Chitosan: Novel Applications in Food Systems

Chitosan: Novel Applications in Food Systems is a practical resource for those looking to understand new applications of chitosan in the food industry. The content presented is written by experts in the field who have worked on the latest application of chitosan-based research to help researchers and scientists understand how recent applications combined with traditional food preservation hurdles, or novel hurdles such as active packaging, irradiation and essential oils can improve methods of controlling microorganisms in foods. With an emphasis of potential of chitosan in food safety this reference briefly summarizes what chitosan-based research has already done for the industry, including potential applications.

• Explains the role of chitosan nanoparticles to fight against food pathogens
• Provides the latest developments on chitosan and food packaging, especially on active food packaging chitosan film production
• Presents chitosan research as a natural antimicrobial to enhance food safety
• Includes nutritional aspects of chitosan used in food applications

• Language: English
• Publisher: Academic Press
• Release date: Mar 8, 2023
• ISBN: 9780128232354

Book preview

Preface

Ioannis N. Savvaidis

Chitosan is commercially produced from chitin, recognized as a promising biomaterial for use in the fields of biomedical engineering, food packaging, cosmetics, and agriculture due to its good biodegradability, biological nontoxicity, and film-forming properties. Chitosan possesses antibacterial and antifungal properties and has been extensively studied as a potential natural antimicrobial agent in the pharmaceutical, cosmetic, agricultural, and food industries.

Over the years, there has been a rapid increase in research focusing on biodegradable antimicrobial packaging. In this regard, chitosan has been shown to be the optimal candidate to use in making bio-based antimicrobial packaging. Besides its inherent antimicrobial capacity and superior film-forming abilities, chitosan has other desirable attributes, including being natural, biocompatible, and nontoxic. Chitosan can form edible films or coatings on food, the main function of which is to protect the product from external factors. Films made from natural polymers form a good barrier against oxygen and are characterized by high mechanical properties. Chapter 1 deals with one of the most promising applications of chitosan is the preparation of chitosan-based films and coatings, which have emerged as an effective and eco-friendly way to extend the shelf life of perishable foods. Chitosan-based films might be a sustainable alternative to eco-unfriendly synthetic plastics after the incorporation of various components, for example, plant extracts capable of enhancing the antioxidant and/or antimicrobial properties and therefore protective capacity of foods. So far, numerous plant extracts have been studied regarding their effects on techno-functional characteristics of the packaging films intended for food protection. As natural plant extracts possess antimicrobial and antioxidant properties, incorporation into chitosan-based films could contribute to a shelf life extension of perishable foods. Interest in producing films from renewable and biodegradable polymers, such as polysaccharides, has increased in recent years, and this is the main discussion of Chapter 2. The massive and uncontrolled use of food packaging derived from petroleum-based plastics has created a serious environmental problem. Hence, the food packaging industry needs to develop packaging from biodegradable polymers. Among the many raw materials studied in the literature, chitosan is one of the most abundant polysaccharides in the nature. Hence, chitosan especially combined with active food packaging has gained attention and offers an alternative to the conventional plastics used in the food industries, as numerous studies conducted so far have shown.

