Application of electrospinning to fabricate phycocyanin- and Spirulina extract-loaded gliadin fibers for active food packaging.

This study explored the active food packaging application of phycocyanin- and Spirulina extract-loaded gliadin electrospun fibers (GPhy and GSPE5%). SEM findings confirmed that the morphology of fibers was tubular, showing the GPhy and GSPE5% as the optimum fibers. The loading efficiencies of GPhy and GSPE5% were also around 90%, which proved the well-incorporated compounds within the fibers. Simulation results of α-gliadin dissolved in acetic acid illustrated the denaturation of the protein. FTIR and TGA confirmed that after electrospinning the chemical/structural changes and enhanced thermostabilities occurred, respectively. Antibacterial and antioxidant tests detected higher bactericidal and antioxidative effects of GSPE5% than GPhy. In the application part, it was found that GPhy and GSPE5% were able to decrease PV and TBA values as the indications of walnut kernels' protection from lipid oxidation. This work shows a facile and an efficient way to fabricate active food packaging materials using electrospinning and natural compounds.

Integration of physicochemical, molecular dynamics, and in vitro evaluation of electrosprayed γ-oryzanol-loaded gliadin nanoparticles.

Electrospraying is a technique to improve the application and stability of bioactive compounds in food. Here, electrospraying was applied to fabricate gliadin particles incorporated γ-oryzanol. The round particles were obtained, with an average diameter of 481.56 ± 283.74 nm, from scanning electron microscopy. Simulations demonstrated how γ-oryzanol-loaded gliadin particles were unfolded in acetic acid and culminated in their globular shape under an electric field. The results also revealed that γ-oryzanol was present in gliadin particles. Moreover, there was a successful formation of particles with a homogeneous distribution and an enhanced thermostabilization of γ-oryzanol. In food simulants, γ-oryzanol demonstrated an initial burst release, followed by a subsequent, slower release that occurred gradually. Finally, MTT assays showed concentration- and time-dependent inhibitions of γ-oryzanol-loaded gliadin particles on HT-29 cells, with IC50 values of 0.47 and 0.40 mg/mL for 24 and 48 h, respectively. This study described a protocol for developing γ-oryzanol-loaded gliadin particles with enhanced stability, valuable release-behavior, and decreased HT-29 proliferation.

On the Use of Persian Gum for the Development of Antiviral Edible Coatings against Murine Norovirus of Interest in Blueberries.

In the last decades, berries have been identified as important vehicles for the transmission of foodborne viruses and different strategies are being explored to eliminate or reduce viral contamination in these fruits. The aim of this work was to develop novel edible coatings with antiviral properties for inactivating and reducing murine norovirus (MNV). Firstly, the effect of gelatin (G) addition on Persian gum (PG) films was studied in terms of microstructural, mechanical, optical, and water barrier properties. The following PG:G ratios were considered: 100:0, 75:25, 50:50, 25:75, and 0:100. Microstructure analysis revealed the compatibility of both hydrocolloids since no phase separation was observed. The addition of G to PG films provided stiffer and more deformable films than pure PG, with lower water vapor permeability values. Specifically, films prepared with 50:50 PG:G ratio presented better mechanical and barrier performance. Interestingly, pure PG showed antiviral activity on murine norovirus, probably due to the presence of some impurities (mainly tannins). Adding allyl isothiocyanate (AITC) enhanced the PG antiviral activity at refrigerated temperatures in blueberries, not being affected by the AITC concentration. This effect was not observed at ambient temperature, probably due to the volatilization of AITC.

Nano/microencapsulation of anthocyanins; a systematic review and meta-analysis.

