Behavior of dairy protein in different simulated thermal processing conditions

Abstract

Milk protein products (MPP) are routinely used by the industry, with the aim to provide improved texture, yield and palatability for processed food products. Understanding the behavior of the thermal protein denaturation for ingredients in the food matrix and its fundamental importance to the industry, this property may influence the attributes of the processed products. The objective of this study was evaluate the kinetics of the viscosity´s development from the rehydrated MPP in different concentrations, when used in different conditions of thermal processing using the Rapid Visco Analyzer (RVA) as a process simulator. Commercial samples of skimmed milk powder (SMP), whey protein concentrate (WPC), milk protein concentrate (MPC), whey powder (WP) and demineralized whey powder (DWP) were analyzed. The solid-liquid ratio evaluated were 0.1 g.g-1 a 0.4 g.g-1 for the WPC/MPC and 0.4 g.g-1 a 0.8 g.g-1 of dry solids per 1 g of water for SMP, WP and DWP because of the sensibility of the system to the concentration of solids. The Brazilian setup of industrial heat treatment used were 65oC/30min, 85o/15min and 95oC/5 min. Thus, the results could be interpreted as a function of the thickening rate during the heating and cooling. It was possible to optimize the different conditions of parameters of the MPP with the interpretations of the viscographic profiles obtained, with reference to the thermal behavior of proteins, especially for the WPC and MPC. Indeed, the RVA can be considered an emerging analytical tool for the study and knowledge of PDI, aiding to optimize the choice for the technological application in the food industry, through ongoing analysis of viscosity to estimate the rate of the protein denaturation.