The Physical Processes of Digestion

ISBN-13: 9781489985576 / Angielski / Miękka / 2014 / 279 str.

Roger G Lentle;Patrick W M Janssen

Opis

Food research (and funding) is becoming more and more focused on health. While researchers and product developers have made great strides in food engineering, there needs to be increased focus on what happens when the food is actually digested. How is the food absorbed? Do the benefits remain? Digestion is a complex topic, and this will be the first book aimed at food researchers. Authored by a physiologist and a food engineer, the book will be a welcome addition to the literature.

Spis treści

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 size

Rheology Viscometry Viscoelastic behaviour Time dependent behaviour

Permeametry

Hindered settling function

Permeability and other measures

Methods for evaluating the relationship between motility and flow of digesta

Solid and liquid phase markers

Reactor mixing

Spatiotemporal mapping

Physical behaviour of fluid digesta

Macroscopic 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 elements

Physical behaviour of solid digesta

The continuum between solids and liquids viscoselasticity securing efficient absorption from fluids and from viscoelastic fluids

Permeability 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 flow

Glycocalyceal 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

O autorze

<b>Roger Lentle</b> 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.<P>

<b>Patrick Janssen</b> 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. 

Blurb

This book is aimed at physiologists, pharmacologists, nutritionists and food technologists whose work requires an understanding of the physical processes of digestion. <P>

 

The book provides an overview of what is known of the physical processes of digestion in man and other simple-stomached vertebrates in two broad sections. The first section considers the physical constraints that govern the dissolution and digestion of the various macronutrients within food particles, and the physical factors that influence their subsequent transfer to the gut wall, notably the rheology and permeability of digesta. The second section examines the effects of the alimentary, mechanical and biophysical processes on mixing and mass transfer. Included is a comprehensive review of the effects of the various types of contractile activity in the gut wall in securing efficient mixing and onflow of digesta through the various segments of the gut. The section also examines what is known of the actions of the mucinous and cellular components of the gut wall in lubricating the passage of digesta and in limiting the permeation and absorption of nutrients, pharmaceuticals and microbial products. The section concludes with a review of the effects of the various physical and morphological components of the gut wall that constitute the ‘unstirred water layer’ on the process of absorption. <P>

 

The authors are leaders in their field and have extensively researched the literature. The work cites over 1500 references including those pertaining to the latest developments.