Nanotechnology is an emerging field of science, and nanotechnological concepts have been intensively studied for potential applications in the food industry. Nanoparticles (with dimensions ranging ...from one to several hundred nanometers) have specific characteristics and better functionality, thanks to their size and other physicochemical properties. Polyphenols are recognized as active compounds that have several putative beneficial properties, including antioxidant, antimicrobial, and anticancer activity. However, the use of polyphenols as functional food ingredients faces numerous challenges, such as their poor stability, solubility, and bioavailability. These difficulties could be solved relatively easily by the application of encapsulation. The objective of this review is to present the most recent accomplishments in the usage of polyphenol-loaded nanoparticles in food science. Nanoparticles loaded with polyphenols and their applications as active ingredients for improving physicochemical and functional properties of food, or as components of active packaging materials, were critically reviewed. Potential adverse effects of polyphenol-loaded nanomaterials are also discussed.
The objective of this research was to investigate the impact of high-intensity ultrasound (HIU) generated by a probe-type sonicator (frequency 20 ± 0.2 kHz and an amplitude of 40%) for 2–20 min on ...the selected functional and structural properties of egg white proteins (EWPs) and their susceptibility to hydrolysis by alcalase. The protein solubility, foaming, and emulsifying properties were studied as a function of ultrasonication time and related to protein particle and structural properties. The length of ultrasonication exhibited important effect on EWP particle size, uniformity, and charge, affecting also the protein conformation and susceptibility to alcalase hydrolysis and determining functional properties. There was a linear correlation between the particle size decrease and the solubility while a two-step linear correlation between the foam capacity (FC)/foam stability (FS) and particle size was apparent. Specifically, FC and FS sharply increased with decreasing particle size for range from ∼370 to ∼260 nm, and below this range from 260.6 to 68.4 nm, the changes were not that substantial. Besides, the solubility, FC, and FS were directly and linearly related with the absolute value of the particle zeta potential. The overall emulsifying properties were also improved with an increase of sonication time, through both the decrease of the mean particle diameter and the increase of zeta potential, but there was no direct correlation between the emulsion activity/stability index and protein particle size and/or charge. Analysis of EWP structure by Raman spectroscopy revealed that the HIU leads to changes in the secondary structure, while heat and ultrasound generated by the ultrasound bath were not sufficient to exhibit this effect.
Graphical abstract
The influence of different phospholipid types (pure phospholipids 1‐palmitoyl‐2‐oleoyl‐sn‐glycero‐3‐phosphocholine, POPC, 1,2‐dipalmitoyl‐sn‐glycero‐3‐phosphocholine, DPPC, and one commercial ...phospholipid mixture, Lipoid H100), sterol types (cholesterol vs. β‐sitosterol), and various sterol concentrations (5–50 mol%) on liposomal membrane fluidity, thermotropic properties, liposome size, zeta potential, and lipid oxidation kinetics using fluorescent lipid probe BODIPY 581/591 C11 (4,4‐difluoro‐5‐4‐phenyl‐1,3‐butadienyl‐4‐bora‐3a,4a‐diaza‐s‐indacene‐3‐undecanoic acid) are investigated. DPPC bilayer is more rigid than POPC and phospholipids mixture membranes. Pure DPPC gives the smallest liposomes, while liposomes of Lipoid H100 have the largest diameter. Both sterols reduce membrane fluidity of all liposomes, increase absolute zeta potential, cause significant changes in particle size, and decrease phase transition temperature (Tm) and enthalpy of DPPC. POPC/β‐sitosterol liposomes exhibit the most significant lipid oxidation of the lipophilic probe. Along with beneficial effects of phytosterols on human health, better membrane fluidity, more favorable and stabilizing interactions with phospholipids, smaller vesicle size, and enhanced physical stability in comparison to cholesterol are some of the encouraging results for the use of β‐sitosterol in liposome formulations for potential application in foods, pharmaceutics, and cosmetics.
