Fabrication and characterization of tea polyphenols loaded pullulan-CMC electrospun nanofiber for fruit preservation

Poly(lactic acid)/polycaprolactone nanofibrous packaging containing different functional agents for blackberry postharvest preservation

Electrospun nanofibrous films containing different active agents were prepared and compared to improve the storage quality of blackberries. We added different essential oils, phenolic acids, microbial antagonists and plant growth regulators to poly(lactic acid)/polycaprolactone (PP) nanofilms and compared their antimicrobial properties against bacteria and fungi. Based on the results, oregano essential oil/PP (OPP), chlorogenic acid/PP (CPP), natamycin/PP (NPP) and methyl jasmonate/PP (MPP) were selected. The addition of active agents decreased the tensile strength and increased the elastic modulus and elongation at break. These active agents did not affect the thermal stability, water contact angle (except for NPP) or water permeability (except for NPP and MPP) of the nanofilms. Nanofilms also controlled the release of active agents and showed antioxidant activity and biosafety. Different nanofilms were applied to blackberry postharvest storage, and OPP contributed the lowest to deterioration in appearance, 'red small drupelets' phenomenon, decay rate, weight loss and softening. Among these nanofilms, the OPP nanofilm exhibited the best shelf-life extension of blackberry.

Development of pectin/chitosan-based electrospun biomimetic nanofiber membranes loaded with dihydromyricetin inclusion complexes for wound healing application

Accidents and surgical procedures inevitably lead to wounds, presenting clinical challenges such as inflammation and microbial infections that impede the wound-healing process. This study aimed to address these challenges by developing a series of novel wound dressings known as electrospun biomimetic nanofiber membranes. These membranes were prepared using electrostatic spinning technique, incorporating hydroxypropyl-β-cyclodextrin/dihydromyricetin inclusion complexes. The prepared electrospun biomimetic nanofiber membranes exhibited randomly arranged fiber morphology with average fiber diameters ranging from 200 to 400 nm, resembling the collagen fibers in the native skin. These membranes demonstrated excellent biocompatibility, hemocompatibility, surface hydrophilicity, and wettability, while also releasing dihydromyricetin in a sustained manner. In vitro testing revealed that these membranes, loaded with hydroxypropyl-β-cyclodextrin/dihydromyricetin inclusion complexes, displayed higher antioxidant potential and inhibitory effects against Staphylococcus aureus and Escherichia coli. Furthermore, these membranes significantly reduced the M1 phenotypic transition in RAW264.7 cells, even when stimulated by lipopolysaccharides, effectively restoring M2 polarization, thereby shortening the inflammatory period. Additionally, the in vivo wound healing effects of these membranes were validated. In conclusion, this study introduces a promising nanofiber membrane with diverse biological properties that holds promise for addressing various crucial aspects of the wound-healing process.

Aloe vera and tea polyphenols composite coating delays passion fruit senescence by promoting phenolic and flavonoid accumulation

Passion fruits are highly perishable during postharvest storage and transportation, prompting the exploration of natural preservatives. This study investigates the synergistic effects of Aloe vera (ALV) and tea polyphenols (TP) coatings on quality retention, ripening modulation, and associated regulatory mechanisms in stored "golden" passion fruit (Passiflora spp.) at 10 °C. The application of a composite coating comprising 40 % ALV and 0.1 g/L TP led to notable improvements in fruit preservation over a 28-day storage period. At the day of 28, quantitatively, the ALV + TP treatment reduced weight loss by 41.60 %, shrinkage index by 28.13 %, and decay index by 50 %, significantly outperforming the control and individual treatments; the treated fruits exhibited enhanced firmness, reduced ethylene production, and the respiration peak was delayed about 6 days. Metabolomic analysis revealed pronounced alterations in key metabolic pathways, notably phenylpropanoid and flavonoid biosynthesis. Specifically, significant increases in metabolites such as phenolic acids (Feruloylmalic acid and Acropyrone) and flavonoids (Okanin-4'-O-glucoside, Apigenin-8-C-Arabinoside, Quercetin-3-O- (2'-O-galloyl) galactoside, and Catechin callate) were observed. Concurrently, transcript levels of key biosynthetic genes including cinnamate 4-hydroxylase (PeC4H), 4-coumarate-coenzyme a ligase (PeC4L), hydroxycinnamoyl transferase (PeHCT) and flavonol synthase (PeFLS) were significantly up-regulated by ALV + TP coating, indicating a robust activation of these pathways. The findings underscore the effectiveness of the ALV + TP composite coating as an environmentally friendly strategy for enhancing postharvest quality by promoting the accumulation of beneficial phenolic acids and flavonoids in passion fruits.

