Gellan gum conjugation with soy protein via Maillard-driven molecular interactions and subsequent clustering lead to conjugates with tuned technological functionality

Abstract

Soy proteins are frequently used in the food industry; however, they have rigid and compact structure with relatively poor interfacial properties and solubility. This study was therefore aimed to modify techno-functional characteristics of soy protein isolate (SPI; 0.1% w/v) by conjugating to low acyl gellan gum (LAGG; 0.1, 0.2, and 0.3% w/v), through the Maillard reaction (at 90 °C for 90 min). The SPI-LAGG conjugates were confirmed by changes in pH, glycation degree (DG; up to 48%), Fourier transform infrared spectroscopy, and sodium dodecyl sulphate polyacrylamide electrophoresis. The conjugates were then classified into three clusters of low, medium, and high DG, via K-means clustering method. The low DG conjugate had lower surface hydrophobicity and foaming capacity, and higher thermal stability, solubility, emulsifying properties, foam stability, and antioxidant activity compared to the other clusters. This indicated that a low DG is required to enhance the functional properties of proteins.

Keywords

• Soy protein isolate
• Interfacial activity
• Gellan gum
• Protein-polysaccharide conjugate
• Conjugation degree
• Functional properties