Agro-Waste Derived Biopolymers and Biocomposites E-Book
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- Herausgeber: John Wiley & Sons
- Kategorie: Fachliteratur
- Sprache: Englisch
AGRO-WASTE DERIVED BIOPOLYMERS AND BIOCOMPOSITES This comprehensive book describes the fundamental principles and major advancements in the utilization of agro-waste for deriving biopolymers, and their applications to fabricate composite, nanocomposite, and hybrid food packaging films and coatings. The book serves as a complete, systematic, comprehensive account of the contemporary developments in the area of novel and environment-friendly valorization of agro- and food wastes into value-added products like biodegradable polymer and active functional agents for food packaging applications. It also describes the hurdles and challenges in the commercialization of these novel biopolymer-based materials, including their composites, their applications, safety, and legal ramifications. This book consists of fifteen chapters covering different aspects of agro- and food waste utilization, the development of biodegradable polymers, and their composites for sustainable food packaging applications. The first thirteen chapters detail the processing of various agro- and food wastes of plant and animal origin to synthesize different biopolymers, such as starch, cellulose, chitosan, silk proteins, pectin, etc., and their applications for the fabrication of sustainable food packaging materials and composites that are attractive alternatives to synthetic plastic packaging. These chapters also summarize the effectiveness of these biopolymers and their composites in developing active films and edible coatings for shelf-life extension and preservation of perishable foods. A chapter is devoted to issues of biodegradability, including analyses of various biodegradation reactions, such as depolymerization, mineralization, biochemical, and abiotic degradation both in soil and aquatic environments. The book concludes with a chapter addressing the concerns associated with the possible migration of components or additives from these biodegradable packaging into packaged food items. Audience The primary audience for this book is researchers, scientists, and engineers working in food science and technology, food engineering and technology, food biotechnology, sustainable food packaging, etc. Additionally, food entrepreneurs and associated businesses, such as the packaging and coatings industries, will also have a keen interest in the book.
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Veröffentlichungsjahr: 2024
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Table of Contents
Cover
Table of Contents
Series Page
Title Page
Copyright Page
Preface
1 Promising Agro-Wastes for Food Packaging
1.1 Introduction
1.2 Current Global Status of Agro-Wastes
1.3 Types of Agro-Wastes
1.4 Extraction of Biopolymers from Agro-Wastes
1.5 Extraction of Bioactive Compounds from Agro-Wastes
1.6 Conclusion and Future Perspectives
References
2 Natural Fiber–Based Composite for Food Packaging
2.1 Introduction
2.2 Fiber Types
2.3 Plant Fiber–Based Composite for Food Packaging
2.4 Animal Fiber–Based Composite for Food Packaging
2.5 Nanomaterials from Natural Fiber
2.6 Natural Fiber–Based Composite for Circular Economy
2.7 Conclusion and Future Perspective
Acknowledgment
References
3 Corncob Waste for Food Packaging
3.1 Introduction
3.2 Isolation of Cellulose from Corncob
3.3 Isolation of Hemicellulose from Corncob
3.4 Microbial Biosynthesis of Polyhydroxy Butyrate (PHB) from Corncobs
3.5 Biopolymers-Based Food Packaging Reinforced with Corncob Fibers
3.6 Hybrid Nanocomposite of Corncob for Food Packaging
3.7 Conclusion and Future Perspectives
References
4 Coir Fibers for Sustainable Food Packaging
4.1 Introduction
4.2 Coir Fibers as Reinforcement Material for Synthetic Polymers
4.3 Coir Fibers as Reinforcement Material in Biopolymers
4.4 Biodegradable Package/Container from Coconut Coir
4.5 Conclusion and Future Perspective
References
5 Sugarcane Bagasse for Sustainable Food Packaging
5.1 Introduction
5.2 Chemical Composition and Characteristics of Sugarcane Bagasse (SB)
5.3 Cellulosic and Hemicellulosic Fractions of Sugarcane Bagasse
5.4 Pretreatment Approaches for SB
5.5 Sugarcane Bagasse in Biopolymer Matrix as Reinforcement Filler
5.6 Food Containers and Trays Made From SB
5.7 Conclusion and Future Perspective
References
6 Husk and Straw of Cereals Grains for Sustainable Food Packaging
Abbreviations
6.1 Introduction
6.2 Extraction and Purification of Cellulose from Husk and Straw
6.3 Cellulose Nanocrystals
6.4 Use of Cellulose and Its Derivatives in Food Packaging
6.5 Paper-Based Package from Straw and Husk
6.6 Tableware and Food Containers from Straw and Husk
6.7 Conclusion and Future Perspective
References
7 Sericulture Waste for Edible Films and Coating of Fruits and Vegetables
7.1 Introduction
7.2 Sericulture Wastes
7.3 Extraction and Purification of Silk Protein/Fibroin
7.4 Silk Protein–Based Active Food Packaging
7.5 Toxicological and Food Allergy Assessment of Silk Protein/Fibroin
7.6 Conclusion and Future Perspective
References
8 Functional Agents from Agro-Waste for Active and Intelligent Food Packaging
8.1 Introduction
8.2 Functional Agents in Active and Intelligent Packaging
8.3 Active and Intelligent Agents in Biopolymer-Based Food Packaging
8.4 Conclusion and Perspective
References
9 Starch from Agro-Waste for Food Packaging Applications
9.1 Introduction
9.2 Starch from Agro-Waste
9.3 Modifications in Starch for Food Packaging
9.4 Starch-Based Composite, Nanocomposite, and Hybrid Films
9.5 Food Packaging Applications
9.6 Conclusion and Perspectives
References
10 Chitosan from Agro-Waste for Food Packaging Applications
List of Abbreviations
10.1 Introduction
10.2 Sources of Chitosan
10.3 Chitosan Extraction
10.4 Chitosan and Its Functional Properties
10.5 Chitosan-Based Composites and Nanocomposites
10.6 Food Packaging Applications
10.7 Conclusion and Future Perspectives
References
11 Biodegradable Synthetic Poly(Lactic Acid) (PLA) for Food Packaging Application
11.1 Introduction
11.2 Synthesis of PLA
11.3 Properties of PLA
11.4 Food Packaging Applications of PLA
11.5 Conclusion and Future Prospects
References
12 Pectin from Agro-Waste Residues for Food Packaging
12.1 Introduction
12.2 Structure and Classification of Pectin
12.3 Agro-Waste as Sources of Pectin
12.4 Techniques for Pectin Extraction from Agro-Waste
12.5 Food Packaging Applications of Pectin-Based Films and Coatings
12.6 Conclusion and Perspective
References
13 Cellulosic Nanomaterials and Its Derivatives from Agro-Waste for Food Packaging Applications
13.1 Introduction
13.2 Cellulose Structure and Its Nano-Derivatives
13.3 Agro-Waste as Source of Cellulose
13.4 Extraction of Cellulose from Agro-Waste
13.5 Cellulose-Derived Biopolymers
13.6 Food Packaging Applications of Cellulose and Its Derivatives
13.7 Conclusion and Perspective
References
14 Biodegradability of Biopolymers
14.1 Introduction
14.2 Biodegradability of Traditional Food Packaging
14.3 Biodegradability of Biopolymers
14.4 Mechanisms and Pathways of Biopolymer Degradation
14.5 Biodegradation of Biopolymer-Based Food Packaging
14.6 Conclusion and Perspective
References
15 Migration Concerns of Biopolymer-Based Food Packaging
15.1 Introduction
15.2 Migration Concerns of Biopolymer-Based Nanocomposite
15.3 Migration of Oligomers From Biopolymers in Contact with Food
15.4 Migration of Nanomaterials
15.5 Biopolymer-Based Nanocomposite Films and Coatings
15.6 Effect of Polymer and Migrant Geometry on Migration
15.7 Diffusion Modeling of Migration in Food Packaging
15.8 Conclusion and Future Perspectives
References
Index
End User License Agreement
List of Tables
Chapter 1
Table 1.1 Extraction of bioactive compound from agro-wastes.
