Biological and thermodynamic stabilization of lipid-based delivery systems through natural biopolymers; controlled release and molecular dynamics simulations.

Nowadays, the use of lipid-based nanocarriers for the targeted and controlled delivery of a variety of hydrophobic and hydrophilic bioactive-compounds and drugs has increased significantly. However, challenges such as thermodynamic instability, oxidation, and degradation of lipid membranes, as well as the unintended release of loaded compounds, have limited the use of these systems in the food and pharmaceutical industries. Therefore, the present study reviews the latest achievements in evaluating the characteristics, production methods, challenges, functional, and biological stabilization strategies of lipid-based carriers (including changes in formulation composition, structural modification, membrane-rigidity, and finally monolayer or multilayer coating with biopolymers) in different conditions, as well as molecular dynamics simulations. The scientists' findings indicate the effect of natural biopolymers (such as chitosan, calcium alginate, pectin, dextran, xanthan, caseins, gelatin, whey-proteins, zein, and etc.) in modifying the external structure of lipid-based carriers, improving thermodynamic stability and resistance of membranes to physicochemical and mechanical tensions. However, depending on the type of bioactive compound as well as the design and production goals of the delivery-system, selecting the appropriate biopolymer has a significant impact on the stability of vesicles and maintaining the bioaccessibility of the loaded-compounds due to the stresses caused by the storage-conditions, formulation, processing and gastrointestinal tract.

Preparation, characterization and release behavior of chitosan-coated nanoliposomes (chitosomes) containing olive leaf extract optimized by response surface methodology.

This study was dedicated to the optimization and preparation of chitosan-coated liposomes (chitosomes) as promising nanocarriers for retention of olive leaf extract optimized by Response surface methodology (RSM) based on central composite design. Accordingly, the best sample was chosen for further tests with the encapsulation efficiency, stability and electrical conductivity of 94%, 98% and 9.545 mS respectively. The average size of the optimal chitosome and nanoliposome were lower than 100 nm and the zeta potential was altered from a negative charge to positive after addition coating process with chitosan. Moreover, the differential scanning calorimetry of blank and loaded chitosome revealed the increase of fluidity and lower temperature of phase transition in loaded chitosome compared to blank one. FTIR spectra demonstrated that electrostatic interactions and hydrogen bonds occur between phospholipid polar groups, chitosan amine moieties and major olive leaf extract polyphenols including oleuropein and hydroxy tyrosol. Furthermore, the optimal loaded chitosome had the highest stability during 25 days at the temperature of 4 °C. Finally, the in vitro release tests were best fitted with Peppas-Sahlin and Kopcha models in food simulants and gastrointestinal simulated juice respectively revealing erosion-based release model. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at (10.1007/s13197-021-04972-2).

Inorganic and metal nanoparticles and their antimicrobial activity in food packaging applications.

Nanotechnology has revolutionized almost all the fields of science and technology, particularly the food packaging industry. Accordingly, some nanoparticles can be used in food contact materials to preserve food products for longer periods. To date, many inorganic and metal nanoparticles have been implemented to synthesize active food packaging materials and to extend the shelf-life of foods. Packaging with nanocomposites containing these nanoparticles offers advantages, such as reduction in the usage of preservatives and higher rate of reactions to inhibit the microbial growth. Nevertheless, the safety issues of employing the metal and inorganic nanoparticles in food packaging are still a major concern and more studies along with clinical trials need to be carried out prior to the mass production of these promising food containers. In this review, we have evaluated recent studies plus the applications of inorganic and metal nanoparticles mostly in food packaging applications along with their antimicrobial properties and reaction mechanisms. Many examples have been provided with the aim of opening new horizons for researchers to implement inorganic and metal nanoparticles in active food packaging field.

Nutritional, biological, and structural properties of bioactive peptides from bellflower, Persian-willow, and bitter-orange pollens.

