Rheological and gel properties of hydroxypropyl methylcellulose/hydroxypropyl starch blends

Effect of zein-pectin composite particles on the stability and rheological properties of gelatin/hydroxypropyl methylcellulose water-water systems

To improve the compatibility of gelatin (GA) and hydroxypropyl methylcellulose (HPMC), we investigated the effects of zein-pectin composite particles (ZCPs) with various zein/pectin ratios (1:0, 1:0.5, 1:1, 1:1.5, and 1:2) on the physical stability, microstructure, and rheological properties of the GA/HPMC water-water systems. With increasing pectin ratio, the particle size of the composite particles increased from 234.53 ± 1.48 nm to 1111.00 ± 26.91 nm, and their zeta potential decreased from 20.60 mV to below -34.77 mV. Macroscopic and microstructure observations indicated that pectin-modified ZCPs could effectively inhibit phase separation behavior between GA and HPMC. Compared to pure HPMC, the GA/HPMC water-water systems possessed a higher viscosity and dynamic modulus at room temperatures but lower gel temperatures (reduction of about 11 %). The viscosity and modulus of the water-water systems increased with increasing pectin ratio in ZCPs. However, the ratio had no impact on the gel-sol (sol-gel) transition temperatures (not statistically significant (P < 0.05)). This study may serve as a reference for advancing the processability of HPMC.

A hydroxypropyl methylcellulose/hydroxypropyl starch nanocomposite film reinforced with chitosan nanoparticles encapsulating cinnamon essential oil: Preparation and characterization

Active packaging derived from polysaccharides plays an important role in prolonging the shelf life of food. In this study, cinnamon essential oil (CEO)-loaded chitosan nanoparticles (CNs) were prepared and embedded in hydroxypropyl methylcellulose (HPMC)/hydroxypropyl starch (HPS) blends to enhance the physicochemical and biofunctional properties of the formed films. Different concentrations (25, 50, 75, and 100 μL/mL) of CEOs were encapsulated with CNs to form CEO-CNs, as confirmed by Fourier Transform Infrared Spectrometer (FTIR), X-Ray Diffraction (XRD), and scanning electron microscope (SEM) images. The prepared CEO-CNs were incorporated into the HPMC/HPS film-forming matrix to prepare reinforced nanocomposite films. SEM images showed that the CEO-CNs were dispersed in the HPMC/HPS matrix, thus filling the void space in the composite matrix and significantly improving the mechanical and barrier properties of the bio-nanocomposite films. The elongation at break of the reinforced films improved from 8.54 ± 0.53 MPa to 24.81 ± 0.47 MPa, and the water vapor permeability was reduced by nearly 30 %. FTIR and XRD analyses indicated the formation of hydrogen bonds between CEO-CNs and HPMC/HPS polymer molecules. Release studies showed that the nanocomposite film was capable of sustained release of CEO, which imparted antioxidant (radical scavenging activity of 27.66-42.19 %) and antimicrobial properties (inhibition of Escherichia coli and Aspergillus flavus growth). Therefore, these HPMC/HPS nanocomposite films with enhanced properties may have great potential for food preservation.

Fabrication of 3D-printed octreotide acetate-loaded oral solid dosage forms by means of semi-solid extrusion printing

Semi-solid extrusion (SSE) 3D printing technology was utilized for the encapsulation of octreotide acetate (OCT) into 3D-printed oral dosage forms in ambient conditions. The inks and the OCT-loaded 3D-printed oral dosage forms were characterized by means of rheology, Fourier-transform infrared (FTIR) spectroscopy and Nuclear Magnetic Resonance (NMR). In vitro studies demonstrated that the formulations released OCT in a controlled manner. The application of these formulations to Caco-2 cell monolayers revealed their capability to induce the transient opening of tight junctions in a reversible manner as evidenced by Transepithelial Resistance (TEER) measurements. Cellular assays (CCK-8 assay) demonstrated the viability of intestinal cells in the presence of these formulations. The in vitro transport studies across Caco-2 monolayers demonstrated the ability of these formulations to enhance the OCT uptake across the cell monolayer over time due to opening of the tight junctions.

Quantitative analysis of degree of substitution/molar substitution of etherified polysaccharide derivatives

Due to the unique properties such as nontoxicity, biodegradability, availability from renewable resources, and cost-effectiveness, polysaccharides play a very important part in the science and technology field. The various chemically modified derivatives of these offer a wide range of high value-added in both food and non-food industries. Among the chemical modification, etherified polysaccharide is one of the most widespread derivatives by introducing an ether group which is commonly stable in both acidic and alkaline conditions. Hydroxyalkylation, alkylation, carboxymethylation, cationization, and cyanoethylation are some of the modifications commonly employed to prepare polysaccharides ethers derivatives. There also has been a growing tendency for creating new types of modification by combining the different means of chemical techniques. The correct determination of degree of substitution (DS)/molar substitution (MS) is crucially important. The objective of this article is to summarize developments in synthetic etherified polysaccharides, involving analytical methods for determination of MS/DS, measurement processes, and the associated mechanisms.

Morphology and Rheology of a Cool-Gel (Protein) Blended with a Thermo-Gel (Hydroxypropyl Methylcellulose)

This study investigates the morphological and rheological properties of blended gelatin (GA; a cooling-induced gel (cool-gel)) and hydroxypropyl methylcellulose (HPMC; a heating-induced gel (thermo-gel)) systems using a fluorescence microscope, small angle X-ray scattering (SAXS), and a rheometer. The results clearly indicate that the two biopolymers are immiscible and have low compatibility. Moreover, the rheological behavior and morphology of the GA/HPMC blends significantly depend on the blending ratio and concentration. Higher polysaccharide contents decrease the gelling temperature and improve the gel viscoelasticity character of GA/HPMC blended gels. The SAXS results reveal that the correlation length (ξ) of the blended gels decreases from 5.16 to 1.89 nm as the HPMC concentration increases from 1 to 6%, which suggests that much denser networks are formed in blended gels with higher HPMC concentrations. Overall, the data reported herein indicate that the gel properties of gelatin can be enhanced by blending with a heating-induced gel.