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.

Trends in polysaccharide-based hydrogels and their role in enhancing the bioavailability and bioactivity of phytocompounds

Over the years, polysaccharides such as chitosan, alginate, hyaluronic acid, k-carrageenan, xanthan gum, carboxymethyl cellulose, pectin, and starch, alone or in combination with proteins and/or synthetic polymers, have been used to engineer an extensive portfolio of hydrogels with remarkable features. The application of polysaccharide-based hydrogels has the potential to alleviate challenges related to bioavailability, solubility, stability, and targeted delivery of phytocompounds, contributing to the development of innovative and efficient drug delivery systems and functional food formulations. This review highlights the current knowledge acquired on the preparation, features and applications of polysaccharide/phytocompounds hydrogel-based hybrid systems in wound management, drug delivery, functional foods, and food industry. The structural, functional, and biological requirements of polysaccharides and phytocompounds on the overall performance of such hybrid systems, and their impact on the application domains are also discussed.

Pullulan nanofibrous films incorporated with W/O emulsions via microfluidic solution blow spinning technology

In this work, pullulan (PUL) nanofibrous films incorporated with water-in-oil emulsions (PE) were prepared by microfluidic blowing spinning (MBS). The microstructures of nanofibers were characterized by scanning electron microscopy (SEM), fourier transform infrared (FT-IR), and X-ray diffraction (XRD). With the addition of W/O emulsions, the thermal stability, mechanical, and water barrier properties of PUL nanofibers were improved. Increases in emulsion content significantly affected the antioxidant and antimicrobial properties of nanofibrous films. ABTS and DPPH free radical scavenging rates increased from 10.26 % and 8.57 % to 60.66 % and 57.54 %, respectively. The inhibition zone of PE nanofibers against E. coli and S. aureus increased from 11.00 to 20.00 and from 15.67 to 21.17 mm, respectively. In addition, we investigated the freshness effectiveness of PE nanofibrous films on fresh-cut apples. PE nanofibrous films significantly maintained the firmness, and reduced the weight loss and browning index of the fresh-cut apple, throughout the 4 days of storage. Thus, the PE nanofibrous films exhibited good potential to prolong the shelf life of fresh-cut fruit and promote the development of active food packaging.

Electrospraying of phytosterols and their controlled release characteristics under in vitro digestive conditions

Phytosterols reduce cholesterol and low-density lipoprotein concentrations in humans. The use of phytosterols is restricted due to their high melting temperature, low water solubility, and chalky taste. In addition, due to its structure, it is easily oxidized and its absorption and bioavailability by the human body decrease. For these reasons, the phytosterol mixture was encapsulated by electrospraying. The carrier materials and their concentrations were optimized in mixture design as responses of the phytosterol release, minimum in the model stomach and maximum in the model intestinal solutions. As a result of the optimization, the most successful carrier material composition; was 7.19 g whey protein isolate/100 mL distilled water, 9.03 g inulin/100 mL distilled water, and 3.78 g resistant starch/100 mL distilled water. The phytosterol capsules produced in the electrospraying process at the optimized conditions were released 115.19 mg/kg in the stomach and 312.49 mg/kg in the intestinal conditions.

Exploring the potential of pullulan-based films and coatings for effective food preservation: A comprehensive analysis of properties, activation strategies and applications

Pullulan is naturally occurring polysaccharide exhibited potential applications for food preservation has gained increasing attention over the last half-century. Recent studies focused on efficient preservation and targeted inhibition using active composite ingredients and advanced technologies. This has led to the emergence of pullulan-based biofilm preservation. This review extensively studied the characteristics of pullulan-based films and coatings, including their mechanical strength, water vapor permeability, thermal stability, and potential as a microbial agent. Furthermore, the distinct characteristics of pullulan, production methods, and activation strategies, such as pullulan derivatization, various compounded ingredients (plant extracts, microorganisms, and animal additives), and other technologies (e.g., ultrasound), are thoroughly studied for the functional property enhancement of pullulan-based films and coatings, ensuring optimal preservation conditions for diverse food products. Additionally, we explore hypotheses that further illuminate pullulan's potential as an eco-friendly bioactive material for food packaging applications. In addition, this review evaluates various methods to improve the efficiency of the film-forming mechanism, such as improving the direct coating process, bioactive packaging films, and implementing layer-by-layer coatings. Finally, current analyses put forward suggestions for future advancement in pullulan-based bioactive films, with the aim of expanding their range of potential applications.

