Gelatin Glycerol Research Articles

Development of a pH-sensing indicator for shrimp freshness monitoring: Curcumin and anthocyanin-loaded gelatin films.

An intelligent pH-sensing indicator containing Roselle (Hibiseus sabdariffa L.) (RS) anthocyanin and curcumin (CR) was developed and characterized as on-package indicator tags to check the freshness of shrimp during the storage at 4°C. FE-SEM and FT-IR analysis showed that RS and CR were successfully immobilized in the gelatin-glycerol film-forming substrate. The addition of various natural dyes increased the thickness and antioxidant action of the colorimetric film. To assess the response to changes in the pH, the colorimetric film was immersed in different buffers. Based on volatile amines secreted by shrimp, a test application of a colorimetric film containing natural dyes at a ratio of CR:RS = 1:4 (v/v) was conducted in shrimp at 4°C. The total volatile basic nitrogen (TVB-N) and the pH of shrimp were monitored during refrigerated storage for 10 days, and the color changes of the indicator were recorded simultaneously. The results indicated that the designed colorimetric film could produce various colors, which are thought to be indicative of the freshness and spoilage of packaged shrimp. Therefore, the target film can be utilized as a promising smart packaging material for monitoring the freshness of shrimp and aquatic products in real time.

Properties of Roselle and alizarin mixed loaded gelatin films as a pH‐sensing indicator for shrimp freshness monitoring

AbstractAn intelligent pH‐sensing indicator containing Roselle (Hibiscus sabdariffa L.) (ROS) anthocyanin and alizarin (ALZ) was developed and characterized as on‐package indicator tags to check the shrimp freshness during the storing at 4°C. Fourier transform infrared (FT‐IR) analysis showed that ROS and ALZ were successfully immobilized in the gelatin–glycerol film‐forming substrate. The addition of various natural dyes enhanced the thickness and antioxidant action of the colourimetric film. To assess the response to changes in the pH, the colourimetric film was immersed in different buffers. Based on volatile amines secreted by shrimp, a test application of a colourimetric film containing natural dyes at a ratio of ROS:ALZ = 4:1 (v/v) was conducted in shrimp at 4°C. The findings indicated that the designed colourimetric film could produce various colours, which are thought to indicate the freshness and spoilage of packaged shrimp. Therefore, the target film can be utilized as a promising smart packaging material for monitoring the freshness of shrimp and aquatic products in real time.

Chlorella vulgaris Extract-Decorated Gold Nanoparticle Hybridized Antimicrobial Hydrogel as a Potential Dressing

This study reports a novel design of a moisturizing and antimicrobial hydrogel with injectable properties, using a green solvent (glycerol) as a cross-linking agent and gold nanoparticle reduced by Chlorella extract as an antimicrobial approach. We have synthesized gold nanoparticles (AuNPs) with environmentally friendly and bio-safe properties using Chlorella aqueous extracts (AuNPs@Chlorella). Characterization of the nanoparticles by ultraviolet-visible spectroscopy (UV-Vis), Fourier transform infrared spectroscopy (FTIR), Raman spectrum, and transmission electron microscope (TEM) confirmed that spherical AuNPs with the particle size of 10-20 nm were successfully synthesized. An analysis of the enhancement of the stability of gelatin hydrogels by the addition of glycerol and AuNPs was performed by rheometry. In addition, we also used Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) to confirm the good antibacterial activity. Therefore, the as-prepared gelatin-glycerol hydrogels containing AuNPs@Chlorella are most likely promising alternatives for wound healing dressings.

Lyophilized Probiotic Lactic Acid Bacteria Viability in Potato Chips and Its Impact on Oil Oxidation.

To produce a new probiotic-containing food product, potato chips, as the most preferred fast food, were chosen. Preferably, it should be preserved for a long period without oxidation. The presented study aimed to compare potato chips containing two lyophilized probiotic lactic acid bacteria (Bifidobacterium longum ATCC 15708 and Lactobacillus helveticus LH-B02) in order to retard lipid oxidation. Lyophilization of probiotics was carried out into two cryoprotective media—skim milk (SM) and gelatin/glycerol (GG) as lactose-free medium. Results revealed that GG and SM media were the most suitable for lyophilization of B. longum and L. helveticus, respectively. The lyophilized live cells were incorporated in potato chips, packed and their effect on oil oxidation was assessed. Results showed that the lyophilized B. longum in SM remained alive at 6.5 log CFU/g for 4 months at 30 °C. Interestingly, potato chip bags containing B. longum lyophilized in SM medium exhibited a decrease in peroxide value (PV) and acid value (AV) of the extracted oil by 40.13% and 25%, respectively, compared to the control bags. The created probiotic potato chips containing B. longum fulfill the criteria of the probiotic product besides the prime quality and sensory attributes.

Thermosensitive Chitosan-Gelatin-Glycerol Phosphate Hydrogels as Collagenase Carrier for Tendon-Bone Healing in a Rabbit Model.

