Exploration of interaction between α-lactalbumin and β-lactoglobulin under dUHT treatment and storage: experimental and molecular dynamics study.

Direct ultra-high temperature (dUHT) milk is considered as the next generation of liquid milk product because it keeps more nutritional ingredients and better flavor than UHT milk. However, sedimentation and age gelation are urgent problems to develop dUHT milk. The role of whey protein interaction in the destabilization of dUHT milk is rarely reported. In this study, the interaction between α-lactalbumin (α-La) and β-lactoglobulin (β-Lg) was investigated by thermodynamics, spectroscopy and silico approach at 75 °C (preheat), 145 °C (dUHT) and 37 °C (storage). The results showed that α-La could interact with β-Lg via hydrophobicity along with exothermic reaction. During dUHT and storage, the average molecular weight (MW) distribution of α-La/β-Lg complexes increased from 20.3 kDa to 274.4 kDa. The particle size increased from 135.53 ± 5.26 nm to 153.50 ± 3.83 nm and the zeta potential decreased from-27.80 ± 5.90 mV to-7.73 ± 2.65 mV. Fibrous cluster-like protein bridges...