Polysaccharides of green Arabica and Robusta coffee beans

Fischer, Monica; Reimann, S.; Trovato, Véronique; Redgwell, Robert J.

doi:10.1016/s0008-6215(00)00272-x

Cited by 118 publications

(107 citation statements)

References 13 publications

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“…The literature reports wide-ranging degrees of substitution from 47:1 (Wolfrom and Patin, 1961), 130:1 (Bradbury and Halliday, 1990), 30:1 (Fischer et al, 2001a), 1:7 and 1:40 (Redgwell et al, 2003) and 3:1 and 9:1 (Oosterveld et al, 2004). It is likely that the mannan molecules in coffee consist of a heterogeneous mixture of substituted and unsubstituted polymers but definitive data on the exact nature of this mixture is not available.…”

Section: Galactomannansmentioning

confidence: 99%

Coffee carbohydrates

Redgwell

Fischer

2006

Braz. J. Plant Physiol.

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This review summarises recent advances in the chemistry, physiology and molecular properties of coffee carbohydrates with a particular focus on the cell wall polysaccharides. The results of detailed chemical studies have demonstrated novel structural features of both the galactomannans and the arabinogalactan polysaccharides of the green and roasted coffee bean. For the first time immunological probes based on monoclonal antibodies for specific polysaccharide epitopes were used to reveal the patterns of distribution of the galactomannans, arabinogalactans and pectic polysaccharides in the coffee bean cell wall. Finally, the results of physiological and molecular studies are presented which emphasise the growing awareness of the potential role the metabolic status of the green bean may play in final coffee beverage quality. Key words: Coffea, cell wall, beverage quality, seed. Carboidratos do café:Este artigo sumariza os mais recentes desenvolvimentos nas áreas de química, fisiologia e propriedades moleculares dos carboidratos do café, com um particular interesse nos polisacarídeos presentes nas paredes celulares. Os resultados dos estudos químicos detalhados demonstraram novas características estruturais tanto nos galactomananos como nos polissacarídeos dos arabinogalactanos do grão de café verde ou torrado. Pela primeira vez, estudos imunológicos baseados em anticorpos monoclonais foram usados para revelar a distribuição dos galactomananos, dos arabinogalactanos e dos polissacarídeos pectídicos na parede celular do grão de café. Finalmente, os resultados dos estudos fisiológicos e moleculares são apresentados de maneira a sublinhar a influência do status metabólico do grão verde do café na qualidade final da bebida. Palavras-chave: Coffea, parede celular, qualidade da bebida, semente.

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Section: Galactomannansmentioning

confidence: 99%

Coffee carbohydrates

Redgwell

Fischer

2006

Braz. J. Plant Physiol.

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“…1A) (1). Mannans are widely distributed in nature in parts of the hemicellulose fraction in hardwoods and softwoods (1), legume seeds (2), and beans of carob trees (3).…”

mentioning

confidence: 99%

Biochemical and Structural Characterization of the Intracellular Mannanase AaManA of Alicyclobacillus acidocaldarius Reveals a Novel Glycoside Hydrolase Family Belonging to Clan GH-A

Zhang

Peng

et al. 2008

Journal of Biological Chemistry

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An intracellular mannanase was identified from the thermoacidophile Alicyclobacillus acidocaldarius Tc-12-31. This enzyme is particularly interesting, because it shows no significant sequence similarity to any known glycoside hydrolase. Gene cloning, biochemical characterization, and structural studies of this novel mannanase are reported in this paper. The gene consists of 963 bp and encodes a 320-amino acid protein, AaManA. Based on its substrate specificity and product profile, AaManA is classified as an endo-␤-1,4-mannanase that is capable of transglycosylation. Kinetic analysis studies revealed that the enzyme required at least five subsites for efficient hydrolysis. The crystal structure at 1.9 Å resolution showed that AaManA adopted a (␤/␣) 8 -barrel fold. Two catalytic residues were identified: Glu 151 at the C terminus of ␤-stand ␤4 and Glu 231 at the C terminus of ␤7. Based on the structure of the enzyme and evidence of its transglycosylation activity, AaManA is placed in clan GH-A. Superpositioning of its structure with that of other clan GH-A enzymes revealed that six of the eight GH-A key residues were functionally conserved in AaManA, with the exceptions being residues Thr 95 and Cys 150 . We propose a model of substrate binding in AaManA in which Glu 282 interacts with the axial OH-C(2) in ؊2 subsites. Based on sequence comparisons, the enzyme was assigned to a new glycoside hydrolase family (GH113) that belongs to clan GH-A.Mannans are polysaccharides found in plants and consist of a backbone of ␤-1,4-linked mannose and glucose units. Mannose residues often carry an ␣-galactosyl substitute at O-6, and the degree of substitution depends on the plant of origin (Fig. 1A) (1). Mannans are widely distributed in nature in parts of the hemicellulose fraction in hardwoods and softwoods (1), legume seeds (2), and beans of carob trees (3).Endo-␤-1,4-mannanases (mannanases; EC 3.2.1.78) are glycoside hydrolases that randomly cleave the ␤-1,4-linkage in mannans (Fig. 1, A and B) (4); these enzymes have been isolated from bacteria, fungi, plants, and some mollusks (5-8). Interest in these enzymes has been increasing due to their importance in hemicellulose hydrolysis and various other applications (5, 9, 10). During the last 2 decades, more than 80 sequences of the catalytic domains of mannanase have been reported (see the CAZy site on the World Wide Web) and classified into glycoside hydrolase (GH) 2 families 5 and 26, based on their sequence similarities (11). In recent years, crystallographic resolution of the structures of these enzymes has yielded information on their structure. At present, the tertiary structures of seven mannanases have been determined, of which five are from GH family 5 (12-16) and two are from family 26 (17, 18). All of these mannanases share a common (␤/␣) 8 barrel fold, a retaining reaction mechanism (Fig. 1C), and two conserved catalytic residues (two glutamate residues at the C termini of ␤4 and ␤7, respectively). Therefore, all of these enzymes have been assigned to the same GH ...

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“…37) Many researchers have been studying the cell walls such as the chemical extraction of the green and roasted coffee beans, the compositions, and the changes in galactomannan, arabinogalactan, and cellulose or xyloglucan, 28,29) or the chemical extraction of the mannan and its structures. 27) Coffee beans are also composed of various organs. Redgwell et al .…”

Section: Coffee Beansmentioning

confidence: 99%

“…However, the insolubility of the cell walls makes them difficult to analyze and use. 26,27) Galactomannan is the main insoluble polymer of carbohydrates. 28,29) Some arabinogalactans are very tightly cross linked with protein (arabinogalactan protein).…”

Section: Coffee Beansmentioning

confidence: 99%

“…26,29 33) Glucan is proposed to exist as a mannan cellulose in the cell walls. 27) These characteristic compositions and structures would prevent the digestion and extraction for a long time. We have been studying the efficient digestion of the soybean and its characteristics, 1 4) and applied to the results and the approaches to coffee beans.…”

Section: Coffee Beansmentioning

confidence: 99%

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