Effects of protein sources and heat treatment on plant-dairy hybrid Cheddar cheese gels, containing microbial transglutaminase.

This study evaluated how plant protein type and heat treatment influence the structure and functionality of hybrid Cheddar-type cheese gels prepared using microbial transglutaminase (mTGase), with 40% partial replacement of bovine milk proteins by plant proteins (soy, pea or faba bean). Heating cheese milk preparations at 80 °C for 30 min prolonged the coagulation stage of gelation in cheese systems manufactured using mTGase. Compared with bovine milk gels, hybrid systems showed lower storage modulus (G'). Bovine milk exhibited a firmer gel structure, while the soy-based hybrid showed better integration and gel strength than pea and faba. FTIR analysis indicated heat-induced conformational changes, with decreased α-helix and increased β-sheet content, consistent with protein unfolding and subsequent re-aggregation. Whey composition analysis and SDS-PAGE confirmed higher protein retention in soy and pea-based systems than in faba-based systems following heating in the presence of mTGase. Microstructural analysis revealed that soy-based hybrid gels formed more continuous and dense protein networks than pea and faba-based systems, while faba-based gels exhibited more heterogeneous structures. In cheese systems prepared with mTGase, heating promoted protein aggregation across all formations. Overall, gel structure was influenced by protein composition and heat treatment, with heating promoting intermolecular interactions and network formation. These findings provide insight into structure-function relationships in plant-dairy hybrid cheese systems.