Physical properties and microstructure of hybrid processed cheeses formulated with plant protein and milk protein ingredients

Hybrid processed cheese analogues (HPCAs) containing either mung bean (MPI) or hemp protein (HPI) with rennet casein (RC) at various ratios were prepared and analysed to understand their spatial and microstructural distribution and related physical properties, such as rheological properties, texture profile, meltability, and stretchability. In addition, protein composition and secondary protein structure were studied using SDS–PAGE and FTIR spectroscopy, while CLSM and TEM were employed to visualise the microstructure of the cheese matrix. Results indicated that plant protein types and concentration significantly affected the physical properties and microstructure of HPCAs. The addition of 30 % or more plant protein altered the physical and textural properties as well as the microstructure of the cheese analogues, with a decrease in β-sheet content and an increase in random coil structures. Mung bean protein–based HPCAs exhibit greater stretchability (e.g. 93.8 mm in 30 % MPI vs 41.53 mm in 30 % HPI), rheological, and textural properties, but not meltability (e.g. 1 % in 70 % MPI vs 48 % in 70 % HPI), compared with the hemp protein system at the same mixing ratios. This difference can be attributed to the size of the plant protein aggregation. All data were analysed by one-way ANOVA with Tukey's test (p < 0.05). These findings deepen our understanding of plant protein-based and hybrid cheeses, paving the way for optimised plant-based dairy alternatives.