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At least 19 recordsLinked to original sources
PubMed1976

Steam volatile aroma constituents of roasted coffee: neutral fraction.

The volatile components of roasted coffee, isolated by normal-pressure steam distillation, were separated into basic and neutral fractions. The neutral fraction was analysed on a UCON HB 5100 glass capillary column (200 m x 0.31 mm i.d.) coupled to a low-resolution mass spectrometer. One hundred and twenty compounds were identified, of which twenty-six had not been previously reported in coffee aroma. Identification of the structures of the newly identified compounds was accomplished by comparison of their mass spectra with reference spectra. GLC retention times were used to confirm identifications. The new compounds identified for the first time in roasted coffee include 15 furans, 6 pyrroles, 3 thiophenes, and 2 ketones. Of the 15 furans eight methylvinylfurans, dimethyl-vinylfurans and alkenylfurans, which had not been previously found in roasted foodstuffs, should be specially mentioned. Mass-spectral data of the newly identified substances are tabulated. Fragmentation patterns of N-acetyl-2-methylpyrrole, N-furfuryl-2-methylpyrrole, 2-vinyl-3-methylfuran and 2-vinyl-3,5-dimethylfuran are discussed. Comments are made with respect to possible formation patterns and precursors in green coffee beans.

Coffee↗
PubMed1978

[Diphenols and caramel compounds in roasted coffees of different varieties. II. (author's transl)].

Eleven diphenols and seven caramel compounds were extracted from roasted coffee with pentane/ether (1 + 1), silylated with BSTFA, characterized, and semiquantified by GC-MS. Seven phenols and five caramel components were identified for the first time in roasted coffee. Robusta coffee contained the highest amounts of phenols and maltol. Arabica showed higher amounts of furaneol (2.5-dimethyl-4-hydroxy-3(2H)-furanone), isomaltol, 5-hydroxymaltol, and 5-hydroxy-5.6-dihydromaltol.

Chromatography, Gas↗
PubMed1978

[Phenols in roasted coffees of different varieties. I. (author's transl)].

Thirty phenols were isolated from roasted coffee by distillation-extraction, separated from other constituents by absorption-chromatography, and characterized by means of GC-MS. Robusta coffee contained the largest amount of phenols, followed by Arabusta (Côte d'Ivoire) and Arabica. Quantity and type of phenols depends on variety as well as on the roasting conditions.

Adsorption↗
PubMed2026

Assessment the Effects of Roasted and Non-Roasted Coffee Extracts on Colon Cancer Cells.

Coffee extracts contain numerous bioactive compounds. Given the dietary link between coffee consumption and colorectal cancer, this study compared the effects of roasted and green (unroasted) coffee extracts on human colorectal cancer cells (HCT116) and non-cancerous fibroblasts (BJ-5ta) to evaluate how processing influences proliferation and molecular signaling. Real-time cell analysis (RTCA), qRT-PCR, and label-free quantitative proteomic analysis were performed to assess cellular responses. MTS and RTCA showed that in BJ-5Ta fibroblasts, coffee extracts increased proliferation in the order CNR < CAR < CAU < CNU, whereas the trend was reversed in HCT116 cancer cells. Proteomic analysis revealed that in BJ-5Ta cells, unroasted coffee extract caused downregulation of the ribosome pathway, and natural coffee extract caused downregulation of the gap junction pathway, indicating reduced protein synthesis and cell-cell communication as a potential stress-adaptive response. In contrast, in HCT116 cells, unroasted coffee extract upregulated the ribosome pathway. Also, natural coffee extract upregulated the pentose phosphate pathway in HCT116 cells, which may enhance NADPH production and reduce oxidative stress. Current evidence suggests coffee's bioactive compounds may have different effects varying by coffee extract type and their preparation.

Humans↗
PubMed1975

[Investigation on coffee and coffee-substitutes. XVII. Behaviour of polysaccharide-complexes of robusta-coffee during roasting].

Two varieties of Coffea robusta of light, medium and dark roasting degree were investigated. The results were similar to those which were published earlier concerning Coffea arabica. One part of the mannane and galactane is destroyed. Another part, which exists originally as a constituent of the holocellulose, is made water soluble. Of this part, the mannane is found in the complex of water soluble polysaccharides, the galactane in the complex of galactoarabane.

Cellulose↗
PubMed1978

Extraction and analysis of coffee bean allergens.

