This PhD project will gain an in depth fundamental understanding of oral processing behaviour and the dynamics perception of food texture and taste. This fundamental research will result in a better understanding of eating behaviour and consequently, of food appreciation. Oral food processing is by itself a highly dynamical process in which the food is gradually broken down until it can be safely swallowed.
For each bite of a solid food or sip of a liquid food, oral processing is characterized by three phases, ingestion, processing and swallowing: After taking a sip or bite, food is first transported by the tongue. When solid, the food is then reduced in particle size by chewing and lubricated. A distinction can be made in the processing phase between the start of an oral process, first bite, and the further chewing or mastication. When semi-solid or liquid, food is reduced by palatal reduction, i.e. the structural disintegration of the food by squeezing it against the palate with the tongue. Finally, when the food is broken down to a bolus that can be swallowed safely, it is transported to the back of the mouth and subsequently swallowed. Besides this digestive purpose, human oral processing is essential for the perception of food texture and, consequently, for appreciation.
This PhD project hypothesize that the exact degradation process of the food is the result of specific oral behaviours, which in turn may be related to specific food texture and taste sensations. Different sensations will reflect the different stages of oral processing and/or specific movements.
To gain more insight in these specific behaviours, this project focusses on facial muscle behaviour during oral processing. To explore the extent and the intensity of muscle activity, electromyography (EMG) is used as a method to monitor the electrical activity generated by muscle cells during oral processing. Electromagnetic articulography (EMA) is used to explore spatial displacement of oral tissues including the tongue and the jaws during food oral processing. EMG will be combined with sensory methods and together the connection can be made between specific sensory sensation and specific muscle activities at different specific stages of food oral processing. The project will gain a fundamental understanding of oral behaviour in relation to food composition, food properties, individual differences and sensory task instructions.