Antimicrobial effect of nisin electrospun amaranth: pullulan nanofibers in apple juice and fresh cheese

Zein-based nisin-loaded electrospun nanofibers as active packaging mats for control of Listeria monocytogenes on peach

Zein-based nanofibers (NFs) functionalized with nisin (NS), reinforced with montmorillonite nanoclay (nMMT) were fabricated by uniaxial electrospinning (ES) for the first time to preserve yellow peach. Spinnability/viscosity/conductivity optimizations generated porous (95.09%), bead-free, ultrathin (119 nm) NFs of low hydrophobicity (26.05°). Glutaraldehyde (GTA) crosslinking fostered positive outcomes of tensile strength (1.23 MPa), elongation (5.0%), hydrophobicity (99.46°), surface area (201.38 m2.g-1), pore size (2.88 nm), thermal stability (Tmax = 342 °C), antioxidant/cytotoxic activities in optimized NFs that released NS sustainably according to Korsmeyer-Peppas model indicating a Fickian diffusion mechanism with R2 = 0.9587. The novel NFs inhibited growth of Listeria monocytogenes/aerobic mesophilic populations in peach after 4 days of abusive storage, evincing their robustness in food contact applications. Simultaneously, quality parameters (moisture/texture/browning/total soluble solids/pH) and peach physical appearance were maintained for up to 8 days, endorsing the practical value of zein-based NFs as a non-thermal postharvest intervention for prolonging fruits storage life.

Bacteriocins sourced from traditional fermented foods for ensuring food safety: the microbial guards

Concerns about food safety have consistently driven the exploration of potent antimicrobials with probiotic origins. Identification of probiotic-derived bacteriocins as robust alternatives to antibiotics has gained traction following the COVID-19 pandemic. Additionally, the global market is witnessing an increasing preference for minimally processed food products free from chemical additives. Another contributing factor to the search for potent antimicrobials is the escalating number of infections caused by antibiotic-resistant bacteria and the need to mitigate the significant damage inflicted on the commensal human microbiota by broad-spectrum antibiotics. As an alternative bio-preservation strategy, there is substantial enthusiasm for the use of bacteriocins or starter cultures producing bacteriocins in preserving a variety of food items. This review specifically focuses on bacteriocins originating from lactic acid bacteria associated with fermented foods and explores their technological applications as nanobiotics. The food-grade antibiotic alternatives, whether utilized independently or in combination with other antimicrobials and administered directly or encapsulated, are anticipated to possess qualities of safety, stability and non-toxicity suitable for application in the food sector. © 2024 Society of Chemical Industry.

Amaranth proteins: From extraction to application as nanoparticle-based delivery systems for bioactive compounds

Amaranth proteins can be produced more sustainably than animal proteins, and they have amino acid compositions that are nutritionally balanced, which makes them attractive candidates for various applications in the food and pharmaceutical industries. This article provides an overview of the composition and techno-functional properties of amaranth protein, including its solubility, emulsification, gelation, foaming, and binding properties. These properties play an important role in the use of amaranth proteins for formulating nanoparticle-based delivery systems with good functional attributes. Amaranth proteins have structural and physicochemical properties suitable for fabricating protein-based nanoparticles. These nanoparticles can be used to encapsulate and control the release of bioactive compounds. However, challenges associated with the presence of anti-nutritional factors in amaranth proteins need to be addressed. These antinutrients negatively affect the bioavailability and digestibility of proteins and bioactive compounds. Hence, strategies to mitigate these challenges are discussed, including processing technologies and genetic engineering methods.

