Dense Phase Carbon Dioxide E-Book

• Herausgeber: John Wiley & Sons
• Kategorie: Fachliteratur
• Sprache: Englisch

Seitenzahl: 568

Veröffentlichungsjahr: 2012

Beschreibung

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.

Leseprobe

Contents

Preface

Contributors

1  Introduction to Dense Phase Carbon Dioxide Technology

2  Thermodynamics of Solutions of CO2 with Effects of Pressure and Temperature

2.1 Introduction

2.2 Thermodynamics of liquid–vapour phase equilibria

2.3 Application to CO2–H2O system model

2.4 Thermodynamics of solid–vapour equilibria

2.5 List of symbols

3  Experimental Measurement of Carbon Dioxide Solubility

3.1 Introduction

3.2 Solubility of carbon dioxide in water

3.3 Experimental methods for carbon dioxide solubility measurement

3.4 Review of experimental results

3.5 Conclusions

4  Effects of Dense Phase Carbon Dioxide on Vegetative Cells

4.1 Introduction

4.2 Gases used for inactivating microorganisms

4.3 Effect of DPCD on vegetative microorganisms

4.4 Factors affecting the sensitivity of microorganisms to DPCD

4.5 Mechanisms of microbial inactivation by DPCD

4.6 Characterization of CO2 states and survival curves

4.7 Quantifying inactivation

4.8 Conclusions

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

5.1 Introduction

5.2 Inactivation of bacterial spores by DPCD

5.3 Inactivation of fungal spores by DPCD

5.4 Conclusion

6  Effects of DPCD on Enzymes

6.1 Introduction

6.2 Effects of gas bubbling

6.3 Alteration of the protein structure

6.4 Studies with multiple enzymes

6.5 Effects on specific enzymes

6.6 Conclusions and suggestions

7  The Kinetics of Microbial Inactivation by Carbon Dioxide under High Pressure

7.1 Introduction

7.2 The survival curve

7.3 Application of the models to published experimental data

7.4 Concluding remarks

7.5 List of symbols

8  Applications of DPCD to Juices and Other Beverages

8.1 Introduction

8.2 Juices processed with DPCD

8.3 Other beverages processed with DPCD

8.4 Conclusions

9  Use of Dense Phase Carbon Dioxide in Dairy Processing

9.1 Introduction

9.2 Carbon dioxide in milk

9.3 Enzymes and microorganisms in milk

9.4 Application of carbon dioxide to milk

9.5 Application of carbon dioxide for enzyme inactivation

9.6 Application of carbon dioxide to cottage cheese production

9.7 Application of carbon dioxide to yogurt and fermented products

9.8 Application of carbon dioxide to casein production

9.9 Conclusions

10  Particle Engineering by Dense Gas Technologies Applied to Pharmaceuticals

10.1 Introduction

10.2 Dense gas as a solvent

10.3 Dense gases as antisolvents

10.4 SCFs as co-solvents

10.5 Dense gases as aerosolisation aids (spray-drying assistance)

10.6 Conclusion

11  Industrial Applications Using Supercritical Carbon Dioxide for Food

11.1 Overview

11.2 Past development

11.3 Mechanism of microbial inactivation

11.4 scCO2 commercialization activities

11.5 Porocrit process

11.6 Conclusions

12  Outlook and Unresolved Issues

12.1 Introduction

12.2 Unresolved issues

12.3 Future outlook and conclusions

12.4 Acknowledgements

References

Index

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Library of Congress Cataloging-in-Publication Data

Dense phase carbon dioxide: food and pharmaceuticalapplications / edited by Murat O. Balaban, Giovanna Ferrentino. p. cm.Includes bibliographical references and index.

ISBN 978-0-8138-0649-5 (hardback)1. Chemical preservation. 2. Dense phase carbon dioxide pasteurization. 3. Food–Pasteurization. 4. Liquid carbon dioxide–Industrial applications. 5. Dense nonaqueous phase liquids–Industrial applications. I. Balaban, Murat O. II. Ferrentino, Giovanna. TP371.46.D46 2012 664′.0286–dc23

2011049103

A catalogue record for this book is available from the British Library.

Wiley also publishes its books in a variety of electronic formats. Some content that appears in print may not be available in electronic books.

