What substances give rise to the different sensations? 20

Transcription

1 Preface xiv Contributors xvii PART ONE ORAL ANATOMY AND PHYSIOLOGY 1 1 Oral Cavity 3 Luciano José Pereira 1.1 Introduction The oral cavity Salivary glands and saliva secretion Orofacial muscles The tongue Concluding remarks 12 Acknowledgements 12 References 13 2 Oral Receptors 15 Lina Engelen 2.1 Introduction to oral receptors Babies sense the world around them through the mouth Receptors Innervation and transduction Taste Taste receptors Taste molecules and modalities What substances give rise to the different sensations? Mechanoreception Tactile stimulation Function during eating 23

2 2.3.3 Mechanoreceptors in the mouth SA1 form and texture FA SA2 shape and position of tongue Proprioceptors Proprioception Muscle spindles Golgi tendon organ Mechanoreceptors as proprioceptors Periodontal receptors Function of periodontal receptors Signal transduction and central processing Nociception Nociceptors Nociception in food Nociceptive transduction Thermal perception Thermal sensation Thermoreceptors Thermal transduction Temperature and food The thermoreception and nociception relation Olfaction Olfaction and food Olfactory receptors and transduction 37

3 2.7 Concluding remarks 38 References 38 3 Role of Saliva in the Oral Processing of Food 45 Guy Carpenter 3.1 Introduction Control of salivary secretion Functionalities of saliva Salivary interactions with the oral mucosa Perception of taste Protection of the oral environment Saliva in bolus formation, swallowing and oral clearance Bolus formation and swallowing Post-mastication oral clearance Concluding remarks 56 Acknowledgements 56 References 57 PART TWO FOOD ORAL MANAGEMENT 61 4 Oral Management of Food 63 Andries van der Bilt 4.1 Introduction Factors infl uencing oral function Dental factors Jaw muscle activity (EMG) and bite force Masticatory performance Swallowing of food Saliva 70

4 4.3 Influence of food characteristics on chewing Influence of food type on muscle activity, chewing force and jaw movement Crispy food Influence of food type and volume on swallowing Muscle activity and jaw movement in various phases of chewing Neuromuscular control of chewing and swallowing Cortical masticatory area Central pattern generator Peripheral feedback Simulated chewing experiments Neuromuscular control of chewing crispy food Concluding remarks 84 References 85 5 Breaking and Mastication of Solid Foods 95 Carolyn F. Ross and Clifford L. Hoye Jr. 5.1 Introduction Mechanical properties and food texture Characterisation of mechanical properties Oral selection of food particles The role of the tongue Selection function Breakage function Definition of breakage function Crack initiation and propagation Correlations between breakage function and food mechanical properties Limitations of breakage function 107

5 5.6 Concluding remarks 107 References Oral Behaviour of Food Emulsions 111 Anwesha Sarkar and Harjinder Singh 6.1 Introduction Food emulsions in general Interfacial layers Emulsion stability Depletion flocculation Bridging flocculation Coalescence Behaviour of emulsions under oral conditions Saliva-induced destabilisation Neutral or negatively charged emulsion saliva interactions Positively charged emulsion saliva interactions Shear-induced destabilisation Relating oral destabilisation to sensory perception Droplet flocculation Droplet coalescence Concluding remarks 131 References Bolus Formation and Swallowing 139 Jianshe Chen 7.1 Introduction Mechanisms of swallowing Stages of swallowing 139

6 The oral phase The pharyngeal phase The oesophageal phase Oral pressure and bolus swallowing Bolus location before swallowing The oral pressure Measurements of oral pressure The formation of a food bolus and the triggering criteria of bolus swallowing Dynamics of bolus formation Critical criteria in triggering a swallow Influences of food properties on bolus formation Concluding remarks 154 References 155 PART THREE FOOD ORAL PROCESSING AND SENSORY PERCEPTION Oral Processing and Texture Perception 159 Lina Engelen and René A. de Wijk 8.1 Introduction What is texture? Why is texture important for the perception of foods? Where is texture sensed in the mouth? The special case of the texture of fat Texture versus food structure Liquids Semi-solids Solids Crispy and crunchy food 163

7 8.4 The measurement of oral processes Texture versus oral processing Texture attributes are systematically related The role of saliva in texture perception Saliva fl ow rate and texture perception Saliva composition and texture perception Salivary enzymes and texture perception Oral temperature and texture perception Concluding remarks 172 References Oral Processing and Flavour Sensing Mechanisms 177 Sarah Adams and Andrew J. Taylor 9.1 Introduction Mechanisms for sensing and measuring taste Taste thresholds Food structure, oral breakdown and tastant release Mechanisms for sensing and measuring aroma Mechanisms for sensing and measuring texture Multi-sensory interactions Measuring food breakdown and deposition in vivo Imaging food in vivo Spectroscopy of food components in vivo Following mastication in vivo Biochemical fl avour changes during oral processing Applications of knowledge to real food products Concluding remarks 195