Nanocomposites and their application in antimicrobial packaging

The advances in nanocomposites incorporating bioactive substances have the potential to transform the food packaging sector. Different nanofillers have been incorporated into polymeric matrixes to develop nanocomposite materials with improved mechanical, thermal, optical and barrier properties. Nanoclays, nanosilica, carbon nanotubes, nanocellulose, and chitosan/chitin nanoparticles have been successfully included into polymeric films, resulting in packaging materials with advanced characteristics. Nanostructured antimicrobial films have promising applications as active packaging in the food industry. Nanocomposite films containing antimicrobial substances such as essential oils, bacteriocins, antimicrobial enzymes, or metallic nanoparticles have been developed. These active nanocomposites are useful packaging materials to enhance food safety. Nanocomposites are promising materials for use in food packaging applications as practical and safe substitutes to the traditional packaging plastics.

Cracking spoilage in jar cream cheese: Introducing, modeling and preventing

This study aimed to investigate the modeling of antimicrobial activity (AA) of nisin and sorbate on Clostridium sporogenes in jar cream cheese (JCC) using the linear regression (LR), multilayer perceptron (MLP) neural network, and reduced error pruning tree (REPTree) methods, in order to prevent the late blowing defect (LBD) in the cheese. Both preservatives used in JCC samples showed AA against C. sporogenes; so that sorbate at all the concentrations used in JCC samples inhibited cracking spoilage during storage period at 35 °C. However, nisin could not inhibit cracking spoilage at concentration of 30 ppm in the samples, and a higher concentration of it was needed. The three models used in this study, followed the similar pattern in both training and validation datasets for nisin and sorbat in JCC. The R2 and root mean square error (RMSE) values of training and validation datasets showed the superiority of the REPTree model compared to the MLP and LR models (conventional methods) in the modeling of AA of nisin and sorbate against C. sporogenes in JCC.

Electrospun plant protein-based nanofibers in food packaging

Electrospinning is a relatively simple technology capable to produce nano- and micron-scale fibers with different properties depending on the electrospinning conditions. This review critically investigates the fabrication of electrospun plant protein nanofibers (EPPNFs) that can be used in food and food packaging applications. Recent progress in the development and optimization of electrospinning techniques for production of EPPNFs is discussed. Finally, current challenges to the implementation of EPPNFs in food and food packaging applications are highlighted, including potential safety and scalability issues. The production of plant protein nanofibers and microfibers is likely to increase in the future as many industries wish to replace synthetic materials with more sustainable, renewable, and environmentally friendly biopolymers. It is therefore likely that EPPNFs will find increasing applications in various fields including active food packaging and drug delivery.

Nanostructured Antimicrobials for Quality and Safety Improvement in Dairy Products

In the food sector, one of the most important economic activities is the dairy industry, which has been facing many challenges in order to meet the increasing demand by consumers for natural and minimally processed products with high quality. In this sense, the application of innovative and emerging technologies can be an interesting alternative, for example, the use of nanotechnology in packaging and as delivery systems. This technology has the potential to improve the quality and safety of dairy products, representing an interesting approach for delivering food preservatives and improving the mechanical, barrier and functional properties of packaging. Several applications and promising results of nanostructures for dairy product preservation can be found throughout this review, including the use of metallic and polymeric nanoparticles, lipid-based nanostructures, nanofibers, nanofilms and nanocoatings. In addition, some relevant examples of the direct application of nanostructured natural antimicrobials in milk and cheese are presented and discussed, as well as the use of milk agar as a model for a preliminary test. Despite their high cost and the difficulties for scale-up, interesting results of these technologies in dairy foods and packaging materials have promoted a growing interest of the dairy industry.

Pullulan-Based Hydrogels in Wound Healing and Skin Tissue Engineering Applications: A Review

