Colouration of polymeric electrospun nanofibrous mats – a mini review

Abstract

Since its evolution, polymeric nanofibres made with electrospinning emerged to have commercial success for various technical/industrial applications such as filtration, cold separation, biosensing, healing and functional reinforcement in composites. In the start of twenty-first century, the electrospun nanofibres found their way for use as a laminate in apparel and furnishing textiles where aesthetics play one of the basic roles. Therefore, colouration of electrospun nanofibres grabbed attention of scientists and experts. As a result, many studies have appeared on colouration of electrospun nanofibrous mats over the recent decade. The present article summarizes a review on the fundamentals and methods, reported so far, of making coloured electrospun nanofibres of various polymers. The review focuses on preparing various polymeric nanofibrous mats with polymer solution via electrospinning as well as principle colouration techniques, i.e. conventional methods such as batchwise and pad dyeings, using ultrasonic energy (an emerging processing technology), dope dyeing and printing.     

静电纺蛋白质和多糖纳米纤维及其在食品行业的应用进展

静电纺丝技术是一种简单且有效地制备纳米纤维的方法,所得纳米纤维具有纤维直径可控、孔隙率高及比表面积大等优良特性,在生物医学、过滤材料、传感器、酶固定化及食品包装等领域具有良好的应用前景。应用于食品行业的电纺纳米纤维必须生物相容性好、毒性低且可生物降解,故目前常采用蛋白质和多糖等天然聚合物进行静电纺丝。本文主要综述了含蛋白质(大豆分离蛋白、玉米醇溶蛋白、乳清蛋白等)或多糖(壳聚糖、透明质酸、淀粉、普鲁兰多糖等)电纺纳米纤维的制备过程、电纺过程中各主要因素对纤维形貌的影响,所得纳米纤维的特性及其在食品行业,包括抗菌保鲜、抗氧化和控制释放等方面的潜在应用,并展望了静电纺蛋白质和多糖纳米纤维未来的研究方向。     

静电纺多级结构空气过滤材料的研究进展

为促进静电纺纳米纤维在空气过滤领域中的应用,开发性能更加优异的新型纳米纤维空气过滤膜,以近年来国内外静电纺丝技术制备多级结构纳米空气过滤材料的相关研究为基础,综述了静电纺制备具有微纳米凸起、纳米蛛网、层层复合、多孔、刺状、树枝状及核壳等结构空气过滤材料的最新研究进展,分析和讨论了多级结构微纳米空气过滤材料的制备方法,指出了现有研究中存在的不足,并对未来的发展方向进行了总结和展望。认为多级结构可有效实现过滤材料高效率、低阻力、高强度、阻燃等的功能化,相较于传统的纳米纤维过滤材料具有更好的应用前景。     

Advances in electrospinning: The production and application of nanofibres and nanofibrous structures

The use of electrospun nanofibres in applications such as medical products, fuel cells, photocatalysis, filtration, sensors and actuators is reviewed. Yarn production is classified into two types, namely hollow and core-shell structures; the methods used for producing the two structures for different polymers are discussed. Explanations are given for the various arrangements for producing nanofibre yarns and bundles in non-twisted or twisted forms to suit their end use. Natural and synthetic polymer products for biomedical uses and their applications in the form of polymer nanofibres are reviewed and polymeric optical fibres for use in photonic devices and optical circuits are evaluated. The production and development of nanofibrous filtration devices is explored with specific reference to water treatment and the control of air pollution. Particular attention is then given to the evaluation of different electrospinning methods for PVDF (polyvinylidene fluoride), a piezoelectric polymer widely used in sensor applications in terms of their ability to harvest more energy after agitation of the sensor and the effects of different additives on the piezoelectric properties of PVDF. Priorities for further research are then outlined.     