Chapter 2
Table 2.1 Animal fiber–based composite and their applications.
Table 2.2 Nanofibers synthesized from natural fibers and their uses/advantages...
Chapter 3
Table 3.1 Annual production of corn in the year 2022 [10].
Table 3.2 Properties of fiber reinforced composite.
Table 3.3 Mechanical properties of composites.
Chapter 4
Table 4.1 Mechanical properties of coir fiber blended composites of natural an...
Chapter 5
Table 5.1 Sugarcane as reinforcement material in biopolymer-based composites.
Table 5.2 Sugarcane bagasse–based containers and trays for food packaging appl...
Chapter 6
Table 6.1 The derivatizations of cellulose extracted from husk and straw of ce...
Table 6.2 Cereal grains byproducts and composition [125].
Table 6.3 List of a few manufacturers producing cellulose-based packaging mate...
Chapter 7
Table 7.1 Applications of silk protein/fibroin in the fabrication of active fi...
Table 7.2 Applications of silk protein/fibroin in the fabrication of edible co...
Chapter 8
Table 8.1 Intelligent food packaging system incorporated with different agro-w...
Chapter 9
Table 9.1 Starch from agro-waste and their applications in food packaging.
Chapter 10
Table 10.1 Production of chitosan from agro-waste and their yields.
Table 10.2 Chitosan and chitosan-based films/coatings on the shelf life and qu...
Table 10.3 Chitosan and chitosan-based films/coatings on the shelf life and qu...
Chapter 11
Table 11.1 Application of PLA for food packaging.
Chapter 12
Table 12.1 Various agro-waste sources for the extraction of pectin using diffe...
Table 12.2 Pectin-based edible coating applications on muscle foods.
Chapter 13
Table 13.1 The dimensions and angles of a different polymorph of cellulose.
Table 13.2 Recent studies on the production of cellulose from different agrowa...
Table 13.3 Production of CMC from different agro-sources by etherification, de...
Table 13.4 Production of CA from different agro-waste using glacial acetic aci...
Table 13.5 Production of CNF from a different source of agricultural biomass u...
Table 13.6 Application of cellulose and its derivatives for packaging of diffe...
Chapter 15
Table 15.1 Total migrant of TBHQ and BHT antioxidants from PLA films.
Table 15.2 Oligomer of PLA and their migration in different three food simulan...
Table 15.3 FDA-approved inorganic nanoparticles according to FDA [42–44].
List of Illustrations
Chapter 1
Figure 1.1 Utilization of agro- and food wastes in sustainable food packaging ...
Figure 1.2 Bioactive compounds extraction from agro-waste employing various ex...
Chapter 2
Figure 2.1 Properties of food packaging required for improved shelf life of fo...
Figure 2.2 Classes of natural fibers.
Figure 2.3 (a) Bamboo fiber, (b) optical microscopy of bamboo fiber (untreated...
Chapter 3
Figure 3.1 Structure of cellulose.
Figure 3.2 Structure of typical hemicellulose.
Chapter 4
Figure 4.1 (a
1
and b
1
) Coir fibers before pretreatment; (a
2
and b
2
) treatment ...
Figure 4.2 Schematic procedure for coir fiber– and henna powder–based PUR comp...
Chapter 5
Figure 5.1 Some pretreatment techniques for sugarcane bagasse adopted with per...
Chapter 6
Figure 6.1 Schematic diagram showing extraction of crystalline cellulose from ...
Figure 6.2 Major modifications of CNC.
Figure 6.3 Properties of straw fiber–based biocomposite boards [131].
Figure 6.4 Steps involved in the production of compostable tableware using whe...
Figure 6.5 Properties of packaging materials produced from wheat straw plastic...
Chapter 7
Figure 7.1 Procedure of silk fibroin extraction from silk cocoons [22].
Figure 7.2 Effects of silk fibroin coating on freshly picked (a) strawberries ...
Chapter 8
Figure 8.1 Schematic diagram representing biobased indicators, phenolic compou...
Figure 8.2 The development of different intelligent packaging in the food pack...
Chapter 9
Figure 9.1 Utilization of agro-waste for the production of starch-based food p...
Figure 9.2 Different seeds and tuber waste for extracting starch.
Figure 9.3 Modification of starch for packaging film [56].
Figure 9.4 Desire properties of starch for food packaging.
Figure 9.5 Starch for food packaging applications [56].
Chapter 10
Figure 10.1 Various sources of chitosan.
Figure 10.2 Molecular structure of (a) chitin and (b) chitosan.
Figure 10.3 Film fabrication techniques.
Chapter 11
Figure 11.1 (a) Trend for annual plastic production in the worldand (b) demand...
Figure 11.2 Global production (a) of biobased polymers and PLA and (b) capacit...
Figure 11.3 The life cycle of PLA.
Figure 11.4 (a) Isomers of lactic acid and corresponding lactide and (b) synth...
Figure 11.5 Different PLA production pathways depending upon prospective appli...
Figure 11.6 Mechanical stability of PLA at elevated temperature.
Figure 11.7 PLA and stereocomplex PLA; (a) XRD patterns and (b) DSC thermogram...
Chapter 12
Figure 12.1 Types of biopolymers obtained from renewable sources.
Figure 12.2 Various extraction techniques [2] and properties of pectin and its...
Figure 12.3 Schematic of structural representation of pectin containing differ...
Figure 12.4 Schematic representation of plant cell wall consisting of pectin a...
Chapter 13
Figure 13.1 (a) Structure of xylan, (b) xyloglucan, (c) mannans, and (d)
β
...
Figure 13.2 The source of agro-waste and pretreatment methods for cellulose ex...
Figure 13.3 The mechanism of CMC production.
