Dense Phase Carbon Dioxide

Dense phase carbon dioxide (DPCD) is a non-thermal method for
food and pharmaceutical processing that can ensure safe products
with minimal nutrient loss and better preserved quality attributes.
Its application is quite different than, for example, supercritical
extraction with CO 2 where the typical solubility of materials in
CO 2 is in the order of 1% and therefore requires large volumes of
CO 2. In contrast, processing with DPCD requires much less CO 2
(between 5 to 8% CO 2 by weight) and the pressures used are at
least one order of magnitude less than those typically used in
ultra high pressure (UHP) processing. There is no noticeable
temperature increase due to pressurization, and typical process
temperatures are around 40°C.

DPCD temporarily reduces the pH of liquid foods and because
oxygen is removed from the environment, and because the temperature
is not high during the short process time (typically about five
minutes in continuous systems), nutrients, antioxidant activity,
and vitamins are much better preserved than with thermal
treatments. In pharmaceutical applications, DPCD facilitates the
production of micronized powders of controlled particle size and
distribution. Although the capital and operating costs are higher
than that of thermal treatments, they are much lower than other
non-thermal technology operations.

This book is the first to bring together the significant amount
of research into DPCD and highlight its effectiveness against
microorganisms and enzymes as well as its potential in particle
engineering. It is directed at food and pharmaceutical industry
scientists and technologists working with DPCD and other
traditional or non-thermal technologies that can potentially be
used in conjunction with DPCD. It will also be of interest to
packaging specialists and regulatory agencies.

Auteur
Murat O Balaban, PhD is Professor of Food Processing and Engineering in the Food Science and Human Nutrition Department, University of Florida, Gainesville, FL. Current research areas include food processing and engineering with emphasis on supercritical fluid technology; mathematical modeling and computer vision applications, thermal processing and reaction kinetics; ohmic thawing; and seafood processing and technology. Dr. Balaban holds five US patents, including one for the inactivation of enzymes in foods with pressurized CO2 and another for the method and apparatus for continuous flow reduction of microbial and/or enzymatic activity in a liquid beer product using carbon dioxide.

Résumé

Dense phase carbon dioxide (DPCD) is a non-thermal method for food and pharmaceutical processing that can ensure safe products with minimal nutrient loss and better preserved quality attributes. Its application is quite different than, for example, supercritical extraction with CO 2 where the typical solubility of materials in CO 2 is in the order of 1% and therefore requires large volumes of CO 2. In contrast, processing with DPCD requires much less CO 2 (between 5 to 8% CO 2 by weight) and the pressures used are at least one order of magnitude less than those typically used in ultra high pressure (UHP) processing. There is no noticeable temperature increase due to pressurization, and typical process temperatures are around 40°C.

DPCD temporarily reduces the pH of liquid foods and because oxygen is removed from the environment, and because the temperature is not high during the short process time (typically about five minutes in continuous systems), nutrients, antioxidant activity, and vitamins are much better preserved than with thermal treatments. In pharmaceutical applications, DPCD facilitates the production of micronized powders of controlled particle size and distribution. Although the capital and operating costs are higher than that of thermal treatments, they are much lower than other non-thermal technology operations.

This book is the first to bring together the significant amount of research into DPCD and highlight its effectiveness against microorganisms and enzymes as well as its potential in particle engineering. It is directed at food and pharmaceutical industry scientists and technologists working with DPCD and other traditional or non-thermal technologies that can potentially be used in conjunction with DPCD. It will also be of interest to packaging specialists and regulatory agencies.

Contenu

Preface xi

Contributors xiii

1 Introduction to Dense Phase Carbon Dioxide Technology 1
Giovanna Ferrentino and Murat O. Balaban

2 Thermodynamics of Solutions of CO2 with Effects of Pressure and Temperature 5
Sara Spilimbergo and Ireneo Kikic

2.1 Introduction 5

2.2 Thermodynamics of liquidvapour phase equilibria 6

2.2.1 Calculation of g 10

2.2.2 Calculation of f 13

2.2.3 Calculation of the liquidvapour phase equilibria 20

2.3 Application to CO2H2O system model 24

2.3.1 Non-electrolyte models 24

2.3.2 Electrolyte models 26

2.4 Thermodynamics of solidvapour equilibria 28

2.5 List of symbols 31

3 Experimental Measurement of Carbon Dioxide Solubility 37
Giovanna Ferrentino, Thelma Calix, Massimo Poletto, Giovanna Ferrari, and Murat O. Balaban

3.1 Introduction 37

3.2 Solubility of carbon dioxide in water 38

3.2.1 Definition and brief review of early studies 38

3.2.2 Physical properties associated with the phase diagram of carbon dioxide 41

3.2.3 Effect of pressure and temperature on carbon dioxide solubility in water 42

3.3 Experimental methods for carbon dioxide solubility measurement 45

3.3.1 Analytical methods 46

3.3.2 Synthetic methods 55

3.4 Review of experimental results 58

3.5 Conclusions 66

4 Effects of Dense Phase Carbon Dioxide on Vegetative Cells 67
Osman Erkmen

4.1 Introduction 67

4.2 Gases used for inactivating microorganisms 68

4.3 Effect of DPCD on vegetative microorganisms 69

4.3.1 Effect of DPCD on bacterial cells 69

4.3.2 Effect of DPCD on vegetative forms of fungi, pests and viruses 73

4.4 Factors affecting the sensitivity of microorganisms to DPCD 74

4.4.1 Effect of CO2 physical states 75

4.4.2 Effect of temperature and pressure 75

4.4.3 Effect of CO2 concentration 76

4.4.4 Effect of agitation 77

4.4.5 Effect of water content 77

4.4.6 Effect of pressurization and depressurization rates 78

4.4.7 Effect of pressure cycling 79

4.4.8 Effect of microbial type 79

4.4.9 Effect of initial microbial number 80

4.4.10 Effect of physical and chemical properties of suspension 80

4.4.11 Effect of culture conditions and growth phases 81

4.4.12 Injured microorganisms 82

4.4.13 Effect of combination processes 83

4.4.14 Effect of type of system 83

4.4.15 Treatment time and inactivation kinetics 84

4.5 Mechanisms of microbial inactivation by DPCD 85

4.5.1 Solubilization of CO2 under pressure into suspension 87

4.5.2 Cell membrane modification 88

4.5.3 Cytoplasmic leakage 88

4.5.4 Intracellular pH decrease 89

4.5.5 Key enzyme inactivation 90

4.5.6 Inhibitory effect of molecular CO2 and HCO3 - on metabolism 90

4.5.7 Intracellular precipitation and electrolyte imbalance 91

4.5.8 Extraction of vital cellular constituents 91

4.5.9 Physical cell rupture 92

4.6 Characterization of CO2 states and survival curves 93

4.7 Quantifying inactivation 96

4.8 Conclusions 96

5 Effects of Dense Phase Carbon Dioxide on Bacterial and Fungal Spores 99
Patricia Ballestra

5.1 Introduction 99

5.2 Inactivation of bacterial spores by DPCD 101

5.2.1 Effect of temperature 101

5.2.2 Effect of pressure 104

5.2.3 Effect of pH and aw of the treatment medium 105

5.2.4 Susceptibility of different bacterial spores 105

5.2.5 Effects of combination treatments 106

5.2.6 Mechanisms of bacterial spore inactivation 1…