8 Acknowledgements 196 References Multi-sensory Integration and the Psychophysics of Flavour Perception 203 Charles Spence 10.1 Introduction Taste/Gustation Olfactory gustatory interactions in multi-sensory flavour perception Oral somatosensory contributions to multi-sensory flavour perception Auditory contributions to multi-sensory flavour perception Visual flavour : visual contributions to multi-sensory flavour perception The cognitive neuroscience of multi-sensory flavour perception Concluding remarks 216 References 219 PART FOUR PRINCIPLES AND PRACTICES OF INSTRUMENTAL CHARACTERISATION FOR EATING AND SENSORY PERCEPTION STUDIES Oral Rheology 227 Jason R. Stokes 11.1 Introduction to food rheology and oral processing Liquid food rheology and structure Dispersions of particles and polymers Shear thinning Viscoelasticity Linear viscoelasticity Non-linear viscoelasticity: normal stresses Extensional viscosity Instrumentation for liquid foods 237

9 Cone-and-plate Parallel plate Concentric cylinder Extensional viscosity Soft food rheology and microstructure Microstructure: gels and glasses Rheology Mechanical properties and fracturing behaviour Solid food breakdown and rheology Saliva and rheology Saliva Real or artificial saliva to study food saliva interactions? Saliva rheology Sensory perception and the fluid dynamics between tongue and palate Shear flow Shear flow and sensory thickness: what is the shear rate in the mouth? Squeeze flow Shear and squeeze flow: defining an oral shear stress? Micro-rheology: gap dependency, confinement and slip Concluding remarks 258 References Oral Tribology 265 Jason R. Stokes 12.1 Introduction Principles of tribology Hydrodynamic lubrication and the Reynolds equation 266

10 Elastohydrodynamic lubrication Film thickness and friction in isoviscous elastohydrodynamic lubrication Limits of hydrodynamic lubrication: Stribeck curve Boundary lubrication Food lubrication Kokini models for smoothness and slipperiness Biosubstrates and simulated oral contacts Soft-tribology Master curves Emulsions Hydrocolloids Saliva Concluding remarks 284 Acknowledgements 285 References Applications of Electromyography (EMG) Technique for Eating Studies 289 Yadira Gonzalez Espinosa and Jianshe Chen 13.1 Introduction Principles of electromyography technique Muscle motors and their activation Surface electromyography vs. intra-muscular electromyography Main mastication muscles for surface electromyography studies EMG experimental design and set-up Electrodes, location and placement Selection criteria of subjects for EMG studies Experimental procedures 299

11 Preparation Set-up Set-up checking and validation Test performance Data analysis Processing of raw EMG signals Rectifi cation Integration Root mean square (RMS) Masticatory parameters: analysis of chewing sequence and individual chewing cycles Analysis of the whole chewing sequence Analysis of individual chewing cycles Case studies Concluding remarks 314 References Soft Machine Mechanics and Oral Texture Perception 319 Micha Peleg and Maria G. Corradini 14.1 Introduction Sensory terms and vocabulary Soft machine mechanics The signal generated by stiff and soft machines Mechanical sensitivity of soft machines The amplifier and sensory sensitivity Adaptation and fatigue Concluding remarks 334

12 References 335 PART FIVE APPLICATIONS AND NEW PRODUCT DEVELOPMENTS Appreciation of Food Crispness and New Product Development 339 Paula Varela and Susana Fiszman 15.1 Introduction Appreciation of crispy and crunchy texture Mechanical and structural features of crispy/crunchy food Wet-crisp food products Dry-crisp food products Crusted or multi-layered food products Characterisation of crispy/crunchy textures Sensory perception and measurement of crispness/crunchiness Instrumental characterisation of crispness/crunchiness Texture measurements Acoustics Instrumental characterisation of crispness structure and microstructure Infl uence of the product design and formulation, process and storage conditions in the attainment, enhancement and maintenance of the crispy/crunchy character in wet, dry and crusted food products Wet-crisp products Dry and crusted products Bread as an example of composite crisp food Deep fried products Concluding remarks 353 References Design of Food Structure for Enhanced Oral Experience 357 Adam Burbidge

13 16.1 Introduction Biophysics of oral perception Structural stimuli of mechanoreceptors Engineering of microstructures in food Freeze drying Puffed cereals Spray dried powders Ice cream production Acknowledgements 378 References 378 Index 381