Effect of Curdlan on the Rheological Properties of Hydroxypropyl Methylcellulose

This work focuses on the effect of curdlan (CL) on dynamic viscoelastic property, thermal reversible property, viscosity, and the fluid types of hydroxypropyl methylcellulose (HPMC) at different temperatures. Compared to the blends at 25 °C, the blends had a smaller linear viscoelastic region (LVR), a higher gel strength, and larger storage modulus (G') and loss modulus (G") values at 82 °C. G', G", gel strength, and viscosity increased with the increase of CL. Repeated temperature sweep led to increased G' and G" of HPMC/CL blends. For HC6 and HC8, the gel formation temperature of the repeated temperature sweep was significantly lower than that of the first sweep. The samples at 82 °C, except for the sample with 8% CL, were all yield-shear thinning fluids, and the samples at 40 °C were shear thinning fluids. The creation of HPMC/CL and its rheological research might provide some methodological references for the study of other thermal-thermal gel blends.

In situ microemulsion-gel obtained from bioadhesive hydroxypropyl methylcellulose films for transdermal administration of zidovudine

This study aims to develop in situ microemulsion-gel (ME-Gel) obtained from hydroxypropyl methylcellulose (HPMC) films for transdermal administration of Zidovudine (AZT). Firstly, HPMC films containing propylene glycol (PG) and eucalyptus oil (EO) were obtained and characterized. Later, a pseudo-ternary phase diagram composed of water, EO, tween 80 and PG was obtained and one microemulsion (ME) with a similar proportion of the film components was obtained. ME was transformed in ME-Gel by the incorporation of HPMC. Finally, HPMC films were hydrated with Tween 80 solution to yield in situ ME-Gel and its effect on AZT skin permeation was compared with HPMC film hydrated with water (F5_hyd). The results showed that the ME and ME-Gel presented a droplet size of 16.79 and 122.13 μm, respectively, polydispersity index (PDI) < 0.39 and pH between 5.10 and 5.40. The incorporation of HPMC resulted in viscosity about 2 times higher than the use of ME. The presence of AZT did not alter the formulation properties. The in situ ME-Gel promoted a two-fold increase in the permeated amount of AZT compared to F5_hyd. The results suggest that it was possible to obtain an ME-Gel in situ from HPMC films and that its effect on transdermal permeation of AZT was significant.

Humectability and physical properties of hydroxypropyl methylcellulose coatings with liposome-cellulose nanofibers: Food application

The objective of this study was to investigate the physical, rheological and humectability properties of edible coating forming suspensions (ECS) based on hydroxypropyl methylcellulose (HPMC) containing: liposomes that encapsulate rutin, glycerol and cellulose nanofibers on sliced surfaces of almonds and chocolate. On average, liposomes measured between 110.6 ± 10.0 nm and were characterized as stable and homogeneous suspensions. Adding these liposomes to the edible coatings produced significant changes (p< 0.05) in the density and surface tension, which favor the final appearance of the coating. The presence of liposomes increased the apparent viscosity of the ECS, showing a purely viscous and fluid behavior with a good fit (R² = 0.9996) with the Power Law model. The presence of liposomes and cellulose nanofibers decreased the value of the cohesive energy of the ECS. The studied ECS partially hydrate the surfaces of almond and chocolate as they showed contact angles under 90°.

New insights on solvent implications in flow behavior and interfacial interactions of hydroxypropylmethyl cellulose with cells/bacteria

The properties of polymers in solutions are affected by the solvent characteristics used in the processing stage. This work contributes to understanding the conformation changes under shear rheology of hydroxypropylmethyl cellulose (HPMC) in different solvents. Flow behavior in a large shear rate domain provides information on establishing the proper conditions in which the polymer solutions can be processed into uniform films. It was found that HPMC/solvent interactions influence the final architecture of macromolecules in the solid phase and implicitly the organization of polar/non-polar groups at the surface. This led to variable wettability and consequently to adhesion or cohesion of HPMC with biological agents. These new findings are important in tuning surface properties as demanded in bioengineering or regenerative medicine, where it is essential to establish adequate spreading conditions at the HPMC interface with cells or bacteria.

Functional Properties of Glutinous Rice Flour by Dry-Heat Treatment

Glutinous rice flour (GRF) and glutinous rice starch (GRS) were modified by dry-heat treatment and their rheological, thermal properties and freeze-thaw stability were evaluated. Compared with the native GRF and GRS, the water-holding ability of modified GRF and GRS were enhanced. Both the onset and peak temperatures of the modified samples increased while the endothermic enthalpy change decreased significantly (p < 0.05). Meanwhile, dry heating remarkably increased the apparent viscosities of both GRF and GRS. Importantly, compared with GRS samples, the storage modulus (G') and loss modulus (G") values of modified GRF increased more greatly and the tanδ values decreased more remarkably, indicating that the dry-heat treatment showed more impact on the GRF and a higher viscoelasticity compared with GRS. Our results suggest the dry-heat treatment of GRF is a more effective method than that of GRS, which omits the complex and tedious process for purifying GRS, and thereby has more practical applications in the food industry.