Healing of an anterior cruciate ligament graft in bone tunnel yields weaker fibrous scar tissue, which may prolong an already prolonged healing process within the tendon–bone interface. In this study, gelatin molecules were added to thermosensitive chitosan/β-glycerol phosphate disodium salt hydrogels to form chitosan/gelatin/β-glycerol phosphate (C/G/GP) hydrogels, which were applied to 0.1 mg/mL collagenase carrier in the tendon–bone junction. New Zealand white rabbit’s long digital extensor tendon was detached and translated into a 2.5-mm diameter tibial plateau tunnel. Thirty-six rabbits underwent bilateral surgery and hydrogel injection treatment with and without collagenase. Histological analyses revealed early healing and more bone formation at the tendon–bone interface after collagenase partial digestion. The area of metachromasia significantly increased in both 4-week and 8-week groups after collagenase treatment (p < 0.01). Micro computed tomography showed a significant increase in total bone volume and bone volume/tissue volume in the 8 weeks after collagenase treatment, compared with the control group. Load-to-failure was significantly higher in the treated group at 8 weeks (23.8 ± 8.13 N vs 14.3 ± 3.9 N; p = 0.008). Treatment with collagenase digestion resulted in a 66% increase in pull-out strength. In conclusion, injection of C/G/GP hydrogel with collagenase improves tendon-to-bone healing in a rabbit model.

Optimization of chicken skin gelatin film production with different glycerol concentrations by response surface methodology (RSM) approach.

This study investigated the optimization of chicken skin gelatin film production using different concentrations of glycerol as plasticizer, specifically for use as biodegradable food packaging. Response surface methodology (RSM) was used to optimize the production of gelatin films by following a central composite design (CCD) for two quantitative modulators-(A) gelatin at 1.0, 2.5 and 4.0g; and (B) glycerol at 0, 0.75, 1.50g-with outcome metrics to predict tensile strength (TS), elongation at break (EAB) and water vapor permeability (WVP). Potentially optimized conditions were experimentally validated to confirm the model's suggestions of 4.0g for gelatin and 1.5g for glycerol. Experimental results yielded a TS of 3.81N/mm, which was higher than the RSM predicted value of 3.09N/mm (p < 0.05). Both EAB and WVP experimental results were slightly lower than predicted values (3.04 vs. 3.14%) (p < 0.05); and (1.27 × 10-9 vs. 1.31 × 10-9kPa) (p < 0.05), respectively. Overall, experimental results agreed with the model's predicted values. Hence, this study demonstrates that optimized conditions for the production of chicken skin gelatin films are affected by glycerol concentration and gelatin quantity. Results also suggest that chicken skin gelatin-glycerol film blends have excellent potential for the production of biodegradable food packaging with improved properties.

An efficient and innovative method to preserve the harvested plums during storage

This research was undertaken to establish the preservative role of lactic acid (LA) and salicylic acid (SA) included in a gelatin–glycerol film over the harvested plums. The results showed that highest catalase activity was achieved for the plums modified with LA 0.2% wt and with SA 0.00375 M, after 12 days of storage. The most reduced variation of the physical, chemical, and enzymatic parameters was noticed in the plums coated with LA 0.2% wt. Statistical processing showed that the variation of all physical–chemical parameters, excepting catalase is significant. Variation of catalase is significant only in the case of the plums modified with LA 3% wt and of reference plums. Thus, the coating of the harvested plums with a low amount of LA (≤0.2% wt) can be considered as preservation method during storage for 12 days. Practical applications Lactic acid (LA) and salicylic acid (SA) were coated on the harvested plums and their role as preservative during the fruit storage was established. The results showed that coating the harvested plums with a gelatin–glycerol film modified with LA at low concentration (≤0.2% wt) is an efficient method for preservation at room temperature for 12 days, taking in consideration that the commercial shelf life of harvested plums is 2–6 weeks, at 0 °C.

Developing and physicochemical evaluation of cross-linked electrospun gelatin–glycerol nanofibrous membranes for medical applications

This study aims to develop optimal cross-linked electrospun gelatin–glycerol (GEL-GLY) nano-fibrous mats suitable for tissue engineering and wound dressing applications. The optimized procedure involves heating the gelatin and gelatin–glycerol solutions up to 90 °C. The electrospinning process was performed, followed by further cross-linking of electrospun films in a container containing glutaraldehyde (GTA) vapor. The results of X-ray diffraction (XRD), Fourier transformed infrared (FTIR), and Differential thermal analysis (DTA) confirmed that heating gelatin solution up to 90 °C in the presence of glycerol affected the cross-linking efficiency and interactions between GTA molecules and gelatin chains. Scanning Electron Microscope (SEM) analysis showed that GEL-GLY nano-fibrous mats with weight ratios less than or equal (12:3 w/w) exhibited a regular morphology with defect free in addition to increasing the degradation time, cross-linking efficiency, and swelling degree of electrospun gelatin/glycerol.