Figure 13.4 Mechanism of CMC production.
Figure 13.5 The different physical and chemical treatment processes for CNF pr...
Figure 13.6 The production of cellulose and its derivatives through the blendi...
Chapter 14
Figure 14.1 Advantages of biopolymers and their life cycle.
Figure 14.2 Schematic representation of polymer degradation.
Chapter 15
Figure 15.1 Schematic representation of plasticizer (triacetin) migration from...
Figure 15.2 Migration path of plasticizer and structural change in different s...
Figure 15.3 Microstructure of PLA and PLA-based nanocomposites in ethanol at 4...
Figure 15.4 Migration of Ti from PLA/TiO
2
nanocomposites for (a) 3 % acetic ac...
Figure 15.5 Overall migration of PHBV/CNC-me nanocomposites films [19].
Figure 15.6 Overall migration in standard food simulants for (a) PBSA, PBSA UV...
Figure 15.7 Area intensities of nonvolatile components for PLA-based films for...
Figure 15.8 (a) Migration testing for silver-based biopolymer films (b) migrat...
Figure 15.9 SEM images of PLA and SiOx/PLA-coated films for 1% antioxidants (a...
Guide
Cover Page
Table of Contents
Series Page
Title Page
Copyright Page
Preface
Begin Reading
Index
WILEY END USER LICENSE AGREEMENT
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Scrivener Publishing100 Cummings Center, Suite 541JBeverly, MA 01915-6106
Publishers at ScrivenerMartin Scrivener ([email protected])Phillip Carmical ([email protected])
Agro-Waste Derived Biopolymers and Biocomposites
Innovations and Sustainability in Food Packaging
Edited by
Santosh Kumar
Dept. of Food Engineering and Technology, Central Institute of Technology Kokrajhar, Assam, India
Avik Mukherjee
Dept. of Food Engineering and Technology, Central Institute of Technology Kokrajhar, Assam, India
and
Vimal Katiyar
Dept. of Chemical Engineering, Indian Institute of Technology, Indian Institute of Technology Guwahati, Guwahati, Assam, India
This edition first published 2024 by John Wiley & Sons, Inc., 111 River Street, Hoboken, NJ 07030, USA and Scrivener Publishing LLC, 100 Cummings Center, Suite 541J, Beverly, MA 01915, USA© 2024 Scrivener Publishing LLCFor more information about Scrivener publications please visit www.scrivenerpublishing.com.
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Library of Congress Cataloging-in-Publication Data
ISBN 978-1-394-17455-3
Cover image: Pixabay.ComCover design by Russell Richardson
Preface
The concept of this book formed sometime in early 2022, in light of tremendous global concerns associated with the indiscriminate use of synthetic plastics, and their impacts on the environment and human health. Given these concerns, agro- and food waste management and the valorization to obtain bioplastics for innovative food packaging applications have been of increased importance in the pursuit of a sustainable circular economy. The decision to develop a book on this emerging area of innovations and applications was compelled by the need for a sustainable future.
This book serves as a complete, systematic, comprehensive account of the contemporary developments in the area of novel and environment-friendly valorization of agro- and food wastes into value-added products like biodegradable polymer and active functional agents for food packaging applications. Also, the book describes the hurdles and challenges in the commercialization of these novel biopolymer-based materials, including their composites, their applications, safety, and legal ramifications. It is a unique resource material for educators and researchers, students, entrepreneurs, professionals in agriculture, food manufacturing, handling, and packaging industries, as well as other interested readers.
This book consists of fifteen chapters covering different aspects of agro- and food waste utilization, the development of biodegradable polymers, and their composites for sustainable food packaging applications.
The first thirteen chapters detail the processing of various agro- and food wastes of plant and animal origin to synthesize different biopolymers, such as starch, cellulose, chitosan, silk proteins, pectin, etc., and their applications for the fabrication of sustainable food packaging materials and composites that are attractive alternatives to synthetic plastic packaging. These chapters also summarize the effectiveness of these biopolymers and their composites in developing active films and edible coatings for shelf-life extension and preservation of perishable foods.
Chapter 14 discusses biodegradability, including analyses of various biodegradation reactions, such as depolymerization, mineralization, biochemical, and abiotic degradation both in soil and aquatic environments. On the other hand, the last chapter of the book addresses the concerns associated with the possible migration of components or additives from these biodegradable packaging into packaged food items.
It has been a great pleasure and a privilege to collaborate with the contributing authors affiliated with different academic institutes and universities of international repute in India and abroad. This book will benefit readers with interests in any one or more of the entire spectra of food, agriculture, waste management, agro- and food waste management, and valorization. The book will also have tremendous potential to appeal to industries, businesses, and government bodies. We could not have achieved success in our efforts without the support, cooperation, and understanding of our peers, friends, and families, which stems from our unwavering dedication and commitment to this book project.
Santosh KumarAvik MukherjeeVimal KatiyarMarch 2024
1Promising Agro-Wastes for Food Packaging
L. Susmita Devi, Avik Mukherjee and Santosh Kumar*
Department of Food Engineering and Technology, Central Institute of Technology Kokrajhar, Kokrajhar, BTR, Assam, India
Abstract
The agricultural sector produces a substantial amount of waste, typically left unused, and these wastes are a growing risk to human health, food security, and the environment. Transforming these waste materials into valuable products holds the potential to be advantageous for both the environment and significant cost savings. Agro- and food wastes originating from various sources have the potential to serve as a primary resource for creating value-added products, extracting food-related compounds, and producing biopolymers for sustainable food packaging. The increasing consumer demand has spurred the development of new eco-friendly food packaging, leading the packaging industry to focus on creating sustainable, renewable, biodegradable, and environment-friendly packaging materials from agro-based resources. Moreover, these agro-based materials hold immense potential for replacing petrochemical-based plastics in the packaging sector due to their abundant availability and biodegradable nature. Various agro-wastes, and their potential for extraction of different natural biopolymers, and bioactive compounds are discussed in detail in this chapter. In addition, the applications of agro-waste–based biopolymers and bioactive compounds in biodegradable sustainable food packaging systems have also been discussed. The chapter also delves into future considerations, particularly in the realm of enhancing the effectiveness and efficiency of agro-waste packaging systems, while simultaneously addressing the inherent production challenges. This article holds particular significance within the context of the biorefinery concept, which is dedicated to the conversion of agricultural waste into a diverse range of valuable products.