Wound healing is a complex process of overlapping phases with the primary aim of the creation of new tissues and restoring their anatomical functions. Wound dressings are fabricated to protect the wound and accelerate the healing process. Biomaterials used to design dressing of wounds could be natural or synthetic as well as the combination of both materials. Polysaccharide polymers have been used to fabricate wound dressings. The applications of biopolymers, such as chitin, gelatin, pullulan, and chitosan, have greatly expanded in the biomedical field due to their non-toxic, antibacterial, biocompatible, hemostatic, and nonimmunogenic properties. Most of these polymers have been used in the form of foams, films, sponges, and fibers in drug carrier devices, skin tissue scaffolds, and wound dressings. Currently, special focus has been directed towards the fabrication of wound dressings based on synthesized hydrogels using natural polymers. The high-water retention capacity of hydrogels makes them potent candidates for wound dressings as they provide a moist environment in the wound and remove excess wound fluid, thereby accelerating wound healing. The incorporation of pullulan with different, naturally occurring polymers, such as chitosan, in wound dressings is currently attracting much attention due to the antimicrobial, antioxidant and nonimmunogenic properties. Despite the valuable properties of pullulan, it also has some limitations, such as poor mechanical properties and high cost. However, these properties are improved by blending it with different polymers. Additionally, more investigations are required to obtain pullulan derivatives with suitable properties in high quality wound dressings and tissue engineering applications. This review summarizes the properties and wound dressing applications of naturally occurring pullulan, then examines it in combination with other biocompatible polymers, such chitosan and gelatin, and discusses the facile approaches for oxidative modification of pullulan.

Recent advances in electrospun protein fibers/nanofibers for the food and biomedical applications

Electrospinning (ES) is one of the most investigated processes for the convenient, adaptive, and scalable manufacturing of nano/micro/macro-fibers. With this technique, virgin and composite fibers may be made in different designs using a wide range of polymers (both natural and synthetic). Electrospun protein fibers (EPF) shave desirable capabilities such as biocompatibility, low toxicity, degradability, and solvolysis. However, issues with the proteins' processibility have limited their widespread utilization. This paper gives an overview of the features of protein-based biomaterials, which are already being employed and has the potential to be exploited for ES. State-of-the-art examples showcasing the usefulness of EPFs in the food and biomedical industries, including tissue engineering, wound dressings, and drug delivery, provided in the applications. The EPFs' future perspective and the challenge they pose are presented at the end. It is believed that protein and biopolymeric nanofibers will soon be manufactured on an industrial scale owing to the limitations of employing synthetic materials, as well as enormous potential of nanofibers in other fields, such as active food packaging, regenerative medicine, drug delivery, cosmetic, and filtration.

Antimicrobial Active Packaging Containing Nisin for Preservation of Products of Animal Origin: An Overview

The preservation of food represents one of the greatest challenges in the food industry. Active packaging materials are obtained through the incorporation of antimicrobial and/or antioxidant compounds in order to improve their functionality. Further, these materials are used for food packaging applications for shelf-life extension and fulfilling consumer demands for minimal processed foods with great quality and safety. The incorporation of antimicrobial peptides, such as nisin, has been studied lately, with a great interest applied to the food industry. Antimicrobials can be incorporated in various matrices such as nanofibers, nanoemulsions, nanoliposomes, or nanoparticles, which are further used for packaging. Despite the widespread application of nisin as an antimicrobial by directly incorporating it into various foods, the use of nisin by incorporating it into food packaging materials is researched at a much smaller scale. The researchers in this field are still in full development, being specific to the type of product studied. The purpose of this study was to present recent results obtained as a result of using nisin as an antimicrobial agent in food packaging materials, with a focus on applications on products of animal origin. The findings showed that nisin incorporated in packaging materials led to a significant reduction in the bacterial load (the total viable count or inoculated strains), maintained product attributes (physical, chemical, and sensorial), and prolonged their shelf-life.

