Pea protein isolate modified by Persian gum and ultrasound treatment as a thickening agent for dysphagia-oriented instant rice porridge

Abstract

In this study, pea protein isolate (PPI) was modified using two strategies: complexation with Persian gum and ultrasound treatment. Pea protein isolate–Persian gum complexes (PPI–PG) were prepared at mass ratios of 4:1 and 2:1, and ultrasound-treated pea protein isolates (UPPIs) were obtained by subjecting PPI dispersions to ultrasound treatment at two power levels (100 and 300 W) for 10 and 20 min. The structural and functional properties of the modified PPIs (MPPIs) were characterized, followed by evaluation of their potential as functional thickening agents in instant rice porridge (IRP) for dysphagia management. Both modifications increased the solubility and surface charge of PPI and altered its water-holding capacity (WHC). PPI–PG complexes exhibited larger particle sizes, whereas UPPIs showed reduced particle sizes. However, prolonged ultrasound treatment at 300 W for 20 min adversely affected these properties. FTIR spectroscopy also revealed changes in the secondary structure of the MPPIs. IRPs containing MPPIs exhibited higher WHC and enhanced rheological and textural properties than porridges prepared with native PPI. Compared with PPI–PG complexes, UPPIs led to greater increases in WHC and textural properties of the reconstituted IRPs. SEM further revealed a more structured 3D network in UPPI-thickened porridges. Based on International Dysphagia Diet Standardisation Initiative (IDDSI) tests, porridges containing UPPI treated at 100 W for 10 and 20 min met the requirements for Level 4 and exhibited the best sensory characteristics. These findings highlight the potential of MPPIs, particularly UPPIs, as effective thickening agents in texture-modified IRPs for individuals with dysphagia.