In this study, the composition of amino acids, nutritional characteristics, degree of hydrolysis (DH), antioxidant properties, and antibacterial activity of proteins and hydrolysates of bellflower (Campanula latifolia), Persian willow (Salix aegyptiaca), and bitter orange (Citrus aurantium L.) were investigated under the influence of different proteases (Alcalase: Al, trypsin: Tr, pancreatin: Pa, and pepsin: Pe). Evaluation of the structural features of the proteins showed amide regions (amide A, B, I-III) and secondary structures. Hydrophobic amino acids (∼38%), antioxidants (∼21%), and essential types (∼46%) form a significant part of the structure of flower pollen. The digestibility and nutritional quality (PER) of the hydrolyzed samples (CP: 1.67; CA: 1.89, and PW: 1.93) were more than the original protein. Among proteins and peptides, the highest degree of hydrolysis (34.6%: Al-PWH), inhibition of free radicals DPPH (84.2%: Al-CPH), ABTS (95.2%: Pa-CPH), OH (86.7%: Tr-CAH), NO (57.8%: Al-CPH), reducing power (1.31: Pa-CPH), total antioxidant activity (1.46: Pa-CPH), and chelation of iron ions (80%: Al-CPH and Al-CAH) and copper (50.3%: Pa-CAH) were affected by protein type, enzyme type, and amino acid composition. Also, the highest inhibition of the growth of Escherichia coli (25 mm) and Bacillus cereus (24 mm) were related to CP and PW hydrolysates, respectively. The results of this research showed that hydrolyzed flower pollens can be used as a rich source of essential amino acids as well as natural antioxidants and antibacterial in food and dietary products. PRACTICAL APPLICATION: Enzymatic hydrolysis of Campanula latifolia, Persian willow, and Citrus aurantium pollen proteins was performed. The hydrolyzed ones had high nutritional quality and digestibility (essential amino acids and PER index). Antioxidant properties and chelation of metal ions of peptides were affected by the type of protein and enzyme. The hydrolysates showed inhibitory activity against the growth of Esherichia coli and Bacillus cereus.

A critical review on approaches to regulate the release rate of bioactive compounds from biopolymeric matrices.

Recently, there has been a growing interest in novel food formulations and packaging materials using controlled release systems in order to enhance the functional performance of food bioactive ingredients and to prolong the shelf-life of food products. Correspondingly, numerous types of matrices (polymers, biopolymers, synthetic materials) could be implemented as carriers based on their compatibility with the bioactive ingredients and the type of releasing medium. A plethora of applications of controlled release can be identified in the pharmaceutical, agriculture, cosmetics, and particularly the food industries. Moreover, several physical and chemical stimuli are applied to regulate the release behavior of a bioactive molecule in the desired medium, which is under development. This review highlights the strategies applied to regulate the release rate of biopolymeric networks mainly including mixing of biopolymers, physical and chemical crosslinkers along with encapsulation systems, furthermore, the future prospects of release concept are discussed.

Review on Approved and Inprogress COVID-19 Vaccines.

The last generation of Coronavirus named COVID-19 is responsible for the recent worldwide outbreak. Concerning the widespread and quick predominance, there is a critical requirement for designing appropriate vaccines to surmount this grave problem. Correspondingly, in this revision, COVID-19 vaccines (which are being developed until March 29th, 2021) are classified into specific and non-specific categories. Specific vaccines comprise genetic-based vaccines (mRNA, DNA), vector-based, protein/recombinant protein vaccines, inactivated viruses, live-attenuated vaccines, and novel strategies including microneedle arrays (MNAs), and nanoparticles vaccines. Moreover, specific vaccines such as BCG, MRR, and a few other vaccines are considered Non-specific. What is more, according to the significance of Bioinformatic sciences in the cutting-edge vaccine design and rapid outbreak of COVID-19, herein, Bioinformatic principles including reverse vaccinology, epitopes prediction/selection and, their further applications in the design of vaccines are discussed. Last but not least, safety, challenges, advantages, and future prospects of COVID-19 vaccines are highlighted.

Strategies of confining green tea catechin compounds in nano-biopolymeric matrices: A review.

Catechins are polyphenolic compounds which abundantly occur in the plants, especially tea leaves. They are widely used in nutraceutical and pharmaceutical formulations due to their capability of lowering the risk of developing various diseases. Nevertheless, low stability, loss of antioxidant and antimicrobial activities hinder the direct application of catechins in food formulations. To surmount this pervasive challenge, bioactive ingredients should be entrapped in a biopolymeric matrix. Thus, nanoencapsulation technology would be an appropriate strategy to improve the stability of these bioactive compounds and to protect them against degradation. Among different types of nanocarriers, biopolymer-based nanovehicles has captured a lot of attention in both industry and academia due to their safety and biocompatibility. This revision enlarges upon the various types of biopolymeric nanostructures used for accommodation of catechins, namely nanogels, nanotubes, nanofibers, nanoemulsions and nanoparticles. Last but not least, the applications of the entrapped catechins in the food industry are highlighted.

Nanoliposomal encapsulation of saffron bioactive compounds; characterization and optimization.

