Proteins occur as natural and engineered assemblies in foods. This paper focuses on the microstructural aspects of some protein assemblies and their relation to processing and functionality. Examples discussed include: (a) disassembly of protein bodies in seeds during aqueous extraction;(b)freeze‐texturization and gelation of muscle proteins; (c) formation of large protein aggregates during caking of fish hydrolysate powders;(d)transformation of globular to fibrous aggregates and the role ofTgduring extrusion cooking;(e)formation of mixed and filled dairy gels; and (f) kinetics of aggregation of β‐lactoglobulin.