Structure, gelation mechanism of plant proteins versus dairy proteins and evolving modification strategies

As concern regarding human health, environmental increases, and the need for sustainable food supplies rises, plant proteins are gaining increasingly popularity as alternatives to dairy proteins. The substantial disparity in structural properties and gelation mechanisms between plant proteins and dairy proteins, along with a lack of comprehensive and systematic understanding of their underlying mechanisms under various modification strategies, pose challenges in unlocking the potential substitution of dairy proteins with different plant proteins. The review offers insights into the structure, gelation mechanisms of heat and cold-induced gels of dairy proteins and plant proteins. Furthermore, diverse modification techniques for tailoring the structure of these proteins have been discussed, including chemical, physical, and biological modifications, as well as modifying mechanisms and their advantages and disadvantages. As with whey globular proteins, plant globular proteins usually have compact globular structures and are more prone to heat, making denaturing their globular proteins a prerequisite for gelation. Contrary to globular proteins, casein micelles exhibit flexible random coil structures and good conformational stability to heating in neutral or higher pH but lose stability in acidic conditions. Different modification strategies exhibit diverse mechanisms and peculiarities. Complex coacervation is highly system dependent, while the enzymatic hydrolysis should be controlled in limited degree. Transglutaminase treated gels behave differently when the amount and accessibility of target lysine and glutamine residues differs. Moreover, exploring effective modification strategies for binary plant and dairy proteins to improve their gelation performance can be done in the future.