Effects of Litsea cubeba Essential Oil-Chitosan/Corn Starch Composite Films on the Quality and Shelf-Life of Strawberry (Fragaria × ananassa)

In this work, we have developed a composite chitosan film incorporating the Litsea cubeba essential oil (LCEO) and starch with good physical properties, and investigated the effect of coating strawberries with this composite film. The best formula of the LCEO/chitosan/corn starch/glycerol (LCEO/CH/CS/gly) composite films is 0.25% LCEO, 2.75% CH, 0.40% corn starch, and 0.75% glycerol. Coating strawberries with CH/CS/gly film or LCEO/CH/CS/gly films resulted in significantly lower respiration intensity and a slower decay rate, much slower decreases in the firmness, and reductions in the sugar and ascorbic acid content of the fruit during storage (p < 0.05). The coatings also led to a much slower accumulation of malondialdehyde and anthocyanins (p < 0.05). The LCEO/CH/CS/gly film was generally more effective than the CH/CS/gly film; however, the effect was more obvious in the later stages of storage. Thus, coating strawberries with CH/CS/gly film or LCEO/CH/CS/gly film can be a viable method for extending the shelf-life of the fruit.

Effects of carboxymethyl cellulose fiber formations with chitosan incorporation via coating and mixing processes

To date, the utilization of carboxymethyl cellulose (CMC) fibers are only restricted to weak mechanical application such as wound dressing. Physically, CMC has a weak mechanical strength due to the high hydrophilicity trait. However, this flaw was saved by the extensive number of reactive functional groups, allowing this macromolecule to form linkages with chitosan to ensure its versatility. This work successfully fabricated CMC-chitosan fiber via dissolution, crosslinking, dry-jet wet-spinning extrusion, and coagulation processes. Chitosan was constituted with CMC fiber in two approaches, coating, and inclusion at various concentrations. Morphologically, chitosan incorporation has triggered agglomerations and roughness toward CMC fibers (CMCF). Chemically, the interaction between CMC and chitosan was proved through FTIR analysis at peaks 1245 cm-1 (ECH covalent crosslinking), while 3340 cm-1 and 1586 cm-1 were due to ionic and hydrogen bonding. The result from analysis showed that at higher chitosan concentrations, the chitosan-included CMC fiber (CMCF-I) and chitosan-coated CMC fiber (CMFC) were mechanically enhanced (up to 86.77 and 82.72 MPa), thermally more stable (33 % residual mass), and less hydrophilic compared to the plain CMCF. The properties of CMC-chitosan fibers have opened up vast possible applications, especially as a reinforcement in a watery medium such as a hydrogel.

Arginine-carboxylated pullulan, a potential antibacterial material for food packaging

Pullulan possesses excellent film-forming properties and oxygen isolation capabilities. However, it exhibits limited antibacterial properties and poor water resistance, thereby hindering its application in the field of food preservation. In this study, we synthesized D-arginine-succinic anhydride-pullulan (Arg-SA-Pul) by carboxylating pullulan and subsequently grafting it with D-arginine. The antimicrobial test demonstrated that Arg-SA-Pul exhibited comparable antibacterial activity against Escherichia coli and Staphylococcus aureus. Using Arg-SA-Pul as the primary material and glycerol as the plasticizer, we fabricated an antibacterial film via the tape casting method. The film's light transmittance, water solubility, and water vapor permeability were evaluated. Compared to the natural pullulan film, the Arg-SA-Pul film exhibited lower vapor permeability. Additionally, we conducted preservation tests on cherries by coating them with the Arg-SA-Pul film. The results demonstrated that the Arg-SA-Pul film exhibited a significant preservation effect on cherries and effectively delayed their ripening and senescence. In the future, the Arg-SA-Pul film could be employed as a bacteriostatic preservation material to extend the shelf life of fruits.

Encapsulation of tea polyphenols into high amylose corn starch composite nanofibrous film for active antimicrobial packaging

Starch-based composite nanofibrous films loaded with tea polyphenols (TP) were successfully fabricated through electrospinning high amylose corn starch (HACS) with aid of polyvinyl alcohol (PVA), referred as HACS/PVA@TP. With the addition of 15 % TP, HACS/PVA@TP nanofibrous films exhibited enhanced mechanical properties and water vapor barrier capability, and their hydrogen bonding interactions were further evidenced. TP was slowly released from the nanofibrous film and followed Fickian diffusion mechanism, which achieved the controlled sustained release of TP. Interesting, HACS/PVA@TP nanofibrous films effectively improved antimicrobial activities against Staphylococcus aureus (S. aureus) and prolonged the shelf life of strawberry. HACS/PVA@TP nanofibrous films showed superior antibacterial function by by destroying cell wall and cytomembrane, and degrading existing DNA fragments, stimulating excessive intracellular reactive oxygen species (ROS) generation. Our study demonstrated that the functional electrospun Starch-based nanofibrous films with enhanced mechanical properties and superior antimicrobial activities were potential for the application in active food packaging and relative areas.