Practical Applications: Adjusting the composition of liposomal membrane (lipid type, sterol type, and concentration) can be used as a tool to control membrane fluidity, permeability, and thermotropic properties, and thus predict release properties, physical, thermal, and oxidative stability. A commercial phospholipid mixture of different natural phospholipids with impurities creates less uniform liposomal membrane that is characterized by higher fluidity in comparison to DPPC. The type of phospholipid has huge influence on MLVs size. β‐sitosterol, which is a phytosterol with beneficial effects on human health can be used as a replacement for cholesterol in liposomal formulations, but with the following in mind: β‐sitosterol reduces fluidity of the phospholipid bilayer to a lesser extent than cholesterol, β‐sitosterol gives smaller MLVs than cholesterol, DPPC/β‐sitosterol SUVs are bigger than 100 nm in diameter (relevant for intravenous administration), MLVs with ≥30 mol% of β‐sitosterol can be considered as physically stable (unlike those with cholesterol), irrespective to the phospholipid type.
The influence of different phospholipid types, sterol types, and various sterol concentrations on liposomal membrane fluidity, thermo tropic properties, liposomesize, zeta potential, and lipid oxidation kinetics are investigated.
The influence of different phospholipid types, sterol types, and various sterol concentrations on liposomal membrane fluidity, thermo tropic properties, liposomesize, zeta potential, and lipid oxidation kinetics are investigated.
•Antioxidant films based on chitosan or starch containing thyme extract were obtained.•Thyme extract changed the microstructural and physical properties of the films.•Crosslinking between polyphenols ...and chitosan enhanced filḿs mechanical response.•Antioxidant activity of thyme extract was better preserved when using chitosan films.
The aim of this study was to analyse the antioxidant activity of different polymeric matrices based on chitosan and starch, incorporating a thyme extract (TE) rich in polyphenols. TE provided the films with remarkable antioxidant activity. When mixed with chitosan, the polyphenols interacted with the polymer chains, acting as crosslinkers and enhancing the tensile behaviour of films. The opposite effect was observed when incorporated into the starch matrix. All the films became darker, more reddish and less transparent when TE was incorporated. These colour changes were more marked in starch matrices, which suggests that TE compounds were poorly encapsulated. The use of chitosan-based matrices carrying TE polyphenols is recommended as a means of obtaining antioxidant films, on the basis of their tensile response and greater antioxidant activity, which could be associated with the development of polyphenol-chitosan interactions, contributing to a better protection of the functionality of polyphenols during film formation and conditioning.
•Chitosan microbeads were prepared by emulsion crosslinking technique.•Thyme polyphenols were encapsulated by simultaneous swelling/encapsulation processes.•The behavior of microbeads was examined in ...simulated gastrointestinal conditions.•The high loading degree and significant antioxidant potential were achieved.•The obtained encapsulation system can be used as a functional food additive.
In this work chitosan microbeads were prepared by emulsion technique and loaded with thyme polyphenols by diffusion from an external aqueous solution of Thymus serpyllum L. The effects of concentrations of chitosan (1.5–3% (w/v)) and GA (glutaraldehyde) (0.1–0.4% (v/v)), as a crosslinking agent on the main properties of microbeads were assessed. The obtained microgel beads from ∼220 to ∼790μm in diameter were exposed to controlled drying process at air (at 37°C) after which they contracted to irregular shapes (∼70–230μm). The loading of dried microbeads with polyphenols was achieved by swelling in the acidic medium. The swelling rate of microbeads decreased with the increase in GA concentration. Upon this rehydration, thyme polyphenols were effectively encapsulated (active load of 66–114mgGAEgbeads−1) and the microbeads recovered a spherical shape. Both, the increase in the amount of the crosslinking agent and the presence of polyphenols, contributed to a more pronounced surface roughness of microbeads. The release of encapsulated polyphenols in simulated gastrointestinal fluids was prolonged to 3h.
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•The obtained multilamellar vesicles were between 1350 and 1900 nm.•Gentisic acid was effectively encapsulated when nGA/nlip was higher than 0.01.•Suppression of lipid peroxidation ...was directly related to concentration of GA.•Diffusion resistance of GA increased for 50% in samples with 50 mol % β-sitosterol.•GA release in vitro was affected by pH of SGF and the presence of cholates in SIF.
