PREPARATION OF KNOJAC GLUCOMANNAN ESTERS OF LONG FATTY\=ACID AND STUDIES ON THE EMULSIFYING PROPERTIES

Four series of konjac glucomannan esters (KGME) of long fatty acid are prepared by heterogeneous method.Differential thermal analysis (DTA) thermographs show the transitions of crystalline structure of KGME.With the increase of degree of substitution (DS) for palmitoylated konjac glucomannan (PKGM), the samples show new crystalline states at higher temperature and the former crystalline state of konjac glucomannan (KGM) disappears.X\|ray diffraction spectra indicate the effect of the length of acyl chain on the crystalline structure of KGME.At high DS of octanolylated KGM(OKGM), dodecanolylated KGM(DKGM), PKGM and octadecenoylated KGM(OLKGM) the intercrystalline distances are 210, 245,258 and 339nm,respectively,and the effect of DS of KGME on its emulsifying ability has been investigated in aromatic hydrocarbon in water and cycloalkane in water (O/W) emulsions.It is demonstrated that in the proper range of DS,KGME has good emulsifying ability in O/W emulsion,even in high salt concentration and in ac idic pH.Clove oil\|water (O/W) emulsion has good stability within four weeks at room temperature,and the breakage of emulsion was not brought about.\=