Computer simulation of whey protein β-lactoglobulin behavior under ultrasound treatment of its solutions at different pH levels

Abstract

One of the important and complicated process at dry milk products reconstitution is the protein fraction hydration and its transition to a stable emulsion-colloidal state. In this regard, the aim of this work was to study the process of hydration protein fractions of dry whey using electro-activated aqueous media with different pH that are reconstituted by cavitation disintegration. Various effects of water pH level used for whey reconstitution on whey protein (β-lactoglobulin) hydration were studied with using computer molecular modeling in the programs: visual molecular dynamics (VMD), nanoscale molecular dynamics (NAMD), and adaptive Poisson-Boltzmann solver (APBS) plugin. The β-lactoglobulin molecule was placed in a water chamber corresponding to the size of the molecule, and the needed pH level was set by the plug-in APBS. The con-formational state of the protein was calculated by the molecular dynamics method in NAMD. The VMD program was used to visualize the calculation results. Cavitation effect initiated under reconstitution process was simulated used method, which consist of setting of a specially calculated temperature gradient depending on the heat capacity and density of the product according to condition that all energy produced at cavitation disintegration transmitted to the heat energy in close system. According to the data obtained during the modeling process, it was established that the protein molecule, immersed in an alkaline medium (pH = 11), had several active centers into molecule, that provided high reac-tivity of the studied molecule under cavitation treat-ment. There were similar results in acidic medium (pH = 2) when duration of cavitation treatment was up to 90 sec. Method of process simulation allowed to determine the more relevant regimes of reconstitution as well as optimal pH value of the liquid system used for whey proteins hydration. The most optimal conditions were provided when acidic (pH = 2), and alkaline (pH = 11) aqueous media were used under short cavitation treatment up to 30 sec