静电纺丝蛋白基纳米纤维的研究进展

蛋白质不仅能为人类提供必需的营养,同时具备良好的加工及应用特性。蛋白基纳米纤维因其高比表面积而被广泛应用于营养递送、空气过滤、生物医药和组织工程等领域。静电纺丝（电纺）技术作为一种简单有效、成本低廉的纳米纤维有效制备手段,为蛋白基纳米纤维的进一步应用提供了技术保障。本文从电纺蛋白基纳米纤维的制备过程、电纺条件（流速、电压、接收距离等）对纤维形貌的影响、静电纺丝蛋白基纳米纤维的应用（食品工业、药物载送、组织工程、空气过滤）等方面进行了综述,并展望了蛋白基纳米纤维的潜在研究方向,以期为静电纺丝蛋白基纳米纤维的可控构建、功能特性的改善以及静电纺丝的产业化研究和应用提供参考。     

Application of Cellulosic Nanofibers in Food Science Using Electrospinning and Its Potential Risk

Cellulose is the most abundant and a low‐cost biodegradable by‐product in the food and agricultural industries. Electrospun cellulosic nanofibers have remarkable physicochemical properties that make them attractive for many applications in the food sector. In this review, electrospinning is investigated as an easy method for producing nanofibers from polymers. Moreover, the most important applications of cellulosic nanofibers in food science are presented. These applications are (a) immobilization of bioactive substances such as enzymes, vitamins, and antimicrobials; (b) nutraceutical delivery systems and controlled release of materials; (c) as biosensors; (d) filtration; and (e) for reinforcing composites and in films. Finally, some potential risks of using electrospinning in food science are reviewed.     

How chemophobia affects public acceptance of pesticide use and biotechnology in agriculture

Protecting crops from infestations is critical to ensuring stable, safe food production. However, many consumers are concerned about the use of pesticides and agricultural biotechnology (agri-biotech) applications. A lack of consumer acceptance can prevent potentially beneficial applications from being utilized. This study examines consumer acceptance of pesticide use in conventional and organic agriculture and agri-biotech applications as crop-protection measures. An online between-subject experiment was conducted with participants from the German-speaking part of Switzerland (N = 643). The results revealed that consumers were most willing to accept gene transfers as a protection measure, provided the gene came from a wild variety of the same species as the cultivated plant. Both chemophobia and the importance of naturalness in food influence consumer acceptance of pesticide use and agri-biotech applications. Addressing chemophobia and informing consumers about the role of technologies in pest-management and crop-protection could lead them to trust and accept related agricultural policies.     

Recent developments in nanotechnology transforming the agricultural sector: a transition replete with opportunities

The applications and benefits of nanotechnology in the agricultural sector have attracted considerable attention, particularly in the invention of unique nanopesticides and nanofertilisers. The contemporary developments in nanotechnology are acknowledged and the most significant opportunities awaiting the agriculture sector from the recent scientific and technical literature are addressed. This review discusses the significance of recent trends in nanomaterial‐based sensors available for the sustainable management of agricultural soil, as well as the role of nanotechnology in detection and protection against plant pathogens, and for food quality and safety. Novel nanosensors have been reported for primary applications in improving crop practices, food quality, and packaging methods, thus will change the agricultural sector for potentially better and healthier food products. Nanotechnology is well‐known to play a significant role in the effective management of phytopathogens, nutrient utilisation, controlled release of pesticides, and fertilisers. Research and scientific gaps to be overcome and fundamental questions have been addressed to fuel active development and application of nanotechnology. Together, nanoscience, nanoengineering, and nanotechnology offer a plethora of opportunities, proving a viable alternative in the agriculture and food processing sector, by providing a novel and advanced solutions. © 2017 Society of Chemical Industry     

Sustainable control strategies for plant protection and food packaging sectors by natural substances and novel nanotechnological approaches

An overview is provided of the current technological strategies (also at the nanoscale level) recently involved in plant and/or food protection. In addition, the potential use of natural and sustainable substances, instead of traditional synthesized molecules or chemical-based compounds, is addressed both with respect to packaging systems and novel pesticide formulations. In this context, nanotechnological approaches represent promising strategies for the entire agriculture industry chain, from the field to consumers. Traditional plant protection strategies are often insufficient and the application of chemical-based pesticides has negative effects on animals, humans and the environment. Novel greener tools could represent efficient alternatives for the management of plant diseases using promising strategies; the use of nanotechnologies allows the promotion of the more efficient assembly and subsequent release of environmentally sustainable active principles, limiting the use of chemicals in terms of economic losses. At the same time, new sustainable, antimicrobial and antioxidant systems have been rapidly promoted and investigated in the food packaging sector as a valid eco-friendly possibility for improving the safety and quality of food products and reducing and/or limiting the environmental impact with respect to traditional materials. Together, the scientific community and the growing interest of consumers have promoted the development of new edible and eco-friendly packaging that reduces waste and any environmental impact. In this context, the aim is to provide evidence of the usefulness of strategies aiming to limit agrochemicals, as well as the potential of nanomaterials, in sustainable plant and food protection for agriculture management and the packaging sector. © 2018 Society of Chemical Industry     

