scholarly journals Rheological Characterization of Hydrogels from Alginate-Based Nanodispersion

Polymers ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 259 ◽  
Author(s):  
Francesca Cuomo ◽  
Martina Cofelice ◽  
Francesco Lopez
Keyword(s):  
Essential Oil ◽  
Tween 80 ◽  
Creep Recovery ◽  
Ion Release ◽  
Rheological Characterization ◽  
Burger Model ◽  
Food Industries ◽  
Hydrogel Network

The interest toward alginate and nanoemulsion-based hydrogels is driven by the wide potential of application. These systems have been noticed in several areas, ranging from pharmaceutical, medical, coating, and food industries. In this investigation, hydrogels prepared through in situ calcium ion release, starting from lemongrass essential oil nanodispersions stabilized in alginate aqueous suspensions in the presence of the nonionic surfactant Tween 80, were evaluated. The hydrogels prepared at different concentrations of oil, alginate, and calcium were characterized through rheological tests. Flow curves demonstrate that the hydrogels share shear thinning behavior. Oscillatory tests showed that the strength of the hydrogel network increases with the crosslinker increase, and decreases at low polymer concentrations. The hydrogels were thixotropic materials with a slow time of structural restoration after breakage. Finally, by analyzing the creep recovery data, the hydrogel responses were all fitted to the Burger model. Overall, it was demonstrated that the presence of essential oil in the proposed hydrogels does not affect the mechanical characteristics of the materials, which are mainly influenced by the concentration of polymer and calcium as a crosslinker.

scholarly journals Processing and Formulation Optimization of Mandarin Essential Oil-Loaded Emulsions Developed by Microfluidization

Materials ◽  
2020 ◽  
Vol 13 (16) ◽  
pp. 3486
Author(s):  
Jenifer Santos ◽  
Nuria Calero ◽  
Luis Alfonso Trujillo-Cayado ◽  
María José Martín-Piñero ◽  
José Muñoz
Keyword(s):  
Essential Oil ◽  
Guar Gum ◽  
Loss Modulus ◽  
Flow Behavior ◽  
Physical Stability ◽  
Tween 80 ◽  
Rheological Characterization ◽  
Food Preservatives ◽  
Starting Point ◽  
Droplet Sizes

Emulsions can be used as delivery systems for bioactive ingredients for their incorporation in food products. Essential oils are natural compounds found in plants that present antioxidant and antimicrobial activity. Therefore, the main goal of this work was to develop emulsions, containing mandarin essential oil stabilized by two food-grade surfactants and guar gum, and to evaluate their physical stability. The initial droplet size of emulsions developed by microfluidization was optimized, obtaining diameters below one micron regardless of the processing conditions. However, the emulsion processed at 25,000 psi and one pass exhibited the lowest mean droplet sizes and polidispersity, and therefore, a higher stability. Different ratios of Tween 80 and Span 80 were assessed as stabilizers. Results obtained indicated that the ratio of surfactants had a significant effect on the mean droplet sizes, physical stability, and rheological properties. Thus, we found that the optimum ratio of surfactants was 75/25 (Tween80/Span80) on account of the lowest droplet mean diameters, lack of coalescence, and a low creaming rate. The rheological characterization of the stable emulsions showed a shear thinning flow behavior, and G″ (loss modulus) values higher than G′ (storage modulus) values, in all the frequency range. The rheological behavior may be governed by the guar gum, which was confirmed by field emission scanning electron microscopy (FESEM). This research can be considered as the starting point for future applications of mandarin essential oil in emulsions, which can be incorporated in products as food preservatives.

Synthesis and characterization of silver cluster particles in hydrogels

2015 ◽  
Vol 35 (4) ◽  
pp. 303-309
Author(s):  
Aman Deo ◽  
Syed Sauban Ghani
Keyword(s):  
Silver Cluster ◽  
Maximum Size ◽  
Spectrophotometric Analysis ◽  
E Coli ◽  
Hydrogel Network ◽  
Microscopy Analysis ◽  
Antibacterial Material ◽  
Spectroscopy Studies

Abstract A chitosan-based hydrogel network was crosslinked with genipin; the crosslinked and uncrosslinked hydrogels were prepared and studied. Uniformly distributed silver cluster particles (AgCPs) were prepared using these hydrogel networks as a carrier via in situ reduction of silver nitrate (AgNO3) in the presence of sodium borohydride (NaBH4) as a reducing agent; UV irradiation reduction was also done. Fourier transform infrared (FTIR) spectroscopy studies of the hydrogels gave results on the decree of crosslinking and some indication on the presence of the AgCPs. The spectrophotometric analysis indicated the presence of AgCPs, as a peak appeared around 400 nm. The microscopy analysis gave images of the presence of AgCPs and their size; it showed that the crosslinked hydrogels have uniformly distributed AgCPs and as the crosslinking increased, the AgCPs size decreased. The studies on the increasing concentration of AgNO3 solution gave an increase AgCPs size; the maximum size of AgCPs clusters was ∼0.2 micron in uncrosslinked chitosan. It was demonstrated, by using Escherichia coli (E. coli) bacterium, that the AgCPs hydrogel can be effectively employed as antibacterial material.

Rheological characterization of a charged cationic hydrogel network across the gelation boundary

Polymer ◽  
2006 ◽  
Vol 47 (4) ◽  
pp. 1124-1131 ◽  
Author(s):  
Nurettin Sahiner ◽  
Mohit Singh ◽  
Daniel De Kee ◽  
Vijay T. John ◽  
Gary L. McPherson
Keyword(s):  
Rheological Characterization ◽  
Hydrogel Network

Rheological Characterization of in Situ Cross-Linkable Hyaluronan Hydrogels

2005 ◽  
Vol 6 (5) ◽  
pp. 2857-2865 ◽  
Author(s):  
Kaustabh Ghosh ◽  
Xiao Zheng Shu ◽  
Robert Mou ◽  
Jack Lombardi ◽  
Glenn D. Prestwich ◽  
...  
Keyword(s):  
Rheological Characterization

In-Situ Rheological Characterization of Drilling Mud

SPE Journal ◽  
2000 ◽  
Vol 5 (04) ◽  
pp. 377-386 ◽  
Author(s):  
Roberto Maglione ◽  
Giovanni Robotti ◽  
Raffaele Romagnoli
Keyword(s):  
Drilling Mud ◽  
Rheological Characterization

In situ rheological characterization of epithelial mucus1

Biorheology ◽  
1976 ◽  
Vol 13 (1) ◽  
pp. 59-65 ◽  
Author(s):  
A. Gilboa ◽  
A. Silberberg
Keyword(s):  
Rheological Characterization

Inulin hydrogels as carriers for colonic drug targeting. Rheological characterization of the hydrogel formation and the hydrogel network

1999 ◽  
Vol 88 (2) ◽  
pp. 209-214 ◽  
Author(s):  
L. Vervoort ◽  
I. Vinckier ◽  
P. Moldenaers ◽  
G. Van Den Mooter ◽  
P. Augustijns ◽  
...  
Keyword(s):  
Drug Targeting ◽  
Rheological Characterization ◽  
Hydrogel Network ◽  
Hydrogel Formation
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