Natural biopolymer-based nanocomposite films for packaging applications

Concerns on environmental waste problems caused by non-biodegradable petrochemical-based plastic packaging materials as well as the consumer's demand for high quality food products has caused an increasing interest in developing biodegradable packaging materials using annually renewable natural biopolymers such as polysaccharides and proteins. Inherent shortcomings of natural polymer-based packaging materials such as low mechanical properties and low water resistance can be recovered by applying a nanocomposite technology. Polymer nanocomposites, especially natural biopolymer-layered silicate nanocomposites, exhibit markedly improved packaging properties due to their nanometer size dispersion. These improvements include increased modulus and strength, decreased gas permeability, and increased water resistance. Additionally, biologically active ingredients can be added to impart the desired functional properties to the resulting packaging materials. Consequently, natural biopolymer-based nanocomposite packaging materials with bio-functional properties have a huge potential for application in the active food packaging industry. In this review, recent advances in the preparation of natural biopolymer-based films and their nanocomposites, and their potential use in packaging applications are addressed.     

Trends and challenges of biopolymer-based nanocomposites in food packaging

The ultimate goal of new food packaging technologies, in addition to maintaining the quality and safety of food for the consumer, is to consider environmental concerns and reduce its impacts. In this regard, one of the solutions is to use eco-friendly biopolymers instead of conventional petroleum-based polymers. However, the challenges of using biopolymers in the food packaging industry should be carefully evaluated, and techniques to eliminate or minimize their disadvantages should be investigated. Many studies have been conducted to improve the properties of biopolymer-based packaging materials to produce a favorable product for the food industry. This article reviews the structure of biopolymer-based materials and discusses the trends and challenges of using these materials in food packaging technologies with the focus on nanotechnology and based on recent studies.     

Advances in green synthesis of selenium nanoparticles and their application in food packaging

The past decade has seen nanotechnology progressively being adopted by the food industry. Its wide application in food packaging has redefined conservative food packaging with active and intelligent packaging. Nanomaterials do not only influence food quality and safety but also offer health-related benefits. Selenium nanoparticles (SeNPs) have been preferred in recent years because of their high biological activity. However, they are generally synthesised using physicochemical methods which are associated with toxicity. In the past decade, efforts have been directed towards advancement of green synthesis of SeNPs to minimise hazardous by-products. The antioxidant and biocidal effects of SeNPs are generally investigated by direct contact between the oxidisable matter and/or test organisms. Lately, there is focus on the effect SeNPs incorporated into packaging films. This paper will review developments on SeNPs synthesised via plant extracts from the year 2010 to present and their potential application in active food packaging.     

食品包装涂布纸生物聚合物基质分类及应用

随着社会的发展,人们的食品安全和环境保护意识不断提高,对无毒可降解食品包装材料的需求不断增加。针对此现状,该文综述了涂布型食品包装纸生物聚合物基质的分类及应用的研究进展,分析了纸基材料作为食品包装的优势及性能缺陷,介绍了作为纸张涂料的生物聚合物基质(多糖、蛋白质、复合基质)及纸基材料所具有的功能特性,总结了涂布型纸张在食品包装方面的应用。将涂布纸作为食品包装,能有效地保持食品的品质,赋予纸张的功能特性还能够延长食品保质期,具有巨大的市场价值,有望为食品工业进一步开发绿色和可持续的纸基包装材料提供参考。     

Silk fibroin-based films in food packaging applications: A review

Plastic pollution is a significant concern nowadays due to wastes generated from non-biodegradable and non-renewable synthetic materials. In particular, most plastic food packaging material ends up in landfills, creating mass wastes that clog the drainage system and pollute the ocean. Thus, studies on various biopolymers have been promoted to replace synthetic polymers in food packaging and consequently, the high number of research in biopolymers food packaging, especially in the characterization, properties and also the development of the biopolymer. For biopolymer-based food packaging, silk fibroin (SF) has been highlighted because of its biodegradability and low water vapor permeability properties. This review focuses on the different properties of SF films prepared through solution casting and electrospinning for food packaging. Discussions encompassed chemical properties, mechanical properties, permeability, and biodegradability. This review also discussed the studies that used SF as the biomaterial for food packaging.     

