Skull Vibration During Chewing of Crispy Food

Abstract

When we chew crispy food, the jaw decelerates and accelerates as a result of resistance and breakage of food particles, and a characteristic sound of the breakage of the food particles is produced. Our aim was to investigate how physical responses, in the form of vibrations, change during chewing. This will give an impression of how food characteristics change during the chewing process. Force resistance and sound emission of three crispy foods (biscuits) and one noncrispy food (cake) were determined with a texture analyzer. We measured skull vibration, while the subjects chewed and swallowed the foods. Clear skull vibrations were observed while the subjects started to chew the biscuits. The skull vibrations gradually decreased upon further chewing down to the level of skull vibrations produced by chewing on noncrispy cake. Then, the biscuits were chewed long enough to form a well‐moistened food bolus that was ready for swallowing. PRACTICAL APPLICATIONS The crispy nature of food products is an important sensory characteristic on which consumers base their appreciation. Rheological measurements have often turned out not to be completely satisfactory in explaining the relationship between food structure and texture perception. This could be explained by the notion that this approach disregards the oral processing and physiology of the mouth. The measurement of skull vibration, produced by the breakage of crispy food during chewing, provides information on how food characteristics gradually change during chewing. This information may help to understand the relationship between food structure and texture perception.

Measurement of the texture of dry crisp products

“…While testing using humans provides a direct link with sensory perception, it has been shown that sounds produced during instrumental testing of crisp products are strongly correlated with the bone-conducted vibrations occurring when an individual bites into the product (van der Bilt et al, 2010). This research provides support for previously published research presenting sounds recorded during mechanical breakage of crisp products (Chen et al, 2005;Varela et al, 2006;Primo-Martin et al, 2009;Salvador et al, 2009;Saeleaw and Schleining, 2010).…”

The influence of auditory and visual information on the neuromuscular control of chewing crispy food

“…1C). Furthermore, skull vibrations gradually decreased upon further chewing because the food particles are fragmented by the teeth and mixed with saliva to form a bolus that can be swallowed (9–11). Just before swallowing, the skull vibrations produced by chewing had decreased to the level recorded when chewing a non‐crispy cake (11).…”

“…Apparently, the participants were uncertain about what they were chewing, which resulted in longer cycle durations. In a later phase, chewing sounds and vibrations were no longer present as the crispy biscuits had been transformed into a well‐moistened food bolus (11). The effects of visual masking were present at the beginning, as well as halfway through the chewing process, while just before swallowing the effects of visual masking had disappeared.…”

“…Breakdown of particles and moistening of crispy food during chewing result in lower sound levels (9). Furthermore, skull vibrations, generated by breakage of crispy food, gradually decrease upon further chewing down to the level of skull vibrations produced while chewing a non‐crispy food (10, 11).…”

Acoustic vibration method for food texture evaluation using an accelerometer sensor

“…Therefore, most of these studies used a microphone to detect the sound of the sample breaking (see Duizer, 2001;Taniwaki and Sakurai, 2010a for review). The microphone method for recording mastication sounds from the panelists has several drawbacks for quantitative and reproducible evaluation of food texture, such as variations in the microphone performance (Chen et al, 2005), the experimental conditions (room size, arrangement of auditory equipment, and environmental noise), the resonant frequencies of the mouth cavity and the skull bone connected to the mouth (van der Bilt et al, 2010), and the quantity and rate of saliva during mastication (Szczesniak, 2002). Most of the above drawbacks stem from the inevitable variation between the individual panelists.…”