Small strain oscillatory shear and microstructural analyses of a model processed cheese.

Area of Science:

• Food Science
• Materials Science
• Rheology

Background:

• Processed cheese rheology is influenced by composition and processing.
• Understanding these relationships is crucial for product development and quality control.

Purpose of the Study:

• To investigate the rheological and microstructural properties of a model processed cheese.
• To determine the impact of disodium phosphate (DSP) concentration, processing time, and pH on cheese texture.
• To propose a model for the gel network structure of processed cheese.

Main Methods:

• Small-strain oscillatory shear rheology was employed to measure mechanical spectra.
• Large-strain fracture properties were also considered.
• Model processed cheese formulations varied in protein, fat, NaCl, and DSP content.
• Processing parameters like time and pH were systematically adjusted.

Main Results:

• Processed cheese transitioned from an entangled macromolecular dispersion to a gel structure at DSP concentrations above 2.0%.
• Rheological parameters, particularly moduli at 8°C and cooling-induced changes, correlated with fracture properties.
• Three distinct rheological states were identified based on small strain results.

Conclusions:

• DSP concentration is a key factor in determining the gel network structure of processed cheese.
• The proposed model explains the gel network based on para-casein aggregate breakdown and the interplay of aggregates and amphiphilic molecules.
• Rheological properties are directly related to the balance between casein aggregates and their breakdown products.