淀粉基抗菌食品包装膜的研究进展

随着全球环保意识的提升,以来源广、可再生、成本低的淀粉为原料制备的淀粉基抗菌包装膜取代传统石油基包装材料的研究受到了广泛的关注。淀粉基抗菌膜通常是以天然淀粉/改性淀粉为原料加入塑化剂和抑菌剂并经热加工制备,其中抑菌剂的性质是决定抗菌膜抑菌活性的关键因素。此外,淀粉基抗菌膜的制备方法和材料性能也受到抑菌剂的来源和性质的影响。本文综述了基于不同抑菌剂制备的淀粉基抗菌膜的材料性能和抑菌活性,并提出在未来仍需研究安全性高、材料性能好和抑菌能力强的淀粉基抗菌材料,以期为开发绿色环保、性能优异的淀粉聚合物基抗菌食品包装材料提供指导。     

纳米二氧化钛抗菌食品包装复合膜的研究进展

纳米二氧化钛具有较好的抗菌作用,且在传统包装材料中有较好的分散性,添加了纳米二氧化钛的食品包装薄膜具有较好的抗菌效果,能在一定程度上延长食品的保质期。目前,有较多关于纳米二氧化钛食品包装复合膜的研究,主要是围绕抗菌性,机械性能和安全性等方面展开,研究表明：纳米二氧化钛复合膜的抗菌性受光照影响;复合膜的机械性能、热力学性能和阻隔性等随纳米二氧化钛的加入有所改变;复合膜中的纳米二氧化钛可能会迁移到包装的食品中,造成食品安全隐患;制备复合膜时需综合考虑以上因素。本文主要对纳米二氧化钛的抗菌机理、纳米二氧化钛抗菌食品包装薄膜的制备和应用、纳米二氧化钛的迁移研究进展进行概述,旨在扩展纳米二氧化钛复合膜更好更安全地应用于食品包装。     

Chitosan-based biodegradable functional films for food packaging applications

Chitin is the structural material of crustaceans, insects, and fungi, and is the second most abundant biopolymer after cellulose on earth. Chitosan, a deacetylated derivative of chitin, can be obtained by deacetylation of chitin. It is a functionally versatile biopolymer due to the presence of amino groups responsible for the various properties of the polymer. Although it has been used for various industrial applications, the recent one is its use as a biodegradable antimicrobial food packaging material. Much research has been focused on chitosan-based flexible food packaging and edible food coatings to compete with conventional non-biodegradable plastic-based food packaging materials. Various strategies have been used to improve the properties of chitosan - using plasticizers and cross-linkers, embedding the polymer with fillers such as nanoparticles, fibers, and whiskers, and blending the polymer with natural extracts and essential oils and also with other natural and synthetic polymers. However, much research is still needed to bring this biopolymer to industrial levels for the food packaging applications.Industrial relevanceAs a major by-product of the seafood industry, a massive amount of crustacean shell waste is generated each year, which can be used to produce value-added chitin, which can be converted to chitosan using a relatively simple deacetylation process. Being extracted from a bio-waste product using many energy-efficient methods, chitosan is much cheaper as compared to other biopolymers. Nevertheless, the exceptional properties of chitosan make it a relatively stronger candidate for food packaging applications. Chitosan has already been used in various industries, such as biomedical, agriculture, water treatment, cosmetics, textile, photography, chromatography, electronics, paper industry, and food industry. This review article compiles all the essential literature up to the latest developments of chitosan as a potential food packaging material and the outcomes of its practical utilization for this purpose.     

