Title
Two horseradish peroxidase-based modifications result in two milk protein products with ordered secondary structure and enhanced in vitro antigenicity
Author
Ying-Hua Zhang, Huan Wang, Yan-Le Liu, Xin-Huai Zhao
Year
2016
Journal
Journal of Food
Abstract
In this study, two horseradish peroxidase (HRP)-based modifications were used to treat whey protein isolate (WPI) and skim milk powder (SKMP) at protein concentration of 50 g/L, pH 7.0, and 37°C, via dityrosine formation in protein molecules. When HRP, glucose oxidase, and glucose were used to treat WPI and SKMP, suitable usages of HRP, glucose oxidase, and glucose, and reaction time were selected from single factor trials based on relative dityrosine contents of the modified products. After that, the selected HRP plus the calculated H2O2 were used to treat WPI and SKMP. Electrophoretic analysis demonstrated that the modified products contained some cross-linked proteins with greater molecular weights. Other analyses showed that the modified products had more ordered secondary structure, and higher in vitro α-lactalbumin and β-lactoglobulin antigenicity than the respective substrates. HRP–glucose oxidase–glucose system was more potent than HRP–H2O2 system to enhance in vitro antigenicity of WPI and SKMP.
Instrument
J-815
Keywords
Circular dichroism, Secondary structure, Biochemistry, Food science