Preface Chapter 1 Chapter 2 Chapter 3 Chapter 4

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1 Preface This book addresses the past, present and future prospects of bio-based and/or biodegradable polymers in specific food-packaging applications, as well as their importance and advantages over fossil polymer-based packaging materials. Furthermore, this book also examines the current commercial overview of bio-based and/or biodegradable polymers and nanocomposites, and the structure property relationship required for various advanced applications. Chapter 1 introduces the growing field of bio-based and biodegradable polymers and their use and benefits as sustainable packaging materials, along with the classification and importance of biodegradable packaging. A glimpse of the past, present and future prospects of packaging, advances in polymer-based packaging, including the origin and advantages of bio-based and biodegradable polymers for food packaging, are presented. The subsequent chapters provide a basic understanding on various bio-based and biodegradable plastics used in food packaging. The current scenario and commercial status of bio-based and biodegradable polymers in food packaging are discussed with a statistical comparison of various packaging materials, such as glass, metals and polymers. Comprehensive information is presented in Chapter 2 regarding sustainable polymers in relation to production statistics, including production cost and the expected growth of biodegradable polymers as food-packaging materials. Chapter 3 discusses various biopolymers including cellulose, chitosan (CS), gums, silk and so on, which are available in abundance in our surroundings and can be extracted from available biomass for food-packaging applications. In this section, biopolymers based on their origin, methods of extraction, processing capabilities and other specific properties in relation to food packaging are discussed in detail. This category of bio-based polymers mainly includes polysaccharides, proteins and other bio-based polymers. In addition, we have explained the role of these biopolymers in enhancing the properties of existing food packages. Chapter 4 covers polymers whose precursors are obtained from renewable resources and are transformed into polymers known as bio-derived polymers. These polymers can be synthesised by chemical or biochemical, or both, approaches. Amongst iii

2 Bio-based Plastics for Food Packaging Applications all the biopolymers that fall into this category, polylactic acid (PLA) has shown enormous potential to replace a wide variety of petrochemical-based conventional polymers and is produced commercially on a large scale for food packaging and other applications. Therefore, we have included recent case studies regarding PLA-based bionanocomposites with special emphasis on their application in food packaging. Bio-based polymers obtained via fermentation processes using microorganisms are discussed in Chapter 5. A representative polymer in this category is polyhydroxyalkanoates (PHA), a type of bio-based polymer that can be produced on a commercial scale. This chapter focuses on the production, processing and foodpackaging applications through case studies. Chapter 6 gives a detailed discussion of the properties that are essential for food packaging, such as thermal stability, mechanical properties, gas-barrier properties, morphology and optical properties, which are important factors for sustainable plastics to be used for targeted food and its packaging. This chapter also extends the discussion on the appropriate match of degradable plastics for the preservation of perishable foods and the techniques of in situ characterisation of shelf life of food behaviour when active food packaging is used. Chapter 7 discusses the recent advancement in biodegradable polymers for foodpackaging applications, in terms of technology and product development, taking into account various sustainable non-toxic natural biopolymer-based nanofillers including those derived from starch, cellulose, CS, silk, gum and so on. It is worth mentioning that bioplastics filled with these bionanofillers produce a new class of bionanocomposites with significantly improved properties which are desirable for food-packaging applications. This chapter also includes the development strategies of biodegradable polymeric foams in order to develop degradable packaging which is cost competitive with fossil-based packaging. The current selling price of biodegradable plastics is deemed to be expensive. In Chapter 8, we focus on the use of potential blends of biodegradable and nonbiodegradable polymers in food-packaging applications, along with case studies, to provide direction for students and young researchers to investigate the utilisation of degradable polymers in combination with existing packaging. Chapter 9 covers the important laws, regulations and legislation, and different protocols for the use of biodegradable polymers for food-packaging applications, which are extensively discussed with regard to environmental assessment and health and safety. Special attention has been given to the legislation regarding the migration of various polymer additives into packaged food. iv

3 Preface Biopolymer-based edible coatings for food-packaging applications is the subject of Chapter 10, highlighting the benefits of edible coatings over conventional petroleumbased plastics for food-packaging applications. This chapter contains details regarding the essence of edible coatings based on polysaccharides, proteins, lipids and composite materials in combination with various active agents and their applications for preservation and shelf life improvement of perishable food. Chapter 11 discusses the various trends for end-of-life products including recycling, reuse of waste food packages and subsequent composting. This chapter also contains an in-depth discussion on the recycling of non-biodegradable and biodegradable packaging polymers, and the reuse and final composting behaviour of various biodegradable polymers. Chapter 12 presents the authors views on the development of versatile biodegradable polymers in food packaging. This chapter highlights the shortcomings of biodegradable polymers and the possible modifications required to their properties in order to replace conventional plastic materials for food-packaging applications, along with the scope of future research on the utilisation of biodegradable polymers. v

