Polysaccharide constituents of coffee-bean mucilage

Alcohol-insoluble residues (AIRs) were isolated from hand-dissected and com mercial mucilages of depulped coffee beans. Both AIRs had similar polysacch aride composition: pectic substances (about 30%), cellulose (about 8%), and neutral noncellulosic polysaccharides (about 18%). Crude pectins were extr acted from AIRs (dry-matter yield: about 23% to 35%) with dilute nitric aci d (pH 1.5, 90 degreesC). Both pectins contained about 60% uronic acids with high degree of methyl esterification (about 62%) and moderate degree of ac etylation (about 5%). Their molecular weights were low (about 12 to 29 kDa) . They did not gel in the presence of sucrose at acidic pH.