Chapters 3 and 4 deal with chitosan nanoparticles as used against food pathogens and in combination with essential oils in food preservation. The consumer demand for preservative-free foods, along with tightened legislation regarding current synthetic or chemical preservatives, has led to increased research into the incorporation of naturally derived antimicrobials into food packaging. The recent years have witnessed an astronomical increase in the number of studies focusing on utilizing essential oils. Additionally, essential oils as antimicrobial agents have successfully been incorporated into biodegradable films, which allowed for controlling microbial growth on food surfaces besides prolonging product shelf life and ensuring its quality. It is widely known that chitosan is an advanced biomaterial for antimicrobial packaging to meet the growing needs of safe and biodegradable packaging. The application of natural essential oils as antimicrobial agents effectively controls the growth of spoilage and pathogenic microbes. Thus chitosan edible coatings and films incorporated with essential oils have expanded the general applications of antimicrobial packaging in food products. With the rising demand for fresh and ready-to-eat foods, while at the same time consumer demand and also concern, poses a challenge in the food processing industries to both maintain food quality and reassure safety. To meet such demand, the use of nanoparticles combined with chitosan and/or with added essential oils’ potential antimicrobial packaging has been suggested and developed to control or prevent microbial spoilage or growth of potentially found pathogenic bacteria in foods. Nanomaterials/nanoparticles are currently involved in most human activities such as nutritional, agricultural, industrial, biomedical, and pharmaceutical fields. Nanoencapsulation and nanoconjugation of chitosan with natural antimicrobial agents, including essential oils, can provide many beneficial advantages, in terms of an improvement in food safety, and in the shelf life extension of perishable food products, as essential oils are generally recognized as safe compounds for application in human foods, therefore offering new possibilities for food-related applications. Essential oils (such as eugenol) incorporated in chitosan nanoparticles, as shown in recently conducted studies, exhibit potent bioactivities, which enable their application as antibacterial, antioxidant, antiinflammatory, preservative, and antifungal agents. In the last years research studies have highlighted the potential applications of chitosan-essential oils’ composite films or coatings in antimicrobial packaging for food preservation.

One of the current challenges faced by the food industry involves the production of natural foods, safer and with extended shelf life. Consumers and public health agencies are concerned about the adverse toxicological effects of using synthetic food additives. Among the critical issues involved in this context are microbial growth, enzymatic browning, and lipid oxidation, among others, in food products. Thus the search for safe, bioactive, and natural additives has attracted the attention of researchers. Recent trends in new concepts of chitosan-based nanoparticles and other forms of chemical modification of this biopolymer with novel properties and applications in the food industry have also been in evidence. Besides the biological potential of chitosan, another aspect that appeals to more attention is the possibility of using waste from the fishing industry precisely through the production of chitosan. This possibility of obtaining a natural additive as a value-added product from an agro-industrial residue appears to be an interesting environmental strategy, aligned with the principles of green chemistry and circular economy. Chapter 5 reviews chitosan and its derivatives’ main sources and techniques for production, focusing on the antimicrobial activity of chitosan, and discusses also diverse forms of adding chitosan in food matrices and how it can promote shelf life extension in these products. Seafood is a rich source of nutrients known to improve consumer well-being based on their nutraceutical value, and they are also highly prone to spoilage by microorganisms and oxidation. Considering the recent advances in chitosan extraction and standardization of process has led to the production of uniform quality. Besides, chitosan production addresses the issue of waste management associated with shrimp processing. Due to their natural origin, nontoxic nature, and ability to inhibit oxidation and microbial growth, chitosan has become popular application for preservation of seafood. Chapter 6 focuses on an overview of chitosan source and extraction, bioactivity and health benefits, as well as novel nanotechnological approaches associated with chitosan and its application in different forms and techniques for preservation and quality retention of seafood.

Introducing novel food packaging with plant-based bioactive agents brings the refreshing essence of nature to the food industry. Chitosan film with gel and porous characteristics could trap bioactive compounds of pomegranate and could be a good choice for application in food packaging and alternative to nonrenewable sources. Chapter 7 attempts to give an overview of state-of-the-art research studies conducted on chitosan in combination with pomegranate-based films and discusses applications in foods.

Chapter 8 attempts to provide recent data and information, although limited to date, on chitosan as an antimicrobial agent to increase the shelf life of salad dips and ethnic foods. As chitosan is a natural antimicrobial agent and as studies have shown, if added at controlled concentrations, it to be a pleasant addition to foods, having a citrus lemony zest, it could appeal to consumers seeking natural and home taste like foods, without the presence of chemical preservatives, that are also safe. Ethnic or traditional foods are finding nowadays on global restaurant menu and are challenging continuously, both the well-informed or the less experienced consumer, therefore chitosan added to ethnic and or traditional foods is likely to appeal in new demands as the food is growing worldwide due to globalization and ever-increasing immigration rates. Selected examples, especially conducted on traditional salad dips, of Arabic origin, show the effectiveness of chitosan in preserving, extending the shelf life, and in also assuring the safety of foods, for example, hummus is known to be potentially contaminated with Salmonella spp., and when combined as part of a hurdle technology, even having a greater efficacy, as a natural antimicrobial agent to be used in potential future applications in food processing.

