•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.
•The influence of five extraction factors on the polyphenols yield was evaluated.•The efficiency of the extraction techniques was UAE>HAE>maceration.•The optimal extraction conditions were determined ...by full factorial design.•The best extraction conditions: 0.3mm particle size, 1:30 ratio and 50% ethanol.
Despite the fact that Thymus serpyllum is well-known medicinal plant and its chemical profile and biological activity have been investigated, there is no detailed study regarding the influence of different techniques and conditions on the extraction of polyphenolic compounds from Serpylli herba. The aim of this study was optimization of the extraction parameters that improves the efficiency of polyphenols extraction from T. serpyllum: particle size, solid-to-solvent ratio, solvent type and extraction time, by using maceration, heat- and ultrasound-assisted extraction (HAE and UAE). The extraction efficiency was expressed via total polyphenol content (TPC) and total flavonoid content (TFC). The statistical analysis (one-way ANOVA and full factorial design) has revealed that the optimal conditions for achieving the best polyphenols yield were particle size of 0.3mm, 1:30 solid-to-solvent ratio and 50% ethanol, as environmentally friendly extraction medium, while extraction time has not shown statistically significant influence on polyphenols concentration, in all procedures. Under these conditions, the measured TPC was 26.6mg GAE/L in maceration, 29.8mg GAE/L in HAE and 32.7mg GAE/L in UAE, which was in agreement with the predicted values, while TFC was 14.3mg CE/L, 12.4mg CE/L and 16.7mg CE/L for maceration, HAE and UAE, respectively. According to total polyphenols yield, the efficiency of the extraction methods for all variables was ranked by significance in the following order: UAE>HAE>maceration, whereas total flavonoids yield was the highest in UAE, although there was no statistically significant difference between maceration and HAE. According to our results, UAE could be selected as the most successful and suitable technique for extraction of bioactive polyphenolic compounds from Serpylli herba. Using LC/MS and HPLC analysis, 9 polyphenolic compounds were identified and quantified: 6,8-Di-C-glucosylapigenin, chlorogenic acid, 6-hydroxyluteolin 7-O-glucoside, caffeic acid, luteolin 7-O-glucuronide, apigenin glucuronide, salvianolic acid K isomer, rosmarinic acid and salvianolic acid I. This study was an initial step in production of polyphenols-rich wild thyme extracts aimed to be used for formulation of foodstuffs and medicines.
The food industry expects increasingly complex properties (such as delayed release, stability, thermal protection, and suitable sensorial profile) from food ingredients, which often would not be able ...to be achieved without microencapsulation. This paper presents the state of the art in encapsulation technology for delivery of bioactive compounds to food. It reviews common encapsulation technologies (emphasizing their advantages and limitations) versus novel, interesting approaches in emerging technologies. This review includes a presentation of benefits resulting from the use of microencapsulated ingredients in the food industry; these benefits are going to be illustrated via few case studies bringing innovative processing. Spray drying has been used for more than 60 years to protect flavor oils against degradation/oxidation/evaporation, but melt dispersion technique has been used lately to effectively stabilize an aroma compound. Microgels produced by extrusion and emulsification techniques are considered for delivering synergistic antioxidant effects of plant extract polyphenols, their off-taste masking, and improved handling. Apart from microgels, microemulsions (produced by microfluidization or micelle formation techniques) are taken into account for entrapment of extracts containing polyphenols and essential oils. Innovative and interesting coacervation processes are depicted here as they facilitate the commercialization of coacervated food ingredients. Liposomes are gaining increasing attention in the food sector as they can provide good stability even in a water surrounding and also targeted delivery. The new scalable manufacturing protocols for the production of liposomes evolved in recent years (e.g., proliposome method) are presented here. Fluidized bed technology has been offering a versatile possibility to produce encapsulates which should release ingredients at the right place and the right time. Complex systems such as lipids in hydrogels are newly developed structures for controlled release of bioactive compounds. Finally, the effect encapsulates have when incorporated into real food products will be discussed, in particular with regard to the production of innovative functional food products. As an example, textural, sensorial, and physical quality assessment of chocolates enriched with encapsulated polyphenolic antioxidants from yarrow (
Achillea millefolium
L.) will be reviewed.
