RHAMNOGALACTURONAN-II, A DOMINANT POLYSACCHARIDE IN JUICES PRODUCED BY ENZYMATIC LIQUEFACTION OF FRUITS AND VEGETABLES

Rhamnogalacturonan II (RG-II), a small complex pectic polysaccharide, is released from apple (Malus domestica), carrot (Daucus carota), and tomato (Solanum lycopersicum) by treatment with two commercial liquefy ing enzyme preparations. RG-II was isolated by size-exclusion chromato graphy from apple, tomato, and carrot juices obtained by enzymic lique faction. All the RG-IIs contained the diagnostic sugars, apiose, 2-O-m ethyl-L-fucose 2-O-methyl-D-xylose, aceric acid, Kdo and Dha. Glycosyl -linkage compositions of the neutral and acidic sugars, including acer ic acid, were consistent with the hypothetical model described for syc amore RG-II confirming the conservation of RG-II in plants. Thus, when pectinolytic enzyme preparations are used to process fruits and veget ables, RG-II is released as a main soluble polysaccharide fraction whi le other pectic polysaccharides are heavily degraded. (C) 1997 Elsevie r Science Ltd.