Finally, Chapter 9 summarizes limited data available, on chitosan either added itself into foods, or as part of a hurdle technology, in both cases such interventions may be potentially of use and interest to food industries, in designing natural food formulations, without the toxicity of chemical preservatives, reassuring, the freshness, shelf life, as well as the safety of foods (ready-to-eat, ready-to-cook, new food formulations). Its use however, as to the present writing, is limited, as further data are needed to establish it, as a safe natural| food additive, and also to convince the consumer that its controlled addition may impart a challenging new taste or flavor to existing foods, worth experiencing by the traditional consumer or those seeking a new innovative food formulation.

The demand for fresh, ready-to-eat, or semifinished foods is increasing, and the need to maintain food safety and quality further exacerbates the challenges in the supply chain, especially with the globalization of food trade and the use of centralized processing facilities for food distribution. Hence, food products with a prolonged shelf life are needed to reach the largest possible market segments. Also, the potential for spoilage and/or pathogenic microorganisms to contaminate food products remains a significant concern, negatively affecting shelf life, and increasing foodborne illness risk. Several traditional food preservation methods that are currently in use can provide some level of preservation but can also negatively impact food quality by reducing its nutritional value. For these reasons, alternative and innovative strategies are required to overcome the challenges and to guarantee food safety and quality, and this hopefully may be done with application of chitosan, as a natural antimicrobial agent, either added itself or in combination with foods. However, as interactions of chemical food constituents are complex, further studies and data will be needed on chitosan activity to be used more in commercial products, and research efforts should be targeted to define the exact mechanism of chitosan’s biological activities.

Chapter 1

Application of chitosan in active food packaging

Layal Karam¹ and Angy Mallah²,    ¹Human Nutrition Department, College of Health Sciences, QU Health, Qatar University, Doha, Qatar,    ²Department of Nursing and Health Sciences, Faculty of Nursing and Health Sciences, Notre Dame University-Louaize, Zouk Mosbeh, Lebanon

Abstract

Food packaging has an essential role in protecting food products from external factors such as heat, oxidation, and light. Improvements in food packaging studies created active packaging that aims at extending perishable foods’ shelf life, as well as maintaining, or enhancing their quality and safety. Nowadays, researchers’ main focus is being dedicated to the development of bioactive packaging, due to consumers’ concerns toward the packaging based on chemical additives which has hazardous effects on the health and environment. Hence, they started to look for natural alternatives where chitosan is taking precedence among all the numerous bio-based materials, due to its antimicrobial and antioxidant characteristics. This chapter focuses on the application of chitosan in active food packaging. Antioxidant and antimicrobial properties of chitosan-based films combined with free or encapsulated antimicrobials and antioxidant agents have been discussed. In addition, this chapter combines the recent advances in chitosan uses as a promising material in active food packaging.

Keywords

Chitosan; active packaging; antioxidant; antimicrobial; shelf life

1.1 Introduction

Food packaging has an essential role in protecting the food from external and environmental factors such as heat, oxidation, and light. Improvements in food packaging studies have created active packaging that aims at extending perishable foods’ shelf life, preventing contamination as well as maintaining, or enhancing the quality and the safety of the food products. As stated by the EU Regulation No 450/2009 (Commission of the European Communities, 2009), active materials and articles means that are intended to extend the shelf life or to maintain or improve the condition of packaged food; they are designed to deliberately incorporate components that would release or absorb substances into or from the packaged food or the environment surrounding the food. Moreover, active packaging could be an alternative for the addition of active compounds into foods with the related limited efficiency and interactions with the food matrices (Sharma et al., 2021). Such packaging has the ability to decrease foodborne illness outbreaks as well as food recalls (Karam et al., 2013d; Karam et al., 2016; Vilela et al., 2018).

