New approach to food difficulty perception: food structure, food oral processing and individual’s physical strength

This study aims to study the effect of the interaction between food physics and human physical strengths on food oral processing and difficulty perception in the young population. As the first step in human nutrition is the food oral processing, special emphasis has been given to the oral strengths. Fracture mechanics of fifteen commonly consumed food products of fruits, vegetables and dairy origin were analysed using penetration test. Among the different products studied, six products (carrot, banana, mozzarella, potato, soft cheddar and hard cheddar) were selected and given to 11 young participants (<25 y.o.). Individual physical assessments included measurements of dominant hand grip force, isometric tongue pressure and bite force. Participants ranked the food products in the order of difficulty perceived using a visual analogue scale. Additionally, the number of chews and the time at swallow were analysed from video-recording for each participant. Food score difficulty showed that high break force of food products were related linearly with difficulty perceived (r = 0.729) and with higher oral processing time (r = 0.816). Other food breakdown characteristics such as number of peaks and gradient of the penetration curves showed linear correlation with mastication time (r = 0.830, r = 0.840) and number of chew cycles (r = 0.903, r = 0.914). However, no relationship could be established between individual physical forces (hand and oral) and food perception difficulty for young participants interviewed. This might be attributed to the selected healthy and young population having higher hand force/tongue force ratio, which might not interfere with their eating process.