Keywords: Solid waste, sustainable packaging, biopolymers, organic compounds, eco-friendly
1.1 Introduction
Rapid urbanization, population growth, and industrialization generate a vast amount of agro-waste every year [1]. Agro-wastes are the residue left after processing and producing different agro-products, such as fruits, vegetables, muscle foods, and dairy products that are liquids, slurries, or solids in nature [2]. These wastes are generally left untreated or unutilized and are either burned on-site, disposed of by dumping, or unplanned landfilling, leading to climate change by increasing greenhouse gas emissions causing a threat to the environment and human health [3, 4]. The lack of efficient waste management techniques creates a huge challenge for mankind to deal with such massive food and agro-wastes. Most of the food wastes are generated during production, harvesting, transportation, industrial processing, and consumption [5]. Agro-wastes have the potential to be used as raw materials for value-added products, renewable energy production, extraction of food compounds, and packaging material manufacturing [6]. Agro-industry byproducts are also composed of numerous bioactive compounds such as carbohydrates, proteins, and lipids that can be extracted and used to produce biodegradable food packaging [7]. Agro- and food wastes are rich in nutrients and organic compounds that can be processed to recover valuable products including biopolymers [8]. The biopolymers are directly extracted either by chemical synthesis or by genetically modified organisms from agro-industrial wastes and can be converted into biodegradable packaging materials. However, the treatment methods or downstream processing of such waste are usually complex, expensive, and time-consuming and cause secondary pollutants due to their heterogeneous nature [3]. On the other hand, waste generated from the food industries is extremely nutritious in nature, making substrates for microbial fermentation and enzyme production [9]. The oil industries also produce a large number of residues known as oil cakes that contain high concentrations of fats, oils, greases, suspended solids, and dissolved solids, contributing to air, water, and solid waste pollution [8]. Such environmental problems can be reduced or minimized if these wastes are utilized for the extraction of biopolymers and other valuable products.
Food packaging serves as a vital part of the food system that protects food and food products from degradation and damage, maintains food safety and hygiene, enhances shelf life, and reduces food waste and food losses [10]. A wide variety of synthetic plastic materials are being used in food packaging that raise environmental pollution concerns [11]. The food packaging sector consumes the largest amounts of synthetic plastics globally, and it is the primary contributor to synthetic plastic waste [12]. Waste generated from food packaging accounts for about 66% of total packaging waste, and thus, there is a growing prerequisite for sustainable and biodegradable packaging materials that have the desired physical, mechanical, and barrier properties for food packaging applications. Biopolymers derived from bioresources, i.e., agro- and food wastes have shown potential for use as food packaging (Figure 1.1). Extraction and purification of the biopolymers from agro-wastes to produce a food packaging material can replace petrochemical-based synthetic plastics in the food packaging industry [1]. The growing market for food delivery services is expected to boost packaging material consumption in the future, and a sustainable approach to materials development requires agro- and food waste–based materials to fill the gap between industrial supply and consumer demand [13]. The major benefits of agro-waste valorization include nontoxicity, improving ecosystems, encouraging circular economy, increasing employment, and biocompatibility with other materials [14, 15]. This chapter presents a summary of the potential uses of agro-wastes for the extraction of biopolymers for technological applications. Furthermore, the chapter summarizes existing information concerning various waste types of agro-wastes and their treatment for extracting valuable compounds for applications in the sustainable food packaging sector.
Figure 1.1 Utilization of agro- and food wastes in sustainable food packaging [16].
1.2 Current Global Status of Agro-Wastes
Solid waste generation increases with the growing population, urbanization, industrialization, living standards, disposable incomes, and consumption of goods and services [17]. In the last century, China, India, and Africa have experienced significant increases in agro-waste generation alongside rapid population growth and economic development. In India, agro-waste remains the predominant form of solid waste, with annual production ranging from 350 to 990 million tonnes (Mt). India produces more than 130 Mt of paddy straw each year, of which half is used as animal feed and the other half is dumped, making it the second-largest producer of agricultural waste in the world after China [18]. Approximately 34% of Asia’s biomass residues are burned in the field, and open-field burning of crop residues contributes significantly to greenhouse gas emissions in countries like China and India [19]. Managing these solid wastes is a worldwide problem because waste collection, transportation, segregation, treatment, and disposal are complex processes and have detrimental effects on the environment. Additionally, inappropriate solid waste management results in several environmental pollutions and health problems including waterborne diseases, respiratory illnesses, soil pollution, and groundwater contamination [20]. Thus, it is important to identify efficient ways of utilizing and managing agro-residues. These agro-wastes can be utilized in different food sectors, however, lack of knowledge about their characterization and processing methods hinders their applications in the food sector [19]. The global economy is planning an integral waste management strategy, which is based on the concept of biorefinery and on the reduction, reuse, and recycling of waste with the goal of recovering resources derived from wastes as renewable resources [21]. Agriculture being one of the largest sectors with the highest waste production becomes an essential part of the bioeconomy, which promotes the conversion of agro-wastes into value-added products such as bioenergy, bioproducts, feed, and foods [22]. The increasing global population accelerates over utilization of natural resources and generates a large amount of waste, which is expected to double by 2050 to 4 billion tonnes at the current rate of production and consumption [23]. Agro-residues obtained after harvesting grains are used in different applications such as animal feed, raw material for animal bedding, loose-fill insulation, fuels, composites, bioplastics, biorefineries, and as raw material in the paper and pulp industry, as an absorbent of uranium residues, and as a substrate for solid state for microbial growth [1, 24].
The global population has increased from 3.7 billion to 8.0 billion during 1970–2022, and it is predicted to reach 8.5 billion, 9.7 billion, and 11.2 billion by 2030, 2050, and 2100, respectively. As a result, ensuring food security in the future would be a formidable challenge, and fulfilling the high demand of a growing population, livestock, and crop production has to increase significantly, which will simultaneously increase the generation of agricultural waste [25]. Currently, the global economy relies on biorefineries and the concept of reusing, recycling, and reducing waste with the aim of recovering valuable materials from waste [21]. There have been various studies from all around the world that have confirmed the importance of food waste reduction and its valorization. In recent years, various published literature discussed on utilization of agro-waste for various applications in food industries [26]. In addition, promoting the conversion of waste into value-added products such as food, feed, and bio-based products can also contribute to the development of new green markets and jobs [27]. Surendra et al. (2022) studied the bioconversion of agro-waste into fuel, feed, fertilizer, and biobased products [28]. Pomegranate wastes such as peel, seed, and pomace generated from the pomegranate juice and jam industry have high antimicrobial, antimutagenic, and free radicals scavenging properties that increased interest in this byproduct for the development of active food packaging films [29, 30]. Bagasse, a byproduct obtained from the sugar industry during juice extraction from sugarcane, also has several applications including the production of ethanol, paper, hydrogen, and bio-oil [31]. John et al. (2023) studied the feasibility of utilizing agricultural biomass such as wheat bran and rice bran to produce bioethanol by enzymatic hydrolysis (EH) followed by saccharification [32]. The waste generated after the processing of cashew nut is reportedly used in a variety of products, including adhesive resins, bioethanol, biodiesel, surface coating agents, dyes, insecticides, larvicides, anti-termite, and rubber [25, 33, 34].
