Abstract: The goal of this study was to investigate the effect of whether or not whey protein concentrate (WPC) is involved in starch gelatinization and WPC concentration on the lubricating properties of a starch-WPC mixed system as evaluated using polydimethylsiloxane as the friction pair under simulated oral conditions. The results showed that during the first 60 seconds of oral processing, the lubricating properties of starch-WPC mixed systems significantly varied depending on whether or not WPC was involved in starch gelatinization and on the species of starchy plants used (P < 0.05). Addition of 1%–7% of WPC significantly improved the lubricating properties of starch gels in a nonlinear manner (P < 0.05). The results of this study provide a theoretical basis for improving the texture and taste of starch-protein based foods.

Key words: starch gels; whey protein; mouthfeel; lubricating; tribology