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There could not be a clearer and at the same time shocking demonstration of our non‐sustainable way of living than the recent COVID‐19 pandemic, which started in late 2019 in Wuhan, China, expanding all over the world in just few months. The occurrence and the extremely rapid expansion are connected to human dietary shifts toward consumption of animal products never used before due to increasing nutrition demand, extraordinary population densities, and unprecedented environmental pollution. The pandemic, its fast spread, and its consequences all over the planet in a very short period made evident that we are living in a closed system, interconnected in ways that are out of our control and we have to face the global problems with common strategies. Sustainable living has become essential, and a global sustainable consciousness must be formed and immediate decisions and actions need to be taken toward this direction.

Sustainability should be radically established in our lifestyle, habits, and actions. The massive use of plastics and their uncontrolled disposal in the last four decades are habits that need to be changed immediately. The uncontrolled production and use of plastic have brought the planet's pollution to levels never seen before. Only in 2018, 359 million metric tons of plastic were produced globally, while a total of about 9.2 billion metric tons were produced between 1950 and 2017. From all this plastic ever produced, it is estimated that about 9% has been recycled, 12% incinerated, and the remaining 79% has ended up in landfills or the environment. For example, it is estimated that 4.8 to 12.7 million metric tons of plastic enter the marine environment every year [1]. Photographs of animals and fish suffocating in their habitats due to dumped plastics, or of extended areas full of plastic garbage, especially from developing countries that have become the waste disposal fields for the developed ones, as well as studies on how toxic chemicals released from wrongly disposed plastics compromise our health are reaching us daily.

The most important source of badly disposed plastic waste is packaging. In 2017, around 15 million metric tons of plastic packaging waste was generated only in the European Union. In the general packaging sector, food packaging has the most important plastic demand. Plastic food packaging production in Europe is 8.2 million tons per year, included in the 20.5 million tons per year production for the general packaging sector and in the 51.2 million tons per year of the total European plastic demand [2]. Its short lifetime and frequent contamination from food makes it the most voluminous, wrongly disposed, plastic waste. For this reason, the introduction of biodegradable‐compostable plastic packaging, either from petrochemical sources or preferably from natural renewable resources, has become mandatory and attracts a great deal of research and industrial interest. This, in combination with the various governmental stringent requirements and incentives related to plastic reduction throughout the planet, makes sustainable food packaging an emerging application area that expectantly will find its way to the market substituting the currently used recalcitrant plastic packaging solutions.

This book deals exactly with this rapidly emerging research and application field of Sustainable Food Packaging. It starts with Part I “Review on Biopolymers for Food Protection.” This part of the book presents review chapters 1, 2, and 3 on the most relevant biopolymers that slowly find their way to the food packaging market, but also on biopolymers that are not yet industrialized (either due to high costs of extraction and transformation in packaging materials or due to lack of investment), but have a great potential due to their unique properties. In particular, Chapter 1 “Emerging Trends in Biopolymers for Food Packaging,” by Sergio Torres‐Giner et al., starts with a detailed and comprehensive introduction to the different types of biopolymers, and their classification according to their origin and biodegradability characteristics. The chapter continues with the presentation of the most important biopolymers that are currently available and describes their origin, chemistry, synthesis/extraction, and/or chemical modification methods. It also positions these biopolymers in the current plastic market and describes their prospects, advantages, and disadvantages in the sector of food packaging. In their concluding remarks, the authors give an expert point of view on where the bioplastic efforts for food packaging should be directed in order to have an important positive future environmental impact. Chapter 2 “Biopolymers Derived from Marine Sources for Food Packaging Applications,” by Jone Uranga et al., presents the two most important biopolymers for food packaging, originating from marine biomass, fish gelatin and chitosan. Regarding gelatin, the chapter describes the extraction methods of collagen by fish waste biomass, and the subsequent production gelatin by partial hydrolysis of collagen. The authors continue with a presentation of the methods of development of gelatin coatings and films as food packaging and their impact on the food shelf life extension. Regarding chitosan, the authors first analyze the extraction methods of chitin by marine biomass, such as crustacean shells and squid pens, before its transformation to chitosan by deacetylation. Finally, the development, properties, and effect on the packaged food life extension are analyzed for the various chitosan coatings and films presented in the literature as food packaging solutions. Chapter 3 “Edible Biopolymers for Food Conservation,” by Elisabetta Ruggeri et al., describes the innovative idea of natural polymeric protective coatings or films for food preservation and freshness extension that can be consumed together with the food, accompanied by the various regulations that would cover such use. The authors analyze the various biopolymers that can be transformed into edible packaging, classifying them as polysaccharides, proteins, lipids, and their mixtures. They present the various ways of development of the films for wrapping or of the coatings applied directly onto the food, their properties, and the possibility to act as matrices for functional additives, like antimicrobial and antioxidant agents. Finally, the authors provide information on the possible limitations and on the future perspectives of natural edible food packaging.

