference material. A red color loss at 140 °C was also confirmed by lower absorbance values in the spectra at 525 nm. Drying at 60 °C did not significantly affect the sample characteristics evaluated. Keywords: Wine byproducts; grape pomace peels; antioxidant activity; drying temperature
Article
Mild pyrolysis (228 °C, 15 min) of rosmarinic, chlorogenic, and caffeic acids increased their antioxidative efficacy in a biological rat liver membrane assay by 4-, 11-, and 460-fold, respectively. The active components in the caffeic acid pyrolysates were identified as the recently isolated novel tetraoxygenated 1,3-cis- and 1,3-trans-phenylindan isomers, which showed comparable IC50 values (0.041 and 0.04 μM, respectively) and were 8-fold more active than butylated hydroxytoluene (BHT). Comparison of nonroasted, light-roasted, and dark-roasted coffee extracts showed that the degree of roasting is positively correlated to the inhibition of lipid peroxidation in rat liver membranes. The potent reducing properties of the phenylindan isomers resulted in (a) prooxidative effects at relatively higher concentrations in an ethyl linoleate peroxidation assay, and (b) promotion of hydroxylation of 2‘-deoxyguanosine to afford 8-oxo-2‘-deoxyguanosine. However, the results of the rat liver homogenate model system show that pyrolysis of caffeic acid and its esters chlorogenic acid and rosmarinic acid can procure potent antioxidants and underlines the potential use of heat processing to generate novel bioactive molecules. Keywords: Caffeic acid; phenylindan isomers; antioxidants, prooxidants; polyphenols; lipid peroxidation
Article
A method is presented that allows the indirect determination of the organic roasting loss (ORV) in unknown coffee samples. After determination of the relative contents of both enantiomers of alanine, leucine, phenylalanine and glutamic acid by capillary gas chromatography, the ORV can be calculated with high precision using an equation derived by multiple correlation. This method is independent of roasting temperature, roasting process duration, variety of the coffee plant and steam pretreatment of the green coffee.Es wird eine Methode vorgestellt, die es erlaubt, den organischen Rstverlust (ORV) von unbekannten Kaffeeproben indirekt zu bestimmen. Sie beruht auf der Bestimmung der Verhltnisse beider Enantiomeren von Alanin, Leucin, Phenylalanin sowie Glutaminsure durch Capillargaschromatographie. Aus einer durch multiple Korrelation erhaltenen Gleichung kann der ORV mit hoher Genauigkeit bestimmt werden. Die Methode ist unabhngig von Rsttemperatur, Rstdauer, Rstverfahren, Kaffeeart und Wasserdampfvorbehandlung des Rohkaffees.
Article
The ORACFL assay was used in non-automated mode to evaluate the specific peroxyl radical scavenging properties of the aqueous soluble components of green and roasted Arabica and Robusta coffee samples. A relationship between ORACFL and the concentration of CQAs (caffeoyl quinic acids) was found for the extracts from green coffee beans. Aqueous extracts from roasted coffee beans possessed equal or stronger scavenging power than that obtained for the green coffee beans extracts and the scavenging activity depended on the variety of coffee and the roasting conditions. Brews from Robusta coffee beans showed the highest ORACFL. The best scavenging properties for the brews from Arabica coffee beans were detected in samples prepared from coffee beans roasted under light conditions. The data indicate that, during roasting, a complex network of reactions takes place leading to the formation of a wide number of compounds possessing specific scavenging properties. Under mild roasting conditions, caffeoyl quinic acids appear to be the main components responsible for the free radical scavenging power of coffee brews. In contrast, Maillard reaction products may be the principal components with free radical scavenging activity in more severely (medium and dark) roasted coffees.
Article
Capillary electrophoresis with amperometric detection (CE-AD) has been used for the determination of catechin, rutin, ferulic acid, o-dihydroxybenzene, chlorogenic acid, caffeic acid, gallic acid, and protocatechuic acid in coffee. Comparison of extraction efficiency of antioxidants using different polar solvents was also conducted by this method. Effects of several important factors including the acidity and concentration of running buffer, separation voltage, and working electrode potential, were evaluated to obtain the optimum analysis conditions. The working electrode was a 300um carbon disc electrode at an applied potential of +0.95V (vs. saturated calomel reference electrode). Under the optimum conditions, the analytes can be well separated within 26min in a 75cm length fused-silica capillary (i.d. 2.5×10−5m). The current response was linear over three orders of magnitude with detection limits (S/N=3) ranging from 6.0×10−8 to 3.6×10−7g/mL for all analytes.