Nanoliposomes are among the most important lipid-based nanocarriers for both hydrophilic and hydrophobic bioactives. In this study, saffron-loaded nanoliposomes were produced by evaluating the influence of lecithin (0.5, 1.0, 1.5% w/w), saffron extract (0.15, 0.33, 0.50% w/w), and sunflower oil (25, 30, 35% w/w) on encapsulation efficiency, creaming stability, size and color indices of nanoliposomes. For each response, a second-order polynomial model with a high R2 value (0.950-0.989) was obtained using multiple linear regression analysis. The creaming stability revealed that when oil and saffron contents are enhanced, lecithin level was not enough for the formation of a stable network (reduction of surface tension) and thus stability was lowered. Dynamic light scattering results demonstrated nanoliposomal size of around 100 nm and polydispersity index (PDI) of 98.12 ± 0.11. Moreover, transmission electron microscopy (TEM) images illustrated spherical particles with a homogenous distribution and smooth surfaces. Also, lecithin level (P < 0.01), and saffron concentration (P < 0.05) significantly influenced the color indices, while sunflower oil content had no significant effect. Overall, the optimization results revealed that 0.15% saffron, 35% sunflower oil, and 1% lecithin was the optimum sample in terms of encapsulation efficiency, size and color indices.

Spectroscopic, molecular docking and molecular dynamic simulation studies on the complexes of ß-lactoglobulin, safranal and oleuropein.

Herbal bioactive compounds have captured pronounced attention considering their health-promoting effects as well as their functional properties. In this study, the binding mechanism between milk protein bovine ß-lactoglobulin (ß-LG), oleuropein (OLE) and safranal (SAF) found in olive leaf extract and saffron, respectively via spectroscopic and in silico studies. Fluorescence quenching information exhibited that interactions with both ligands were spontaneous and hydrophobic interactions were dominant. Also, the CD spectroscopy results demonstrated the increase in ß-sheet structure and decrease in the α-helix content for both ligands. Size of ß-LG-OLE complex was higher than ß-LG-SAF due to the conformation and larger molecular size. Molecular docking and simulation studies revealed that SAF and OLE bind in the central calyx of ß-LG and the surface of ß-LG next to hydrophobic residues. Lastly, OLE formed a more stabilized complex compared to SAF based on the molecular dynamic simulation results.

Protein nanotubes as state-of-the-art nanocarriers: Synthesis methods, simulation and applications.

Application of food proteins as a tool to form nanostructures (especially nanotubular shapes) has been an interesting topic for both the food and pharmaceutical sectors. Organic and protein nanostructures have better biocompatibility and biodegradability compared to inorganic counterparts like carbon nanotubes; in addition, they can undergo surface modifications. Several organic nanotubes have been developed, meanwhile, the engineered protein nanotubes in the food science have been prepared from α-lactalbumin, ovalbumin, cyclic peptide nanotubes, collagen, bovine serum albumin, lysozyme and hydrophobins which are of great interest to be applied in the food industry considering their outstanding properties. This revision underlines the production of protein nanotubular structures and their applications as well as introducing the in silico studies which is a novel field in predicting the interactions of proteins with different molecules before running experimental tests and finally exploring the safety of protein nanotubes. Protein nanotubes have several advantages over other morphologies, such as the functionalizing ability of both the outer and inner layers, enabling an efficient delivery and controlled release and their ability as gelling agents. Also, regarding their natural source in foods, they are promising alternatives to carbon nanotubes.

Evaluation of Physicochemical and Antioxidant Properties of Yogurt Enriched by Olive Leaf Phenolics within Nanoliposomes.

Olive leaf extract is a rich source of phenolic compounds and oleuropein which is well-known regarding its antioxidant and antimicrobial attributes. However, the mentioned phenolic compounds will lose their beneficial properties during storage and induce undesirable aftertaste in food products. In this study, olive leaf extract-bearing nanoliposomes were produced via the ethanol injection method and using phosphatidyl choline plus cholesterol as the reagents for the wall material. Later, the prepared nanocarriers were examined in regard to their zeta potential, stability, encapsulation efficiency, and particle size. Moreover, the prepared nanoliposome-loaded yogurt samples were examined considering syneresis, antioxidant activity, pH, acidity, color, and sensorial properties. The mean particle size of the fabricated nanoliposomes was in the range of 25-158 nm. Also, the entire formulation had a negative charge. The encapsulation efficiency was between 70.7 to 88.2%. Besides, the application of nanoliposomes in yogurt improved the antioxidant activity, and unlike the yogurt with nonencapsulated olive extract, no significant changes in color and sensorial attributes were observed and even the syneresis rate was minimized. To conclude, olive leaf phenolics can be entrapped within nanoliposomes with a considerable encapsulation efficiency for application in food products like yogurt to increase their nutritional value and public acceptance.