STRUCTURE OF AN EXOCELLULAR POLYSACCHARIDE OF LACTOBACILLUS-HELVETICUS TN-4, A SPONTANEOUS MUTANT STRAIN OF LACTOBACILLUS-HELVETICUS TY1-2

Lactobacillus helveticus strain TN-4, a spontaneous mutant strain of Lactobacillus helveticus TY1-2, produced an exocellular polysaccharide from reconstituted skim milk. On the basis of the results of methylation analysis, enzymatic digestion, mild Smith degradation, mild acid hydrolysis, acetolysis, and 1D and 2D H-1-NMR spectroscopy, it was concluded that the polysaccharide has a D-galactofuranose containing hexasaccharide repeating unit with the following structure: [GRAPHICS] he more stable O-(2-oxo)propyl derivatives. To halve the number of degradation products, the methyl glucosides could be reduced to the corresponding 1,5-anhydroglucitols. Results for two model compounds [degree of substitution (ds) 0.33 and 0.46] and three cationic starches (ds 0.02-0.05) are given.