Mixed gels from whey protein isolate and cellulose microfibrils.

Area of Science:

• Food Science and Technology
• Materials Science
• Biopolymer Interactions

Background:

• Whey proteins form diverse gel structures influenced by processing conditions.
• Polysaccharides can modify whey protein gelation.
• Bacterial cellulose (BC) microfibrils offer unique structural properties for composite materials.

Purpose of the Study:

• To investigate the heat-induced gelation of whey protein isolate (WPI) with bacterial cellulose (BC) microfibrils.
• To determine the effect of BC microfibrils on WPI gel structure, dynamics, and rheological properties.
• To examine the influence of varying NaCl concentrations on WPI-BC composite gel formation.

Main Methods:

• Preparation of homogeneous dispersions of WPI and BC microfibrils at pH 7.
• Heat-induced gelation experiments monitored by rheological measurements.
• Analysis of gel structure and dynamics under different NaCl concentrations.

Main Results:

• WPI and BC microfibrils formed independent gels, creating a composite structure without phase separation.
• BC microfibrils increased the storage modulus of WPI gels, particularly at lower gel strengths.
• WPI gel structure transitioned from fine-stranded to particulate with increasing NaCl concentration, while BC structure remained stable.

Conclusions:

• WPI and BC microfibrils form stable composite gels where BC enhances mechanical properties without altering WPI gelation kinetics.
• The rheological properties and water-holding capacity of the composite gels are primarily governed by the WPI component.
• This study highlights the potential of BC microfibrils as a reinforcing agent in whey protein-based food systems.