Anthocyanins, a kind of phenolic compounds are present in plant kingdom. They exhibit biological activities such as anti-inflammatory and anti-cancer properties as well as imparting colors to various plants. The objective of this review is to provide a systematic evaluation of the evidence and a meta-analysis of published researches on the nano/microencapsulation of anthocyanins. A comprehensive literature search was conducted for articles published in 2016 to 2019 on PubMed, Web of Sciences and Scopus databases. Overall 45 eligible articles (51 cases; some authors studied 2 or more encapsulation methods) with appropriate data were included in the statistical analysis. In the current work, based on the technique and equipment applied for the formulation of micro/nanoencapsulation systems, the anthocyanin-loaded nano/microcarriers were classified into five main classes: (a) spray dried particles (spray-drying); (b) freeze-dried particles (freeze-drying); (c) lipid-based particles (emulsification and liposomal encapsulation); (d) electrospun fibers and electrosprayed particles (electrohydrodynamic encapsulation); and (e) nano/micro-gels (gelation). Based on the results from the meta-analysis, the studied technique for encapsulation of anthocyanins can be ordered as: spray-drying (33.33%), freeze-drying (27.08%), gelation (20.83%), lipid-based particles (14.58%) and electrohydrodynamic processes (4.17%). In addition, carbohydrates such as maltodextrin (19.56%) and gums (15.22%) have been the most frequently used biopolymers for encapsulation of anthocyanins in the selected studies.

Food-grade gliadin microstructures obtained by electrohydrodynamic processing.

This paper presents a comprehensive study on the electrohydrodynamic processing of gliadin to develop food-grade delivery systems with different morphologies. The effects of biopolymer concentration, applied voltage and solution flow-rate on particle morphology, molecular organisation, crystallinity and thermal properties were investigated. Gliadin concentration influenced the apparent viscosity and conductivity of the solutions, giving raise to particle morphologies at 10 wt% gliadin and beaded-free fibers above 25 wt% gliadin. In general, increasing the voltage resulted in smaller average sizes of the obtained structures, while no significant differences in morphology were observed among the tested flow rates. Interestingly, the amide I position in the FTIR reflected changes in protein conformation which could be correlated with the final morphology attained. Moreover, the acetic acid used for solution preparation disrupted the original amino acid chain packing of the gliadin fraction, being the electrospun/electrosprayed samples amorphous. These gliadin-based microparticles and microfibers obtained could serve as food-grade delivery vehicles.

Active Food Packaging Coatings Based on Hybrid Electrospun Gliadin Nanofibers Containing Ferulic Acid/Hydroxypropyl-Beta-Cyclodextrin Inclusion Complexes.

In this work, hybrid gliadin electrospun fibers containing inclusion complexes of ferulic acid (FA) with hydroxypropyl-beta-cyclodextrins (FA/HP-ß-CD-IC) were prepared as a strategy to increase the stability and solubility of the antioxidant FA. Inclusion complex formation between FA and HP-ß-CD was confirmed by Fourier transform infrared spectroscopy (FTIR), differential scanning calorimeter (DSC), and X-ray diffraction (XRD). After adjusting the electrospinning conditions, beaded-free fibers of gliadin incorporating FA/HP-ß-CD-IC with average fiber diameters ranging from 269.91 ± 73.53 to 271.68 ± 72.76 nm were obtained. Control gliadin fibers containing free FA were also produced for comparison purposes. The incorporation of FA within the cyclodextrin molecules resulted in increased thermal stability of the antioxidant compound. Moreover, formation of the inclusion complexes also enhanced the FA photostability, as after exposing the electrospun fibers to UV light during 60 min, photodegradation of the compound was reduced in more than 30%. Moreover, a slower degradation rate was also observed when compared to the fibers containing the free FA. Results from the release into two food simulants (ethanol 10% and acetic acid 3%) and PBS also demonstrated that the formation of the inclusion complexes successfully resulted in improved solubility, as reflected from the faster and greater release of the compounds in the three assayed media. Moreover, in both types of hybrid fibers, the antioxidant capacity of FA was kept, thus confirming the suitability of electrospinning for the encapsulation of sensitive compounds, giving raise to nanostructures with potential as active packaging structures or delivery systems of use in pharmaceutical or biomedical applications.