Active packaging has two categories: chemoactive and bioactive. The chemoactive packaging is based on the chemical additives, whereas bioactive packaging is based on the incorporation of natural antimicrobial and antioxidant agents (Karam et al., 2013a; Sharma et al., 2021). Nowadays, researcher’s main focus is being dedicated to the development of bioactive packaging, due to consumers’ concerns toward the chemoactive packaging which has hazardous effects on the health and the environment (Karam et al., 2013b). For example, Domínguez et al. (2018) incorporated butylated hydroxyanisole, which is a synthetic antioxidant into active packaging and reported an enhancement in the quality of the food product. This improvement was attributed to the butylated hydroxy anisole’s antioxidant characteristic in preventing lipid oxidation. However, it was found that butylated hydroxyanisole may induce problems in the human endocrine system (Pop et al., 2013). The use of natural antioxidants and antimicrobials in food preservation is preferable since the consumers nowadays are moving toward additive free products (Karam et al., 2013c; Ibarra-Sánchez et al., 2020). Hence, researchers have started to look for natural alternatives, where chitosan is taking precedence among all the numerous bio-based materials, due to its antimicrobial and antioxidant characteristics. Chitosan is a linear polysaccharide made of randomly distributed β-(1–4)-linked D-glucosamine and N-acetyl-D-glucosamine and produced by the deacetylation of chitin (Siripatrawan, 2016). Chitosan is also a bio-based eco-friendly material (Bégin & Van Calsteren, 1999) and has a promising future in active packaging as a food preservative material (Siripatrawan, 2016).

This chapter focuses on the application of chitosan in active food packaging. Antioxidant and antimicrobial properties of chitosan-based films combined with free or encapsulated antimicrobials and antioxidant agents have been discussed. In addition, this chapter combines the recent advances in the use of chitosan in active food packaging.

1.2 Active chitosan-based packaging—antimicrobial properties

Chitosan’s antimicrobial activity is very broad and exhibits inhibition against Gram-positive and Gram-negative bacteria, fungi, as well as yeasts. According to the literature, this activity is explained by the interaction between the amino groups of chitosan and the negatively charged bacterial cell membrane, which increases the permeability of the cell wall leading to the leakage of intracellular components (Siripatrawan, 2016). Many studies have tested the antimicrobials properties of chitosan-based packaging (Table 1.1). For example, it has been reported that the antimicrobial activity of chitosan (CS)—pure poly (vinyl alcohol) (PVA) films was strongly attributed to the antibacterial property of CS since PVA did not display any inhibition zone against tested bacteria (Liu et al., 2018; Narasagoudr et al., 2020a; Tripathi et al., 2009). Pure poly (vinyl alcohol) (PVA) is a relatively harmless and eco-friendly synthetic polymer that has great miscibility and film forming characteristics. PVA can be utilized to immobilize chitosan through the development of hydrogen bonds and thus enhance the mechanical properties of chitosan (Liu et al., 2018). Liu et al. (2018) found that the optimal PVA/CS film was with 75:25 ratio, which demonstrated the highest antibacterial efficacy for inhibiting Staphylococcus aureus (99.16%±6.58%) and Escherichia coli (98.8%±4.56%) growth. Similarly, Tripathi et al. (2009) tested CS-PVA films on the preservation of minimally processed tomato into two forms: (1) as a whole and (2) into two pieces. The CS-PVA 1 wt.% films demonstrated a higher inhibitory zone capacity against E. coli (1.5 cm) and Bacillus subtilis (1.4 cm) than S. aureus (1.2 cm). In another study, quaternary ammonium chitosan HACC, a chitosan derivative, and PVA coatings were designed and evaluated for their antibacterial and antifogging activities on the storage of strawberries at 25°C for 5 days. Results showed that the increase in HACC content successfully extended the shelf life of strawberries, by retaining their original color, flavor, and freshness (Min et al., 2020) (Table 1.1). Moreover, antifungal and antibacterial activities of plasticized poly (lactic acid) (PLA) films were also enhanced with the incorporation of chitosan (Râpă et al., 2016). The biocomposite films containing 1 and 3 wt.% of chitosan showed a significant bacterial count reduction which was higher in E. coli (5.54–5.58 log units, respectively) than in S. aureus (2.7–2.8 log units, respectively) (Table 1.1). According to the literature, PLA film had no capacity to inhibit bacterial growth but is considered as an excellent bio-based and green polymer utilized as a short duration film for the packaging of food (Niu et al., 2018). Moreover, it was concluded that 1 wt.% of chitosan ensured a satisfactory antifungal activity, with no necessary need in increasing its concentration (Râpă et al., 2016) (Table 1.1). To summarize, 1 wt.% of chitosan was denoted as the optimum concentration for the antimicrobial properties of the films. Likewise, Castillo et al. (2017) in their study developed biodegradable films by combining chitosan oligomers (CO) and thermoplastic cornstarch (TPS) and tested its antifungal activity on different food products. The films reduced yeasts growth by ~58% in strawberries and ricotta, and by 86% in flavored breads (Table 1.1).