Multifunctional liposomes incorporating β-sitosterol were developed for delivery of gentisic acid (GA). The interactions of both compounds with phospholipid bilayer were interpreted viaeffects of different β-sitosterol content (0, 20 and 50 mol %) and different gentisic acid to lipid ratio (nGA/nlip from 10-5 to 1) on membrane fluidity and thermotropic properties. Multilamellar vesicles of phosphatidylcholines (with size range between 1350 and 1900 nm) effectively encapsulated GA (54%) when nGA/nlip was higher than 0.01. Suppression of lipid peroxidation was directly related to concentration of GA. The resistance to diffusion of gentisic acid from liposomes increased for ˜50% in samples incorporating 50 mol % β-sitosterol compared to sterol-free liposomes. Finally, simulated in vitro gastrointestinal conditions showed that the release was mainly affected by low pH of simulated gastric fluid and the presence of cholates in simulated intestinal fluid, rather than by enzymes activity.
The goal of this study was to investigate the characteristics of grape skin extract (GSE) spray dried with different carriers: maltodextrin (MD), gum Arabic (GA) and skim milk powder (SMP). The grape ...skin extract was obtained from winery by-product of red grape variety
Prokupac
(
Vitis vinifera
L.). The morphology of the powders, their thermal, chemical and physical properties (water activity, bulk and tapped densities, solubility), as well as release studies in different pH conditions were analyzed. Total anthocyanin content and total phenolic content were determined by spectrophotometric methods. MD and GA-based microparticles were non-porous and spherical, while SMP-based ones were irregularly shaped. The process of spray drying
Prokupac
GSE using these three carriers produced powders with low water activity (0.24–0.28), good powder characteristics, high yields, and solubility higher than 90%. The obtained dissolution/release profiles indicated prolonged release of anthocyanins and phenolic compounds in different mediums, especially from GSE/GA microparticles. These results have shown that grape skin as the main by-product of wine production could be used as a source of natural colorants and bioactive compounds, and microencapsulation as a promising technique for the protection of these compounds, their stabilization in longer periods and prolonged release.
Several different methods for production of liposomes incorporating resveratrol were investigated and compared from the aspect of size distribution, surface charge, entrapment efficiency, phase ...behavior and stability. Thin film method and proliposome method provided high entrapment efficiency (92.9% and 97.4%, respectively). Extrusion and sonication techniques were applied to obtain particles of the average diameter between 120 and 270nm. The sonicated liposomes incorporated resveratrol (44–56%) fewer than extruded vesicles (92–96%). Antioxidative activity of resveratrol was retained upon encapsulation. Differential scanning calorimetry was performed in order to study the interaction of liposomal membranes with resveratrol, and their physical state. The release studies performed in Franz diffusion cell showed that liposomes impart slow diffusion of resveratrol, where diffusion resistance derived from liposomal membrane ranged from 5.90∙105 to 9.55∙105s/m depending on the size of particles. Cytotoxicity of the formulations was evaluated via morphological changes of keratinocytes treated by liposomes.
Resveratrol displays many health-beneficial properties and possesses a remarkably strong antioxidant activity. Although often consumed in food, the positive effects of resveratrol are restricted because it is prone to oxidation, poorly absorbed when orally administrated, and cytotoxic in higher total dosages (though relatively high local concentrations are required for an effect). Encapsulation is one way to improve bioavailability and stability of resveratrol; herein the main challenge is to find a suitable solution, as resveratrol is weakly water soluble. This has motivated us to design new formulations based on liposomes for delivering of resveratrol.