The book continues with Part II “Food Packaging‐Based on Individual Biopolymers and Their Composites,” where the most promising biopolymers and their composites for the food packaging sector are presented separately. Part II describes both the biopolymers that have already found their way to the market together with their future challenges, and the biopolymers that are not yet in the market but due to their unique properties have a good potentiality. Indeed, Chapter 4 “Polylactic acid (PLA) and Its Composites: An Eco‐friendly Solution for Packaging,” by Swati Sharma, describes research advancement related to food packaging based on PLA and its composites, indisputably the most available and promising biopolymer currently present in the market. The chapter starts with the synthetic routes of PLA and continues with the description of its physical properties, emphasizing the ones essential for food packaging materials. Subsequently, the author presents a review on the various fillers, i.e. synthetic and natural fibers or nanoparticles, that have been used to enhance the relevant properties of PLA, and closes the chapter with the current uses in the market and the future perspectives of this exceptional biopolymer. Chapter 5 “Green and Sustainable Packaging Materials using Thermoplastic Starch,” by Anshu Anjali Singh and Maria Erminia Genovese, is dedicated to biocomposites based on thermoplastic starch, a biopolymer with great potentiality for food packaging due to its abundance, biodegradability, and low price, that has already found its way to the market. Although the chapter is dedicated to a specific biopolymer, the authors make an analytical introduction to the plastic threat that has made vital the need of sustainable polymers especially in the food packaging sector, and present the various categories of biopolymers available for this purpose emphasizing on starch. They continue with the presentation of research studies on thermoplastic starch composites developed for packaging applications underlining their most relevant properties, such as mechanical properties, gas and vapor permeability and biodegradability, their processing methods, their possible drawbacks, while they also present the commercially available packaging solutions. Finally, they conclude with the challenges to be addressed and the future developments needed for starch, its composites, and its derivatives in food packaging. Chapter 6 “Cutin‐inspired Polymers and Plant Cuticle‐like Composites as Sustainable Food Packaging Materials,” by Susana Guzman‐Puyol et al., presents the unique biopolymer cutin, the main component of cuticle, which constitutes the outer surfaces of plants and serves as a protective layer from the environment. The authors introduce the dramatic effect of plastics to the environment and the alternative bio‐based and biodegradable biopolymers. They continue with the description of plant cuticle, its natural role, its structure and its composition, where the principle component cutin is introduced. A quantitative comparison of the physical properties of cutin and various biodegradable biopolymers reveals the strong and weak points of the former, and the ways to obtain cutin from its main resource, the tomato pomace, are described. The authors also present scalable techniques for the synthesis of cutin‐inspired polyesters and methods to tune their properties. Finally, the methods to fabricate cutin‐inspired coatings and cuticle‐like composites as protective packaging for food are presented. Chapter 7 “Zein in Food Packaging,” by Ilker S. Bayer, gives an exhaustive presentation of the protein biopolymer, zein, highly promising for food packaging mainly due to its film‐forming capability and hydrophobic properties. Its origin, molecular structure, and general properties are first introduced. The focus of the chapter is on the fabrication methods of zein‐based films and their characterization as food packaging materials. The presented methods are solvent casting, melt extrusion, solvent or melt blending with biopolymers, and lamination, either with other bio‐polymers or petroleum‐based polymeric films. The author closes the chapter with the future perspectives and his point of view on the directions that zein development should follow in order to be a valid candidate for the food packaging industry.