Direct electrospinning of nanofibre yarns using a rotating ring collector

Nanofibres prepared by electrospinning typically have randomly oriented fibrous structure. They have large surface-to-volume (or weight) ratio and excellent porous characteristic, which have shown enormous potential in diverse applications. However, electrospun nanofibres are often prepared in the form of randomly orientated fibrous web, which are fragile and difficult to be tailored in fibrous structures. Herein, we demonstrate a novel yarn electrospinning method which uses a rotating ring collector to convert newly electrospun nanofibres directly into a continuous yarn. The use of ring collector separates the yarn formation from the electrospinning zone. The deposition of later-spun nanofibres to the inner surface of fibrous cone eliminates hooked or curled nanofibres in the final yarn. The effects of polymer concentration and operating parameters on nanofibre and yarn morphology, diameter and the ring collector on yarn twist feature were examined. The nanofibre yarns had a surface twist angle up to 54.4°, and tensile strength as high as 93.6 MPa (elongation at break 242.6%). Increasing twist levels improves tensile strength and strain values.     

Emulsion electrospinning: Fundamentals,food applications and prospects

BackgroundIn the past decades, many natural bioactive compounds with antioxidant, immunoregulatory, antimicrobial, and anticancer activities have been successfully identified in plant and animal materials. However, due to their poor solubility, unfavorable flavor, low bioavailability and instability during food processing and storage, the development of bioactive compounds used in the food industry presents many technological challenges.Scope and approachEmulsion electrospinning is a novel and simple technique to fabricate core-shell nanofibers, and either water-in-oil (W/O) or oil-in-water (O/W) emulsions can be electrospun to directly encapsulate hydrophilic or hydrophobic compounds into core-shell fibers, respectively. This review introduces fundamentals and advantages of emulsion electrospinning as well as its food applications. The effects of different types of emulsifiers on the formation of emulsion systems and emulsion-based electrospun fibers are highlighted. Further, the existing limitations and scope for future research are discussed.Key findings and conclusionsRecent studies have found that the emulsion-based electrospun nanofibers can enhance the encapsulation efficiency, stability, and bioavailability of bioactive compounds, as well as achieve targeted delivery and controlled release, thus providing new strategies to improve their barrier performance compared to conventional electrospinning and therefore facilitating the development of emulsion-based electrospun mats in the food industry.     

Nanomaterials for products and application in agriculture,feed and food

BackgroundNanotechnology applications can be found in agricultural production, animal feed, food processing, food additives and food contact materials (hereinafter referred to as agri/feed/food). A great diversity of nanomaterials is reported to be currently used in various applications, while new nanomaterials and applications are reported to be in development.Scope and approachIt is expected that applications of nanomaterials in agri/feed/food will increase in the future and thereby increase the human and environmental exposure to such materials. To gain up-to-date knowledge we explored and reviewed the already marketed and in-development applications of nanomaterials in the agri/feed/food sectors upon the request of the European Food Safety Authority (EFSA). In this paper the results of the project are highlighted and discussed in more detail.Key findings and conclusionsThe majority of the applications of nanomaterials that we identified concerned application in food as food additives and food contact materials, while much fewer applications seem to be developed for agriculture and feed. Nano-encapsulates, silver, titanium dioxide and silica are the most often mentioned nanomaterials in the literature. About half of the identified applications are claimed to be already in use. In-development applications are found for nano-encapsulates and nano-composites in novel foods, food and feed additives, biocides, pesticides and food contact materials.     

铁蛋白纳米笼分子装载途径及食品活性物质递送的研究进展

铁蛋白(ferritin)是一种广泛存在于动物、植物和微生物中的多亚基笼形结构蛋白,具有调节体内铁代谢平衡的功能,同时可以保护细胞免受因各种环境胁迫而导致的细胞氧化损伤。近年来,随着研究的深入,铁蛋白独特的纳米笼形结构以及特殊的理化性质使其成为一种具有广泛应用前景的新型蛋白质纳米载体材料。文章对铁蛋白的分子结构和功能进行了简要阐述,介绍了铁蛋白纳米颗粒的制备方法,总结了铁蛋白装载外源性小分子的基本途径:基于可逆组装特性的分子装载途径和基于环境响应的通道"门控"特性的分子装载途径;并综述了铁蛋白作为纳米载体在食品生物活性物质应用中的最新研究进展,以期为铁蛋白纳米载体的开发及在食品领域的应用提供研究思路。     

