Glycated modification of the protein from Rana chensinensis eggs by Millard reaction and its stability analysis in curcumin encapsulated emulsion system

Forest frog (Rana chensinensis) eggs contain high-quality protein but have not been well utilized. In this study, the total protein of forest frog eggs was extracted and 4491 protein/peptides were identified by HPLC-MS/MS. The egg protein was glycated using monosaccharides (lactose, fructose, xylose and glucose). The xylose modified egg protein showed excellent emulsifying ability, high viscosity and uniform structure under the laser confocal microscope in a concentration dependent way (1-3%, w/v). We next used xylose glycated egg protein to encapsulate curcumin to determine the stability of its emulsion system. This emulsion system showed low particle size (< 400 nm) and high Zeta-potential (> 30 mV with absolute value) at pH > 6. The system was stable under 4 degrees C, 25 degrees Cand 37 degrees C after seven weeks' storage, especially for the emulsions at 3% and 5% concentrations. Therefore, the glycated frog egg protein can be used to encapsulate hydrophobic nutrients.

Automated summary

Forest frog eggs, which contain high-quality protein, can be efficiently utilized by glycating the egg protein with xylose to improve its emulsifying ability and stability. The resulting xylose glycated egg protein demonstrated excellent emulsion characteristics and could be used to encapsulate hydrophobic nutrients.