Abstract
In this paper, electron beam irradiated rice protein hydrolysates (ERPHs) were assessed for their ability to prevent hydrogen peroxide-induced oxidative stress in human HepG-2 cells. The related mechanism was also studied by analyzing the structural changes. Cytotoxicity experiments showed that rice protein hydrolysates pretreated with electron beam irradiation (EBI) were not toxic to cells if appropriate concentrations were applied. Cell viability markedly increased when the cells were treated with ERPHs before H2O2 induction. Furthermore, the ERPHs effectively suppressed H2O2-induced ROS production and lipid peroxidation and increased the protein expression levels of the intracellular antioxidant enzymes SOD, GSH-Px and CAT in H2O2-stressed HepG-2 cells. Consequently, the loss of mitochondrial membrane potential and cell apoptosis was alleviated. Circular dichroism analysis showed that pretreatment of rice protein with EBI significantly changed the secondary structure (the conversion of α-helices to random coils), which is beneficial to the improvement of its antioxidative activity. ERPHs exhibited stronger antioxidative effects than those without irradiation, possibly because of the difference in molecular weight distribution and amino acid composition. These findings indicate an efficient way to produce peptides with better antioxidant activity.
Highlights
Rice protein (RP) is a byproduct of starch extraction manufacturing
The inhibitory activity of NRPHs and electron beam irradiated rice protein hydrolysates (ERPHs) (EBI-treated rice protein hydrolysates (RPHs)) in H2O2-induced cellular stress in HepG-2 cells, which would be shown in the following study, was not due to toxicity
The results indicated that RPHs, especially electron beam irradiation (EBI) pretreated rice protein hydrolysates, had the ability to protect the mitochondrial membrane from oxidative damage caused by exogenous hydrogen peroxide
Summary
Rice protein (RP) is a byproduct of starch extraction manufacturing. RP has gained much attention recently because of its high yield, high nutritional value and economic value[1]. This improvement may be attributable to protein unfolding and scission induced by the energy generated by an electron beam accelerator Such changes in protein structure could expose more peptide bonds to proteolytic enzymes, which may contribute to an increase in antioxidant activity[5]. The modification of these protein hydrolysates could promote their application in food industries as antioxidants. The samples pretreated with EBI are expressed by ERPHs (EBI-treated rice protein hydrolysates) Both enzymes are RPHs. The results of this study are expected to provide a theoretical basis for the development of the electron beam irradiation technique and provide technical support for further research on new antioxidant peptides
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
