The chemistry of coffee extraction in relation to polysaccharides

Thaler, H.

doi:10.1016/0308-8146(79)90026-8

Cited by 29 publications

(16 citation statements)

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“…The values are comparable to those reported by [20,29] for different types of coffee. The difference with the freezing point of water (0°C) corresponded to the freezing point depression.…”

Section: Resultssupporting

confidence: 81%

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Rheological Behaviour, Freezing Curve, and Density of Coffee Solutions at Temperatures Close to Freezing

Moreno¹,

Raventós²,

Hernández³

et al. 2014

International Journal of Food Properties

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The physical properties of coffee solutions were determined for temperatures close to the freezing point. Rheological behaviour, freezing curve, density and their relationship between coffee mass fraction and brix degrees were determined for coffee mass fractions between 5 and 50% (wet basis) in the -6°C to 20°C temperature interval. Values of viscosity varied from 1.99 to 1037 mPa·s and values of density from 1000 to 1236 kg·m -3 . The freezing curve was generated using the undercooling method, giving values within freezing curves for food fluids. The results were used to generate mathematical models to predict viscosity, freezing point depression, and density as a function of coffee mass fraction and temperature.

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“…The values are comparable to those reported by [20,29] for different types of coffee. The difference with the freezing point of water (0°C) corresponded to the freezing point depression.…”

Section: Resultssupporting

confidence: 81%

“…The freezing curve of coffee is between the freezing curves of glucose and sucrose, within the typical region of food fluids proposed by [24]. This can be attributed to the polysaccharides content of coffee extract, which varies from 20 to 75% dry basis [29][30][31], depending on coffee variety, roasting and extracting processes.…”

Section: Resultsmentioning

confidence: 99%

Rheological Behaviour, Freezing Curve, and Density of Coffee Solutions at Temperatures Close to Freezing

Moreno¹,

Raventós²,

Hernández³

et al. 2014

International Journal of Food Properties

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“…This sugar composition allows the inference that most of the polysaccharides present were galactomannans. The relative abundance of Man, Gal, and Glc residues in Et50 fractions and their variation with DR was very similar to that obtained by Thaler (24) for the copper-precipitated polysaccharides obtained from the aqueous extracts of roasted coffee. In WIppt fractions, the most abundant monosaccharide residue was also Man (50-90 mol %); but some fractions also showed significant amounts of Gal (6-23 mol %) and Glc (2-25 mol %) residues.…”

Section: Influence Of the Dr On The Amount And Chemicalsupporting

confidence: 71%

Chemical Characterization of Galactomannans and Arabinogalactans from Two Arabica Coffee Infusions As Affected by the Degree of Roast

Nunes

Coimbra

2002

J. Agric. Food Chem.

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Galactomannans and arabinogalactans compose almost exclusively the polysaccharide fraction of roasted coffee infusions. To increase the knowledge about the effect of the degree of roast (DR) in the amount and chemical structure of the galactomannans and arabinogalactans, two arabica coffees of different geographical origins (Costa Rica and Brazil) were roasted for three degrees of roast (DRs 4.7-5.0, 8.7, and 10% of dry weight loss of green coffee beans, on a dry basis). The high molecular weight material was extracted with hot water and dialyzed (molecular weight cutoff >12 kDa), and the material was separated in three cold-water-soluble fractions by graded addition of ethanol. The degree of polymerization and the degree of branching of the galactomannans decreased with the increase of the DR. As the DR increased, less branched arabinogalactans were extracted. The relative amount of terminally linked arabinosyl residues of the arabinogalactans decreased with the increase in DR, and the terminally linked galactosyl residues increased. Also, the size of the arabinosyl side chains of the arabinogalactans decreased with the increase in DR.

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“…The differences in the body attribute can be explained by the production of sediments in the coffee extract. When coffee solutions are cooled, gelation is still in the solution (Delgado et al, 2008;Thaler, 1978). Cryogels could be the result of freezing and thawing (Doyle et al, 2006) considering the galactomannan content in the coffee extract.…”

Section: Sensory Analysismentioning

confidence: 99%

Volatile compounds, sensory quality and ice morphology in falling-film and block freeze concentration of coffee extract

Moreno

Quintanilla-Carvajal

Sotelo

et al. 2015

Journal of Food Engineering

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Please cite this article as: Moreno, F.L., Quintanilla-Carvajal, M.X., Sotelo, L.I., Osorio, C., Raventós, M., Hernández, E., Ruiz, Y., Volatile compounds, sensory quality and ice morphology in falling-film and block freeze concentration of coffee extract, Journal of Food Engineering (2015), doi: http://dx.doi.org/10.1016/j.jfoodeng. 2015.05.018 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. ruth.ruiz@unisabana.edu.co AbstractCoffee extract was freeze-concentrated through block and falling-film techniques.Solute retention and concentration efficiency were determined after one stage of these processes. Ice morphology was characterized through image analysis.Preservation of volatile compounds was determined through GC-MS. The effect of coffee extract on flavour was determined after freeze concentration through sensory evaluation. Solute occlusion was higher for falling-film than for block freeze-concentration, with an average distribution coefficient of 0.45 and 0.29, respectively. The ice crystal size was lower for the falling-film technique; this explains the higher solute occlusion. The dewatering capacity was higher for the falling-film technique, as this process is faster than block freeze-concentration. The most abundant volatile compounds of the coffee extracts were preserved after freeze concentration with both techniques. In the same way, no differences were found in most of the sensory attributes of the freeze-concentrated extract obtained using both techniques. Our results confirm the benefits of the block and falling-film freeze concentration techniques in preserving the quality of coffee extracts.

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The chemistry of coffee extraction in relation to polysaccharides

Cited by 29 publications

References 0 publications

Rheological Behaviour, Freezing Curve, and Density of Coffee Solutions at Temperatures Close to Freezing

Rheological Behaviour, Freezing Curve, and Density of Coffee Solutions at Temperatures Close to Freezing

Chemical Characterization of Galactomannans and Arabinogalactans from Two Arabica Coffee Infusions As Affected by the Degree of Roast

Volatile compounds, sensory quality and ice morphology in falling-film and block freeze concentration of coffee extract

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