Fate of mucilage cell wall polysaccharides during coffee fermentation.
Effects of a 20-h fermentation on cell wall polysaccharides from the mucilage of pulped coffee beans were examined and compared to those of unfermented beans, on alcohol insoluble residues (AIRs), their hot-water-soluble crude pectic substances (PECTs), and their hot-water-insoluble residues (RESs). Yields and compositions were very similar: AIRs, which consisted of approximately 30% highly methylated pectic substances, approximately 9% cellulose, and approximately 15% neutral noncellulosic polysaccharides, exhibited no apparent degradation. However, PECTs from fermented beans were shown to have undergone a slight reduction of their intrinsic viscosity and weight-average molecular weight by capillary viscosimetry and high-performance size-exclusion chromatography. After fermentation, hot-water-insoluble pectic substances of RES exhibited partial de-esterification. Removal of coffee bean mucilage by natural fermentation seems to result from a restricted pectolysis, the mechanism of which remains to be elucidated.
Avallone
S
S
Département CP and Département FLHOR, Centre de Coopération Internationale en Recherche Agronomique pour le Développement (CIRAD), TA 50/16, Avenue Agropolis, 34398 Montpellier Cedex 5, France.
Guiraud
J P
JP
Guyot
B
B
Olguin
E
E
Brillouet
J M
JM
D002473:Cell Wall / Q000378:metabolism*; D002850:Chromatography, Gel; D002851:Chromatography, High Pressure Liquid; D003069:Coffee / Q000378:metabolism*; D005285:Fermentation; D008970:Molecular Weight; D011134:Polysaccharides / Q000737:chemistry / Q000378:metabolism*; D014783:Viscosity
D003069:Coffee; D011134:Polysaccharides