Impact of temperature fluctuations during frozen storage on mozzarella cheese: insights from linear and nonlinear rheology and structure-function relationships

The short functional shelf-life of pasta-filata cheeses and their increasing global demand have attracted studies on the suitability of its frozen storage. However, the effects of temperature fluctuations (TF) during frozen storage (at −18 °C) on the structural and functional properties of low-moisture, part-skim (LMPS) mozzarella cheese remain unexplored. This study investigated the influence of different TF conditions on the linear and non-linear rheological behaviour, texture, and microstructure of commercial LMPS mozzarella blocks. The side and middle portions of LMPS mozzarella blocks were examined as distinct regions, identified from heat transfer profiles recorded using thermocouples and a data logger during freezing. Linear viscoelastic parameters (G', G") distinguished TF effects only within a limited temperature range and through power-law fitting of frequency sweep data (9.9–99 rad/s). In contrast, intracycle non-linear rheological indicators revealed strain-resolved transitions in shear-thickening ( T > 0) or thinning ( T < 0) below γ