Effect of enzyme-assisted extraction on the physicochemical properties of mucilage from the fronds of Asplenium australasicum (J. Sm.) Hook.

Enzyme-assisted extraction (EAE) possesses the advantages of being environmentally friendly and easily operated owing to relatively mild reaction conditions. Thus, mucilage from Asplenium australasicum was extracted with xylanase, glucanase and simultaneous application of both enzymatic preparations then investigated for their physicochemical properties. It was observed that compared to the control, the yield of mucilage increased significantly by EAE (from 3.64% to 6.04-6.86%), while the average molecular weight also increased slightly. SEM results showed that enzymes can erode the raw material which contributed to the higher extraction efficiency of polysaccharide. Furthermore, EAE modified the monosaccharide composition profile of A. australasicum mucilage considerably, especially there was a significant increase in glucose and galacturonic acid content. Although the FT-IR fingerprint did not change pronouncedly due to the action of the enzymes, but the degree of polysaccharide branching seemed to be more complicated, thus significantly reducing the intrinsic viscosity and water holding capacity of mucilage.