Predictive criteria for paste formation in concentrated whey systems: Development and experimental validation of a coagulation–crystallisation model based on heterocoagulation concepts

Background The valorisation of whey into intermediate‐moisture concentrates (pastes) without nondairy stabilisers is a technological challenge. The formation of a stable paste depends on the interplay between lactose crystallisation and protein coagulation, but quantitative predictive criteria are lacking. Aims To develop and experimentally validate two complementary quantitative criteria (K sf and K energ ) for predicting paste formation in concentrated whey systems based on composition, crystal size and thermodynamic energies. Methods A structural criterion (K sf ) balancing the protein's structure‐forming potential against the crystalline phase mass factor and an energetic criterion (K energ ) comparing coagulation bond energy to the lactose crystal lattice energy were formulated. They were validated on a new experimental dataset (seven samples) and external literature data using receiver operating characteristic (ROC) analysis, sensitivity and specificity. Key Findings Threshold values were established: = 14 (AUC = 0.95) and = 0.5 (AUC = 0.93). The simultaneous application of both criteria (i.e. requiring K sf > 14 and K energ > 0.5) achieved correct classification of all samples (7/7 samples in the validation dataset and 18/18 samples in independent literature data), reliably distinguishing paste‐like, creamy and liquid consistencies. Scientific/Industrial Implications The criteria enable the design of whey pastes with targeted textures without nondairy stabilisers, aligning with clean‐label trends. They provide engineering tools for optimising whey processing, controlling quality and enhancing the valorisation of this dairy by‐product.