Oral processing of hydrogels: influence of food material properties versus individuals' eating capability.

Food material properties play an important role in the sensory perception and consumer acceptance of foods. However, the actual oral processing behaviour may depend on both the material properties of the food that is being consumed as well as individuals' oral capabilities. This study aimed to examine the relationships between intrinsic (oral capabilities of healthy participants), as well as extrinsic (food material properties of a set of hydrogels) variables to the real oral processing behaviour. Three κ-carrageenan hydrogels (κC), differing in fracture mechanics and oral tribology properties, were prepared: native κC, κC with added Na-alginate and a κC matrix with added Ca-alginate beads of 300 μm. A composite score of eating capability (EC) was measured with non-invasive techniques (maximum bite force and tongue pressure) using a panel of 28 untrained consumers. The oral processing behaviour (number of chews, oral residence time and chewing rate) was analysed with the same participants using frame-by-frame video analysis. It was found that the EC scores did not correlate with any of the oral processing behaviours. The number of chews and oral residence time showed a strong correlation to the fracture force and friction force at orally relevant speeds (10-100 mm/s), whereas chewing rate did not vary with these properties. The results from this study indicate that oral processing in healthy adults seems mainly motivated by food material properties, and the chewing rate seems to relate more to individual differences and EC than to food properties. Understanding the interplay between food material properties, consumers' eating capability and oral processing behaviour is important to advance knowledge and to translate this to applications for the food industry, such as designing foods with improved textural properties. We employed a combination of eating capability measurements, texture analysis, oral tribology as well oral processing video analysis as a feasible approach to understand the importance of intrinsic eating capability versus extrinsic food material properties on oral processing behaviour. Insights from this study, using model hydrogels, have helped to promote knowledge on oral processing behaviour in healthy individuals, could bridge the gap between consumer science, psychology and food science, and may be of interest to product developers in designing foods with pleasant texture properties. This article is protected by copyright. All rights reserved.