The impact of pH environment on the lubrication performance of starch gel in simulating oral processing

This study focuses on how varying pH environments affect the physical properties of corn and potato starch gels during simulated oral chewing. Significant pH changes were observed in both starch gels after treatment with different concentrations of citric acid (0.005%, 0.01%, and 0.1%) and sodium bicarbonate (1%) (P < 0.05). Texture, water distribution, rheological, and tribological properties were evaluated. Results showed that a weakly alkaline environment (pH ≈ 8.1) improved lubrication, reducing the friction coefficients of corn (μ = 0.88) and potato (μ = 1.00) starch pellets by 17.28% and 2.91%, respectively. In acidic conditions (pH ≈ 2.88), the friction coefficients of corn (μ = 0.82) and potato (μ = 0.98) starch pellets decreased by 22.36% and 3.88%, respectively. PLSR analysis under acidic conditions revealed that free water (A 24 ) and hardness negatively correlated with friction coefficient, while apparent viscosity showed a positive correlation (P<0.05). These findings provide insights for optimizing the sensory texture of starch-based foods. • PH affects the physical properties of starch gels in simulated oral process. • An alkaline pH of 8.1 improves the lubricity of starch gel pellets by 2.91–17.28%. • An acidic pH of 2.88 improves the lubricity of starch gel pellets by 3.88–22.36%. • The percentage of free water and hardness negatively correlated with friction.