Medium Internal Phase Emulsions Stabilized by Soy Protein Isolates: Protein Solubility Effect and Stabilization...

Area of Science:

• Food Science
• Protein Chemistry
• Colloid and Surface Science

Background:

• Soybean protein isolate (SPI) solubility degrades during storage and transport.
• This impacts its functionality in food emulsions.
• Developing stable emulsions with varying SPI solubility is crucial.

Purpose of the Study:

• To formulate and assess medium internal phase emulsions (MIPEs) stabilized by SPI variants with different solubilities.
• To understand the relationship between SPI solubility and MIPE stability.
• To explore the application potential of low-solubility SPI.

Main Methods:

• Preparation of MIPEs using SPI variants (SPI80, SPI70, SPI60, SPI50) with solubility levels from 80% to 50%.
• Measurement of contact angles, zeta potential, interfacial protein adsorption, and rheological properties (G', G″).
• Microstructural analysis using Confocal Laser Scanning Microscopy (CLSM) and Cryo-Scanning Electron Microscopy (Cryo-SEM).

Main Results:

• SPI solubility significantly influenced MIPE stability, with lower solubility leading to decreased stability.
• Zeta potential, interfacial protein adsorption, and rheological properties (viscosity, G', G″) decreased with reduced SPI solubility.
• Microstructural analysis showed less uniform emulsions with reduced network interconnectedness as SPI solubility decreased.

Conclusions:

• SPI solubility is a critical factor determining the stability and microstructure of MIPEs.
• Low-solubility SPI can be used to create MIPEs, but stability is compromised.
• Findings offer a theoretical basis for using low-solubility SPI in MIPE applications.