Effect Of Glycerol Concentration Research Articles

Effect of Glycerol Concentrations on the Characteristics of Cellulose Films from Cattail (Typha angustifolia L.) Flowers.

Plastic waste has become a big problem for the environment globally. Biodegradable polymers are a potential replacement for plastics that can have a positive outcome both environmentally and economically. In this work, we used acid hydrolysis and alkaline treatment to extract cellulose fibers from cattails. The obtained cellulose was used as a substrate for the fabrication of cellulose film using a casting technique on plastic plates. Different concentrations of the plasticizer, glycerol, were used to prepare films for comparison, and its effects on the film's characteristics were observed. The morphology, chemical structure, and thermal stability of the cattail cellulose (CTC) films were studied using techniques such as scanning electron microscopy (SEM), attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR), and thermogravimetric analysis (TGA), respectively. Measurements of transparency, moisture content (MC), water solubility (MS), and water contact angle (WCA) were also performed. Introducing glycerol into the films increased the transparency, MC, and WS values, as well as the gap width between film textures. However, it resulted in a decrease in the WCA of the films, showing that the hydrophilicity of the films is increased by the addition of glycerol. The interaction between the functional groups of cellulose and glycerol was established from the ATR-FTIR and XRD data. The obtained results indicated that glycerol affected the thermal stability and the degree of crystallinity of the produced films. Accordingly, the hydrophilicity of the cellulose film was increased by increasing the glycerol content; therefore, cattail cellulose films can be used as a biodegradable alternative to plastic in the future.

The Effect of Glycerol Concentration on The Characteristics of Edible Film of Kimpul Starch (Xanthosoma sagittifolium)

The Effect of Glycerol Concentration on The Characteristics of Edible Film of Kimpul Starch (Xanthosoma sagittifolium)

Effect of glycerol concentration on levels of toxicants emissions from water-pipe tobacco smoking (WTS)

Glycerol, flavorings and sweeteners constitute approximately 70% of water-pipe tobacco smoking (WTS) mixtures. Tobacco mixture combustion produces smoke toxins (e.g. carbonyl compounds), of which the type and amount are highly dependable on tobacco mixture formula. While glycerol in tobacco mixture contribute to enhanced smoking experience, its’ combustion produces toxicants such as acrolein. According to WHO, there are no approved international upper limits regulations on WTS ingredients. This study aims to assess toxicant emission levels corresponding to increasing glycerol concentration in WTS mixtures, which may aid in developing tobacco regulations towards harm reduction.MethodsLaboratory experimental study. Using laboratory water-pipe smoking machine, levels of toxicant emissions in the smoke from WTS mixture samples containing varying glycerol concentrations were measured using High-performance Liquid Chromatography (HPLC). Smoke from 5 consecutive smoking cycles with 35 puffs each (ISO 22486 standard) was led through a trapping system as described in the Cooperation Centre for Scientific Research Relative to Tobacco (CORESTA) recommended method No. 74 (Determination of selected carbonyls in mainstream cigarette smoke by HPLC). Trapped carbonyls were then analysed by HPLC with a DAD detector.ResultsAcrolein emission is associated with glycerol addition in WTS mixture indicated by lab-made samples throughout all glycerol concentrations (10%, 20%, 40% and 60%), and brand samples with glycerol concentrations 10% to 20%. However, brand samples showed no increase in acrolein emission corresponding to the increase in glycerol concentrations from 20% to 60%.ConclusionThe effect of glycerol addition in waterpipe tobacco on acrolein emission varies between products. Tobacco fillers, additives and contents quality and other factors may affect toxicant emission levels. Therefore, regulatory recommendations towards defining upper limits of content concentrations require further investigations regarding potential confounders in acrolein emissions and health effects of market-available glycerol concentrations in waterpipe tobacco smoking.