4 Bio-based Plastics for Food Packaging Applications vi

5 Contributors Purabi Bhagabati Umesh Bhardwaj Siddharth Mohan Bhasney Shasanka Sekhar Borkotoky Gourhari Chakraborty vii

6 Bio-based Plastics for Food Packaging Applications Prodyut Dhar Kiran Kumar Gali Indian Institute of Technology Guwahati, Department of Biosciences and Bioengineering, Surendra Singh Gaur Tabli Ghosh Arvind Gupta Naba Kumar Kalita Vimal Katiyar viii

7 Contributors Medha Mili Akhilesh Kumar Pal Rahul Patwa Narendren Soundararajan Melakuu Tesfaye Neelima Tripathi ix

8 Bio-based Plastics for Food Packaging Applications x

9 Contents 1 Sustainable Polymers for Food Packaging: An Introduction Types of Food Packaging Primary Packaging or Sales Packaging Secondary Packaging or Group Packaging Tertiary Packaging or Transport Packaging Materials for Food Packaging Glass Material Metals Paperboards Polymer-based Food Packaging Petroleum-based Plastics for Food Packagaing Negative Impact of Petroleum-based Plastics in Food Packaging Importance of Bio-based, Biodegradable Plastics for Food Packaging Bio-based Plastics in Food Packaging Advantages of Bio-based Food Packaging Classification of Bio-based Plastics for Food Packaging Differentiating Bio-based and Biodegradable Food Packaging Conclusion Bio-based and Biodegradable Polymers for Food Packaging: Commercial Status Introduction Current Scenario of Food Packaging xi

10 Bio-based Plastics for Food Packaging Applications 2.3 Global Initiatives towards Biodegradable and Bio-based Polymers Bio-based Sustainable Polymers for Food-Packaging Applications Introduction Polysaccharides Starch Cellulose Cellulose Nanocrystals Chitosan Origin of Chitosan Properties of Chitosan Limitations of Chitosan Methods of Chitosan Extraction Functionalisation of Chitosan Chemical Functionalisation of Chitosan Polysaccharide Gums Gum Arabic Guar gum Xanthan Gum Research on Polymers Combined with Natural Gums Protein-based Biopolymers Protein Biopolymer (Silk) Classification of Silk-based Polymers Macro and Fine Structure Processing of Silk Silk Fibres Electrospun/Non-woven Silk Fibroin Mats Silk Fibroin Films xii

11 Contents Silk Fibroin Hydrogels Silk Fibroin Porous Sponges/Foams Surface Modification Degradation Applications of Silk Tissue Engineering Therapeutic Agent Delivery Optics and Sensing Mechanical Immobilisation Conclusions and Outlook Polylactic Acid: Potential Bio-based and Biodegradable Polymer Use in Food Packaging Introduction Polylactic Acid Synthesis of Polylactic Acid Properties of Polylactic Acid Stereocomplex Polylactic Acid Use of a Third Component to Improve Stereocomplexation in Polylactic Acid Stereocomplex Polylactic Acid for Food Packaging Case Study Effect of Incorporating Lactic Acid Oligomer-g-Chitosan Nanofiller in Polylactic Acid Films Effect of Incorporating Lactic Acid-g-Gum Arabic Nanofiller in Polylactic Acid Films Effect of Polymorphic Cellulose Nanocrystal Nanofillers on the Properties of Polylactic Acid-based Nanocomposite Films Effect of Incorporating Sucrose Palmitate Nanofillers in Polylactic Acid Films Summary xiii

12 Bio-based Plastics for Food Packaging Applications 5 Polyhydroxyalkanoates: Microbially Derived Biodegradable Polymers for Food-Packaging Applications Introduction Polyhydroxyalkanoates: Different Types and their Physicochemical Properties Polyhydroxyalkanoate-based Cellulosic Composites General Material Properties Required for Food-Packaging Applications Introduction Material Properties for Food Packaging Barrier Properties Water Vapour Transmission Rate Gas Transmission Rate Barrier Properties of Biodegradable Polymers Mechanical Properties Mechanical Properties of Biodegradable Polymers Thermal Properties Thermal Properties of Biodegradable Polymers Morphological Properties Optical Properties Rheological Properties Biodegradability Petroleum and Bio-based Food-Packaging Polymers Packaging Materials for Milk and Milk Products Importance of Milk and Milk Products Present and Future Prospects of Milk Packaging Packaging Materials for Meat and Poultry Importance of Meat and Poultry Packaging Systems for Meat and Poultry Products xiv