Cover image: © Sean Gladwell / Fotolia.comCover design by Meaden Creative

Preface

There are social evolutionary theories that propose that a critical factor in the progress and advancement of human societies was, is, and will be the production of, and access to, adequate food supplies. Despite the accelerating increase in the internationalization of food trade, the supply chain is far from perfect. Improvement in the production, ­processing, storage, and distribution of food is still an unfinished ­business.

Yet consumers worldwide are becoming more sophisticated and knowledgeable. Foods that used to be local or regional are now coming to be known worldwide. Consumers demand more, and expect more. Safe food is the primary expectation, but still people all over the world experience food poisoning with unacceptable human and economic consequences. Consumers also demand and expect “better” foods. Quality expectations in terms of nutritional value and sensory attributes are getting more stringent. At the same time, there is fierce competition in the marketplace with thousands of new products being introduced every year, and thousands failing and being replaced. This creates serious economic pressures to reduce cost, to increase production, processing, and distribution efficiency, and to optimize their integration. On top of all this, there is a growing concern about the effect of human activities, including agriculture and food production, on the environment, with its consequences on the sustainability of these endeavors.

This is a complex scene where the players (the food industry, regulatory agencies, scientists, and consumers) have sometimes cooperating and sometimes adversarial roles. Yet, our overall objectives are the same: to provide a safe, excellent-quality (in terms of nutritional value and sensory properties), affordable, convenient, optimally distributed, readily available, and sustainable food supply.

In this complex, sometimes conflicting, and ever-changing environ­ment, the introduction of new technologies, new methods, and new products is becoming even more challenging. The food industry, with its dependence on volume sales and its small profit margin, is conservative and reluctant to change. Yet the changing needs of the marketplace, and increasing and conflicting pressures from consumers, are felt best by the industry. The increasing adoption of nonthermal technologies is therefore an indication that they fulfill a need, a niche in the marketplace.

Dense phase carbon dioxide (DPCD) is a nonthermal method of food processing. Its application is quite different from, for example, supercritical extraction with CO2. In extraction, the typical solubility of materials in CO2is in the order of 1%. This requires large volumes of CO2to be used. In contrast, processing with DPCD requires much less CO2. The typical solubility of CO2in many types of liquid foods is in the order of 5%. Even if more CO2was added, the excess would not dissolve and therefore would not be effective in, for example, microbial reduction or enzyme inactivation. 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 with DPCD due to pressurization. The small weight percentage of CO2used assures this. The typical process temperatures are less than 40°C.

DPCD temporarily reduces the pH of the liquid foods with effects on microorganisms and enzymes. Because oxygen is removed from the environment, and because temperature is not high during the short process time (typically about 5 min in continuous systems), nutrients, antioxidant activity, and vitamins are preserved much better than in the case of thermal treatments. The economics of the operation have been studied, and look promising. Although the capital and operating costs are still higher than those of thermal treatments, they are much lower than those of other nonthermal technologies (e.g., UHP operations).

With all its potential for safe foods without nutrient or quality loss, DPCD still has not achieved commercial operation status. A significant number of scientific publications demonstrate its effectiveness against microorganisms and enzymes, and the rate of increase of publications is accelerating. Some of those recent publications are excellent reviews of the technology and its applications. Yet there has been no book that brought together this increasing body of knowledge. This book benefits from the experience and knowledge of individual and groups of international scientists and members of the industry. The editors are indebted to the contributors: the book could not have become a reality without their expertise, experience, and willingness to contribute to this effort.

On behalf of all authors, the editors hope that this book would benefit researchers working in the area of DPCD, and in other nonthermal or traditional technologies with the potential to be used in conjunction with DPCD. We also hope that the industry, the regulatory agencies, and, most importantly, consumers would find interesting and useful information in the book. We believe that DPCD will find its niche in the safe and minimal processing of foods, and will take its place among other commercial nonthermal food- and pharmaceutical-processing operations.