1.3 Types of Agro-Wastes
1.3.1 Agro-Industrial Waste
Agro-industrial residues are wastes generated by the food and agriculture industries. The efficient transformation of these wastes has become a key objective in recent years, in which biodiesel production is getting a lot of attention. It is also possible to obtain new materials, chemicals, and valuable products from agro-industrial wastes [35, 36]. Agro-industrial wastes can be categorized into three main groups, namely, compostable wastes, non-compostable wastes, and hazardous wastes. Compostable wastes are recyclable agricultural residues generated during the processing of agricultural crops into various food products, for example, molasses, bagasse, peels, hulls, husks, seeds, slurry, and cakes. These wastes contain different compositions of cellulose, hemicellulose, lignin, moisture, ash, carbon, nitrogen, and many other compounds [8]. Non-compostable wastes include those produced from farm construction, farm machinery, and livestock protection that are usually nonrecyclable agro-industrial waste, whereas hazardous agro-industrial wastes such as acids, fertilizers, chemically contaminated water, foods, and other materials pose very serious problems if they are not managed properly [37]. Processing of industrial wastes or compostable waste can be economically beneficial, as they can be utilized as substrates for obtaining biopolymers having a wide array of functional properties including antimicrobial and antioxidant properties, biodegradability, and nontoxicity. One of the most effective options is to use these residues as a source of fibrous biomass, which can be used economically to produce paper and bioplastics at a far lower cost that can solve disposal issues and environmental problems [1]. Wastes like pumpkin seeds and peels, grapefruit peels, sunflower heads, sisals waste, pomegranate peels, eggplant peels, and orange peels are found to be used in developing biopolymers such as alginate and pectin [38, 39]. For example, garlic and onion peels contain flavonoids that have antioxidant, antimicrobial, and UV-resistant properties. Agro-industrial waste can also be utilized as low-cost raw materials for the microbial synthesis of valuable primary and secondary metabolites [40, 41].
1.3.2 Crop Residues
Harvest waste, commonly referred to as crop residue, encompasses both field residues left in agricultural fields after crop harvesting and process residues remaining after the crop has been transformed into a usable resource [42]. Crop residue includes leaf, stalk, root, stem, seed pod, and straw waste. Some residues are either used as animal feed or left on the ground to avoid erosion, but these approaches are less efficient and may encourage pest infestations [1]. As per the Ministry of New and Renewable Energy (MNRE), India produces an average of 500 Mt of crop residue annually. The MNRE report also indicates that a significant portion of this crop residue is effectively utilized as animal feed and as a fuel source for both household and industrial applications. Nonetheless, there remains an excess of 140 Mt, with 92 Mt being burned each year [42, 43]. Crop residues constitute a valuable component of agricultural waste, possessing an organic composition that can be harnessed for the betterment of society [42]. These crop wastes are also the most widely available and inexpensive organic waste, and they can be easily converted into a variety of high-value goods [44]. Such wastes are primary sources of polysaccharides that can be used as raw materials to produce a variety of valuable products such as biopolymers, ethanol, and biochemicals [45]. Different studies have shown that rice stubble residues can be converted into carboxymethyl cellulose, which is used as flexible packaging material. Chollakup et al. (2020) developed rice straw–based paper for antibacterial food packaging applications by coating them with pomelo peel extract [46]. Rice hulls and their nanofibers were used as reinforcement fillers in films for improving mechanical, optical, and barrier properties, demonstrating the potentiality of milling waste in biopolymer-based packaging [47]. Safont et al. (2018) used rice husk and almond shells, lignocellulosic wastes, in poly(3-hydroxybutyrate)/fiber composites as high-performance fillers for improving film properties and sustainable way to valorize crop residues [48].
1.3.3 Animal Waste
Animal wastes are produced during meat processing, animal husbandry (such as wash water, urine, dung, and waste feed), poultry waste (such as bedding material, feathers, droppings, and spilled feed), slaughterhouse waste (flesh, blood, hides, hair, and bones), etc. [22, 49]. India’s livestock population was approximately 536.76 Mt, as reported in the 20th Livestock Census in 2019. This population generates around 3 Mt of livestock waste each year [50, 51]. Animal wastes represent substantial environmental challenges that, if not managed appropriately, can result in contamination of both ground and surface water sources [52]. Inappropriate discarding of such waste impacts air and water quality and also upsurges the risk of pathogenic microbes for human health [53]. Moreover, it has the potential to serve as a valuable source for biomass-based conversion processes, particularly in the production of biopolymers, bioenergy, and biofertilizers [54]. Wastes and byproducts from slaughterhouses are known for their rich content of proteins [55]. The extraction of proteins from byproducts primarily involves pretreatment, extraction, and downstream processing [56, 57]. Animal-based proteins are highly nutrient-dense and offer a range of beneficial properties such as film-forming, water- and oil-holding capacity, gelling, and emulsifying properties [58]. Proteins of animal sources like keratin, collagen, myofibrillar, and gelatin proteins, are widely used in biodegradable food packaging films [59].
1.3.4 Aquatic Waste
The fishery and aquaculture play an important role in food nutrition and security. Fish and seafood processing generate a large amount of solid waste from activities like beheading, de-shelling, degutting, removing fins and scales, and filleting [60, 61]. In general, fish byproducts are viscera, muscle tissues, carcasses, heads, fins, skin, scales, and bones, which normally weigh between 50 and 75% of the fresh weight of the fish depending on the species [62]. Fish industry byproducts are also used in animal feed to provide low-value nutrients; however, most are landfilled or incinerated, posing environmental and economic hazards [63, 64]. As fish byproducts contain high microbial load and endogenous enzymes, they are susceptible to rapid degradation if not properly processed or stored posing significant environmental and food-technology challenges. There are two types of aquatic waste: those that can easily degrade with a lot of enzymes, like viscera and blood, and those that are more stable (bones, heads, and skin) [64]. The timely collection and treatment of such wastes are critical to their quality, which makes them suitable raw materials for high-value compounds, like enzymes, lipids, gelatin, collagen, hydrolysates, and bioactive peptides [65]. For example, collagen is mainly obtained from fish skin, bones, fins, and scales, as well as jellyfish and starfish connective tissue. Fish skin contains about 70 to 80% collagen by dry weight [66, 67]. On the other hand, gelatin is a denatured protein formed during the process of partial hydrolysis of collagen and subsequent thermal treatment, which is composed mainly of proteins and polypeptides with different molecular weights [68]. Zavareze et al. (2014) developed a biodegradable film by extracting myofibrillar and protein isolate residue of Whitemouth croaker (Micropogonias furnieri) that achieves high tensile strength and low water vapor permeability at the lowest protein concentration; however, water vapor permeability was higher for films with higher protein concentrations [69]. Similarly, Nie et al. (2017) developed an edible film from silver carp myofibrillar proteins and tannins using alkaline and heat treatment methods [70]. The most valuable products obtained from marine waste are fishmeal and fish oil.
