109: Emulsion Stability Enhancement Through SPI-Maltodextrin-Gum Arabic Ternary Conjugates

Introduction

Soy protein isolate (SPI) is a common emulsifier in food processing, but its functionality is often affected by temperature and pH variations. This study introduces a ternary conjugate combining SPI with maltodextrin (MD) and gum Arabic (GA) to enhance emulsion stability. Analysis of emulsifying properties demonstrates that these ternary conjugates outperform binary systems in food applications.

Methods

SPI-MD-GA ternary conjugates were prepared by mixing 3% (w/w) SPI with polysaccharides at various MD:GA ratios, followed by heating at 80°C. Grafting was assessed by OPA analysis, and emulsion stability by emulsifying activity index (EAI), emulsion stability index (ESI), polydispersity index (PDI), and particle size analysis. Statistical significance was determined using ANOVA (p < 0.05).

Results

Optimal Maillard reaction conditions were achieved with an MD:GA ratio of 1:2 after 8 h of reaction. EAI increased from 68.4 m²/g (SPI) to 71.8 m²/g (SPI-MD-GA), and ESI improved from 534.1 min to 1755.7 min. Emulsion droplet size rose from 478.6 nm (SPI) to 549.0 (SPI+MD+GA) but decreased to 422.9 nm (SPI-MD-GA), effectively reducing droplet aggregation. A PDI below 0.3 ensured uniform dispersion.

Significance

This study highlights the potential of protein-based natural food additives, particularly as emulsifiers with enhanced stability against environmental stresses, including heat, pH fluctuations. The improved physical stability of the wall material supports the development of protein-based delivery systems for bioactive compounds, advancing functional food applications.