A Brief Review on the Electrohydrodynamic Techniques Used to Build Antioxidant Delivery Systems from Natural Sources

Extracts from plants have been one of the main sources of antioxidants, namely polyphenols. The associated drawbacks, such as instability against environmental factors, low bioavailability, and loss of activity, must be considered during microencapsulation for a better application. Electrohydrodynamic processes have been investigated as promising tools to fabricate crucial vectors to minimize these limitations. The developed microstructures present high potential to encapsulate active compounds and for controlling their release. The fabricated electrospun/electrosprayed structures present different benefits when compared with structures developed by other techniques; they present a high surface-area-to-volume ratio as well as porosity, great materials handling, and scalable production-among other advantages-which make them able to be widely applied in different fields, namely in the food industry. This review presents a summary of the electrohydrodynamic processes, main studies, and their application.

Preparation, Properties and Application in Electrospinning of Tremella Polysaccharide-Protein Complex

In this paper, the effects of different proteins (soybean protein isolate, wheat protein hydrolysate, tremella protein) on the activity of tremella polysaccharide under different conditions were studied. The optimal protein-polysaccharide complex was determined by grafting degree and activity screening, and the microstructure and rheological properties were studied. The results showed that when the ratio of soybean protein isolate to tremella polysaccharide was 2:1 and the solution pH was 7, the optimal complex was obtained by heating at 90 °C for 4 h, and its grafting degree and antioxidant activity were the best. Studies have shown that tremella polysaccharide and soybean protein isolate complex (TFP-SPI) solution is pseudoplastic fluids. At the same time, tremella polysaccharide (TFP) and TFP-SPI were used for electrospinning to observe its spinnability. When the ratio of PVA/TFP-SPI/PL was 8:1:1, nanofibers with uniform diameter and good morphology were obtained. This paper provides a theoretical basis for the comprehensive utilization of tremella polysaccharide and its electrospun fiber can be used as active film for food packaging.

Biodegradable hybrid biopolymer film based on carboxy methyl cellulose and selenium nanoparticles with antifungal properties to enhance grapes shelf life

In the current study, cellulose was extracted from sugarcane bagasse and further converted into carboxy methyl cellulose. The morphological, chemical, and structural characterization of synthesizeed carboxy methyl cellulose was performed. Further, the biopolymer was fabricated with mycogenic selenium nanoparticles and used to develop the biopolymer films. The developed biopolymer films were examined for the fruit shelf life stability, antifungal activity, and biodegradation potential. The results revealed that grapes wrapped with biofilms showed enhanced shelf life of fruit at all storage time intervals. The study also witnesses the antifungal activity of biopolymer films with a remarkable inhibitory action on the spores of Fusarium oxysporum and Sclerospora graminicola phytopathogens. Lastly, the biopolymer films were significantly degradable in the soil within two weeks of incubation. Thus, the developed biopolymer films exhibit multifaceted properties that can be used as an alternative to synthetic plastics for fruit packaging and also helps in protecting against fungal contaminants during storage with naturally degradable potential.

Reflections on food security and smart packaging

Estimating the number of COVID-19 cases in 2020 exacerbated the food contamination and food supply issues. These problems make consumers more concerned about food and the need to access accurate information on food quality. One of the main methods for preserving the quality of food commodities for export, storage, and finished products is food packaging itself. In the food industry, food packaging has a significant role in the food supply which acts as a barrier against unwanted substances and preserves the quality of the food. Meanwhile, packaging waste can also harm the environment; namely, it can become waste in waterways or become garbage that accumulates because it is nonrenewable and nonbiodegradable. The problem of contaminated food caused by product packaging is also severe. Therefore, to overcome these challenges of safety, environmental impact, and sustainability, the role of food packaging becomes very important and urgent. In this review, the authors will discuss in more detail about new technologies applied in the food industry related to packaging issues to advance the utilization of Smart Packaging and Active Packaging.

