Industrial processing of proteins often exposes them to different stress conditions (elevated temperature, pH, salts, presence of hydrophobic interfaces, etc.) where protein molecules undergo conformational changes, aggregate and lose their functionality. The aggregation can be suppressed partially or completely by blocking the atomic groups of proteins involved in intermolecular ‘bridging’. This blocking can be achieved with a help of host molecules, chaperones. Selection of optimal chaperones and optimisation of protein processing requires effective real-time monitoring of structural protein rearrangements and formation of protein aggregates, which is a difficult task for most analytical techniques. In our talk we present the results of an application of high-resolution ultrasonic spectroscopy for real-time monitoring of conformational changes and evolution of particle sizes during thermal denaturation, aggregation and subsequent gelation of β-lactoglobulin in the absence and presence of chaperons suppressing the aggregation process. Continuous measurements of ultrasonic velocity and attenuation in the frequency range 2 to 20 MHz performed with the HR-US 102 spectrometer in a temperature ramp mode (up and down temperature ramps between 35-120°C, various ramp speed) allowed us monitoring of thermal transitions and formation of protein particles in aqueous β-lactoglobulin solutions. The results provided information on protein partial unfolding and transition to molten globule state (50-75), formation of protein nano-particles (75-80°C) and formation of particle gel network above 80°C. The data was used to evaluate reversibility of β-lactoglobulin aggregation, the effects of heating rate, pH, ionic strength and action of chaperones on the denaturation and aggregation profiles. Kinetics of unfolding and evolution of size of protein aggregates under a broad range of conditions were analyzed.