Effects of acylation and glycation treatments on physicochemical and gelation properties of rapeseed protein isolate

The aim of this study was to improve the gelation property of rapeseed protein isolates (RPI) by means of acylation and glycation. The results showed that acylation and glycation within RPI occurred at Lys, and Lys, Met, Ile, Leu and Pro, respectively. Acylation and glycation both increased the surface hydrophobicity (So) and molecular weight of RPI, and decreased the free sulfhydryl (SH) content of RPI, while acylation resulted in a lower change of So and SH. The conformational structure of modified RPIs was changed, and acylated RPI (acylation degree, 38 +/- 0.2%) possessed the highest ordered structure content among the modified RPIs. The thermal stability of the protein was improved after either acylation or glycation treatments. Furthermore, native RPI with moderate modification (low degree of acylation, 38 +/- 0.2%) showed an overall improvement in the gelation and gel properties as evidenced by the reduced least gelation concentration and surface roughness, increased water-holding capacity, and better textural properties.