Synergistic effects on microstructural, rheological and functional properties of starch-enhanced processed mozzarella cheese

To explore the feasibility of texture improvement based on gelatinization, the effect of potato starch (POS), glutinous rice starch (GRS) and tapioca starch (TS) on quality characteristics of processed mozzarella cheese (PMC) upon cooling was investigated from scanning electron microscopy (SEM), confocal laser scanning microscopy (CLSM), texture profile analysis (TPA), rheology properties, the oil droplets size distribution and melt-stretch functionality. The results showed that protein's ability to emulsify fat was enhanced due to the addition of starch whereas leading to the formation of a small amount of large-sized oil droplets. And hardness of PMC was significantly increased, with PMC containing GRS (PMC-GRS) being softer than those with other starches. The viscoelasticity and melting temperature of PMC were increased where the melting temperature of the control group (PMC-CG), PMC containing POS (PMC-POS), PMC-GRS, PMC containing TS (PMC-TS) occurred at 60.55℃, 90℃, 73.42℃ and 77.02℃, respectively, and starch prevented PMC from over-hardening after repeated or long-term heating; Starch reduced PMC’s meltability while simultaneously improving its stretchability at room temperature, with PMC-GRS exhibiting the most pronounced effects. PMC- POS, PMC-GRS, PMC-TS produced a significantly higher number of cheese fibers which were more robust and less prone to break but reduced its stretch length by 43.42 %, 7.49 %, and 14.86 %, respectively. Overall, starch especially GRS can effectively enhance stretchability of PMC at room-temperature, while maintaining acceptable viscoelasticity and hardness. These findings provided valuable insights for improving the functional properties of PMC.