Physicochemical properties of hybrid cheddar-type curd gels made from bovine milk and plant protein isolates

Plant proteins are emerging as novel substitutes for dairy proteins; however, their role in hybrid dairy products remains largely underexplored. This study investigated the physicochemical properties of cheddar-type curd gels in which 40% of the bovine milk protein was replaced with either soy, pea, or faba bean proteins. Bovine cheese milk (alone) had a particle volume mean diameter ( d 4,3 ) of approximately 1 μm. When combined with pea and faba bean proteins, the cheese milk exhibited an increase in particle sizes (4 to 6 μm). Heating milk to 80 °C for 30 min had a minor effect on these distribution profiles, except for cheese milk with faba bean proteins, where particle size increased. Curd gel with added plant proteins was less firm than that made from bovine milk. The storage modulus (G') of hybrid curd gels was also lower, with the lowest G' value for the bovine-faba hybrid curd gel. Heat treatment resulted in lower G' values for all curd gels. FTIR analysis revealed a higher β-sheet content in the hybrid gels, which increased for heated samples, presumably due to protein denaturation and interactions. The microstructure of the faba bean hybrid gel exhibited a more open structure. Heated samples exhibited higher whey protein and fat retention, particularly for the soy and pea hybrid gels. Overall, these findings suggest that soy proteins integrate more effectively into ‘traditional’ curd gels than the other types of protein. These findings will underpin the development of dairy-plant hybrid cheese formulations that are similar in quality and taste to traditional dairy cheeses. • Curd gels made with dairy and dairy-plant proteins showed distinct gelation behaviours. • The β-sheet content was greater in curd gels made with plant proteins, especially when heated. • Hybrid curd gels made with soy and pea proteins had denser microstructures than those made with faba bean protein. • Heating enhanced protein aggregation and improved fat and protein retention in curd gels.