Table 1.1

1.3 Active chitosan-based packaging combined with functional ingredients

1.3.1 Antimicrobial properties

Many studies investigated the abilities of chitosan-based films combined with free antimicrobials for their future use as active food packaging (Table 1.2). Narasagoudr et al. (2020b) prepared rutin (Rt—known as a plant pigment)-induced CS/PVA bioactive films and reported that the addition of rutin had a strong effect on the antimicrobial capacity of CS/PVA films, which was due to the acidic nature of the hydroxyl groups of Rt. Furthermore, in another study conducted by Narasagoudr et al. (2020a), Boswellic acid (BA) was added to CS/PVA films (CPBA) and reported that CS and BA had a synergistic antibacterial effect on the films. They also reported the increase of BA content and the inhibitory zone efficacy of CPBA active films, highlighting that the CPBA film containing 0.8% of BA showed the maximum inhibitory effects (mm) in Candida albicans (28±1), E. coli (26±1.5), and S. aureus (26±1). In their turn, Zhang et al. (2017a) developed sodium lactate loaded CS-PVA/montmorillonite films and reported an improved inhibition efficacy (%) of the films against E. coli which significantly increased to 70%±2.1% with NaL content of 5 wt.% at 37°C for 24 hours (Table 1.2).

Table 1.2

aBHIA: brain–heart infusion agar.

bBHIB: brain–heart infusion broth.

According to the literature, lauroyl arginate ethyl (LAE) is one of the most effective antimicrobial components among new food additives with significant and fast antimicrobial abilities against foodborne microorganisms when put directly in contact with these pathogens. LAE revealed a high antimicrobial activity, which was attributed to its cationic nature that disrupts the metabolic processes of a bacterial cell and inhibits its growth leading to its death (Haghighi et al., 2019). It was reported that the incorporation of LAE into films containing chitosan and other components demonstrated an enhanced antimicrobial performance and inhibited the growth of Listeria monocytogenes, E. coli, Salmonella typhimurium, and Campylobacter jejuni (Haghighi et al., 2019; Haghighi et al., 2020) (Table 1.2).

Moreover, Kritchenkov et al. (2020) mixed triazole betaine chitosan (TBC) with succinyl chitosan sodium salt (SC-Na) and tested its antimicrobial efficacy with different ratios. Results showed that 1:4 TBC: SC-Na ratio performed the highest antibacterial activity where the inhibition zones (mm) around S. aureus (36.9±0.23) were higher than those of the E. coli (28.2±0.37) (Kritchenkov et al., 2020) (Table 1.2). However, few studies are currently available on food applications. Interestingly, Tan et al. (2015) tested the antimicrobial capacity of active chitosan-based film combined with grapefruit seed extract (GFSE) on bread application. It was reported that the films containing 1.5% v/v GFSE in chitosan-based film strongly inhibited fungal growth in bread samples, and fungi were only detected on day 10 (Table 1.2).

