Gel filtration chromatography revealed molecular weights
of the purified polysaccharides were similar for the 2 grains,
with apparent molecular weights for these polysaccharides
estimated at 1.7 3 106 Da (Figure 4).
Kefiran has a molecular weight of around 1.0 3 106 and is
composed of branched hexa- and heptasaccharide repeating
units consisting of equimolar amounts of glucose and galactose
(Kooiman 1968; Toba and others 1987). The apparent
molecular weight and sugar composition of polysaccharide
from milk kefir grains were similar to those previously reported,
however, polysaccharide isolated from the soymilk
kefir grains contained more glucose than galactose. It has
been established that growth conditions and medium composition
affect the sugar composition of the exo-polysaccharide produced by lactic acid bacteria. The major fermentable
carbohydrate present in the soymilk was sucrose. Cerning
and others (1992) have reported that addition of 1% sucrose
to milk ultrafiltrate modified the sugar composition of the
exocellular polysaccharide produced by Lactobacillus casei
ssp. casei; with glucose becoming the major monosaccharide,
and galactose present in smaller amounts