Effect of heat treatment and droplet size on the oxidative stability of whey protein emulsions

The present paper examines whether certain processing factors may influence the oxidative stability of whey protein oil-in-water emulsions, which are structurally close to innovative industrial products (e.g. “fresh-cheese” and “non-dairy cream” types).We first checked whether the thermally induced whey protein denaturation might correlate with oxidative changes, in whey protein emulsions prepared with heat pre-treatment at varying temperatures (40–85 °C). The results showed that an increase of whey protein denaturation (in particular at >60 °C temperatures) was associated with a decrease of emulsion oxidative sensitivity, in terms of conjugated diene hydroperoxides production.In model whey protein emulsions prepared at 70 °C under varying homogenisation pressures (30–600 bars), any effect of the droplet size on the oxidative changes was subsequently investigated. The measurements of conjugated dienes or TBARs did not reveal a clear trend of changes for either of these oxidative indicators with emulsion droplet size.