13 Contents Packaging Materials for Fruits and Vegetables Importance of Fruits and Vegetables Packaging Systems for Fruits and Vegetables Up-to-date Advances of Bio-based and Biodegradable Polymers in Food Packaging Introduction Natural Biopolymers for Food Packaging Starch-based Packaging Materials Cellulose-based Packaging Materials Chitosan- and Pectin-based Packaging Materials Polyhydroxyalkanoate-based Packaging Materials Polylactic Acid-based Packaging Materials Case Studies: Up-to-date Advances in Biodegradable Food- Packaging Materials Bionanocomposites in Food Packaging Properties of Polylactic Acid Bionanocomposites Biodegradable Polymeric Foams Development of Polymeric Foams Some Potential Bio-based Polymers for Foaming Sustainable Food Packaging using Bio-based Polymeric Foams Processing Technology for Foam Fabrication Physical/Soluble Foaming Casting and Leaching Foaming using Gases Thermally Induced Phase Separation (TIPS) Reactive Foaming Foam Packaging Developments in Sustainable Foams Polymer Blends for Sustainable Food Packaging xv

14 Bio-based Plastics for Food Packaging Applications 8.1 Introduction Biopolymers Source and Description of Bio-based Polymers Biodegradable Polymer-based Blends Polylactic Acid Polycaprolactone Blend Polylactic Acid Polybutylene Succinate Blend Polylactic Acid Poly(butylene adipate-co-terephthalate) Blend Polycaprolactone/Chitin Chitosan-based Blend Cellulose-based Blend Blends of other Fossil-based Plastics and Bio-based Plastics Polylactic Acid Low-Density Polyethylene Blend Low-density Polyethylene Rice/Potato Starch Blend Recycled Polyethylene Terephthalate Polylactic Acid and Polyethylene Terephthalate Chitosan-based Blends Polylactic Acid Polypropylene Blend Polylactic Acid Polycarbonate Blend Polylactic Acid Polystyrene Blend Low-Density Polyethylene Starch Blend Conclusion Bio-based Biodegradable Polymers in Food Packaging: Regulations and Legislation Introduction Nanoparticles in Food Packaging Experimental Migration Studies Migration Studies on Polylactic Acid Migration Studies on Bionanocomposites Analytical Techniques used for the Characterisation of Migrants Solid-phase Microextraction xvi

15 Contents Electrospray Ionisation Mass Spectrometry High-performance Liquid Chromatography Spectroscopic and Related Techniques Nuclear Magnetic Resonance Regulations due to Possible Migration Conclusion Edible Polymer-based Sustainable Food Packaging Introduction Edible Coating Methods of Coating Types of Coating Materials Active Agents in Edible Coatings Carriers of Antioxidants Carriers of Antidiabetic Agents Carriers of Anticancer Agents Flavour Enhancers Application of Edible Coatings Properties of Coating Materials Case Study Effect of Edible Coating on Papaya Fruit Effect of Edible Coating on Mango Fruit Effect of Edible Coating on Tomato Effect of Edible Coating on Strawberry Quality Conclusion Trends of End-of-Life Options: Recycling, Reusing and Composting of Waste Food Packaging Introduction Recycling of Biodegradable Plastics Mechanical Recycling of Bioplastics xvii

16 Bio-based Plastics for Food Packaging Applications Chemical/Biological (Enzymatic) Recycling Hydrolysis Alcoholysis Enzymatic Depolymerisation Thermal Depolymerisation Recycling of Other Biodegradable Plastics Polyhydroxyalkanoates Polybutylene Succinate Cellulose Acetate Poly(ε-caprolactone) Composting Difference between Bioplastics and Compostable Plastics Importance of Composting of Biodegradable Plastics Principles of Composting Standards for Compostability and Biodegradability ASTM D ASTM D ASTM D Measurement of Biodegradability Challenges and future directions Feedstock Performance Limitation Product Cost Authors Viewpoint on the Developments of Biodegradable Polymers to improve their Versatility in Food Packaging Introduction Limitations of Biodegradable Polymers as Food-Packaging Material Material Properties xviii

17 Contents Mechanical Properties Barrier Properties Thermal Stability Temperature Resistance Processing Conditions Future Horizons for Biodegradable Polymers as a Packaging Material Composites of Biodegradable Polymers Polysaccharide-reinforced Composites Clay-reinforced Composites Carbon Filler-reinforced Composites Metal- and Metal Oxide-reinforced Composites Coated Paper for Active Packaging Abbreviations Index xix