Electrospun pullulan nanofiber loading zanthoxylum bungeanum essential oil/β-cyclodextrin inclusion complexes for active packaging

In this study, zanthoxylum bungeanum essential oil/β-cyclodextrin inclusion complexes (ZBEO/β-CD-ICs) were first prepared by precipitation method. When the addition of ZBEO was 1 g, the reaction time was 4 h and the reaction temperature was 55 °C, the recovery (73.88%) and loading content (9.53%) reached the highest value. The characterization results showed inclusion complexation changed the crystalline structure, enhanced interaction among molecules and increased the thermal stability. Then, nanofiber films containing ZBEO/β-CD-ICs were prepared by electrospinning. When the total polymer concentration was constant at 20%, with the increase of ZBEO/β-CD-IC content, the diameter of nanofiber and mechanical strength decreased, but the temperature corresponding to the maximum rate of weight loss increased. X-ray diffraction analysis proved that the addition of ZBEO/β-CD-IC increased the crystallinity degree of film. The Fourier transform infrared spectra indicated hydrogen bond interactions among molecules. Releasing behavior of ZBEO indicated that increase of temperature and relative humidity accelerated the releasing speed. Antibacterial and antioxidant activity results demonstrated the increase of ZBEO content enhanced antibacterial and antioxidant efficiency, Z40P10 nanofibers had the maximum antibacterial rate of 62.02% against S. aureus and the maximum antioxidant activity of 60.18%.

Challenging Sustainable and Innovative Technologies in Cheese Production: A Review

It is well known that cheese yield and quality are affected by animal genetics, milk quality (chemical, physical, and microbiological), production technology, and the type of rennet and dairy cultures used in production. Major differences in the same type of cheese (i.e., hard cheese) are caused by the rennet and dairy cultures, which affect the ripening process. This review aims to explore current technological advancements in animal genetics, methods for the isolation and production of rennet and dairy cultures, along with possible applications of microencapsulation in rennet and dairy culture production, as well as the challenge posed to current dairy technologies by the preservation of biodiversity. Based on the reviewed scientific literature, it can be concluded that innovative approaches and the described techniques can significantly improve cheese production.

Advancements in Biodegradable Active Films for Food Packaging: Effects of Nano/Microcapsule Incorporation

Food packaging plays a fundamental role in the modern food industry as a main process to preserve the quality of food products from manufacture to consumption. New food packaging technologies are being developed that are formulated with natural compounds by substituting synthetic/chemical antimicrobial and antioxidant agents to fulfill consumers' expectations for healthy food. The strategy of incorporating natural antimicrobial compounds into food packaging structures is a recent and promising technology to reach this goal. Concepts such as "biodegradable packaging", "active packaging", and "bioactive packaging" currently guide the research and development of food packaging. However, the use of natural compounds faces some challenges, including weak stability and sensitivity to processing and storage conditions. The nano/microencapsulation of these bioactive compounds enhances their stability and controls their release. In addition, biodegradable packaging materials are gaining great attention in the face of ever-growing environmental concerns about plastic pollution. They are a sustainable, environmentally friendly, and cost-effective alternative to conventional plastic packaging materials. Ultimately, a combined formulation of nano/microencapsulated antimicrobial and antioxidant natural molecules, incorporated into a biodegradable food packaging system, offers many benefits by preventing food spoilage, extending the shelf life of food, reducing plastic and food waste, and preserving the freshness and quality of food. The main objective of this review is to illustrate the latest advances in the principal biodegradable materials used in the development of active antimicrobial and antioxidant packaging systems, as well as the most common nano/microencapsulated active natural agents incorporated into these food-packaging materials.