Part III of the book is dedicated to the most abundant natural polymer of our planet, the cellulose, and is entitled “Biocomposites of Cellulose and Biopolymers in Food Packaging.” It presents sustainable composites of biopolymers with cellulose in various forms, with exceptional properties, competitive to the conventional nonbiodegradable plastics, for the food packaging market. In particular, Chapter 8 “Cellulose‐reinforced Biocomposites Based on polyhydroxybutyrate (PHB) and poly(3‐hydroxybutyrate‐co‐3‐hydroxyvalerate) PHBV for Food Packaging Applications,” by Estefania Lidon Sanchez‐Safont et al., deals with the microbial polymers polyhydroxyalkanoates (PHAs) and discusses how cellulose fibers can improve their properties to make them competitive for the food packaging market. Specifically, the authors analyze separately, first the strengths, weaknesses, opportunities, and threats (SWOT) of two bacterial biopolymers, PHB and PHBV, and subsequently the properties of lignocellulose fibers that make them ideal candidates as reinforcing fillers in composites. Next, they review the research that has been done so far on the combination of PHB and PHBV with various lignocellulose fibers and they present the great potentiality of such composites as food packaging materials, indicating the weak points to be overcome. Chapter 9 “Poly‐Paper: Cellulosic‐filled Eco‐composite Material with Innovative Properties for Packaging,” by Romina Santi et al., focuses on a very interesting patented material, made of cellulose microfibers in the sustainable, water‐soluble poly(vinyl alcohol) (PVA) matrix, with the name Poly‐Paper. Poly‐paper can be very versatile in terms of manufacturing processes and final properties, and as such, can find many ways to enter into the packaging market. Indeed, it can be processed by extrusion, injection molding, and thermoforming, while at the end of life can reenter in the paper recycling chain. Chapter 10 “Paper and Cardboard Reinforcement by Impregnation with Environmentally Friendly High‐performance Polymers for Food Packaging Applications,” by Uttam C. Paul and José A. Heredia‐Guerrero, describes their research on a different approach to cellulose‐based food packaging. Cellulose is not present as micro or nanofiller in a polymer, but in the form of an intact substrate, like paper or cardboard, impregnated with environmentally safe, biocompatible polymers and composites, in order to attain properties that can expand and reinforce its positioning in the food packaging market, without compromising its biodegradable nature. The treatment offers to the cellulose substrates water and oil resistance, resistance to moisture, and mechanical reinforcement, all properties that cellulose lacks intrinsically, so it can be a viable solution to increase its request in the sustainable food packaging market. The book continues with Chapter 11 “Nanocellulose‐Based Multidimensional Structures for Food Packaging Technology,” by Saumya Chaturvedi et al., which deals with nanocellulose‐based food packaging solutions. The authors present an overview of the different kinds of nanocellulose, which include fibrils or crystallites with at least one dimension in the nanoscale range, and their properties depending on the origin, i.e. plants or bacteria, and the isolation methods. The chapter proceeds with the ways that nanocellulose, alone or combined with polymers, forms various compact structures that can be used for packaging. Finally, the authors focus on two types on nanocellulose, the cellulose nanofibers and the cellulose nanocrystals, emphasizing their differences and reporting the research that was done so far on their freestanding films either alone or as polymer fillers, comparing them with conversional plastics films used in the food packaging sector.

