Determining the Free Liquid Phase of Food Surface for Predicting Food Adhesion Phenomena

Abstract Food adhesion phenomena, including dough adhesion, present significant challenges in the food industry. While various factors influencing dough adhesion have been extensively studied, the interactions within the boundary layer between dough and contact materials remain insufficiently understood. Based on adhesion theories, wetting may play a fundamental role in dough adhesion. To investigate this, a method was developed to quantify the free liquid phase on the dough surface. The approach involves establishing a defined contact between a freshly cut wheat dough surface and a carrier material, allowing diffusion of the wetting liquid into the carrier. The absorbed liquid was analyzed for its quantity, protein content, and low-molecular saccharides. After 60 min of contact, the dough-wetting liquid absorption reached 21.65 ± 0.50 g/m 2 , with protein and low-molecular saccharide contents of 0.14 ± 0.02 g/m 2 and 0.41 ± 0.04 g/m 2 , respectively. These findings confirm the presence of a free liquid phase on the dough surface, which contributes to the wetting of contact materials. The method yielded reproducible results, demonstrating its effectiveness and providing new insights into dough adhesion and related food systems. This advancement establishes a foundation for the further study of correlating wetting behavior with adhesion properties, enabling a knowledge-based selection or development of contact materials to optimize adhesion characteristics and enhance production efficiency.