Glucose-induced glycation enhances the foaming properties of Trichosanthes kirilowii seed protein isolate: Insights into structure, interfacial behavior, and proteomics

Abstract

Improving the foaming properties of plant proteins has recently attracted particular interest. The foaming properties of Trichosanthes kirilowii seed protein isolate (TPI) after glucose glycation (wet heating) were investigated by structural characterization, interfacial behavior evaluation, and quantitative proteomics analysis. The results showed that the highest degree of grafting of TPI (45.54%) with glucose was observed at a reaction time of 2 h. Grafting with glucose unfolded the structure of TPI, which was confirmed by increased molecular flexibility, loss of α-helices, and exposure of hydrophobic groups. The foaming capacity and foaming stability of the TPI was greatly improved after glycation. The bubbles in the TPI–glucose conjugate foams were smaller in size, more uniform, and denser than those in the TPI foams. Moreover, the deterioration rate of the conjugate foams was significantly slower than that of the TPI foams. Mechanistically, the improved foam properties were mainly attributed to increased surface activity, accelerated air/water interfacial adsorption, and enhanced interfacial film thickness. The results of quantitative proteomics indicated that several proteins involved in foam stability and elasticity were upregulated in the initial foams of the conjugates, which partly explains the improved foam properties. Overall, G2 showed the most superior foam properties and interfacial behavior among all the samples. This study offers further insights into the mechanisms by which glycation improves the foaming properties of plant proteins and will be useful for the development of foamed foods from TPI.