Murat O. BalabanGiovanna Ferrentino

Contributors

Murat O. Balaban

Department of Chemical and Materials Engineering

University of Auckland

Auckland, New ZealandPatricia Ballestra

Department of Bioengineering

IUT Périgueux – Bordeaux IV

Périgueux, FranceThelma Calix

Department of Food Science

Zamorano University

Francisco Morazán, HondurasMaria G. Corradini

Instituto de Tecnología

Facultad de Ingeniería y Ciencias Exactas

Universidad Argentina de la Empresa

Ciudad de Buenos Aires, ArgentinaLuu Thai Danh

School of Chemical Engineering

University of New South Wales

Sydney, AustraliaFrank Devlieghere

Department of Food Safety and Food Quality

Laboratory of Food Microbiology and Food Preservation

Food2Know

Ghent University

Ghent, BelgiumKathy Elst

Business Unit Separation and Conversion Technology

Flemish Institute for Technological Research (VITO)

Mol, BelgiumOsman Erkmen

Department of Food Engineering

University of Gaziantep

Gaziantep, TurkeyGiovanna Ferrari

Chemical and Food Engineering Department

ProdAl S.c.ar.l. – Centro Regionale di Competenza sulle Produzioni Agroalimentari

University of Salerno

Fisciano, Salerno, ItalyGiovanna Ferrentino

Department of Materials Engineering and Industrial Technologies

University of Trento

TrentoNeil R. Foster

School of Chemical Engineering

University of New South Wales

Sydney, AustraliaLinsey Garcia-Gonzalez

Business Unit Separation and Conversion Technology

Flemish Institute for Technological Research (VITO)

Mol, BelgiumIreneo Kikic

Department of Materials and Natural Resources

University of Trieste

Trieste, ItalyXiaojun Liao

National Engineering Research Center for Fruit and Vegetable Processing

College of Food Science and Nutritional Engineering

China Agricultural University

Beijing, ChinaRaffaella Mammucari

School of Chemical Engineering

University of New South Wales

Sydney, AustraliaJohn S. Novak

Food Lab City of New York Public Health Laboratory

New York, NY, USAMicha Peleg

Department of Food Science

University of Massachusetts

Amherst, MA USAMassimo Poletto

Department of Chemical and Food Engineering

University of Salerno

Fisciano (SA), ItalySara Spilimbergo

Department of Materials Engineering and Industrial Technologies

University of Trento

Trento, ItalyWen Hui Teoh

Department of Chemical Engineering

Faculty of Engineering

University of Malaya, Malaysia

and

School of Chemical Engineering

University of New South Wales

Sydney, AustraliaLuc Van Ginneken

Business Unit Separation and Conversion Technology

Flemish Institute for Technological Research (VITO)

Mol, BelgiumJames T.C. Yuan

Global Beverage R&D

PepsiCo

Valhalla, NY, USA

1  Introduction to Dense Phase Carbon Dioxide Technology

Giovanna Ferrentino and Murat O. Balaban

Abstract: The introduction aims to bring together accumulated knowledge in the areas of supercritical and dense phase CO2 technology. A summary is given of the areas covered by the book’s chapters. Recognized experts in their fields discuss the following topics: solubility of CO2 in liquids; the effects of supercritical and dense phase CO2 on microorganisms, including vegetative cells and spores; the application of supercritical and dense phase CO2 on juices, beverages, and dairy products; progress in the use of pressurized CO2 in pharmaceuticals. Finally an outlook regarding the future of the technology is presented.

Keywords: overview; dense phase; carbon dioxide; nonthermal processing.

Nonthermal technologies have gained increasing importance in recent years as potentially valuable processes to replace or complement the traditional technologies, currently used for preserving foods and other biological materials. Traditionally, many foods are thermally processed by subjecting them to a temperature range from 60°C to more than 100°C for few seconds to several minutes (Jay 1992). During thermal treatments, heat transferred to the food kills vegetative cells of microorganisms, yeast, and molds, and also inactivates spores depending on the severity of the applied conditions. This process also inactivates many undesirable enzymes in foods that cause quality loss. However, thermal treatment may cause unwanted reactions leading to undesirable changes or formation of ­by-products in the food.

Thermally processed foods can undergo organoleptic changes and a cooked flavor accompanied by a loss of vitamins, essential nutrients, and flavors.

Increased consumer demand for safe, nutritious, fresh-like food ­products with a high organoleptic quality and an extended shelf life resulted in the concept of preserving foods using nonthermal methods.

During nonthermal processing, the temperature of the food is held below temperatures normally used in thermal processing. Therefore, the quality degradation expected from high temperatures is reduced and some vitamins, essential nutrients, and flavors are expected to undergo minimal or no changes (Barbosa-Cánovas 1998). High hydrostatic ­pressure (HHP), dense phase carbon dioxide (DPCD), oscillating magnetic fields, high-intensity pulsed electric fields, intense light pulses, ­irradiation, cold plasma, chemicals, biochemicals, and hurdle technology are some of the possibilities in the area of nonthermal technologies. Compared to traditional techniques, these avoid drawbacks such as loss of flavors and ­nutrients, production of undesirable side reactions, as well as changes in physical, mechanical, and optical properties of the food treated.

