Ultrasonics takes the biscuit
The Challenge
Customer satisfaction of many crispy/crunchy food products such as biscuits and crisps depends largely on its texture and the sounds emitted when eaten. Stable Micro Systems Ltd is a UK based SME which manufactures Texture Analysers. These instruments quantify the texture of food when it is snapped, cut, punctured or crushed.
The Texture Analyser can be coupled with the Acoustic Envelope Detector (AED), to simultaneously measure force and acoustic emissions during the test. However, the AED can only measure sounds up to a frequency of 12.5 kHz.
The company were keen to investigate whether or not crispy/crunchy foods produced sound signatures with frequencies above the capacity of the AED and into the ultrasonic region but did not have the facilities or equipment to do so.
The Solution
Stable Micro Systems Ltd initially approached NPL for help because of the latter's unique acoustic testing facilities and a two-day consultancy with NPL was arranged. The company brought along their Texture Analyser, AED and a range of food samples for testing including rice cakes, biscuits, crisps and chocolate mousse.
The acoustic experiments were conducted in NPL's hemi-anechoic chamber using specialised microphones and high resolution sound recording equipment. The company was delighted by the initial findings that confirmed acoustic emissions of the products tested extended beyond the limits of the AED. They are now quantifying and interpreting the data to identify the importance of these higher frequency emissions in characterising and differentiating crispiness/crunchiness of food materials.
"[The project] has enthused Peter Jardine, the company's scientist, and he is very keen to quantitatively analyse the data."
Jade Bank, Product Specialist, Stable Micro Systems Ltd
Find out more about NPL's research in Sound in Air.
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