1.4 Extraction of Biopolymers from Agro-Wastes
Most of the agricultural wastes are lignocellulosic, which contains high amounts of polysaccharides such as cellulose, hemicellulose, lignin, and other nutrients such as proteins, lipids, and polyphenols [40]. Many lignocellulosic biomasses including agricultural wastes are difficult to degrade due to their composition and chemical structure, and to overcome this complication, a pretreatment process is used [71, 72]. During this process, agro-waste complex molecular structures are broken down into simpler monomers such as cellulose, hemicellulose, and lignin. A major goal of agricultural waste pretreatment is to reduce the energy required during transformation and cost-cutting and produce sugars directly from biomass [73, 74]. It is challenging to utilize agro-waste effectively for certain purposes due to its extremely heterogeneous nature. The biopolymers are extracted from agro-wastes commonly through chemical, biological, mechanical, and thermomechanical treatments, which are briefly discussed below.
1.4.1 Chemical Treatment
1.4.1.1 Acid Treatment
Acid treatment is an extensively used pretreatment process applied to the manufacturing of value-added compounds from lignocellulosic biomass [75]. In the pretreatment process, acids such as HCl, H2SO4, phosphoric acid, HNO3, ethanoic acid, and formic acid are often utilized as reagents for the degradation of cellulose and hemicellulose and promote the release of fermentable sugar. Sulfuric acid treatment has typically proven to be more efficient than other acid treatments; however, strong acids can also cause significant loss of fermentable sugar due to an excessive breakdown of the complex substrate [76]. From an economic viewpoint, strong acids tend to negatively impact the anaerobic digestion (AD) process due to corrosion and the requirement of additional chemicals for neutralization [77]. Therefore, to reduce such risks of toxicity, corrosion, and handling, diluted acids (<4% w/w) are mostly used coupled with higher temperatures treatment (>100°C) in acid pretreatment [76]. According to Ali and Tindyala (2015), pretreatment of rice husk with H2SO4 significantly enhances the thermal conversion of rice husk, and the results showed that the degradation of treated husk initiates occurred at 185°C, whereas decomposition of untreated rice husk occurred nearly at 250°C [78]. In a recent study, Panchami and Gunasekaran (2017) obtained pectin from fruit waste such as citrus peel, apple pomace, mango peel, and banana peel by treating with 0.1 N HCl and boiling for 30 min, and the acid treatment resulted in higher pectin yields of 25.5, 12.5, 8.8, and 2.8%, respectively [79]. Tiwari et al. (2017) also extracted pectin from the peel of an orange upon citric acid treatment for 30 min at pH 1 and 65°C and finally washed with ethanol resulting in a pectin yield of 52.9% [80].
1.4.1.2 Alkali Treatment
Alkaline pretreatment entails using alkaline reagents like NaOH, hydrazine, anhydrous ammonia, KOH, or Ca(OH)2 to liquefy lignin and certain hemicellulose to reduce cellulose crystallinity and to increase the conversion of biomass [81]. Additionally, alkali treatment increases active surface area, causes swelling, and facilitates the substrate’s higher accessibility for anaerobic microbes [77]. The alkali pretreatment method is applied at room temperature or at a little higher temperature (around 40°C) with a long response time that usually takes many hours to days to complete [82]. Alkali treatment is more desirable than acid pretreatments because alkali treatment prevents pH reduction, which improves the conditions for the AD of the waste [77]. They are economical and less hazardous to the environment; however, they need a longer reaction time and neutralization of the pretreated slurry [81]. Ramesh and Radhakrishnan (2019) reported that potato peel powder was treated with 2% NaOH at 50°C for 180 min resulting in high production of cellulose with a yield of 39.8%. The obtained cellulose was subsequently incorporated into polyvinyl alcohol (PVA) films, leading to improved antibacterial characteristics and notably increased free radical scavenging activity, which is advantageous for food packaging applications [83]. As a result of the alkali treatment, Verma and Goh (2021) stated that the agro-waste fibers improved in roughness, thereby improving the adhesion of the fiber to the matrix and cellulose content on the surface of the fiber, which also enhanced the interfacial strength and bonding between the natural fiber and the matrix. By improving fiber interlocking with matrices, polymer-based green composites achieve higher mechanical properties [84].
1.4.1.3 Organic Solvent Treatment
The organic solvent treatment, also known as the organosolv treatment method entails the pretreatment of lignin and the production of other potentially valuable coproducts (such as acetone, butanol, ethanol, and biogas) [85]. Organosolv treatment uses organic solvents such as CH3OH, C2H5OH, ethylene glycol, acetone, and tetrahydrofurfuryl alcohol in order to breakdown of the internal bonds of hemicelluloses and lignin to decompose lignocellulosic material and ensure efficient cellulose conversion [86]. Frequently organic acids like oxalic, acetylsalicylic, and salicylic acids are also utilized as catalysts to speed up the reaction process [87]. Organosolv pretreatments are very promising because of their inherent benefits, including the separation of high-purity cellulose with only minor degradation, the isolation of high-quality lignin, and the higher efficiency of hemicellulose fractionation when compared to other conventional treatments [88]. In a study, Salapa et al. (2017) treated wheat straw with ethanol at 180°C for 40 min that yielded maximum cellulose (89%) and ethanol (67%) [85]. Similarly, Zhao et al. (2009) reported that corn stover treatment with 60% (v/v) ethanol led to a delignification of about 81.7% and a yield of 83.2% total sugar. Such pretreatment is particularly useful for lignocellulosic bio-mass with a high lignin content because it breaks internal linkages between lignin and hemicellulose [89].