Encapsulation of food ingredients

Microencapsulation is a relatively new technology that is used for protection, stabilization, and slow release of food ingredients. The encapsulating or wall materials used generally consist of starch, starch derivatives, proteins, gums, lipids, or any combination of them. Methods of encapsulation of food ingredients include spraydrying, freeze‐drying, fluidized bed‐coating, extrusion, cocrystallization, molecular inclusion, and coacervation. This paper reviews techniques for preparation of microencapsulated food ingredients and choices of coating material. Characterization of microcapsules, mechanisms of controlled release, and efficiency of protection/ stabilization of encapsulated food ingredients are also presented.     

An overview of solid‐phase extraction of food flavor compounds and chemical residues

Abstract

Solid‐phase extraction (SPE) is a rapid and sensitive sample preparation technique whose use has increased considerably within the last decade. This emerging technology has successfully replaced many tedious conventional methods of isolation and extraction of various chemicals in food, environmental, pharmaceutical, and biological samples. Sample preparation and concentration via SPE can be achieved in a one‐step extraction, and the methodology is appropriate for isolating trace amounts of chemical compounds from complex matrices. This paper gives an overview on the use of SPE as a sample preparation tool for the isolation of flavor compounds and chemical residues in food. Applying SPE in the areas of food science and agriculture will be valuable in assuring the safety and quality of our food products.     

热诱导熔接聚氨酯/聚二甲基硅氧烷防水透湿膜的制备及其性能优化

为提高纳米纤维膜的防水、透湿和力学性能,在聚氨酯(PU)纺丝液中添加无氟疏水剂聚二甲基硅氧烷(PDMS),采用静电纺丝法制备静电纺PU/PDMS防水透湿膜,并在此基材上采用静电喷雾法沉积PU/PDMS微球制备静电喷雾PU/PDMS防水透湿膜;利用热诱导工艺分别对静电纺PU/PDMS和静电喷雾PU/PDMS防水透湿膜进行热处理改性,研究了热处理温度和时间对其形貌、孔径分布、防水性能、透气透湿性能及力学性能的影响,并对其影响机制进行分析。结果表明：静电喷雾PU/PDMS防水透湿膜的防水透湿性能优于静电纺PU/PDMS防水透湿膜,但经热处理后由于膜内部产生更多粘连,导致孔隙率降低,防水透湿性能出现下降;热处理后静电纺PU/PDMS防水透湿膜的孔径大大降低,并使其串珠结构向蛛网结构转化,防水性能和力学性能显著提升,当加热温度为100℃,加热时间为90 min时,其水接触角达到144.7°,透湿率为5 666.7 g/(m²·d),透气率为9.91 mm/s,断裂强度为17.9 MPa,断裂伸长率为210.7%。     

Self‐Assembled Carbohydrate Polymers for Food Applications: A Review

The self‐assembled natural and synthetic polymers are booming. However, natural polymers obtained from native or modified carbohydrate polymers (CPs), such as celluloses, chitosan, glucans, gums, pectins, and starches, have had special attention as raw material in the manufacture of self‐assembled polymer composite materials having several forms: films, hydrogels, micelles, and particles. The easy manipulation of the architecture of the CPs, as well as their high availability in nature, low cost, and being sustainable and green polymers have been the main positive points in the use of them for different applications. CPs have been used as building blocks for composite structures, and their easy orientation and ordering has given rise to self‐assembled CPs (SCPs). These macromolecules have been little studied for food applications. Nonetheless, their research has grown mainly in the last 5 years as encapsulated food additive wall materials, food coatings, and edible films. The multifaceted properties (systems sensitive to pH, temperature, ionic strength, types of ions, mechanical force, and enzymes) of these devices are leading to the development of advanced food materials. This review article focused on the analysis of SCPs for food applications in order to encourage other research groups for their preparation and implementation.     

