High internal phase emulsions stabilized by yellow mustard seeds protein–chitosan/chitosan oligosaccharide conjugates via Maillard reaction: Characterization and application as mayonnaise replacers

Plant protein-polysaccharide-stabilized high internal phase emulsions (HIPEs) are of great interest in the food industry. In this study, yellow mustard seed protein (YMP) - chitosan (CS)/chitosan oligosaccharide (COS) Maillard conjugates were employed to prepare HIPEs as mayonnaise replacers. The conjugates formation was confirmed by UV-absorbance at 294/420 nm and SDS-PAGE. The fluorescence peak of conjugates was shifted from 328 nm to 329-338 nm, and FTIR revealed the unfolding structure of YMP. The three contact angles of COS groups increased from 65.1° to 76.8° with improved protein ratios, whereas CS conjugates decreased from 88.1° to 81.7°. The protein adsorption rate peaked was 76.4% when the ratio of YMP:CS at 1:1. Fluorescence microscope observation revealed tightly spherical droplets, and the droplets size was from 33.8 to 177.6 μm. All HIPEs displayed excellent thermal stability without phase separation, but freeze-thaw stability with a loss rate of 56.9%-80.5%. Rheological investigations demonstrated HIPEs exhibited shear-thinning behavior with solid-like properties (G'>G'') and structural recovery ability. The HIPEs complied with IDDSI Level 4-5 standards. The ratio of YMP and CS at 3:1 of HIPEs showed the resemblance to commercial mayonnaise according to the evaluations of color, extrudability, shape retention, and spread ability. The COS-based HIPEs were suitable for dispersible condiments, while CS-based HIPEs serve spreadable applications. • Yellow mustard protein-CS/COS Maillard conjugates stabilized HIPEs. • Protein structure was unfolded through Maillard reaction. • HIPEs exhibited shear-thinning behavior and structural recovery ability. • The HIPEs complied with IDDSI Level 4-5 standards. • Study provided a new perspective for mayonnaise substitute.