Production, stability study, particles size distribution and rheological behavior of oil-in-water systems based on whey proteins / Produção, estudo de estabilidade, distribuição e tamanho de partículas e comportamento reológico de sistemas óleo/água adicionados de soro lácteo

Abstract

The present study evaluated the functionality of whey protein as an emulsifying and stabilizing agent in oil-in-water systems with the purpose of suggesting the use of whey in food, cosmetic or medicines emulsions. A basic emulsion with vegetable oil (20% w/w), whey protein (20% w/w) and xanthan gum (0.1% w/w) was prepared using a mixer equipament. Stability tests and storage conditions, flow test, freeze drying, particles size characterization, analyses of microscopic and rheological measurements were performed. Characterization analyses showed that the formed systems can be classified as emulsions with droplet sizes smaller than 100 µm, non-Newtonian fluids characterized as pseudoplastics and practically constant viscosity at high shear rates. In addition, characterization indicates that the use of Turrax results in more stable emulsions (more homogeneous droplets and reduced diameter) and lower apparent viscosity values. The results showed that emulsions formed by the use of whey include xanthan gum exhibit stability at room temperature, during freezing/thawing and the freeze drying process, suggesting the satisfactory application of these compounds information and stabilization of emulsions that undergo processes involving these unitary operations in pharmaceutical and food industries.