In the food sector, liposomes have been investigated for delivering proteins, enzymes, antioxidants, flavors and vitamins. The mean advantage of liposomes over other encapsulation technologies (spray-drying, extrusion, and fluidized beds) is the stability that liposomes impart to water-soluble compounds in aqueous surroundings. Liposomes are able to stabilize the encapsulated materials against a range of environmental and chemical changes. Another important characteristic of liposomes is that, unlike many other existing encapsulants, they can be utilized in the entrapment, delivery, and release of poorly water soluble compounds, such as resveratrol, and they are also convenient for water-soluble, lipid-soluble, and amphiphilic compounds. As liposomes could be produced from naturally occurring components, regulatory issues that may prevent the application in food systems are potentially diminished, and new formulations could be quickly implemented. Despite benefits described here, up to date little use of liposomes in food systems has been made, as current manufacturing processes are mainly time consuming, often consisting of several steps with high costs of raw materials. Another problem is that devices available commercially which are utilized for production of liposomes are able to process only small quantities. Therefore, our research is devoted to the development of the process for liposome production which is easy to scale up, and at the same time, is effective as the common way based on thin film hydration process. The process elaborated in our study utilizes a commercial lipid mixture. The method used called proliposome method is based on replacement of ethanol solvent by aqueous media. For liposome downsizing, sonication (which can be easily modified to increase sample volume capability) is tested versus membrane extrusion (equipment for small–large batches is readily available). The goal of this article is to provide evidence for food manufacturers and food scientists to make broader use of resveratrol-loaded liposomes that can add value and improve the quality of existing food products.
•Resveratrol was encapsulated in liposomes.•Thin film method and proliposome method were used for production of liposomes.•The size of liposomes was reduced by extrusion and sonication.•Antioxidative activity of resveratrol was retained upon encapsulation.•Liposomes impart slow diffusion of resveratrol.
The influence of resveratrol encapsulated into liposomes (prepared with a commercial lipid mixture of phospholipids, phospolipon 90NG, using the thin film and proliposome methods) on the structural ...properties of the liposome membrane was investigated by electron paramagnetic resonance (EPR) spectroscopy, fluorescence spectroscopy, and differential scanning calorimetry. Two fluorophores and two spin probes were used to monitor the characteristics of membranes made from a commercial mixture of phosphatidylcholine. Resveratrol was positioned rather in the inner part of the liposome membranes causing reduction in membrane fluidity. Moreover, resveratrol induced a concentration‐dependent decrease in the gel‐to‐liquid crystalline phase transition temperature (from 41.3 to 38.3°C, for a saturated 1,2‐dipalmitoyl‐sn‐glycero‐3‐phospatidylcholine bilayer). The antioxidant activity of resveratrol was confirmed by its 95% inhibition of lipid peroxidation, compared to liposomes without resveratrol exposed to the same conditions. Similarly, EPR spectroscopy spin trapping showed an 87% reduction in the spectra intensity of the hydroxyethyl radical, which indicates the efficiency of resveratrol for inhibition of OH radical production. Practical applications: Resveratrol is in the limelight all over the world as a health‐beneficial compound widely investigated as natural antioxidant suitable for prevention of human cardiovascular diseases and inhibition of low‐density lipoproteins oxidation. Public interest in prevention of diseases through enriched staple foods grows each day. Nonetheless, addition of antioxidants to aqueous‐based food can be limited due to their troublesome characteristics. Liposomes are nanocarriers that may be used to overcome the disadvantages and they can be used for food applications. Liposomes could be prepared using only natural components and therefore the new formulations could be quickly implemented. Still, the application of liposomes in food systems is not widespread due to time consuming manufacturing processes and high costs. The presented results provide marks and suggestions to food manufacturers and scientists on how to make broader use of resveratrol‐loaded liposomes which add value and improve the quality of existing food products. The influence of resveratrol encapsulated into liposomes (prepared using the thin film and proliposome methods) on the structural properties of the liposome membrane was investigated by electron paramagnetic resonance spectroscopy, fluorescence spectroscopy, and differential scanning calorimetry. The antioxidant activity of resveratrol was confirmed by its inhibition of lipid peroxidation and by spin trapping.
This paper explores the challenges in meeting the regulatory requirements of short food supply chains in 9 European countries based upon findings from the European H2020 3-year project "SMARTCHAIN". ...The assessments of the barriers that small food producers face in meeting different regulatory requirements are presented. Drawing on the results of 10 multi-actor workshops that involved 124 participants, the most problematic policy frameworks for short food supply chains and key obstacles in different regulatory requirements are summarized. This research shows that current EU and national regulation is an obstacle to the development of short food supply chains, meaning that additional efforts are needed to tailor the regulations to small food producers involved in short supply chains. Furthermore, it is necessary to consider the introduction of more effective support measures for short food supply chains.
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