Physicochemical properties and cellular protection against oxidation of degraded Konjac glucomannan prepared by γ-irradiation

•Irradiation in dosage of 100 kGy leads to excellent dispersibility in KGM.•100 kGy-KGM demonstrates excellent protective effect against oxidative damage.•Possible mechanism for anti-oxidative activity in 100 kGy-KGM was analyzed.•Irradiation was proven an effective method to improve properties of KGM.

Konjac glucomannan (KGM) is an important functional polysaccharide in food research. However, unstable dispersibility of KGM inhibits its in-depth study and wide application. In this study, a degraded KGM (100 kGy-KGM), which showed excellent dispersibility and specific physicochemical properties, were obtained by γ-irradiation in a dosage of 100 kGy. We investigated the protective effect of 100 kGy-KGM against H2O2 induced oxidative damage in LO2 cells. Our results demonstrated that pretreatment of LO2 cells with 100 kGy-KGM not only significantly increased cellular survivals and activities of GSH-Px and CAT, but also reduced levels of LDH, MDA and intracellular accumulation of ROS. The marked protective effect against oxidative damage and excellent dispersibility in 100 kGy-KGM allowed its possible use as an antioxidant. Our study provided fundamental knowledge to understand the structure-functions relationships of degraded-KGM, which could result in a theoretical guidance for the future application of KGM.