1.4.2 Biological Treatment
Biological treatment comprises practices of microorganisms, such as bacteria or fungi, to break down the lignin content in the agro-waste and promote the conversion of lignocellulose material into a useful product. This pretreatment technique is environmentally friendly, emits no harmful substances, uses less energy, and creates no or less inhibitor [90]. Biological treatment is an inexpensive, time-consuming, and slow process that requires longer residence time [91]. The most effective biological treatment method is one that can break down the majority of undesired substances while retaining a high proportion of valuable components in a short period of time [92]. The availability of nutrients like sugars, minerals, and proteins within the agro-waste provides favorable conditions for the abundant growth of microorganisms. These microorganisms have the potential to use the waste as ingredients or a substrate for their growth using fermentation techniques, leading to the creation of various valuable compounds. Utilizing this waste would not just assist in recycling, but it would also lower production expenses and significantly decrease pollution levels [8]. Cellulase, lignolytic enzymes, and industrial enzymes can all be used to digest the lignocellulosic components of agro-wastes. Even though the enzymatic response rate for lignocelluloses is quite slow and requires a large sample size and close monitoring of growth conditions of the microorganism to prevent contamination, biological treatment is known to be useful for biomass containing lignocelluloses because microbial enzymes are effective at decomposing lignocellulosic substances [77]. Bacteria and fungi produce cellulases that break down and hydrolyze lignocellulosic biomass to increase sugar yields and improve the efficiency of microbial fuel cells. The bacteria that generate cellulases include Bacteroides, Erwinia, Clostridium, Bacillus, Cellulomonas, Termomonospora, Acetovibrio, Ruminococcus, Microbispora, and Streptomyces [93, 94]. Gadgey and Bahekar (2017) used enzymatic and fermentation methods for the extraction of chitin, in which enzymes, such as proteases, are used to deproteinize crustacean shells. These enzymes are commonly gained from Lactobacillus spp., Bacillus subtiltis, Serratia marcescens FS-3, and Pseudomonas aeruginosa K-187 [95]. In the biological process, Nielsen et al. (2017) used microbial strains such as Bacillus, Cupriavidus, Comamonass, Pseudomonas, Hydrogenophaga, Acinetobacter, Azotobacter, Burkholderia, Haloferax, and Azohydromonas species to produce poly(3-hydroxybutyric acid) (PHB) and polyhydroxyalkanoates (PHA) from agro-waste [96]. PHB, which is a homopolymer of 3-hydroxybutyrate, is widely used; however, PHA is used less in industrial settings because of its high production costs [97].
1.4.3 Mechanical Processing
In general, lignocellulosic material is pretreated using grinding, chipping, and by using several milling techniques such as colloid milling, vibratory milling, hammer milling, two-roll milling, and other procedures before being treated by AD. In a prior study, meadow grass was processed with a checker plate, sandpaper, and mesh grating plate resulting in a high production of methane by 25 to 27% compared to that achieved without mechanical treatment [98, 99]. Mechanical processing was employed for particle size reduction of lignocellulosic material of particle sizes in the range of 0.2 to 2 mm and 10 to 30 mm by milling and chipping pretreatments, respectively [100, 101]. In another study, wheat straw subjected to roll milling, extrusion, pelletization, and hammer milling, maximum methane production per day (DMPmax), biochemical methane potential (BMP), and EH yield as the amount of released glucan/initial glucan content were used to analyze the impacts of the pretreatments on AD at 37°C and on EH with Cellic CTec2 at 50°C. Maximum BMP of 287 Nml CH4 gVS1, up 21% from untreated wheat straw was produced in roll milling, although extrusion produced the highest rate of methane (52 Nml CH4 gVS1 day−1). According to EH results and specific surface analysis of 0.25- to 1-mm particles, the mechanical pretreatment possibly changes other physicochemical characteristics like crystallinity or melting of the outer wax layer of wheat straw, which in turn influences EH processes and AD [102]. Pretreatment of herbaceous materials requires less energy than pretreatment of woody materials. The energy required to reduce the size of one metric tonne of pine chips, maize stover, switch grass, and poplar was found to be 85.4, 11.0, 27.6, and 118.5 kWh, respectively [103]. Furthermore, increasing the surface area during pretreatment improves the EH of lignocellulosic material [104]. It was also shown that reducing the size of lignocellulosic materials during milling pretreatment increased the buffering capacity of AD, which is beneficial in reducing anaerobic digestion acidification [105].
1.4.4 Thermochemical Processing
This method involves hot water and steam explosion pretreatment, in which biomass is pretreated at higher pressure at a higher temperature (140°C to 220°C) without any chemical intervention [106, 107]. Pressurized water penetrates the biomass, hydrolyzes hemicellulose, increases the surface area, hydrates cellulose, and removes the lignin fraction [108]. This pretreatment attracted attention due to its low-cost and nonchemical requirement [109]. Moreover, this method can increase methane production from lignocellulosic materials and has been extensively used for AD [110]. The hydrothermal pretreatment of sunflower stalks for AD was performed, and the pretreatment increased methane yield by 88.7% [111]. In another study, sunflower stalk was processed for AD at 160°C, 180°C, 200°C, and 220°C by Lee and colleagues (2020), in which the methane yield increased significantly (213.87 to 289.47 ml/g VS) in comparison to the control (129 ml/g VS) [112]. Pretreatment with a steam explosion at 160°C to 250°C and 5- to 50-bar pressure for a small period using saturated steam, followed by a rapid decrease in pressure that destroys the lignocellulosic components. The lignin is partially changed during the steam explosion in addition to the hydrolysis of hemicellulose, which increases the degradability of the ligno-cellulose material [77, 108]. Zhou and team (2016) prepared rice straw for 2 min at 200°C and found a 51% increase in methane output during AD. Steam explosion pretreatment of olive mill solid waste (OMSW) at 200°C and 1.57 MPa for 5 min affected the production of a solid fraction (SF) and a liquid fraction (LF) during the AD [113]. BMP studies of both steam explosion–pretreated and –untreated OMSW showed that the LF had the highest methane production (589 ± 42 mL CH4/g VS) [114]. Another investigation claimed that pretreatment with steam explosion might efficiently increase the generation of methane from water primrose, in spite of the plant’s woody structure and higher lignin content [115].
1.5 Extraction of Bioactive Compounds from Agro-Wastes
Bioactive compounds are secondary molecules produced naturally in small amounts in plants and animals and possess certain functional properties like antioxidant, antimicrobial, anticarcinogenic, and anti-inflammatory [116]. Bioactive compounds are grouped into various classes including nitrogen-containing compounds, terpenoids, organosulfur compounds, alkaloids, and phenolics [117]. Bioactive compounds are being used to improve food quality (nutritional, sensory, and technological aspects), to manufacture functional foods such as nutraceuticals, and can be used to develop smart and active food packaging films and coatings [118–121].
The extraction process stands as the pivotal step in acquiring bioactive compounds from agro-waste, and the selection of optimal extraction methods plays a crucial role in determining both the specific types and quantities of bioactive compounds [122]. The extraction of bioactive compounds is driven by several critical factors, including extraction technique, properties of plant components, solvent used, and extraction condition (Figure 1.2) [123, 124]. Sample preparation constitutes another critical factor influencing the type and quantity of bioactive compounds extracted. For example, Ferri et al. (2020) applied a solvent-based extraction technique on grape pomace for the extraction of bioactive compounds, in which different solvent ratios (1:5 and 1:10) were mixed with the grind pomace and incubated at specific temperatures (50°C and 70°C) in a closed system. After incubation, the liquid extracts were separated from solid residues and stored at −20°C. Solvent types included 50% aqueous-ethanol, 50% aqueous-acetonitrile, and 75% aqueous-acetone. Results revealed that the highest amount of phenolics was obtained using 75% acetone followed by 50% aqueous-acetonitrile and 50% aqueous-ethanol [125]. Another study by Sharif et al. (2023) extracted bioactive phytochemicals from mango peel using a pretreatment combination of ultrasound irradiation and enzyme treatment. The mango peel was treated with enzymes under optimized conditions, followed by ultrasonic pretreatment. The enzymes were then deactivated by heating at 95°C for 5 min, and the treated peel was subjected to extraction using an ethanol-water solvent mixture (80:20 v/v). After incubation at 45°C in an orbital shaker at 120 rpm for 24 hours and centrifugation at 4500 rpm for 10 min, the extracts were filtered and concentrated using a rotary vacuum evaporator. The findings of the study indicated that the mango peel extracts contained a total phenolic content (TPC) of 33.56 ± 1.04 mg GAE/g of fresh weight. Moreover, the mango peel extracts treated under the optimized conditions exhibited a noteworthy Trolox equivalent antioxidant capacity (TEAC) value of 215.42 ± 1.21 mM TE/g [126].