Workers in the coffee industry can develop occupational allergic disease upon exposure to dust associated with coffee manufacturing. Since controversy exists as to the source or chemical nature of these allergens, the mouse model of reaginic antibody production was used to assess the potential sources of allergens in samples obtained from a local coffee manufacturing plant. Mice were immunized with extracts of coffee dust and beans and the resulting reaginic antibody response determined by the passive cutaneous anaphylaxis reaction. Cross-reacting allergens were detected in samples of coffee dust, cleaner can debris and green coffee beans, but not in chaff or roasted coffee beans. None of the allergens detected in coffee samples cross-reacted with extract of castor beans, although these extracts contained the potent castor bean allergen. Green coffee bean allergens partially purified by gel filtration were heterogeneous with respect to molecular size, although quite similar in their reactivity with reaginic antiserum. These results suggest that the green coffee bean is the major source of allergen in coffee manufacturing plants. This allergen is heterogeneous with respect to size and heat lability, and is immunochemically different from the castor bean allergen.

Allergens↗
PubMed1979

Respiratory function in coffee workers.

Respiratory function was studied in three groups of workers employed in processing coffee. The prevalence of almost all chronic respiratory symptoms was significantly higher in coffee processors than in control workers. In each group during the Monday work shift there was a significant mean acute decrease in the maximum expiratory flow rate at 50% vital capacity (VC), ranging from 4.0% to 8.7%, and at 25% VC, ranging from 6.0% to 18.5%. Acute reductions in FEV1.0 were considerably lower, ranging from 1.3% to 2.8%. On Thursdays the acute ventilatory function changes were somewhat lower than on Mondays. Acute decreases in flow rates at low lung volumes suggest that the bronchoconstrictor effect of the dust acts mostly on smaller airways. Administration of Intal (disodium cromoglycate) before the shift considerably diminished acute reductions in flow rates. A comparison of Monday pre-shift values of ventilatory capacity in coffee workers with those in controls indicates that exposure to dust in green or roasted coffee processing may lead to persistent loss of pulmonary function.

Adult↗
PubMed1977

Gas chromatographic determination of residual methylene chloride and trichloroethylene in decaffeinated instant and ground coffee with electrolytic conductivity and electron capture detection.

A method is described for the quantitative determination of residual methylene chloride (MC) and trichloroethylene (TCE) in decaffeinated instant and ground roasted coffees. The residual solvents were isolated by a closed system vacuum distillation technique with toluene as a carrier solvent, chromatographed on Chromosorb 102, detected by both electron capture and electrolytic conductivity detectors, and quantitated by comparison with an internal standard. Average recoveries of MC from instant and ground coffees spiked at 1, 10, and 25 ppm were 100.0 (88-113), 93.2 (92-95), and 97.7% (94-102%); and for TCE, 97.2 (92-101), 96.2 (95-99), and 96.5% (92-100%), respectively. The results from both detectors are compared. At lower attenuations, levels less than 1 ppm can be readily measured. The procedure developed was applied to domestic and imported coffee samples.

Chromatography, Gas↗
PubMed1977

[Studies on coffee and coffee substitutes. XIX. Dependence of the quantity of a highly polymeric galactomannan on the degree of extraction coffee-extracts (author's transl)].

In extracts of Columbia Arabica Coffee the content of galactomannan precipitable with alcaline copper solution decreases slowly up to an extraction yield of 43.6%; it decreases somewhat more rapidly with higher extraction yields. An extract of Angola Robusta Coffee showed opposite behaviour. In this case the content of galactomannan increased with the extraction yield, although not evenly. Calculated on the basis of roasted coffee solids the extract of the Arabica coffee had a rather limited range precipitable polysaccharide, the Robusta coffee in contrast with rated increased amounts of galactomannan. The different behaviour of the two coffee varieties may be due to mote or less strong binding of this high-polymer carbohydrate to the cell wall.

Cell Wall↗
PubMed1977

[Effects of a coffee-antacid-mixture and a commercial coffee with regard to gastrin, pH and gastric secretion (author's transl)].

The influence of a coffee-antazid-mixture was investigated at 30 patients with diseases of the stomach (17 with duodenal ulcer, 6 with gastric ulcer and 7 with chronic gastritis) in comparison to a commercial coffee. The parameters measured were the gastric basal acid output, the continuous registration of the pH by an intragastric electrode and the serum gastrin concentration before and after the application of the tests substances. 75% of the patients with duodenal ulcer showed a positive effect by means of a greater elevation of the intragastric pH after application of the mixture in comparison to coffee. The effect was strongly correlated to the basal acid ouptput. In the group with gastric ulcer and that with duodenal ulcer under the influence of the mixture the pH after the initial rise decreased to less deeper values. There was a close relationship to the patterns of gastric ulcer as well with chronic gastritis there was an additional facourable effect on the symptoms of abdominal pain which occured after coffee and not after the mixture. The group with chronic gastritis showed no difference between the pure coffee and the coffee-antacid-mixture. A possible relationship of the products of coffee roasting and the adsorptive properties of the antacid is discussed.