Assessment of Zataria Multiflora Essential Oil-Incorporated Electrospun Polyvinyl Alcohol Fiber Mat as Active Packaging

In this study, an active packaging containing Zataria multiflora essential oil (ZMEO), a powerful natural antimicrobial agent, encapsulated into polyvinyl alcohol (PVA) fiber via electrospinning is presented. ZMEO was effective on pathogenic bacteria, particularly Gram-positive bacteria (Staphylococcus aureus, Bacillus cereus, Listeria monosytogene), fungi and yeasts (Aspergillus fumigatus, Candida albicans). Results showed that the scanning electron microscopy (SEM) images of fibers had a bead-free and uniform structure. Fourier-transform infrared (FTIR) revealed that ZMEO was encapsulated into PVA through a physical process, without chemical interaction between the ingredients. Strawberries treated with PVA/ZMEO significantly (p < 0.05) preserved the anthocyanin (18.64%), total phenols (12.95%), antioxidant (22.72%), soluble solids (6.44%), titratable acidity (20.88%), firmness (27.2%), and color (15.55%) compared to the control sample during 15 days of cold storage. According to these findings, electrospinning was an efficient method for encapsulating bioactive compounds. ZMEO loaded into PVA fiber delayed the physiological and biochemical changes of fruits and extended the fruit's shelf-life. This study revealed the benefits of incorporating ZMEO into PVA fiber mats, which could lead to new possibilities for active packaging.

A comprehensive review of nano-delivery system for tea polyphenols: Construction, applications, and challenges

Tea polyphenols (TPs) are important bioactive compounds in tea and have excellent physiological regulation functions. However, the extraction and purification of TPs are key technologies affecting their further application, and the chemical instability, poor bioavailability of TPs are major challenges for researchers. In the past decade, therefore, research and development of advanced carrier systems for the delivery of TPs has been greatly promoted to improve their poor stability and poor bioavailability. In this review, the properties and function of TPs are introduced, and the recent advances in the extraction and purification technologies are systematically summarized. Particularly, the intelligent delivery of TPs via novel nano-carriers is critically reviewed, and the application of TPs nano-delivery system in medical field and food industry is also described. Finally, the main limitations, current challenges and future perspectives are highlighted in order to provide research ideas for exploiting nano-delivery carriers and their application in TPs.

Ultrasound-assisted development and characterization of novel polyphenol-loaded pullulan/trehalose composite films for fruit preservation

A novel food packaging film was developed by incorporating a tea polyphenols-loaded pullulan/trehalose (TP@Pul/Tre) into a composite film with ultrasound-assisted treatment of dual-frequency (20/35 kHz, 40 W/L) for 15 min to assess the physicochemical and mechanical properties of a composite film. The optimized ultrasound-assisted significantly increases elongation at break, tensile strength, and improves the composite film's UV/water/oxygen barrier properties. Structure analysis using attenuated total reflectance-Fourier transform infrared, X-ray diffraction and thermal stability revealed that these improvements were achieved through ultrasound-enhanced H-bonds, more ordered molecular arrangements, and good intermolecular compatibility. Besides, the ultrasound-assisted TP@Pul/Tre film has proven to have good antibacterial performance against Escherichia coli and Staphylococcus aureus, with approximately 100 % lethality at 4 h and 8 h, respectively. Moreover, the ultrasound-assisted TP@Pul/Tre film effectively delayed moisture loss, oxidative browning, decay, and deterioration in fresh-cut apples and pears, thereby extending their shelf life. Thus, ultrasound has proved to be an effective tool for improving the quality of food packaging films, with a wide range of applications.

Recent Advances in Natural Polyphenol Research

Polyphenols are secondary metabolites produced by plants, which contribute to the plant's defense against abiotic stress conditions (e.g., UV radiation and precipitation), the aggression of herbivores, and plant pathogens. Epidemiological studies suggest that long-term consumption of plant polyphenols protects against cardiovascular disease, cancer, osteoporosis, diabetes, and neurodegenerative diseases. Their structural diversity has fascinated and confronted analytical chemists on how to carry out unambiguous identification, exhaustive recovery from plants and organic waste, and define their nutritional and biological potential. The food, cosmetic, and pharmaceutical industries employ polyphenols from fruits and vegetables to produce additives, additional foods, and supplements. In some cases, nanocarriers have been used to protect polyphenols during food processing, to solve the issues related to low water solubility, to transport them to the site of action, and improve their bioavailability. This review summarizes the structure-bioactivity relationships, processing parameters that impact polyphenol stability and bioavailability, the research progress in nanocarrier delivery, and the most innovative methodologies for the exhaustive recovery of polyphenols from plant and agri-waste materials.

