milkcoffee dataset

Protein sedimentation during retort sterilization is a persistent quality problem in milk-coffee beverages, and current 4-week accelerated shelf-life tests are too slow for same-shift production decisions. Here we show that ultrasonic phase velocity (UPV) measurement provides a 30-min, non-destructive alternative. Using a 1.5 MHz FFT phase-detection system (mean RSD < 0.005% across 27 experimental groups), the heat-induced velocity change Δc = c(after retort) − c(before retort) was measured across a sodium caseinate (NaCas, 0–0.20 wt%) series in a model milk-coffee matrix (6% coffee, 13% milk, 121°C/30 min). The resulting U-shaped Δc–NaCas profile—minimum 11.8–12.3 m/s at 0.05–0.07 wt% NaCas, rising to 19.2 m/s at 0.20 wt%—maps directly onto the bridging-to-depletion flocculation transition. Laplace decomposition confirmed that adiabatic compressibility drives >80% of the signal; density varied by less than 0.002 g/cm³ across all conditions. SDS-PAGE revealed preferential depletion of α- and β-caseins (31.5%, 33.0%, and 25.1% retention at 0%, 0.4%, and 0.8% LBG respectively) while κ-casein remained near-intact (~103%), consistent with selective inter-chain cross-linking. CLSM and laser diffraction confirmed a three-stage aggregation progression. The method reduces testing time by 96% and establishes a thermodynamic framework for rapid, non-destructive quality monitoring of thermally processed protein beverages.