Figure 1.2 Bioactive compounds extraction from agro-waste employing various extraction techniques.
Zhang et al. (2019) extracted anthocyanin from the black plum peel and effectively used it in chitosan and TiO2 films, where incorporation produces strong barrier characteristics against water vapor and UV light as well as improved mechanical strength. The developed films resulted in higher free radical scavenging, antioxidant, antimicrobial, and ethylene scavenging activities having potential applications as pH-sensitive color-changing food packaging film [127]. Anthocyanins extracted from blueberry juice residue have also been used in producing smart films using cassava starch that can monitor the quality of orange juice, chicken pieces, and corn oil [128]. Betacyanin extracted from dragon fruit shells has been used in developing smart packaging film based on glucomannan-PVA for sensing the freshness of fish. Betacyanin encourages a visible color change from purple to yellowish because of fish deterioration leading to increased levels of TVB-N [129]. In addition, protein hydrolysates obtained from agro-industrial byproducts have also been incorporated as active agents in food packaging films. For example, active films developed from protein hydrolysates and alginate extracted from cotton seed byproducts had excellent antioxidant, light barrier, and antimicrobial properties [130]. Other bioactive compounds like curcumins, tannins, and carotenoids can be extracted from agro-wastes for application as active agents in the development of smart biodegradable food packaging films and coating [131]. There is substantial use of bioactive components in developing active and smart packaging due to their variety, potential interactions, and diverse functions; however, each component must be evaluated properly to ensure maximum effectiveness. Many studies reported the extraction of bioactive compounds from agro-waste and their uses in various food packaging systems (Table 1.1).
Table 1.1 Extraction of bioactive compound from agro-wastes.
Agro-waste
Bioactive compound
Extraction methods
Application
Remark
Reference
Blackberry and blueberry pomace
Anthocyanin
Microwave-assisted extraction
pH indicator film
The developed films had high total phenol content, excellent antioxidant activity, and showed intelligent character, i.e., change in color upon exposure to solutions of different pH
[132]
Blueberry agro-waste
Anthocyanin
Frozen at −40 ± 2°C prior to lyophilization followed by milling and sieving
pH indicator film
Blueberry powder can be used as a pH indicator for sensing deterioration in food
[133]
Blueberry pomace
Anthocyanin
Freeze-dried followed by milling and sieving
Biodegradable films
The developed films had UV light protection properties because of aromatic compounds and thus reduced food deterioration
[134]
Jamun fruit skin
Anthocyanin
Solvent extraction
pH indicator
The developed indicator may be used to monitor the meat quality during refrigerated storage
[135]
Red pitaya peel
Betalains
Solvent extraction
Active and intelligent packaging films
The incorporation of the extract in the developed film improved UV light, water vapor barrier properties, and mechanical, antibacterial, and antioxidant activities. The film was also able to monitor shrimp freshness through visible color changes
[136]
Pomegranate flesh and peel
Polyphenols
Acid-base extraction
Active and intelligent films
The developed films showed a desirable tensile strength, water vapor, and UV light barrier ability of the film and exhibited a pH-sensitive property
[137]
Cashew nut testa
Tannins
Aqueous extraction
Active packaging film
The fabricated films had high antimicrobial and antioxidant (91%) properties and thermal stability (290°C) and thus could be used for shelf-life extension of perishable foods
[138]
Rambutan peel
Polyphenols
Solvent extraction
Whey protein isolate film
The developed films showed high antioxidant ability and moderate antimicrobial properties and may be used for food packaging application
[139]
Jaboticaba peel
Anthocyanins
Microwave-assisted extraction
Carrageenan-based films
The film showed good antimicrobial activities and can extend the postharvest-life of food
[140]
Apple peel
Polyphenols
Ultrasound extraction
Active food packaging film
The developed film improved the film’s opacity, swelling level, and solubility due to the addition of polyphenols
[141]
Pineapple peel
Polyphenols
Solid-liquid extraction
Edible film
The developed films effectively preserved red beef meat, significantly inhibited microbial growth, and delayed lipid oxidation in meat during storage
[142]
Black plum peel
Anthocyanin
Acid-base extraction
Multifunctional food packaging films
The developed film significantly enhanced UV light and water vapor barrier properties, tensile strength, and antioxidant, antimicrobial, and pH-sensitive abilities due to the abundance of phenolics and anthocyanins content
[127]
Hass avocado peel
Flavonoids and chlorophylls
Solvents extraction
Active films
The developed film had compatible and improved tensile strength and UV light barrier characteristics and effectively inhibited
Rhizopus stolonifera
and
Aspergillus niger
growth
[143]
Potato peel
Caffeic, chlorogenic, and neochlorogenic acids
Solvents extraction
Active edible film
The addition of extract in the developed film increased phenolic content and DPPH scavenging activity
[144]
1.6 Conclusion and Future Perspectives
Over the past few years, agricultural wastes have gained significant attention due to the increasing demand for a range of biobased products and environmental concerns. This prompted a shift toward utilizing agro-waste as a source of nutrients, bioactive compounds, and biopolymers. In this chapter, types of agro-waste, their processing, extraction methods, and uses have been discussed. Agro-waste can be recycled to produce various value-added products to ensure a safe and green environment. Agro-waste contains a variety of contaminants, including microorganisms, heavy metals, and pesticides, which may pose health risks to humans and animals. For agricultural sustainability and the security of human food and health, it is imperative to develop solutions for the safe utilization and valorization of agro-waste in order to create value-added products, farmer livelihoods, and job opportunities for youth. The agro-waste generated during the growing and first processing of agriculture can provide a resource for improving the nutritional value of food and improving food security. Future research efforts should also focus on the advancement of innovative biotechnological approaches to effectively valorize agricultural waste. The development of suitable green technologies is essential for the advancement of bioproducts. With effective policies and their proper execution, the economic and market resistance problems can be overcome over time. Managing agro-waste and valorizing it are essential for sustainable development. Considering the benefits of reusing agro-waste in the manufacturing process means resolving important problems today, i.e., environmental pollution and economic sustainability.
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