Electro Fluid Dynamics: A Route to Design Polymers and Composites for Biomedical and Bio-Sustainable Applications

In the last two decades, several processes have been explored for the development of micro and/or nanostructured substrates by sagely physically and/or chemically manipulating polymer materials. These processes have to be designed to overcome some of the limitations of the traditional ones in terms of feasibility, reproducibility, and sustainability. Herein, the primary aim of this work is to focus on the enormous potential of using a high voltage electric field to manipulate polymers from synthetic and/or natural sources for the fabrication of different devices based on elementary units, i.e., fibers or particles, with different characteristic sizes—from micro to nanoscale. Firstly, basic principles and working mechanisms will be introduced in order to correlate the effect of selected process parameters (i.e., an applied voltage) on the dimensional features of the structures. Secondly, a comprehensive overview of the recent trends and potential uses of these processes will be proposed for different biomedical and bio-sustainable application areas.

New perspectives on electrospun nanofiber applications in smart and active food packaging materials

Packaging plays a critical role in determining the quality, safety, and shelf-life of many food products. There have been several innovations in the development of more effective food packaging materials recently. Polymer nanofibers are finding increasing attention as additives in packaging materials because of their ability to control their pore size, surface energy, barrier properties, antimicrobial activity, and mechanical strength. Electrospinning is a widely used processing method for fabricating nanofibers from food grade polymers. This review describes recent advances in the development of electrospun nanofibers for application in active and smart packaging materials. Moreover, it highlights the impact of these nanofibers on the physicochemical properties of packaging materials, as well as the application of nanofiber-loaded packaging materials to foods, such as dairy, meat, fruit, and vegetable products.

Encapsulation of Caffeic Acid in Carob Bean Flour and Whey Protein-Based Nanofibers via Electrospinning

The purpose of this study was to introduce caffeic acid (CA) into electrospun nanofibers made of carob flour, whey protein concentrate (WPC), and polyethylene oxide (PEO). The effects of WPC concentration (1% and 3%) and CA additions (1% and 10%) on the characteristics of solutions and nanofibers were investigated. The viscosity and electrical conductivity of the solutions were examined to determine characteristics of solutions. Scanning electron microscopy (SEM), X-ray diffraction (XRD), thermogravimetric analyzer (TGA), differential scanning calorimetry (DSC), water vapor permeability (WVP), and Fourier transform infrared (FTIR) analysis were used to characterize the nanofibers. According to the SEM results, the inclusion of CA into nanofibers resulted in thinner nanofibers. All nanofibers exhibited uniform morphology. CA was efficiently loaded into nanofibers. When CA concentrations were 1% and 10%, loading efficiencies were 76.4% and 94%, respectively. Nanofibers containing 10% CA demonstrated 92.95% antioxidant activity. The results indicate that encapsulating CA into carob flour–WPC-based nanofibers via electrospinning is a suitable method for active packaging applications.

Development and Characterization of Pullulan-Carboxymethyl Cellulose Blend Film for Packaging Applications

Edible packaging materials have widespread applications in pharmaceutical industries. In this study, the physical, thermal, colour, mechanical, and water barrier properties of a novel edible film based on pullulan (PUL) and carboxymethyl cellulose (CMC) were investigated. The blend films were made by the solution casting method with 3 g of total solid content. The following percentages of 100/0, 75/25, 50/50, 25/75, and 0/100 were used to prepare the films. Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), and thermogravimetric analysis (TGA) were used to analyze the interaction between PUL and CMC. At the level of 75/25 percentage of PUL, CMC film showed the lowest EAB% (5.55%), the highest values for TS (17.30 MPa), WVP value ( $4.12\times {10}^{-10}$  g m-1s-1Pa-1), and water contact angle of 63.43°. By increasing the CMC concentration, blend films became slightly greenish and yellowish but appeared transparent with UV blocking ability. This study reveals that 75/25 (PUL/CMC) blend film has a good potential that can be used in producing edible packaging films to protect the quality of pharmaceutical products with interesting specifications.

Characterization of glycosylated gelatin/pullulan nanofibers fabricated by multi-fluid mixing solution blow spinning

In this work, multi-fluid mixing solution blow spinning was applied to develop gelatin/pullulan composite nanofibers, and then the nanofibers were glycated to enhance the physical properties. The results show that the grafting degree of the nanofibers increased significantly from 17.5 % to 36.0 % as the glycation time increased, and the morphology results indicated that 72 h of glycation did not destroy the structure of the nanofibers. FTIR results show that the glycation consumed the the-NH₂ groups, cleaved sugar units of polysaccharide, and affected the secondary structure of the protein. The glycation enhanced the thermal stability and improved the rigidity of the nanofibers. Besides, after 120 h of glycation, the water contact angle of nanofibers increased from 0° to 79.1°, and the water vapor transmission rates decreased from 12.49 to 8.97 g mm/m² h kPa, indicating the enhanced hydrophobicity and barrier properties. In addition, the glycation improved the water stability of the nanofibers, which increased the applicability of the gelatin/pullulan nanofibers in food packaging. The present work provides a green and efficient method for improving the physical properties of gelatin/pullulan nanofibers.

