The Physical Processes of Digestion (eBook)

Roger Lentle graduated in medicine and in biochemistry from University College London and gained his PhD at Massey University, New Zealand. He has published extensively on the physical processes of digestion and is Professor of Digestive Biomechanics at the Institute of Food Nutrition and Human Health at Massey University.Patrick Janssen gained his PhD in chemical and process engineering at Canterbury University, New Zealand. He worked in the fields of process control and milk fat processing in the dairy industry before developing an interest in the physical processes of digestion. Currently he is a senior lecturer at the Institute of Food Nutrition and Human Health at Massey University. 

Introduction Flow mixing and absorption. The physical problems of extracting nutrients from food items and the possible macroscopic and microscopic solutions. The digestive tube and its limitations. solid to liquid to solid Methods for evaluating the physical properties of digesta Particle sizeRheology Viscometry Viscoelastic behaviour Time dependent behaviour Permeametry Hindered settling functionPermeability and other measuresMethods for evaluating the relationship between motility and flow of digesta Solid and liquid phase markers Reactor mixing Spatiotemporal mapping Physical behaviour of fluid digestaMacroscopic effects Newtonian and non Newtonian behaviour of fluids. Where digesta fit in this system the kinetics of digesta flow Securing efficient absorption from fluids and non-Newtonian fluids, chemical reactor theory and problems Buoyancy Backflow form coiled elementsPhysical behaviour of solid digesta The continuum between solids and liquids viscoselasticity securing efficient absorption from fluids and from viscoelastic fluidsPermeability extrusion of the liquid phase Propulsion and mixing of digesta the interplay between the gut wall and its contents Tension and stretch receptors in the enteric nervous system Maintaining the flow of digesta problems of narrowing and expanding Co-evolution of motility and the physical properties of digesta Micromixing Diffusion. Mucus and the unstirred water layer.Flow in the paravillus space and the crypts.Tight junctions permeability and fluid flowGlycocalyceal signalling of shear The physics of food What is known about how the physical structure of food interacts with the digestive processes e.g starch granule digestion digestion of proteinaceous aggregates eetc ( Dr Allan Hardacre NZ Crop and Food )Flow and microorganisms Adaptions of micro-organisms to move within digesta and mucus Glycocalyceal signalling Messing with the properties of digesta Adulterating foods with viscoactive substances Nutraceuticals planning the rate of nutrient release. Modulating lumen pressure Microencapsulation and adherence to the gut wall