Electrospraying method for fabrication of essential oil loaded-chitosan nanoparticle delivery systems characterized by molecular,thermal, morphological and antifungal properties

Fabrication of essential oil loaded-chitosan nanoparticles using electrospraying technique appears to be a novel strategy to develop thermally stable nanoparticles possessing higher encapsulation efficiency and particle stability. This study aims to fabricate chitosan nanoparticles (CNPs) loaded with Origanum vulgare essential oil (OEO, Origanum vulgare L.) at different proportions (OEO/CH proportions of 0:1, 0.0625:1, 0.125:1, 0.25:1 and 0.5:1 mL/g) using electrospraying technique. The CNPs were characterized in term of their particle size and stability (dynamic light scattering), encapsulation efficiency (spectrophotometry), and molecular (Fourier transform infrared spectroscopy), thermal (differential scanning calorimetry/thermogravimetric analysis), morphological (scanning electron microscopy) and antifungal (agar dilution method) and fungistatic activity properties. The average particle sizes of the CNPs ranged between 290 and 483 nm with a spherical morphology. Positively charged surface characteristics were observed to increase with the increment of OEO concentration in CNPs. The encapsulation efficiency values were determined in the range of 70.1 and 79.6%. The molecular and thermal analyses exposed very decent encapsulation of OEO into thermally stable chitosan nanoparticles. Morphological analysis verified the spherical shapes of these nanoparticles. Above all, the antifungal effectiveness of OEO against the Alternaria alternata AY1 could be significantly (p < 0.05) increased by its encapsulation into chitosan nanoparticles fabricated by the electrospraying technique. Consequently, it can be stated that the electrospraying technique developed is able to fabricate thermally stable nanoparticles owning higher encapsulation efficiency and particle stability. The results and findings suggest that the electrospraying technique would be a promising method to fabricate chitosan-based nanoparticles as an antimicrobial agent to control their release in a prolonged preservative effect in cosmetic, pharmaceutical and food applications for adjustable dosage forms.Industrial relevanceThe fungal agents such as Alternaria alternata cause great damages on post-harvest fresh fruits and vegetables, thus leading to a great economical lose. Therefore, a great variety of methods in struggling with disease have been previously proposed. Nowadays, the most effective leading methods to struggle against plant diseases are those applied with synthetic fungicides to minimize such lose in post-harvest fruit and vegetables. However, intensive and unconscious use of the fungicides leads the pathogens to develop resistance against these agents as well as to accumulation of chemical residues in soil, water and air and finally to formation of carcinogenic effects on human health. Nowadays, a great effort is being exerted to develop novel biodegradable and natural antimicrobial agents for struggling fungal spoilage in postharvest products. Essential oils are among the most widely used natural struggling methods. Essential oils obtained from plants have been extensively used since they are natural antimicrobial agents. However, they cannot be effectively used in spite of their extensive applications. Recently, some researches in the field of nanotechnology have demonstrated that the effectiveness of active substances could be increased by using some techniques. In this respect, we aimed at developing essential-oil-loaded-chitosan-nanoparticle delivery systems using an electrospraying deposition system to prevent fungal colonization on food and plant materials. By increasing antifungal effectiveness of essential oils by their encapsulation into nanoparticles, it will be possible to decrease the levels of regularly applied dose and reflect the obtained outcomes to the food and agriculture industry. This study is the first example of production of essential oil loaded nanoparticles using the electrospraying-hydrodynamic process and showed that encapsulation of oregano essential oil into chitosan based nanoparticles (CNPs) by using the electrospraying deposition technique considerably increased the antifungal effectiveness of the Origanum vulgare essential oil. Our results highlight the potential use of the chitosan nanoparticles (CNPs) loaded with different amounts of Origanum vulgare in food and agriculture industry as an effective fungicidal material against Alternaria alternata, suggesting that the CNPs can be promising tools to compete with synthetic fungicide counterparts and limit use of synthetic ones for struggling of food and plant pathogens. Therefore, the results of this study should be of great importance to industrial applications in terms of development of natural, but effective preservatives as alternative to synthetic ones. In this respect, the CNPs would find a great industrial application area in the food and agriculture industry which seek natural preservatives due to the recent health concerns.     

脂质体在食品中的应用及体外消化研究进展

脂质体是由双亲性物质如磷脂组成的内部为水相、具有类细胞膜结构的双分子层闭合囊泡,因其具有保护、运载、靶向和缓释等特点,目前已在食品营养、医药、化妆品、农业等领域表现出极大的应用潜能。本文简要介绍了脂质体的性质及特点,重点综述了脂质体在脂类、抗氧化剂、酶与蛋白质以及维生素和矿物质等食品领域的研究及应用,最后概述了脂质体作为食品营养因子运载体系在模拟体外胃和肠道消化的研究进展。