Emerging Trends in Pullulan-Based Antimicrobial Systems for Various Applications

Global reports on multidrug resistance (MDR) and life-threatening pathogens such as SARS-CoV-2 and Candida cruris have stimulated researchers to explore new antimicrobials that are eco-friendly and economically viable. In this context, biodegradable polymers such as nisin, chitin, and pullulan play an important role in solving the problem. Pullulan is an important edible, biocompatible, water-soluble polymer secreted by Aureobasidium pullulans that occurs ubiquitously. It consists of maltotriose units linked with α-1,6 glycosidic bonds and is classed as Generally Regarded as Safe (GRAS) by the Food and Drug Administration (FDA) in the USA. Pullulan is known for its antibacterial, antifungal, antiviral, and antitumor activities when incorporated with other additives such as antibiotics, drugs, nanoparticles, and so on. Considering the importance of its antimicrobial activities, this polymer can be used as a potential antimicrobial agent against various pathogenic microorganisms including the multidrug-resistant (MDR) pathogens. Moreover, pullulan has ability to synthesize biogenic silver nanoparticles (AgNPs), which are remarkably efficacious against pathogenic microbes. The pullulan-based nanocomposites can be applied for wound healing, food packaging, and also enhancing the shelf-life of fruits and vegetables. In this review, we have discussed biosynthesis of pullulan and its role as antibacterial, antiviral, and antifungal agent. Pullulan-based films impregnated with different antimicrobials such as AgNPs, chitosan, essential oils, and so on, forming nanocomposites have also been discussed as natural alternatives to combat the problems posed by pathogens.

Plant protein-based fibers: Fabrication, characterization, and potential food applications

Proteins from plants have been considered as safer, healthier, and more sustainable resources than their animal counterparts. However, incomplete amino acid composition and relatively poor functionality limit their applications in foods. Structuring plant proteins to fibrous architectures enhances their physicochemical properties, which can favor various food applications. This review primarily focuses on fabrication of fibers from plant proteins via self-assembly, electrospinning, solution blow spinning, wet spinning, and high-temperature shear, as well as on several applications where such fibrous proteins assemble in quality foods. The changes of protein structure and protein-protein interactions during fiber production are discussed in detail, along with the effects of fabrication conditions and protein sources on the morphology and function of the fibers. Self-assembly requires proteolysis and subsequent peptide aggregation under specific conditions, which can be influenced by pH, salt and protein type. The spinning strategy is more scalable and produces uniformed fibers with larger length scales suitable for encapsulation, food packaging and sensor substrates. Significant progress has been made on high-temperature shear (including extrusion)-induced fibers responsible for desirable texture in meat analogues. Structuring plant proteins adds values for broadened food applications, but it remains challenging to keep processes cost-effective and environmentally friendly using food grade solvents.

Antibacterial nanofibers of pullulan/tetracycline-cyclodextrin inclusion complexes for Fast-Disintegrating oral drug delivery

Tetracycline is a widely used antibiotic suffering from poor water solubility and low bioavailability. Here, hydroxypropyl-beta-cyclodextrin (HPβCD) was used to form inclusion complexes (IC) of tetracycline with 2:1 M ratio (CD:drug). Then, tetracycline-HPβCD-IC was mixed with pullulan- a non-toxic, water-soluble biopolymer - to form nanofibrous webs via electrospinning. The electrospinning of pullulan/tetracycline-HPβCD-IC was yielded into defect-free nanofibers collected in the form of a self-standing and flexible material with the loading capacity of ∼ 7.7 % (w/w). Pullulan/tetracycline nanofibers was also generated as control sample having the same drug loading. Tetracycline was found in the amorphous state in case of pullulan/tetracycline-HPβCD nanofibers due to inclusion complexation. Through inclusion complexation with HPβCD, enhanced aqueous solubility and faster release profile were provided for pullulan/tetracycline-HPβCD-IC nanofibers compared to pullulan/tetracycline one. Additionally, pullulan/tetracycline-HPβCD-IC nanofibers readily disintegrated when wetted with artificial saliva while pullulan/tetracycline nanofibers were not completely absorbed by the same simulate environment. Electrospun nanofibers showed promising antibacterial activity against both gram-positive and gram-negative bacteria. Briefly, our findings indicated that pullulan/tetracycline-HPβCD-IC nanofibers could be an attractive material as orally fast disintegrating drug delivery system for the desired antibiotic treatment thanks to its promising physicochemical and antibacterial properties.