Physical performance of biodegradable films intended for antimicrobial food packaging

Antimicrobial films were prepared by including enterocins to alginate, polyvinyl alcohol (PVOH), and zein films. The physical performance of the films was assessed by measuring color, microstructure (SEM), water vapor permeability (WVP), and tensile properties. All studied biopolymers showed poor WVP and limited tensile properties. PVOH showed the best performance exhibiting the lowest WVP values, higher tensile properties, and flexibility among studied biopolymers. SEM of antimicrobial films showed increased presence of voids and pores as a consequence of enterocin addition. However, changes in microstructure did not disturb WVP of films. Moreover, enterocin-containing films showed slight improvement compared to control films. Addition of enterocins to PVOH films had a plasticizing effect, by reducing its tensile strength and increasing the strain at break. The presence of enterocins had an important effect on tensile properties of zein films by significantly reducing its brittleness. Addition of enterocins, thus, proved not to disturb the physical performance of studied biopolymers. Development of new antimicrobial biodegradable packaging materials may contribute to improving food safety while reducing environmental impact derived from packaging waste. Practical Application: Development of new antimicrobial biodegradable packaging materials may contribute to improving food safety while reducing environmental impact derived from packaging waste.     

Recent advances in biobased and biodegradable polymer nanocomposites,nanoparticles, and natural antioxidants for antibacterial and antioxidant food packaging applications

Inorganic nanoparticles (NPs) and natural antioxidant compounds are an emerging trend in the food industry. Incorporating these substances in biobased and biodegradable matrices as polysaccharides (e.g., starch, cellulose, and chitosan) and proteins has highlighted the potential in active food packaging applications due to more significant antimicrobial, antioxidant, UV blocking, oxygen scavenging, water vapor permeability effects, and low environmental impact. In recent years, the migration of metal NPs and metal oxides in food contact packaging and their toxicological potential have raised concerns about the safety of the nanomaterials. In this review, we provide a comprehensive overview of the main biobased and biodegradable polymer nanocomposites, inorganic NPs, natural antioxidants, and their potential use in active food packaging. The intrinsic properties of NPs and natural antioxidant actives in packaging materials are evaluated to extend shelf-life, safety, and food quality. Toxicological and safety aspects of inorganic NPs are highlighted to understand the current controversy on applying some nanomaterials in food packaging. The synergism of inorganic NPs and plant-derived natural antioxidant actives (e.g., vitamins, polyphenols, and carotenoids) and essential oils (EOs) potentiated the antibacterial and antioxidant properties of biodegradable nanocomposite films. Biodegradable packaging films based on green NPs—this is biosynthesized from plant extracts–showed suitable mechanical and barrier properties and had a lower environmental impact and offered efficient food protection. Furthermore, AgNPs and TiO₂ NPs released metal ions from packaging into contents insufficiently to cause harm to human cells, which could be helpful to understanding critical gaps and provide progress in the packaging field.     

食品包装用复合膜质量现状及安全风险分析

复合膜包装是20世纪70年代末开始在我国迅猛发展起来的新兴行业, 这得益于科学技术的发展和高分子化学工业的发展。食品包装用复合膜作为人们日常接触的食品包装, 被广泛使用, 其质量状况受到人们广泛关注。经过多年的技术积累, 复合膜产品质量越来越好, 品种也非常的多, 但是复合膜产品质量受到多方面因素影响, 在实际生产中会出现很多问题。同时, 由于复合膜产品生产企业存在企业规模小、效益低、技术水平低、管理水平低等原因, 复合膜产品质量仍旧良莠不齐, 监督抽查工作需要被常抓不懈。本文从食品包装用复合膜质量现状、国家监督抽查结果、国内外关注风险项目指标、新旧标准技术指标要求差异等方面, 分析食品包装用复合膜产品质量状况, 并从标准的角度提出建议。     

Nanofibre-based bilayer biopolymer films: enhancement of antioxidant activity and potential for food packaging application

