Exploring cracks, of breads and snacks

Garmt Dijksterhuis1/2*, Hannemieke Luyten1/2/3, Mariska Nijenhuis2

1) WCFS, Wageningen Centre for Food Sciences.

2) WUR-CICS, Centre for Innovative Consumer Studies;

3) Friesland Foods


In order to understand if it is possible to distinguish "crispy/crunchy" food products on the basis of solely the sound they make when bitten, the acoustic emission of fracturing bread and fried snack model products was recorded and presented to a sensory panel. The time between baking/frying and breaking was systematically varied for two varieties of each product type.


Two different studies are reported here:

(1) The presentation of the sounds to the panel takes place according to the method of triadic comparisons. This method produces a dissimilarity score for pairs of sounds which are graphically represented through Multi Dimensional Scaling. The results from the analyses showed that both for breads and snacks larger differences in ageing time lead to sounds that could be distinguished by the panel.

(2) In addition to the triads, the panellists scored some attributes of the sounds in a sensory profiling. The results of the profiling show similar differences between the replicates, and a similar structure as seen in the MDS results for the bread sounds. The attributes crispy, crackling and fresh were found to correlate with each other, while tough is a different property. For the bread products some relation with ageing could be found. Crispy and crackling were more related to fresh breads, and the toughness to aged bread. Some of the snack sounds were presented with an altered sound spectrum. Especially low-pass filtering at higher frequencies showed an effect on the perception of the sound. The results shows an underlying dimension related to perceived ‘freshness’. When frequencies above 8 kHz were removed, the sounds were perceived as more tough and less crispy and fresh than the original fracturing sound of snacks. This may be related to the high auditory threshold for humans at these high frequencies.