Pleurotus eryngii polysaccharide nanofiber containing pomegranate peel polyphenol/chitosan nanoparticles for control of E. coli O157:H7

Pomegranate peel polyphenols (PPP), which are natural, safe, and green antibacterial agents, were introduced and embedded in chitosan to form stable nanoparticles. The PPP@chitosan nanoparticles (PPP@CNPs) were further electrospun into nanofibers based on Pleurotus eryngii polysaccharide (PEP). The preferable distribution of particle size, polydispersity index, and zeta potential was realized through the addition of PPP at 3 mg/mL, which achieved the highest encapsulation rate of 23.71 ± 0.51%. The tensile strength and elongation at break of nanofibers reached 15.76 MPa and 0.69% with the addition of 1% PEP through electrospinning. The results of scanning electron microscopy (SEM) and atomic force microscopy (AFM) demonstrated that the addition of nanoparticles increased the diameter of PEP nanofibers from 148 nm to 163 nm, and the surface roughness of the fibers also increased. Meanwhile, the addition of nanoparticles improved the thermal stability of PEP nanofibers. PPP@CNPs/PEP nanofibers can inhibit the growth of E. coli O157:H7 on pork and cucumber surfaces during the five-days storage, and the inhibition rates were all above 95%. Besides, the nanofibers did not have any impact on the color and texture of foods.

A Systematic Review on Nanoencapsulation Natural Antimicrobials in Foods: In Vitro versus In Situ Evaluation, Mechanisms of Action and Implications on Physical-Chemical Quality

Natural antimicrobials (NA) have stood out in the last decade due to the growing demand for reducing chemical preservatives in food. Once solubility, stability, and changes in sensory attributes could limit their applications in foods, several studies were published suggesting micro-/nanoencapsulation to overcome such challenges. Thus, for our systematic review the Science Direct, Web of Science, Scopus, and Pub Med databases were chosen to recover papers published from 2010 to 2020. After reviewing all titles/abstracts and keywords for the full-text papers, key data were extracted and synthesized. The systematic review proposed to compare the antimicrobial efficacy between nanoencapsulated NA (nNA) and its free form in vitro and in situ studies, since although in vitro studies are often used in studies, they present characteristics and properties that are different from those found in foods; providing a comprehensive understanding of primary mechanisms of action of the nNA in foods; and analyzing the effects on quality parameters of foods. Essential oils and nanoemulsions (10.9-100 nm) have received significant attention and showed higher antimicrobial efficacy without sensory impairments compared to free NA. Regarding nNA mechanisms: (i) nanoencapsulation provides a slow-prolonged release to promote antimicrobial action over time, and (ii) prevents interactions with food constituents that in turn impair antimicrobial action. Besides in vitro antifungal and antibacterial, nNA also demonstrated antioxidant activity-potential to shelf life extension in food. However, of the studies involving nanoencapsulated natural antimicrobials used in this review, little attention was placed on proximate composition, sensory, and rheological evaluation. We encourage further in situ studies once data differ from in vitro assay, suggesting food matrix greatly influences NA mechanisms.

Electrospun nanofibers food packaging: trends and applications in food systems

Food safety is a bottleneck problem. In order to provide information about advanced and unique food packaging technique, this study summarized the advancements of electrospinning technique. Food packaging is a multidisciplinary area involving food science, food engineering, food chemistry, and food microbiology, and the interest in maintaining the freshness and quality of foods has grown considerably. For this purpose, electrospinning technology has gained much attention due to its unique functions and superior processing. Sudden advancements of electrospinning have been rapidly incorporated into research. This review summarized some latest information about food packaging and different materials used for the packaging of various foods such as fruits, vegetables, meat, and processed items. Also, the use of electrospinning and materials used for the formation of nanofibers are discussed in detail. However, in food industry, the application of electrospun nanofibers is still in its infancy. In this study, different parameters, structures of nanofibers, features and fundamental properties are described briefly, while polymers fabricated through electrospinning with advances in food packaging films are described in detail. Moreover, this comprehensive review focuses on the polymers used for the electrospinning of nanofibers as packaging films and their applications for variety of foods. This will be a valuable source of information for researchers studying various polymers for electrospinning for application in the food packaging industry.

