Structure–Function Relationships in Fermented Dairy and Dairy-Alternative Matrices: From Composition and Processing to Rheology, Texture, and Stability

Fermented dairy and dairy-alternative products develop their texture, stability, and sensory properties through changes in composition, processing, fermentation, network formation, and water and fat distribution. This review examines relationships between these factors and rheology, tribology, texture, syneresis, melting, and storage stability across yogurt, cheese, hybrid dairy–plant systems, and plant-based fermented matrices. Literature published from 2019 to 2026 was evaluated using a structure–function approach, emphasizing quantitative outcomes, contrasting findings, and experimental limitations. The protein state, particle organization, polysaccharide characteristics, microbial activity, and processing history were associated with differences in network organization, water mobility, and mechanical response. More continuous or compact networks often coincided with improved water retention and greater resistance to deformation; however, these properties were not consistently coupled, and greater mechanical resistance did not necessarily improve meltability, spreadability, or oral breakdown. Cheese coagulation and ripening followed structural trajectories distinct from acid-set yogurt, whereas hybrid and plant-based systems exhibited composition- and processing-dependent network formation and phase behavior. Evidence primarily supported within-study structural–functional associations, while many molecular mechanisms remained proposed. Methodological heterogeneity limited cross-study comparisons, and scarce direct tribological evidence constrained interpretations of oral lubrication. Future research should prioritize controlled mechanistic studies, harmonized measurements, and validation under realistic manufacturing and storage conditions.