This study aimed to enhance the antioxidant property of biopolymer film without the incorporation of external agents. The active bilayer film with improved antioxidant activity has been developed by electrospinning zein, a prolamine of corn as nanofibre (average diameter of 286 nm) on solvent cast chitosan film. Zein nanofibres exhibited a slight increase in antioxidant activity as compared to solvent cast zein film. But, zein nanofibre coating on chitosan films significantly improved its antioxidant activity from 12.41% to 44.17%. The developed bilayer films were evaluated for its ability to prevent browning in minimally processed apple slices and compared with those of chitosan and zein films plasticised with polyethylene glycol. Higher surface to volume ratio and better affinity of zein nanofibres in the bilayer film helped enhance its anti-browning ability. Thus, zein nanofibre-coated chitosan bilayer films can be used as an effective anti-browning packaging material for the packing of minimally processed fruits.     

Multilayer packaging: Advances in preparation techniques and emerging food applications

In recent years, with advantages of versatility, functionality, and convenience, multilayer food packaging has gained significant interest. As a single entity, multilayer packaging combines the benefits of each monolayer in terms of enhanced barrier properties, mechanical integrity, and functional properties. Of late, apart from conventional approaches such as coextrusion and lamination, concepts of nanotechnology have been used in the preparation of composite multilayer films with improved physical, chemical, and functional characteristics. Further, emerging techniques such as ultraviolet and cold plasma treatments have been used in manufacturing films with enhanced performance through surface modifications. This work provides an up‐to‐date review on advancements in the preparation of multilayer films for food packaging applications. This includes critical considerations in design, risk of interaction between the package and the food, mathematical modeling and simulation, potential for scale‐up, and costs involved. The impact of in‐package processing is also explained considering cases of nonthermal processing and advanced thermal processing. Importantly, challenges associated with degradability and recycling multilayer packages and associated implications on sustainability have been discussed.     

Improved water resistance in edible zein films and composites for biodegradable food packaging

Zein, corn prolamine, was dissolved in several organic solvents to make films and their properties were examined. Ethanol with 20% water and acetone with 30% water were found to dissolve zein well and transform it into a transparent flexible film after moderate drying. Both films showed similar breaking strength to that of commercial thin film of polyvinylidene chloride for food use and were digested with proteases. Only the film prepared from acetone solution showed a relatively low water permeability. This water permeation was found to depend strongly on the rate of diffusion. 1,2-Epoxy-3-chloropropane (ECP) was added into the acetone solution to cross-link the zein molecules for the purpose of improving the breaking strength and water-resistant properties of the film. Alpha-chymotrypsin was found to digest the film even after the modification with ECP. However, this cross-linking resulted in little improvement in the water-resistant properties of the film and also reduced its flexibility.     

Surface coating of silver nanoparticles on polyethylene for fabrication of antimicrobial milk packaging films

In this study, antimicrobial packaging films were prepared by coating silver (Ag) nanoparticles onto the surface of low density polyethylene (LDPE) films modified by corona air plasma. The possibility of these films for use in the packaging of milk was studied. The influence of input power of the corona discharge treatment on the surface modification and performance of the fabricated Ag/LDPE nanocomposite films was also investigated. The prepared antimicrobial packaging films showed promising antimicrobial efficiency against micro‐organisms that are present in milk and were able to increase the microbial shelf life of the milk. Packages fabricated at corona input powers of 210, 500 and 800 W reached the maximum limit after 5, 8 and 14 days (respectively).     

Critical review of controlled release packaging to improve food safety and quality

ABSTRACT

Controlled release packaging (CRP) is an innovative technology that uses the package to release active compounds in a controlled manner to improve safety and quality for a wide range of food products during storage. This paper provides a critical review of the uniqueness, design considerations, and research gaps of CRP, with a focus on the kinetics and mechanism of active compounds releasing from the package. Literature data and practical examples are presented to illustrate how CRP controls what active compounds to release, when and how to release, how much and how fast to release, in order to improve food safety and quality.     

