4. Conclusion
It can be concluded that konjac oligo-glucomannan (KOG) was successfully prepared by degradation of konjac glucomannan (KG)using -mannanase.
A minimum intrinsic viscosity of KOG was obtained under the optimum conditions of time 2 h, temperature 50◦C, pH 6.0, and enzyme concentration 150 U/g.
Through the FTIR spectra, KOG had similar structural characteristics with KG and,KOG retained the characteristics of functional groups of KG.
In addition, KOG exhibited antioxidant activities to some extent, but they were significantly weak compared to VC.
Some researchersreported that with the decrease of molecular weight, the antioxidant activity of chitosan and its derivatives will be enhanced (Sunet al., 2008).
However, there is little research on the relationship between the antioxidant activity and DP of the KOG.
This study suggested KOG with small molecular weight can be successfully prepared by enzymatic hydrolysis, and KOG could potentially be used as a natural antioxidant.