The use of dense phase carbon dioxide (DPCD) has been proposed as an alternative nonthermal pasteurization technique for foods (Spilimbergo et al. 2002), for the first time in the 1950s by Fraser (1951) and Foster et al. (1962) who reported the disruption of bacterial cells by the rapid decompression of carbon dioxide (CO2) from a pressure of 500 lbf/in2 (about 3.45 MPa) to ambient pressure. DPCD involves mostly the supercritical state of CO2, but may also involve subcritical gases and sometimes liquids under pressure. In the DPCD technique, food is contacted with (pressurized) sub- or supercritical CO2 for a certain amount of time in batch, semibatch, or continuous equipment. The DPCD technique presents some advantages over HHP due to its milder process conditions. The pressures applied are much lower (generally < 30 MPa) compared to those used in HHP (300–1200 MPa). In addition, capital expenditure is considerably lower. In 1969 Swift & Co. (Chicago, IL) obtained the first US patent for food product pasteurization with CO2 at “super atmospheric” pressure. Since 1980, others demonstrated the bacteriostatic action and inhibitory effect of CO2 on the growth and metabolism of some microorganisms. Pseudomonas was found to be very sensitive while other types, such as Lactobacillus and Clostridium, were less sensitive. However, it was with the work published by Kamihira et al. (1987) that the inhibitory effect of CO2 under pressure started to be addressed systematically. These authors tested the sterilizing effect of CO2 in supercritical, liquid and gaseous phase on wet and dry Escherichia coli, Staphilococcus aureus and conidia of Aspergillus niger by using a supercritical fluid extraction apparatus. Since then, many studies investigated the effects of CO2 on pathogenic and spoilage organisms, vegetative cells and spores, yeasts and molds, and enzymes. It has been proven that this technique can be considered a cold pasteurization method that affects microorganisms and enzymes, using CO2 under pressures below 50 MPa without exposing foods to the adverse effects of heat. Thus foods retain their physical, nutritional and sensory qualities.

DPCD pasteurization of liquid foods is operational and almost ready to be employed on a commercial scale. Most of the commercialization efforts have been performed so far by Praxair Inc. (Burr Ridge, IL, US). Based on the technology, licensed from the University of Florida (Balaban et al. 1995; Balaban 2004a, b), Praxair developed a continuous process ­system which utilizes the DPCD as a nonthermal process alternative to thermal pasteurization (Connery et al. 2005). This system has been registered under the trademark “Better Than Fresh (BTF).” Praxair ­constructed four mobile BTF units for processing about 1.5 L/min of liquid foods for demonstration purposes. In addition, a commercial-scale unit of 150 L/min has also been constructed (Connery et al. 2005) and tested in an orange juice–processing plant in Florida. For the continuous treatment of liquid foods, pilot-scale equipment was also manufactured by Mitsubishi Kakoki Co. (Tokyo, Japan) on behalf of and according to the patents owned by Shimadzu Co. (Kyoto, Japan) (Osajima et al. 1997, 1999a, b). This equipment consisted of a vessel of 5.8 L through which CO2 and ­liquid foodstuff were simultaneously pumped at maximum flow rates of 3.0 kg/h and 20 kg/h, respectively. In 2003, the apparatus was made available only to research laboratories in Japan (private ­communication, Shimadzu Belgium). At the moment, we have no information available on further commercialization efforts of Shimadzu in the field of DPCD processing for liquid foods. On the basis of their own ­patent (Sims 2000), PoroCrit LLC (Berkeley, CA, US) also developed a membrane contactor consisting of several hollow-fiber membrane ­modules for the ­continuous DPCD pasteurization of liquid foods, mainly beverages, juices, milk, and wine.

As for all non-thermal technologies, the most important issue involved in the commercialization of DPCD process is the regulatory approval. Foods processed thermally or nonthermally must comply with the safety regulations set forth by the US Food and Drug Administration prior to being marketed or consumed. For example, the regulations for thermally processed low-acid canned foods are contained in Title 21, Part 113 of the US Code of Federal Regulations, entitled “Thermally Processed Low-Acid Foods Packaged in Hermetically Sealed Containers.” The ­regulations in Title 21 were established to evaluate (1) the adequacy of the equipment and procedures to perform safe processing operations, (2) the adequacy of record keeping proving safe operation, (3) justification of the adequacy of process time and temperature used, and (d) the qualifications of ­supervisory staff responsible for thermal-processing and container closure operations (Teixeira 1992). However, the validation of DPCD as a nonthermal method and the determination of compliance regulations necessary for commercialization are complex and challenging. The progress in the validation needs to be encouraged to address the regulatory needs in the near future.

