Casein as a Modifier of Whey Protein Isolate Gel: Sensory Texture and Rheological Properties.

Area of Science:

• Food Science and Technology
• Protein Chemistry
• Material Science

Background:

• Whey protein gels are model soft solids with desirable but often unmodifiable textural properties.
• Current food industry demands alternative protein sources and precise control over texture.
• Understanding protein interactions is key to designing functional food ingredients.

Purpose of the Study:

• To investigate casein's role in modifying whey protein gel structure and texture.
• To correlate structural and mechanical properties with sensory texture perception.
• To explore casein as a tool for tailoring food material properties.

Main Methods:

• Preparation of heat-set gels using whey proteins alone or with micellar/dispersed casein.
• Mechanical testing to assess gel strength, elasticity, and fracture behavior.
• Sensory analysis to evaluate attributes like cohesiveness, firmness, and fracturability.

Main Results:

• Casein addition enhanced gel cohesiveness and moisture retention during mastication.
• Gel strength decreased with casein, while elasticity remained largely unchanged.
• Fracture patterns shifted from brittle to ductile, influenced by casein form and pH.
• Sensory attributes like cohesiveness, tackiness, and deformability were significantly altered.

Conclusions:

• Casein effectively modifies whey protein gel structure, increasing cohesiveness and water holding capacity.
• This approach allows for decreased firmness and fracturability, desirable for specific food applications.
• Protein co-structuring offers a versatile method for designing food textures with alternative proteins.