Methodology of Chewing's sound acquisition by different detectors for dry food in terms of crispness and crunchiness

This paper presents an acoustic detection methodology, providing an overview of Sound Profile Analysis (SPA) and objective data for food sensory analysis. The main goal of present work is improving the sensorial evaluation of crispness and crunchiness on dry food by mastication's sound. This is aimed to the definition of a quality index for "crispy" and "crunchy" perceptual parameters, which are the main texture attributes affecting acceptability of food regarding auditory sensations. The innovative approach consists of using acoustical transducers to measure the objective acoustic parameters on chewing's food sound. Three different types of transducers were tested (cardioid condenser microphones at a distance, binaural microphones inserted at the entrance of the ear ducts of subject & piezo-electric transducers placed on cheeks of subject) to cover the main principles of vibro-acoustic propagation: air transmission and bone conduction. The binaural microphones resulted in better signals. The recorded waveforms were processed with existing software for performing spectrum analysis and computing standard acoustical parameters such as levels in dB, reverberation time in seconds and other "objective" acoustical parameters. The ones chosen for SPA are those who revealed better statistical properties and good correlation with laboratory measurements of texture and hardness data.