Polysaccharide Constituents of Coffee‐Bean Mucilage

Alcohol‐insoluble residues (AIRs) were isolated from hand‐dissected and commercial mucilages of depulped coffee beans. Both AIRs had similar polysaccharide composition: pectic substances (about 30%), cellulose (about 8%), and neutral noncellulosic polysaccharides (about 18%). Crude pectins were extracted from AIRs (dry‐matter yield: about 23% to 35%) with dilute nitric acid (pH 1.5, 90 °C). Both pectins contained about 60% uronic acids with high degree of methyl esterification (about 62%) and moderate degree of acetylation (about 5%). Their molecular weights were low (about12 to 29 kDa). They did not gel in the presence of sucrose at acidic pH.