Development of PLA films containing oregano essential oil (Origanum vulgare L. virens) intended for use in food packaging

Consumers’ concerns about the environment and health have led to the development of new food packaging materials avoiding petroleum-based matrices and synthetic additives. The present study has developed polylactic acid (PLA) films containing different concentrations of essential oil from Origanum vulgare L. virens (OEO). The effectiveness of this new active packaging was checked for use in ready-to-eat salads. A plasticising effect was observed when OEO was incorporated in PLA films. The rest of the mechanical and physical properties of developed films did not show much change when OEO was included in the film. An antioxidant effect was recorded only for films containing the highest percentages of the active agent (5% and 10%). In addition, films exhibited in vitro antibacterial activity against Staphylococcus aureus, Yersinia enterocolitica, Listeria monocytogenes, Enterococcus faecalis and Staphylococcus carnosus. Moreover, in ready-to-eat salads, antimicrobial activity was only observed against yeast and moulds, where 5% and 10% of OEO was the most effective.     

Soy protein – Poly (lactic acid) bilayer films as biodegradable material for active food packaging

The preparation and characterization of biodegradable bilayer films from isolated soy protein (SPI) and poly (lactic acid) (PLA) were carried out in this work. The films showed high transparency and strong adhesion between layers without adding an extra component, or without chemically modifying the film surfaces. The application of the PLA layer largely increased the mechanical properties of the films with respect to those of pure SPI films. Furthermore, the hydrophobic characteristics of the PLA layer improved film performance under conditions in which water was involved, markedly decreasing the amount of total soluble matter, the swelling index and the water vapor permeability. The biodegradation under soil burial conditions was evaluated measuring weight loss as a function of time, showing a two-step degradation and a faster degradation rate for the protein component compared to those of PLA layer. The films prepared were evaluated as active packaging by incorporation of an antifungal and an antibacterial agent (natamycin and thymol, respectively) to the SPI layer, showing a marked growth inhibition of mold, yeast and two strains of bacteria by in-vitro microbiological assays.     

Essential oils and their principal constituents as antimicrobial agents for synthetic packaging films

Spices and herbal plant species have been recognized to possess a broad spectrum of active constituents that exhibit antimicrobial (AM) activity. These active compounds are produced as secondary metabolites associated with the volatile essential oil (EO) fraction of these plants. A wide range of AM agents derived from EOs have the potential to be used in AM packaging systems which is one of the promising forms of active packaging systems aimed at protecting food products from microbial contamination. Many studies have evaluated the AM activity of synthetic AM and/or natural AM agents incorporated into packaging materials and have demonstrated effective AM activity by controlling the growth of microorganisms. This review examines the more common synthetic and natural AM agents incorporated into or coated onto synthetic packaging films for AM packaging applications. The focus is on the widely studied herb varieties including basil, oregano, and thyme and their EOs.     

Recent advances in biopolymers and biopolymer-based nanocomposites for food packaging materials

Plastic packaging for food and non-food applications is non-biodegradable, and also uses up valuable and scarce non-renewable resources like petroleum. With the current focus on exploring alternatives to petroleum and emphasis on reduced environmental impact, research is increasingly being directed at development of biodegradable food packaging from biopolymer-based materials. The proposed paper will present a review of recent developments in biopolymer-based food packaging materials including natural biopolymers (such as starches and proteins), synthetic biopolymers (such as poly lactic acid), biopolymer blends, and nanocomposites based on natural and synthetic biopolymers. The paper will discuss the various techniques that have been used for developing cost-effective biodegradable packaging materials with optimum mechanical strength and oxygen and moisture barrier properties. This is a timely review as there has been a recent renewed interest in research studies, both in the industry and academia, towards development of a new generation of biopolymer-based food packaging materials with possible applications in other areas.