Food oral breaking and the determining role of tongue muscle strength

Abstract

Some previous studies have revealed a great variation of tongue muscle strength among healthy individuals. However, the implication of different tongue muscle strengths to individuals' oral capability of food handling is yet to be determined. In this work, vege-gels (with a resilient consistency of jelly) and pastry food (mashed potato) were used to investigate tongue-only oral breaking (smashing) of these foods by individuals who have different tongue muscle strengths. The aim of the work is to determine whether a correlation exists between the tongue muscle strength and its capability of food breaking. A series of vege-gels and mashed potato samples ranging from soft to hard were constituted with increasing consistency. Mechanical/textural properties of test food samples were characterised by a texture analyser. Three experimental tasks were designed: characterisation of individual's tongue muscle strength by measuring the maximum isometric tongue pressure (MITP) (Task 1); assessment of individual's capability of tongue-only food breaking (Task 2); and measurement of tongue–palate pressure generation for food oral breaking (Task 3).Our results confirm the great variability of tongue muscle strength among healthy individuals, with the highest MITP reaching 75kPa and the lowest at only 17kPa. The correlation study of tongue strength and the threshold gel/mashed potato strength for tongue-only oral breaking reveals a positive relationship between the two factors, which suggests that strong tongue muscle strength is always advantageous for oral handling (break/smashing) of viscoelastic and pastry foods. Conclusions obtained from this work can be a useful guidance to food design for elderly consumption.