Chemically-modified rapeseed (Brassica napus) protein via succinylation and glycation with enhanced functional properties

• Rapeseed protein (RP) isolates were modified through succinylation and glycation. • Modified RP showed less free sulfhydryl groups and higher surface hydrophobicity. • Modified RP consisted of less ordered secondary structures and more random coils. • Modified RP displayed higher solubility than pristine proteins. • The emulsifying and foaming properties of RP were enhanced after modification. As an underutilized plant protein source, rapeseed protein is promising in the formulation of plant-based food. Since rapeseed protein’s poor functional properties are limiting its application, chemical modification on protein structure can be a potential solution. In the current study, we applied succinylation and glycation on rapeseed protein isolate, with subsequent determination on the changes of protein structural and functional properties. Both glycation and succinylation of rapeseed protein led to reduced free sulfhydryl group content, increased surface hydrophobicity, and notable alterations in secondary structure, primarily reflected by higher proportions of α-helix and random coils. Results showed that both glycation and succinylation improved protein solubility, led to the increment of 40.30 ± 6.00 % to maximum 65.85 ± 8.45 %, accompanied with increased emulsifying capacity, stability, and foaming capacity. Succinylation was more effective in improving emulsifying stability by 30%, while glycation increased foaming capacity from 77.3 ± 10.69 % to 138.0 ± 15.39 %. Overall, the present work demonstrated that the chemically modified rapeseed proteins with enhanced functional properties, thereby indicating future utilization in plant food manufacture and functional food development.