Electrospinning as a Promising Process to Preserve the Quality and Safety of Meat and Meat Products

Fresh and processed meat products are staple foods worldwide. However, these products are considered perishable foods and their deterioration depends partly on the inner and external properties of meat. Beyond conventional meat preservation approaches, electrospinning has emerged as a novel effective alternative to develop active and intelligent packaging. Thus, this review aims to discuss the advantages and shortcomings of electrospinning application for quality and safety preservation of meat and processed meat products. Electrospun fibres are very versatile, and their features can be modulated to deliver functional properties such as antioxidant and antimicrobial effects resulting in shelf-life extension and in some cases product quality improvement. Compared to conventional processes, electrospun fibres provide advantages such as casting and coating in the fabrication of active systems, indicators, and sensors. The approaches for improving, stabilizing, and controlling the release of active compounds and highly sensitive, rapid, and reliable responsiveness, under changes in real-time are still challenging for innovative packaging development. Despite their advantages, the active and intelligent electrospun fibres for meat packaging are still restricted to research and not yet widely used for commercial products. Industrial validation of lab-scale achievements of electrospinning might boost their commercialisation. Safety must be addressed by evaluating the impact of electrospun fibres migration from package to foods on human health. This information will contribute into filling knowledge gaps and sustain clear regulations.

Preparation and characterization of Sparassis latifolia β-glucan microcapsules

In order to effectively protect the biological activity of Sparassis latifolia β-glucan, improve its stability, and realize its high-value utilization, single-factor test and orthogonal test were carried out to optimize the microencapsulation conditions of S. latifolia β-glucan prepared using spray drying method. The β-glucan microcapsules were characterized by scanning electron microscopy, thermogravimetric analysis, Fourier-transform infrared spectroscopy, and laser particle size analyzer. The results showed that the optimal microencapsulation conditions were as follows: maltodextrin and whey protein with a mass ratio of 1:2, core and wall material with a mass ratio of 1:2, and monoglyceride and core material with a mass percentage of 0.3. Under these conditions, the powder yield and embedding rate of β-glucan microcapsules were 47.32 ± 0.58% and 86.76 ± 1.19%, respectively. The preparation technique was proved to be stable. The β-glucan microcapsules were spherical particles, with the characteristics of a smooth surface, no cracks. The particle size of microcapsules was smaller, and its Dv (50) was 8.43 µm. The distribution of microcapsules was more uniform, and its uniformity was 0.503. The good embedding performance and high thermal stability can effectively protect the biological activity of the core material.

Preparation and characterization of gelatin/zein nanofiber films loaded with perillaldehyde, thymol, or ɛ-polylysine and evaluation of their effects on the preservation of chilled chicken breast

Three edible food packaging films loaded with perillaldehyde (P), thymol (T), or ɛ-polylysine (ɛ-PL) in gelatin/zein (G/Z) nanofibers were prepared and characterized. Their effects on the preservation of chilled chicken breast were evaluated. Results showed that the addition of perillaldehyde, thymol, and ɛ-polylysine improved the morphology and diameter of the G/Z. Loading with perillaldehyde improved the elongation and tensile strength of the G/Z/P by 18% and 55%, respectively. The water vapor permeability and oxygen permeability of the G/Z/P were lower than those of the G/Z/T and G/Z/ɛ-PL. X-ray diffraction, differential scanning calorimetry suggested that perillaldehyde enhanced the thermal stability of the G/Z/P. Measurements of 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), total volatile basic nitrogen, and total viable bacterial counts demonstrated that the G/Z/P had good bio-compatibility and effectively prolonged the shelf life of chilled chicken breasts by over 6 days. Therefore, the G/Z/P developed herein has potential application in chilled meat packaging.

Downstream processing and structural confirmation of pullulan - A comprehensive review

Pullulan is a microbial polymer, commercially produced from Aureobasidium pullulans. Downstream processing of pullulan involves a multi-stage process which should be efficient, safe and reproducible. In liquid-liquid separations, firstly cell free extract is separated. Cell biomass can be separated after fermentation either by centrifugation or filtration. Due to practically insolubility of pullulan in organic solvents, ethanol and isopropanol are the most commonly used organic solvents for its recovery. Pullulan can also be purified by chromatographic techniques, but these are not cost effective for the purification of pullulan. Efficient aqueous two-phase system can be used for the purification of pullulan. The current review describes the methods and perspectives used for solid-liquid separation, liquid-liquid separations and finishing steps for the recovery of pullulan. Techniques used to determine the structural attributes of pullulan have also been highlighted.