1.3.2 Antioxidant properties

Oxidation is an irreversible process that causes deterioration of food products during their processing and storage and alters their nutritional and organoleptic properties. Mainly, foods that are rich in fatty acids are more prone to oxidation particularly known as lipid oxidation. The lipid oxidation process causes discoloration, rancid odor and flavor, development of toxic components, loss of nutrients, and alterations in the texture of the food product. Hence, since it is important to prevent food oxidation, lots of research works have tested the effectiveness of chitosan combined with natural materials in active packaging as an alternative of chemical additives, to ensure the quality of the food products (Sharma et al., 2021). It has been reported that chitosan’s antioxidant property is associated with its scavenging capacity on hydroxyl groups and chelating capacity on ferrous ions. Moreover, this activity is attributed to its efficient chelation that inhibits lipid oxidation by binding to metal ions (Siripatrawan, 2016).

Recently, incorporating antioxidant agents from plant extract with active chitosan-based packaging has been examined Agarwal et al. (2021). For example, Agarwal et al. (2021) reported that Larix decidua Mill. Bark incorporated into chitosan-based film exhibited a significant antioxidant activity, which was due to the phenolic components present in bark extract (the total phenolic content reached 894 mg equivalents of gallic acid (GAE)/g dw in chitosan-based film containing 9% of bark extract, while it was 90 mg GAE/g dw in the control film). Moreover, Bigi et al. (2021) in their study tested the antioxidant activity of nettle leave extract (NLE) and sage leave extract (SLE) blended into chitosan/hydroxypropyl methylcellulose (CS/HPMC) film. They reported that both extracts impressively improved the antioxidant performance of the film; however, CS/HPMC film containing 15% w/w SLE (28.35 μmol TE/g film) exhibited a higher capacity compared to the CS/HPMC film loaded with 15% w/w NLE [17.08 μmol Trolox Equivalent (TE)/g film], which was due to the higher polyphenolic content in SLE (Bigi et al., 2021) (Table 1.3). Similarly, da Rosa Almeida et al. (2022) reported that the antioxidant capacity of chitosan/poly (vinyl alcohol) films increased with the increase in hop (Humulus lupulus L. var. Cascade) extract content in the films (Table 1.3). Similarly, pine needle extract, Ficus carica Linn leave extract, and Aralia continentalis Kitagawa root extract combined with chitosan-based films, or separately, were found to be have a promising potential as antioxidant agents in active food packaging (Kadam et al., 2021;Yilmaz et al., 2022; Wu et al., 2022) (Table 1.3).

Table 1.3

aDPPH: 1, 1-Diphenyl-2-picrylhydrazyl.

bABTS: 2,2′-Azino-bis (3-ethylbenzothiazo-line6-sulfonic acid).

cTPC: total phenolic compounds.

dTEAC: Trolox equivalent antioxidant capacity.

eTPC: total phenolic compounds.

Moreover, studies showed that hawthorn fruit extract and Lycium barbarum fruit extract (LFE) added separately to a chitosan-based films significantly enhanced the antioxidant activity of each of the films due to the synergistic antioxidant effect exhibited by each fruit when combined with chitosan-based film (Kan et al.,2019; Wang et al.,2015). For example, it was reported that chitosan films with 6 wt.% of hawthorn fruit extract exhibited a significant DPPH radical scavenging activity that was increased from 33.42% to 84.40% at 5 mg/mL (Kan et al.,2019). Furthermore, it was found that the DPPH scavenging activity of LFE to chitosan, with a 1:1 weight ratio, attained 35.8%, which was 10-fold higher than the chitosan control film (3.7%) (Table