Enzymatic hydrolysis and biological activities of Konjac glucomannan hydrolysate in different degree of polymerisation

The study explores the enhanced functional and bioactive properties of Konjac Glucomannan Hydrolysate (KGMH) by partially degrading Konjac Glucomannan (KGM) using beta-mannanase over 60 min. KGM concentrations (40% and 50% w/w) were treated with 200-300 U g-1 of the enzyme over 60 min. The hydrolysis of KGM was monitored by colorimetry, with DP values ranging from 4.20 to 6.16 for 40% KGM and 4.10 to 4.60 for 50% KGM. MALDI-TOF-MS analysis confirmed typical oligosaccharides with DP values from 2 to 9 and some acetyl substitutions. The optimal conditions of 40% KGM with 250 U g-1 enzyme and varying hydrolysis times produced KGMHs with a wide range of DPs, demonstrating in vitro antioxidant and anti-glycation activities. The results showed significant bioactivities (P < 0.05) positively correlated with lower DP values. This study emphasises the potential of KGMH as a novel functional food ingredient, highlighting its bioactive properties and the significant impact of DPs on the biological functionality of saccharides.