Nanoencapsulation of casein-derived peptides within electrospun nanofibres

BACKGROUND

Bioactive peptides derived from milk proteins are recognized as functional foods, but their consumption is limited by undesirable or bitter flavour, poor stability, and low bioavailability. Electrospinning is a versatile process for encapsulation of various bioactive compounds in the form of nanosized fibres, which can circumvent these disadvantages. This study was aimed at the preparation of casein-derived peptides-loaded nanofibres through electrospinning and characterizing them for fortification of milk.

RESULTS

Pullulan at 100, 120, and 140 g kg^-1 concentrations was used for electrospinning of peptides. Scanning electron and atomic force micrographs revealed the formation of clean bead-free peptides-loaded pullulan nanofibres at 120 and 140 g kg^-1 concentrations with mean diameter of 60.45-133.05 nm and encapsulation efficiency of 72.95-86.04%. Fourier transform infrared spectra and X-ray diffractograms revealed the absence of interactions between the functional groups of pullulan and peptides during electrospinning. The zeta potential of the peptides-loaded nanofibres ranged from -15.6 to -24.6 mV, and the hydrodynamic diameter varied from 118.7 to 256.2 nm. The peptides from electrospun nanofibres showed sustained release to the extent of 75.3% after 8 h in gastrointestinal pH conditions. The release kinetics of peptides from nanofibres was best fitted to a Peppas-Sahlin model (R²  = 0.987), and through diffusion and erosion mechanisms. The antioxidant activity of pure peptides and those from nanofibres was comparable. The physico-chemical qualities of milk fortified with encapsulated peptides did not show noticeable difference either.

CONCLUSIONS

From the morphological, ultrastructural, particle size, encapsulation efficiency, release kinetics, and antioxidant activity data, it was inferred that electrospinning could be an effective technique for nanoencapsulation of casein-derived bioactive peptides. These peptides-loaded nanofibres could be used for fortification of milk and milk products. © 2021 Society of Chemical Industry.

Kinetic Study of Encapsulated β-Carotene Degradation in Dried Systems: A Review

β-Carotene serves as a precursor of vitamin A and provides relevant health benefits. To overcome the low bioavailability of β-carotene from natural sources, technologies have been designed for its encapsulation in micro- and nano-structures followed by freeze-drying, spray-drying, supercritical fluid-enhanced dispersion and electrospraying. A technological challenge is also to increase β-carotene stability, since due to its multiple conjugated double bonds, it is particularly prone to oxidation. This review analyzes the stability of β-carotene encapsulated in different dried micro- and nano-structures by comparing rate constants and activation energies of degradation. The complex effect of water activity and glass transition temperature on degradation kinetics is also addressed, since the oxidation process is remarkably dependent on the glassy or collapsed state of the matrix. The approaches to improve β-carotene stability, such as the development of inclusion complexes, the improvement of the performance of the interface between air and oil phase in which β-carotene was dissolved by application of biopolymer combinations or functionalization of natural biopolymers, the addition of hydrophilic small molecular weight molecules that reduce air entrapped in the powder and the co-encapsulation of antioxidants of various polarities are discussed and compared, in order to provide a rational basis for further development of the encapsulation technologies.

Nano-Strategies for Enhancing the Bioavailability of Tea Polyphenols: Preparation, Applications, and Challenges

Tea polyphenols (TPs) are among the most abundant functional compounds in tea. They exhibit strong antioxidant, anti-inflammatory, and anti-cancer effects. However, their instability and low bioavailability limits their applications. Nanotechnology, which involves the use of nanoscale substances (sizes ranging from 1 to 100 nm) to improve the properties of substances, provides a solution for enhancing the stability and bioavailability of TPs. We reviewed the preparation, performance, effects, and applications of different types of TPs nanocarriers. First, we introduced the preparation of different nanocarriers, including nanoparticles, nanoemulsions, nanomicelles, and nanolipids. Then, we discussed various applications of tea polyphenol-loaded nanocarriers in functional ingredient delivery, food quality improvement, and active food packaging. Finally, the challenges and future development directions of TPs nanocarriers were elucidated. In conclusion, a nano-strategy may be the “key” to break the application barriers of TPs. Therefore, the use of nano-strategies for the safe, stable, and efficient release of TPs is the direction of future research.