Potential Novel Food-Related and Biomedical Applications of Nanomaterials Combined with Bacteriocins

Bacteriocins are antimicrobial peptides or proteinaceous materials produced by bacteria against pathogens. These molecules have high efficiency and specificity and are equipped with many properties useful in food-related applications, such as food preservatives and additives, as well as biomedical applications, such as serving as alternatives to current antibacterial, antiviral, anticancer, and antibiofilm agents. Despite their advantages as alternative therapeutics over existing strategies, several limitations of bacteriocins, such as the high cost of isolation and purification, narrow spectrum of activity, low stability and solubility, and easy enzymatic degradation, need to be improved. Nanomaterials are promising agents in many biological applications. They are widely used in the conjugation or decoration of bacteriocins to augment the activity of bacteriocins or reduce problems related to their use in biomedical applications. Therefore, bacteriocins combined with nanomaterials have emerged as promising molecules that can be used in various biomedical applications. This review highlights the features of bacteriocins and their limitations in biomedical applications and provides a detailed overview of the uses of different nanomaterials in improving the limitations. Our review focuses on the potential applications of nanomaterials combined with bacteriocins as new designer molecules for use in future therapeutic strategies.

Pullulan based stimuli responsive and sub cellular targeted nanoplatforms for biomedical application: Synthesis, nanoformulations and toxicological perspective

With growing interest in polymers of natural origin, innumerable polysaccharides have gained attention for their biomedical application. Pullulan, one of the FDA approved nutraceuticals, possesses multiple unique properties which make them highly advantageous for biomedical applications. This present review encompasses the sources, production, properties and applications of pullulan. It highlights various pullulan based stimuli-responsive systems (temperature, pH, ultrasound, magnetic), subcellular targeted systems (mitochondria, Golgi apparatus/endoplasmic reticulum, lysosome, endosome), lipid-vesicular systems (solid-lipid nanoparticles, liposomes), polymeric nanofibres, micelles, inorganic (SPIONs, gold and silver nanoparticles), carbon-based nanoplatforms (carbon nanotubes, fullerenes, nanodiamonds) and quantum dots. This article also gives insight into different biomedical, therapeutic and diagnostic applications of pullulan viz., imaging, tumor targeting, stem cell therapy, gene therapy, vaccine delivery, cosmetic applications, protein delivery, tissue engineering, photodynamic therapy and chaperone-like activities. The review also includes the toxicological profile of pullulan which is helpful for the development of suitable delivery systems for clinical applications.

Long-Term Antibacterial Effect of Electrospun Polyvinyl Alcohol/Polyacrylate Sodium Nanofiber Containing Nisin-Loaded Nanoparticles

Response Surface Methodology (RSM) was used to assess the optimal conditions for a Water/Oil/Water (W/O/W) emulsion for encapsulated nisin (EN). Nano-encapsulated nisin had high encapsulation efficiencies (EE) (86.66 ± 1.59%), small particle size (320 ± 20 nm), and low polydispersity index (0.27). Biodegradable polyvinyl alcohol (PVA) and polyacrylate sodium (PAAS) were blended with EN and prepared by electrospinning. Scanning electron microscopy (SEM) revealed PVA/PAAS/EN nanofibers with good morphology, and that their EN activity and mechanical properties were enhanced. When the ultrasonication time was 15 min and 15% EN was added, the nanofibers had optimal mechanical, light transmittance, and barrier properties. Besides, the release behavior of nisin from the nanofibers fit the Korsemeyer–Peppas (KP) model, a maximum nisin release rate of 85.28 ± 2.38% was achieved over 16 days. At 4 °C, the growth of Escherichia coli and Staphylococcus aureus was inhibited for 16 days in nanofibers under different ultrasonic times. The application of the fiber in food packaging can effectively inhibit the activity of food microorganisms and prolong the shelf life of strawberries, displaying a great potential application for food preservation.

