Development and characterization of mixed gels based hydrogel, emulgel and bigel.

The present study was based on development of gel formulations of agar-gelatin hydrogels, emulgels and bigels which were evaluated as delivery modules for metronidazole (MTZ). Agar and gelatin were used for the preparation of mixed food hydrogels. Soyabean oil (SO) was used for the preparation of emulgels and was incorporated within the prepared hydrogel. Organogel was prepared using soyabean oil as a solvent and stearic acid (SA) as organogelator. The bigel was prepared by mixing organogels with the agar-gelatin hydrogel. The prepared gels were characterized for their surface morphology, mechanical properties, chemical interactions and electrical properties. Field emission scanning electron microscopy was used to visualize the surface topography. XRD studies established the amorphous nature of the gels. FTIR study confirmed the interpolymeric bonding between gelatin and agar as well as encapsulation of soyabean oil within the polymeric matrix. There was no interaction between the polymers and drug. The hydrogels showed lower impedance than emulgels and bigels indicating higher content of aqueous phase within it. The hemocompatibility test confirmed the blood compatibility of the preparations. The emulgel showed least mucoadhesive characteristic while the hydrogel sample showed highest mucoadhesion. The leaching study confirmed the presence of oils in the samples. The swelling profiles for the formulations were in tune with in vitro release studies at pH 7.2 phosphate buffer. Metronidazole was used as a model antimicrobial drug to incorporate within the preparations. The antimicrobial efficiency of all the drug loaded formulations was found to be equivalent.

Modulating process parameters to change physical properties of bigels for food applications

The effect of the process parameters involved in the production of bigels was investigated through the study of structural, mechanical and rheological properties. Four level (24) Central Composite Rotational Design (CCRD) configuration was applied in order to study the organogelator concentration, hydrocolloid concentration, organogel:hydrogel ratio and shear of mixing. Gellan gum and high oleic sunflower oil with glycerol monostearate were used to produce hydrogels and organogels, respectively. All formulations were water-in-oil systems with gel-like behavior. FTIR and XRD results showed that bigels were formed only by physical arrangement with no chemical interactions, but gellan gum decreased the crystallinity of the systems due to its amorphous character. However, hydrogel particles acted as an active filler, reinforcing the structure in comparison to pure gels. Also, the glycerol monostearate present in the organogel could self-assemble at the interface in order to interact with the aqueous phase, improving the interaction and affinity between the phases. Moreover, depending on the composition, systems could be softer or harder and present some frequency dependence. CCRD showed that all parameters evaluated changed with organogel:hydrogel ratio and organogel concentration. Shear of mixing was also significant for some parameters; however, hydrocolloid concentration did not exert a significant effect on the range studied. From PCA analysis it was possible to distinguish different groups, which means that some conditions produced bigels with similar characteristics. Thus, it is expected that these results will allow customizing and fine-tuning properties of structured two-phase systems for diverse applications, ranging from food to pharmaceutical and cosmetic industries.This study was also supported by the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UID/BIO/04469/2013 unit and COMPETE 2020 (POCI-01-0145- FEDER-006684) and BioTecNorte operation (NORTE-01-0145-FEDER000004) funded by the European Regional Development Fund under the scope of Norte2020 - Programa Operacional Regional do Norte. and of the Project RECI/BBB-EBI/0179/2012 (FCOMP-01-0124-FEDER027462)info:eu-repo/semantics/publishedVersio

Printability, microstructure, and flow dynamics of phase-separated edible 3D inks

Personalizing the nutrition and sensorial attributes of 3D printed foods primarily requires various multiscale properties to be individually tailored. Herein, multiscale inks are produced by segregative phase separation, a candidate for further 3D inks texture control, of gellan gum (GG), and whey protein isolate (WPI). The inks microstructure, rheological properties, flow dynamics, their impact on printability, and properties-variables interactions are analyzed using experimental design and clustering. The gels are a GG matrix structured with WPI beads or fibers ranging from 100??m in diameter. A straightforward, six-step printability test determines that high-quality prints require increasing viscosity, which is obtained by reducing the size and length of the WPI beads. Also, flow dynamics and rheology models predict the shear stress and extrusion force, according to the print settings and food-inks fluid properties. The phase-separated inks enable printing at high speed (>25/50?mm/s) upon low extrusion forces (<50?N) and low shear stresses (<500?Pa), according to the calculations and model validation. These printability evaluation methodologies and fabrication of phase-separated inks are particularly interesting for 3D food printing, bioprinting, or biomaterials applications.Nanotechnology-based functional solutions project, funded by ERDF and CCDR-N, under the call Norte2020 (Ref. NORTE-01-0145-FEDER-000019) and Enhance Microalgae (High added-value industrial opportunities for microalgae in the Atlantic Area), funded by ERDF, under the Call Interreg Atlantic Area 2014–2020 (Ref. EAPA_338/2016)info:eu-repo/semantics/publishedVersio

Synthesis of Vegetable Fat Containing Chitosan Microparticles with Improved Physical and Delivery Properties

<p>The present study describes the encapsulation of vegetable fats (cocoa butter and mango butter) within chitosan microparticles by double emulsion technique to prevent leaching of the internal apolar phase. Leaching studies suggested negligible leaching of the internal phase (∼12–14%) when the fats were encapsulated as compared to the control (∼40%). Fourier transform infrared spectroscopy and differential scanning calorimeter studies confirmed the successful encapsulation of fats. The release of drug (ciprofloxacin) from the microparticles was diffusion and erosion mediated and were capable to elicit antimicrobial activity against <i>Escherichia coli</i>. The study suggests that the developed microparticles have the potential for controlled delivery of antimicrobials.</p