In a unique double discovery, researchers at the University of Leeds, a leading British college, have shown that massive bursts of ultrasound are generated during the first second of biting into crunchy food - and are analysed simultaneously by the ears and mouth.
Research was carried out using texture expert Stable Micro Systems' revolutionary acoustic envelope detector, which comprises an ultra-sensitive microphone, a TA.XTplus texture analyser and 32-bit software, Exponent. Test results showed that the energy produced by the very first crack of a biscuit breaking is released as distinct pulses of sound.
Professor Malcolm Povey, food physicist at the University of Leeds explains: "Food is, in effect, talking to us and we innately understand what it's saying about texture by interpreting the sensations through our ears and mouths. Our research shows that the sound and texture of food in the mouth can be just as important as taste, look and smell in deciding whether we like something or not."
Slowed down and plotted onto a graph, using Stable Micro Systems' Exponent software, the sound pulses can be seen as a series of tall peaks, but actually last only for milliseconds and are generated across the frequency spectrum into the ultrasonic region.
The discovery of measurable sound pulses is of great interest to the food manufacturers, who in the pursuit of the perfect crispy/crunchy texture for their products, employ an army of trained tasting panels. These people form the crux of manufacturers' efforts at product consistency and quality control in terms of creating the optimum texture for a product.
The technique of measuring the sound of biting or breaking crispy food and simply counting the peaks of soundwaves provides a quantifiable and accurate analysis of texture, that will ensure absolute product consistency: "The more peaks, the crispier it is - it's as simple as that," says Povey.
The research also demonstrates that the human mouth is extremely accurate in its innate analysis of these sound pulses. Test results show a very high correlation to the machine-measured results by both professional tasters working in the food industry and untrained volunteers. "We had no idea that the human ears and mouth were so adept at capturing and analysing this information, especially in the space of milliseconds; it's incredible," he says.
Stable Micro Systems is a leading designer and manufacturer of texture analysis equipment. These instruments are already used in laboratories worldwide for testing in food, pharmaceuticals, personal care, paints and coatings and other manufacturing industries.
Professor Povey's research 'Acoustic envelope detector for crispness of biscuits' has been published in the Journal of Texture Studies (2005)
Stable Micro Systems' products are distributed in the USA and Canada by Texture Technologies Corp.
For further information on this research, please contact: Hannah Love, press officer, University of Leeds, tel: 0113 3434100 or 07974 184542
For further information on the acoustic envelope detector or Stable Micro Systems' other products, please contact: Texture Technologies Corp., 18 Fairview Road, Scarsdale, New York, 10583, USA. Tel: 914 472 0531 Fax: 914 472 0532
Email: [email protected] or visit www.texturetechnologies.com