Molecular properties and gut health benefits of enzyme-hydrolyzed konjac glucomannans

Konjac glucomannan (KGM) with a molecular weight (MW) of 823.4 kDa was partially degraded by endo-1,4-β-mannanase. Two hydrolyzed KGM fractions (KGM-M-1: 147.2 kDa and KGM-M-2: 21.5 kDa) were characterized and applied to the animal tests in comparison with the native KGM. After oral feeding to the mice, KGM-M-1 and KGM-M-2 significantly increased the levels of short chain fatty acids (SCFAs) in the colonic contents and the native KGM increased the SCFAs in the cecum. The more significant effect of the native KGM in the cecum may be attributable to its high viscosity, slowing down the movement of intestinal microflora through the cecum, while the lower MW KGM-M-1 and KGM-M-2 could move more easily through the colon to be fermented by colonic bacteria. This new finding may be useful for future research and development of low-MW KGM polysaccharides through enzyme hydrolysis for the desired gut health benefits.