Adult↗
PubMed1976

[Studies of coffee and coffee-substitute. XVIII. Dependence of the quantity and composition of a high polymer galactomannan on the coffee species and degree of roasting (authors transl)].

It is possible to determine quantitatively with satisfactory accuracy the galactomannan which is precipitated in coffee brew after addition of Fehling solution. The content of polysaccharides in the extracts increases with the degree of roasting. Galactomannan makes up 6.6 to 12.7% of the dry matter of the extracts and 1.8 to 4.4% of that of roast coffee. It consists mainly of mannan, to a much smaller degree of galactan. Often there are traces of glucan. The content of mannan increases with the degree of roasting while that of galactan decreases very rapidly.

Coffee↗
PubMed2026

Furanic compounds in different coffee extraction systems: Analysis of the main influencing factors and correlation with acrylamide.

This study investigates how different coffee types representative of distinct roast profiles and brewing methods jointly affect the occurrence of furanic compounds and acrylamide in brewed coffee. Coffees were prepared using eight extraction methods (AeroPress, Clever, Chemex, French Press, Moka, Pure Brew, Turkish and V60). Five furanic compounds (furfural, furfuryl acetate, 5-methylfurfural, furfuryl alcohol and 5-hydroxymethylfurfural) were quantified in coffee powders and brews by HS-SPME-GC-MS, while acrylamide was determined by UHPLC-MS/MS. Moka and Turkish brews consistently exhibited the highest concentrations of furanic compounds, whereas paper-filtered pour-over methods (V60 and Chemex) showed the lowest levels. Pearson correlation analysis revealed coffee-dependent relationships between furanic compounds, acrylamide and extraction parameters with the strongest associations observed in dark-roasted coffee, reflecting advanced Maillard reaction chemistry. Overall, these results demonstrate that contaminant levels arise from the combined effects of intrinsic coffee chemistry and brewing mechanics and support targeted mitigation strategies: such as roast selection and brewing method optimization.

Acrylamide↗
PubMed1979

Spectrophotometric determination of caffeine in coffee products: collaborative study.

An ultraviolet (UV) spectrophotometric method for determining caffeine in regular and decaffeinated coffee products has been studied collaboratively. Nine laboratories participated in this study which compares the proposed UV method with the official AOAC micro Bailey-Andrew method. Caffeine content was determined on as-is basis on 8 samples of green, roasted, and soluble coffees. The coefficients of variation for the proposed method ranged from 2.02 to 6.98% for the 8 samples studied. The results agreed well with those from the Bailey-Andrew Method. The method was adopted as official first action.

Caffeine↗
PubMed1976

High-pressure liquid chromatography of caffeine in coffee.

A new method is described for the determination of caffeine in coffee, based on high-pressure liquid chromatography. The caffeine is extracted from the sample with water and/or methylene chloride, and then separated from interfering materials by passing an aliquot of the extract through a high-pressure column containing sulfonated cation exchange resin, using 0.01M nitric acid as the mobile phase. An ultraviolet detector measures the absorption of the solution directly. The method is rapid and eliminates the lengthy separations common to other methods. The procedure was applied successfully to decaffeinated and non-decaffeinated green, roasted, and instant coffees. This method gives a more accurate measure of the caffeine content in decaffeinated coffee samples than the micro Bailey-Andrew and modified Levine methods, with equal or better precision. This method gives results equal to those obtained by the official methods for non-decaffeinated samples.

Caffeine↗
PubMed1976

[The influence of coffee and caffeine on gastrin and acid secretion in man (author's transl)].

Intragastric instillation of coffee, decaffeinated coffee and pure caffeine in humans significantly stimulated gastric secretion. After intragastric caffeine, basal serum gastrin concentrations were not changed. However after instillation of coffee and decaffeinated coffee serum gastrin increased significantly. Thus acid secretion was significantly greater after coffee and decaffeinated coffee than after caffeine. Roasted products seem to be responsible for the gastrin-releasing effect of coffee.

Caffeine↗
PubMed1978

[Determination of diterpene glycosides in coffee (author's transl)].

The determination of 3'O-beta-D-glucopyranosyl-2'-O-isovaleroyl-2beta-(2-desoxy-atractyligenin)-beta-D-glucopyranoside (KA 1) and 2-O-beta-d-glucopyranosyl-atractyligenin (KA II) in coffee was carried out by liquid/liquid-partition, column chromatography, thin layer chromatography, and photometry. In robusta and arabusta green coffees KA I levels were below the limit of detection, in arabica green coffees between 170 and 460 mg/kg. KA II was present in robusta green coffees between 10 and 45 mg/kg, in arabusta green coffee at about 60 mg/kg, in arabica green coffees between 290 and 340 mg/kg. During roasting these values are reduced, but not during commercial extraction.

Chromatography, Liquid↗