Postbiotics produced by lactic acid bacteria: The next frontier in food safety

There are many critical challenges in the use of primary and secondary cultures and their biological compounds in food commodities. An alternative is the application of postbiotics from the starter and protective lactic acid bacteria (LAB). The concept of postbiotics is relatively new and there is still not a recognized definition for this term. The word "postbiotics" is currently used to refer to bioactive compounds, which did not fit to the traditional definitions of probiotics, prebiotics, and paraprobiotics. Therefore, the postbiotics may be presently defined as bioactive soluble factors (products or metabolic byproducts), produced by some food-grade microorganisms during the growth and fermentation in complex microbiological culture (in this case named cell-free supernatant), food, or gut, which exert some benefits to the food or the consumer. Many LAB are considered probiotic and their postbiotic compounds present similar or additional health benefits to the consumer; however, this review aimed to address the most recent applications of the postbiotics with food safety purposes. The potential applications of postbiotics in food biopreservation, food packaging, and biofilm control were reviewed. The current uses of postbiotics in the reduction and biodegradation of some food safety-related chemical contaminants (e.g., biogenic amines) were considered. We also discussed the safety aspects, the obstacles, and future perspectives of using postbiotics in the food industry. This work will open up new insights for food applications of postbiotics prepared from LAB.

Antimicrobial-loaded nanocarriers for food packaging applications

Increasing the demands of consumers for organic and safer foods has led to applying new technologies for food preservation. Active packaging (AP) containing natural antimicrobial agents is a good candidate for promoting the shelf life of food products. The efficiency of AP has been enhanced through nanoencapsulation methods, in which antimicrobial-loaded nanocarriers could provide a controlled release of antimicrobial active packaging for keeping the quality of foods during storage. The main objective of this review is to introduce common methods for designing novel encapsulation delivery systems offering controlled release of antimicrobials in the AP systems. The common nanocarriers for enveloping antimicrobial agents are described and the current state of art in the application of nanoencapsulated antimicrobials in development of antimicrobial APs have been summarized and tabulated. Incorporation of a carrier loaded with natural antimicrobial agents is the most effective method for developing AP in the food packaging sector which has become possible by using nanoencapsulated antimicrobials in films or coating structures, instead of using their free form. Nanoencapsulation approaches provide many advantages including protection against environmental stresses, release control, and improving the solubility and absorption of natural antimicrobials in AP, which are the main achievements overcoming the barriers for using natural antimicrobials in food packaging.

Nanosystems as Vehicles for the Delivery of Antimicrobial Peptides (AMPs)

Recently, antimicrobial peptides (AMPs), also called host defence peptides (HDPs), are attracting great interest, as they are a highly viable alternative in the search of new approaches to the resistance presented by bacteria against antibiotics in infectious diseases. However, due to their nature, they present a series of disadvantages such as low bioavailability, easy degradability by proteases, or low solubility, among others, which limits their use as antimicrobial agents. For all these reasons, the use of vehicles for the delivery of AMPs, such as polymers, nanoparticles, micelles, carbon nanotubes, dendrimers, and other types of systems, allows the use of AMPs as a real alternative to treatment with antibiotics.

Derivatization approaches and applications of pullulan

Pullulan (PUL), a linear exo-polysaccharide, is useful in industries as diverse as food, cosmetics and pharmaceuticals. PUL presents many favorable characteristics, such as renewable origin, biocompatibility, stability, hydrophilic nature, and availability of reactive sites for chemical modification. With an inherent affinity to asialoglycoprotein receptors, PUL can be used for targeted drug delivery to the liver. Besides, these primary properties have been combined with modern synthetic approaches for developing multifunctional biomaterials. This is evident from numerous studies on approaches, such as hydrophobic modification, cross-linking, grafting and transformation as a polyelectrolyte. In this review, we have discussed up-to-date advances on chemical modifications and emerging applications of PUL in targeted theranostics and tissue engineering. Besides, we offer an overview of its applications in food, cosmetics and environment remediation.