Encapsulation is a process to entrap active agents within a carrier material and it is a useful tool to improve delivery of bioactive molecules and living cells into foods. Materials used for design ...of protective shell of encapsulates must be food-grade, biodegradable and able to form a barrier between the internal phase and its surroundings. Among all materials, the most widely used for encapsulation in food applications are polysaccharides. Proteins and lipids are also appropriate for encapsulation. Spray drying is the most extensively applied encapsulation technique in the food industry because it is flexible, continuous, but more important an economical operation. Most of encapsulates are spray-dried ones, rest of them are prepared by spray-chilling, freeze-drying, melt extrusion and melt injection. Molecular inclusion in cyclodextrins and liposomal vesicles are more expensive technologies, and therefore, less exploited. There are number of reasons why to employ an encapsulation technology and this paper reviews some of them. For example, this technology may provide barriers between sensitive bioactive materials and the environment, and thus, to allow taste and aroma differentiation, mask bad tasting or smelling, stabilize food ingredients or increase their bioavailability. One of the most important reasons for encapsulation of active ingredients is to provide improved stability in final products and during processing. Another benefit of encapsulation is less evaporation and degradation of volatile actives, such as aroma. Furthermore, encapsulation is used to mask unpleasant feelings during eating, such as bitter taste and astringency of polyphenols. Also, another goal of employing encapsulation is to prevent reaction with other components in food products such as oxygen or water. In addition to the above, encapsulation may be used to immobilize cells or enzymes in food processing applications, such as fermentation process and metabolite production processes. There is an increasing demand to find suitable solutions that provide high productivity and, at the same time, satisfy an adequate quality of the final food products. This paper aims to provide a short overview of commonly used processes to encapsulate food actives.
Freeze drying was compared with spray drying regarding feasibility to process wild thyme drugs in order to obtain dry formulations at laboratory scale starting from liquid extracts produced by ...different extraction methods: maceration and heat-, ultrasound-, and microwave-assisted extractions. Higher total powder yield (based on the dry weight prior to extraction) was achieved by freeze than spray drying and lower loss of total polyphenol content (TPC) and total flavonoid content (TFC) due to the drying process. Gelatin as a coating agent (5% w/w) provided better TPC recovery by 70% in case of lyophilization and higher total powder yield in case of spray drying by diminishing material deposition on the wall of the drying chamber. The resulting gelatin-free and gelatin-containing powders carried polyphenols in amount ~190 and 53–75 mg gallic acid equivalents GAE/g of powder, respectively. Microwave-assisted extract formulation was distinguished from the others by a higher content of polyphenols, proteins and sugars, higher bulk density and lower solubility. The type of the drying process mainly affected the position of the gelatin-derived -OH and amide bands in FTIR spectra. Spray-dried formulations compared to freeze-dried expressed higher thermal stability as confirmed by differential scanning calorimetry analysis and a higher diffusion coefficient; the last feature can be associated with the lower specific surface area of irregularly shaped freeze-dried particles (151–223 µm) compared to small microspheres (~8 µm) in spray-dried powder.
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.
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
Display omitted
Formulating poorly water soluble drugs using ordered mesoporous silica materials is an emerging approach to tackle solubility-related bioavailability problems. The current study was ...conducted to assess the bioavailability-enhancing potential of ordered mesoporous silica in man. In this open-label, randomized, two-way cross-over study, 12 overnight fasted healthy volunteers received a single dose of fenofibrate formulated with ordered mesoporous silica or a marketed product based on micronized fenofibrate. Plasma concentrations of fenofibric acid, the pharmacologically active metabolite of fenofibrate, were monitored up to 96h post-dose. The rate (Cmax/dose increased by 77%; tmax reduced by 0.75h) and extent of absorption (AUC0–24h/dose increased by 54%) of fenofibrate were significantly enhanced following administration of the ordered mesoporous silica based formulation. The results of this study serve as a proof of concept in man for this novel formulation approach.
PDF