Physical, Physicochemical, Mechanical, and Structural Characterization of Films Based on Gelatin/Glycerol and Carbon Nanotubes

A new method to prepare glycerol/gelatin based films, by doping the film with carbon nanotubes (CNTs) and sodium dodecyl sulfate (SDS), was proposed. SDS was used to disperse CNTs in gelatin/glycerol films as follows: gelatin/glycerol (GG) incubated with equal concentrations of CNT and SDS; GG with 0.001% w/w CNT/SDS; GG with 0.002% CNT/SDS and GG with 0.004% CNT/SDS. Diffractograms of CNT/SDS /glycerol films showed an amorphous structure, being consistent with thermograms involving temperature and fusion enthalpy. Mechanical tests showed 30% increase in elongation at break of GG with 0.004% CNT/SDS, with respect to gelatin/glycerol/SDS control. Samples with CNT had increased water vapor permeability (WVP). The film fractal dimension indicated that, with the addition of the highest concentration of CNT, films with a homogeneous surface were obtained, with probable nanotube inclusion in the protein matrix. According to the results, the easy method used to prepare gelatin composite materials gave place to films with better physical, mechanical, and thermal properties.

Micro-PIXE analyses of frozen-hydrated semi-thick biological sections

Cryo-micro-PIXE system and methodology of microanalysis of frozen-hydrated semi-thick biological sections is described. A commercially available cryotransfer system used in electron microscopy has been adapted for this purpose. The analyzed material was frozen by metal–mirror method and sections of 20–50 micron thickness were prepared. Micro-PIXE and simultaneous proton backscattering was performed using 3MeV proton beam. Monitoring of water vapour composition during the proton bombardment showed good stability of the analyzed material. The results of repetitive analyses of standards prepared from gelatin–glycerol solution with added known concentrations of K, Ni, Cu, Zn were in good agreement with expected, calculated values. Mass losses and changes of elemental composition were monitored. Elemental maps obtained for frozen-hydrated semi-thick section of Ni hyperaccumulator Senecio coronatus showed excellent preservation of leaf morphology and the distribution of elements. Quantitative elemental mapping of frozen-hydrated specimens compared with subsequent analysis of the same areas after freeze-drying revealed similar distribution pattern in both cases. It is clear, however, that freeze-drying induces some distortion of cell morphology and specimen shrinkage.

Release of Vancomycin and Teicoplanin from a Plasticized and Resorbable Gelatin Sponge: in Vitro Investigation of a New Antibiotic Delivery System with Glycopeptides

The aim of this study was to evaluate the efficacy of sustained release of vancomycin and teicoplanin from a resorbable gelatin glycerol sponge, in order to establish a new delivery system for local anti-infective therapy. 60 plasticized glycerol gelatin sponges containing either 10 or 20% gelatin (w/v) were incubated in vancomycin or teicoplanin solution at 20 degrees C for either 1 or 24 h. In vitro release properties of the sponges were investigated over a period of 1 week by determining the levels of vancomycin and teicoplanin eluted in plasma using fluorescent polarization immunoassay. The rate constant and the half-life for the antibiotic release of each group were calculated by linear regression assuming first order kinetics. Presoaking for 24 h was associated with a significant increase in the total antibiotic release in all groups opposed to 1 h of incubation, except for the 10% sponges presoaked in teicoplanin. Doubling the gelatin content of the sponges from 10 to 20% significantly increased the total release of antibiotic load only in teicoplanin-containing sponges after 24 h incubation. In all corresponding groups investigated, release of vancomycin was more prolonged compared to teicoplanin, which allowed a gradual release beyond 5 days. The half-life (h +/- SEM) of both types of vancomycin-containing sponges was significantly prolonged by 24 h incubation in comparison to 1 h incubation (29.1 +/- 5.9 vs 5.9 +/- 1.0; p < 0.001, 30.0 +/- 2.1 vs 11.1 +/- 1.9; p < 0.001). However, neither doubling the gelatin content of the sponges nor a prolonged incubation was associated with a significantly prolonged delivery of teicoplanin. This study demonstrated a better diffusion-controlled release of vancomycin-impregnated glycerol gelatin sponges compared to those pretreated with teicoplanin. The plasticized glycerol gelatin sponge may be a promising carrier for the application of vancomycin to infected wounds for local anti-infective therapy.

Isochronal temperature–concentration diagram for a polymer–diluent system

AbstractThe results of an investigation of the viscoelastic and thermal properties of the gelatin–glycerol system are presented in the form of a complete temperature–composition diagram. This diagram shows the isochronal (10‐sec.) mechanical behavior of the system along lines of constant modulus and thereby affords a convenient assessment of variation in viscoelastic behavior along any isotherm or isopleth of interest. Comparison of the results with previously obtained limited sets of data on a number of other polymer–dilent systems indicates the applicability and utility of such a presentation.

Stress relaxation of anhydrous gelatin rubbers

AbstractAnhydrous gelatin–glycerol compositions exhibit rubbery behavior in the temperature region −40 to +40°C. and in the gelatin weight fraction range 0.1–0.4. These rubbers are capable of sustaining considerable stress over several decades of time at room temperature or below but flow rapidly in the region 45–60°C. Stress relaxation moduli at 25°C. appear to be insensitive to the substitution of glycerol with water but shear viscosity data indicate that gelatin–glycerol rubbers flow at temperatures about 15°C. higher than their aqueous counterparts.