Article
The hydrolysis of proanthocyanidins to anthocyanidins in n-BuOH-HCl (95:5) has been shown to be an autoxidation, the yield of anthocyanidin being critically dependent on trace metal-ion impurities. Reproducible yields of anthocyanidin may be achieved if iron (III) salts are added to the reaction medium, and a standard method of analysis of proanthocyanidins based on use of an n-BuOH-HCl-FeIII mixture is given. The ratio of absorbance maxima of the cyanidin (550 nm) produced to that near 280 nm for the original procyanidin polymer solution was ∼ 3.5.
Article
The popularity of tea is increasing on the global aspect because of its role as a significant source of phenolic compounds in human diet. The purpose of this study was to determine and compare the phenolic and methylxanthine composition as well as the antioxidant capacity of white, green, Oolong and black teas, and chamomile and linden infusions depending on the extraction conditions (water temperature and multiple extractions). The content of total phenols and total flavonoids in teas and herbal infusions was determined by using UV/vis spectrophotometric methods, whilst individual polyphenols (phenolic acids and flavan-3-ols) and methylxanthines were identified and quantified by using high performance liquid chromatography coupled with photodiode array detection. In order to determine the antioxidant capacity of teas the 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid) (ABTS) radical scavenging assays were applied. The highest content of phenolic compounds was determined in green tea, which also demonstrated the highest antioxidant capacity, whilst herbal infusions were characterised with the lowest content of phenolic compounds, as well as the lowest antioxidant capacity. The highest content of caffeine, as the most abundant methylxanthine, was determined in black tea. Extraction at 100 °C is the most effective to extract the highest content of polyphenols and methylxanthines in all studied teas.
Article
A method, based on HPLC, described in our previous publication for the analysis of chlorogenic acids in instant coffee, was used in a study of the effect of roasting on the chlorogenic acid composition of Arabica and Robusta coffee. The degradation of seven chlorogenic acids was followed during roasting. Losses of about 60% were observed when mild roasting conditions were used and almost 100% after severe roasting. Considerable differences in degradation rates of individual isomers were observed so that the composition of chlorogenic acids changed throughout the roasting process. Thus the degree of roasting may have a direct influence on the final product flavour as the individual isomers have different sensory properties.
Article
The radical scavenging activity (RSA) of coffee brews obtained from different types of coffee was studied as a function of the roasting degree and equivalent thermal effect (expressed as ), and the relative contribution of the phenolic fraction (PF) and non-phenolic fraction (NPF) to the overall RSA was evaluated. Brews extracted from medium roasted coffee showed a higher RSA than those from green coffee due to an increase of the RSA of the NPF upon roasting. The RSA of the NPF increased with increasing roasting degree together with the accumulation of brown coloured Maillard reaction products (MRPs). Brews from dark coffee showed lower RSA than those from medium roasted coffee due to polyphenols degradation which, in turn, caused an RSA depletion not counterbalanced by an increase of the RSA of NPF. The relative contribution of NPF to the overall RSA of the brew is in fact much lower than that of the PF. Roasting processes with similar values resulted in the same RSA independent of an average temperature variation from 170 to 190 °C and coffee type.The AOA changes in brews from commercial coffee samples (medium and dark roasted) were more dependent on roasting severity than on the type of coffee.
Article
Nutritional factors are widely considered to be critical for human health. Overwhelming evidence from epidemiological studies indicate that diets rich in fruit and vegetables are associated with a lower risk of several degenerative diseases. These results have created a new perspective concerning the potential of diet in preventing serious diseases in the future. However, the health-promoting capacity of fruit and vegetables strictly depends on their processing history. This aspect has been generally neglected or scarcely considered in present nutritional and epidemiological studies. Processing is expected to affect content, activity and bioavailability of bioactive compounds.The aim of this article, therefore, is to review the effects of processing on the antioxidant properties of foods by means of a multidisciplinary approach. It is believed that the implications of this challenging and rapidly advancing area may contribute to enhanced industrial competitiveness as well as consumer health and well-being.