This volume attempts to bring together the accumulated knowledge in the area of DPCD. Experts in many areas have contributed to this book regarding the following topics:

Solubility of CO

2

in liquids, both from a thermodynamics–­theoretical perspective, including models, and from an experimental approach. This is critical because the accumulated evidence points to the ­critical contribution of dissolved (and saturated) CO

2

to microbial inactivation.

Effects of DPCD on microorganisms, including vegetative cells and spores; kinetics of microbial inactivation with DPCD; and inactivation of certain enzymes with DPCD. This area is very important because, first and foremost, a new technology must prove the safety of the foods that are processed using it.

Application of DPCD on juices, beverages, and dairy products. There is a growing body of work in this area, reporting on effects on microorganisms, and especially on quality attributes and nutritional contents. If DPCD applications are to be successful, the organoleptic and nutritional quality of foods processed using DPCD must be known.

Progress in the use of pressurized CO

2

in pharmaceuticals. This is a well-developed area, with many applications. It also opens up the exciting field of treatment of solids and powders with DPCD.

An overview of the current technology. This chapter is written by experts in the industry, who have been involved with the design, development, and commercialization efforts of DPCD. Their hands-on views are very valuable.

An outlook regarding the future of DPCD technology.

It is sincerely hoped that the reader will find the book valuable in bringing information, research results, and most importantly an extensive ­bibliography in the nonthermal field of DPCD.

2  Thermodynamics of Solutions of CO2 with Effects of Pressure and Temperature

Sara Spilimbergo and Ireneo Kikic

Abstract: Knowledge of the thermodynamics of CO2 solutions under pressure is fundamental to the investigation of both the inactivation mechanism and the efficiency of the process as a function of the process parameters of temperature and pressure. In order to evaluate the properties of the solutions during DPCD treatment, it is essential to have reliable high-pressure experimental data and accurate thermodynamic models over a broad range of ­conditions. A large number of experimental and theoretical studies have been conducted on CO2 solubility in pure water; however, the literature lacks studies concerning the phase behavior of CO2–water solutions or CO2–solid components in food applications. In the present chapter. a general ­survey of the published knowledge concerning the thermodynamics of CO2–water phase systems under pressure is given focusing on both the theoretical aspects and the applications, for electrolyte and non-electrolyte ­models.

Keywords: thermodynamic model; liquid–vapor phase equilibria; equation of state.

2.1 Introduction

The phase behaviour of the system carbon dioxide (CO2) + water is of great industrial and scientific interest. For instance, in the petroleum industry many natural gases contain acidic gases which have to be removed, such as CO2 and hydrogen sulphide. Another industrial application is the decontamination of wastewater streams containing dissolved acidic gases. The capture of CO2, a greenhouse gas, has become a great concern: different storage techniques have been considered such as the storage of CO2 in deep saline reservoirs. Also, in geochemical applications, especially in the analysis of CO2-bearing fluid inclusions in minerals, the accurate description of solubility of CO2 in pure-water solutions is required. Recently, the increasing attention to CO2 processing in food applications, in particular in microbial inactivation of food products at low temperature compared to the traditional thermal treatments, makes the knowledge of a CO2–water phase system under pressure fundamental to investigate both the inactivation mechanism and the efficiency of the process as a function of the operating parameters of temperature and pressure.

Therefore, it is essential to have reliable high-pressure experimental data and an accurate thermodynamic model over a broad range of conditions to evaluate the solubility in different conditions. For most of these applications, temperatures (T) up to 100°C and pressures (P) up to 100 MPa are particularly relevant.

A large number of experimental and theoretical studies have been conducted on CO2 solubility in pure water. However, to the best of our knowledge, literature lacks studies concerning phase behaviour of CO–liquid solutions or CO–solid components in food applications. The objective of the present chapter is to give a general survey of the published knowledge concerning the thermodynamics of CO–water phase systems under ­pressure, focusing on the theoretical aspects and the applications, for both electrolyte and non-electrolyte models.