# Comparison of the physical properties and microstructure of bigels prepared from ethyl cellulose oleogels and konjac glucomannan hydrogels containing casein or whey protein isolate

## TL;DR

This study compares how different proteins affect the structure and properties of bigels made from hydrogels and oleogels.

## Contribution

The study introduces a new method to screen binary hydrogels for bigel production based on protein type and concentration.

## Key findings

- Casein-based bigels showed phase inversion with increased concentration, while whey protein isolate-based bigels did not.
- Casein–KGM mixtures had better emulsification performance than whey protein isolate–KGM mixtures.
- Protein type and concentration in binary hydrogels significantly influence bigel microstructure and properties.

## Abstract

Bigels were prepared from ethyl cellulose oleogels and binary hydrogels containing konjac glucomannan (KGM) and two homologous proteins: casein (CS) and whey protein isolate (WPI). An increase in CS concentration led to an initial enhancement, followed by a reduction in the yield stress and hardness of the bigels. Conversely, variations in WPI concentration did not have a significant effect on these properties. As protein concentration increased, WPI-based bigels maintained the hydrogel-in-oleogel structure, whereas CS-based bigels exhibited phase inversion. The change in binary hydrogels was responsible for the structural evolution and property differences in bigels. Both CS–KGM and WPI–KGM binary hydrogels played a role in stabilizing the droplets and decreasing interfacial tension. Notably, CS–KGM mixtures demonstrated superior emulsification performance compared to WPI–KGM mixtures. By changing the type and concentrations of proteins used, different emulsification abilities can be achieved in hydrogel solutions, which in turn control the structural properties of the corresponding bigels.

•Proteins in binary hydrogels can alter the microstructure and properties of bigels.•CS-based BG exhibited phase inversion as its concentration increased, while WPI-based BG did not.•This study offers a fresh way to screen binary hydrogels for producing bigels.

Proteins in binary hydrogels can alter the microstructure and properties of bigels.

CS-based BG exhibited phase inversion as its concentration increased, while WPI-based BG did not.

This study offers a fresh way to screen binary hydrogels for producing bigels.