A book on Sustainable Food packaging could not be complete without Part IV dedicated to “Natural Principles in Active and Intelligent Food Packaging for Enhanced Protection and Indication of Food Spoilage or Pollutant Presence,” since sustainability is closely related to the extension of the shelf life of food and the prevention of food waste. Wasting food is economically nonviable, not ethical, and drains the already very limited natural resources. Chapter 12 “Sustainable Antimicrobial Packaging Technologies,” by Yildirim Selçuk and Bettina Röcker, presents advancements in the use of bioactive substances combined within biopolymers from renewable resources as protective food packaging with antimicrobial action against foodborne pathogens and spoilage microorganisms. The authors introduce the concept of active packaging, its different categories, and specific actions, with a dedicated section on the antimicrobial active packaging, its classes, research advances, and regulations. Then, they analyze separately the most studied natural antimicrobial agents, i.e. essential oils and phenolic compounds; organic acids, their salts and anhydrides; bacteriocins and enzymes; and the antimicrobial polymer chitosan, with references of their use as active additives in packaging of food systems. The authors conclude their chapter with the strategies needed for a successful and rapid introduction of active sustainable antibacterial packaging in the food packaging industry. Chapter 13 “Active Antioxidant Additives in Sustainable Food Packaging,” by Thi Nga Tran, deals also with active packaging but in this case with antioxidant activity. The author starts with an introduction to the urgent need of a significant reduction of food losses and wastes, and how protection from oxidation, using packaging systems of biopolymers combined with natural antioxidant substances, could help. The chapter continues with a detailed analysis of the various antioxidant molecules extracted by plants, their combination with biopolymers into active food packaging, and the properties of the obtained packaging systems, including, of course, their antioxidant activity. A particular mention is made to the possibility of using raw dried plants powders, even from agricultural by‐products, as antioxidant fillers into biopolymers for the development of active sustainable food packaging, avoiding the extraction costs. Part IV of the book ends with Chapter 14 “Natural and Biocompatible Optical Indicators for Food Spoilage Detection,” by Maria E. Genovese et al., which presents another very interesting approach in food waste prevention. The authors describe packaging materials with incorporated natural or biocompatible molecules that change their molecular structure, and thus their optical properties, in the presence of food spoilage. Consequently, when a specific food spoilage by‐product is present, the active packaging changes one or more optical properties (i.e. color, spectral absorption, fluorescence) enabling a real‐time and direct naked eye spoilage detection. The authors introduce the factors determining food spoilage, and analyze thoroughly the conventional methods, as well as the most recent portable technologies for on‐site and on‐package detection of the spoilage, together with the functioning principles of these technologies. Then, the authors focus on the description of the various functional components used for the optical and colorimetric spoilage indication usually embedded in a polymeric, most of times natural renewable, support, as well as the specific spoilage by‐product they can detect. A particular emphasis is given on the sensing potential of natural dyes and pigments extracted from plants, i.e. curcumin and anthocyanins, as well as their synthetic counterparts, due to their eco‐friendly nature.

The book closes with Part V “Technological Developments in the Engineering of Biocomposite Materials for Food Packaging Applications,” where Chapter 15 “Biopolymers in Multilayer Films for Long Lasting Protective Food Packaging: A Review,” by Ilker S. Bayer, presents the possibilities that technology provides to take advantage of the various biopolymers and composites combining them in unique solutions for food packaging. Apart from melt extrusion, injection molding, blow molding, and thermoforming, all techniques used broadly in the plastic industry and mentioned in the various chapters of this book, Chapter 15 describes the ways of making multilayer films that can combine the unique properties of the various biopolymer layers into one material. The chapter reviews both multilayer laminates of biopolymers with conventional oil‐derived polymers and all sustainable laminates, based on proteins, polysaccharides, or biopolyesters. The author concludes that multilayer laminates of carefully chosen biopolymers and biocomposites could be the ideal materials for food packaging since they combine sustainability with optimized desired properties due to their unique construction.

Athanassia Athanassiou

Genova, Italy

29 September 2020