S-Scheme TiO2/CuNb2O6 Nanocomposite Photocatalyst with Enhanced H2 Evolution Activity from Aqueous Glycerol Solution

Steering of photoexcitons via interface engineering of semiconductor photocatalysts is key to achieving a stable and efficient photocatalyst for continuous hydrogen production. Among them, the development of 1D nanostructures with several advantageous properties such as wide surface area, effective light harvesting, and increased electron moving kinetics has received special attention. In this work, 1D titania nanobars were successfully synthesized via the methanol-assisted solvothermal method, in which alcohol formed hydrogen bonds with nuclei, which consequently encouraged the growth of nanobars. Following this, the titania nanobars were integrated with solvothermally synthesized monoclinic CuNb2O6 nanoparticles. TEM analysis revealed the formation of TiO2 nanobars and their uniform interaction with CuNb2O6 nanoparticles. A S-scheme heterojunction is formed at the interface of TiO2 nanobars and CuNb2O6 nanoparticles. 1D morphology of titania and CuNb2O6 plays a key role in light absorption and boosts the photocatalytic activity by promoting the separation and transfer of photoexcited charge carriers. The electrons at the TiO2 conduction band and holes at the valance band of CuNb2O6 facilitated recombination at the heterojunction. The remaining electrons at the conduction band of CuNb2O6 and holes at the valance band of TiO2 tend to participate in redox reactions at their terminals. As the loading of CuNb2O6 increases, the rate of activity initially increases and then decreases, which is consistent with the trend for light penetration-dependent photocatalytic hydrogen evolution. The band edge potentials of TiO2 and CuNb2O6 were also revealed using VB-XPS and UPS analysis. In addition to catalytic stability, the effect of glycerol concentration, catalyst loading, time on stream, recyclability, and parametric analysis which aided in the discovery of ideal experimental conditions is revealed. Under optimal conditions, the photocatalyst showed an enhanced rate of H2 generation (146 mmol h–1 gcat–1) under simulated solar light irradiation. The solar to H2 conversion efficacy is also discussed with comparison.

Pengaruh Konsentrasi Gliserol pada Gelatin Kulit Kelinci terhadap Kadar Air, Ketebalan Film, dan Laju Transmisi Uap Air Edible Film

Utilization of rabbit skin as a food product has not been carried out optimally, it is not in line with the increasing production of meat. The high protein content makes rabbit skin potential to be used as gelatin. Gelatin is a protein-derived compound that has translucent, colorless, and tasteless properties. This makes gelatin suitable as a raw material for the manufacture of edible films. Edible film is a packaging layer for edible food products. film The added glycerol plasticizer can affect the characteristics. This study aims to determine the right concentration to obtain moisture content, film, and water vapor transmission rate of edible film from rabbit skin gelatin. The method used is an experimental method with a completely randomized design (CRD) with 4 treatments consisting of glycerol concentrations of 5%, 10%, 15%, and 20%. Each treatment was repeated 5 times with observed moisture content, thickness , and water vapor transmission rate. The statistical test used ANOVA’s test, then Duncan's advanced test at the 5% level. The results showed that the effect of glycerol concentration on rabbit skin gelatin gave a different response (P<0.05) with the best concentration of glycerol 10% (P2) on the moisture content, thickness , and water vapor transmission rate of the edible film. Keywords : edible film, rabbit skin gelatin, glycerol, moisture content, thickness, water vapor transmission rate

Aqueous-phase reforming of glycerol over Pt-Co catalyst: Effect of process variables

This study examined the influence of process variables (glycerol concentration in feed, coupled temperature/pressure and space velocity) in the catalytic performance in the APR of glycerol over 0.3Pt/CoAl catalyst in a continuous fixed-bed reactor in order to maximize the production of H2. The effect of glycerol concentration in the feed was studied from 5 to 20 wt%, the coupled temperature/pressure varied from 225 °C/25 bar to 260 °C/50 bar and the spatial velocity was changed from 0.68 to 17 h-1. Our results reflected that H2 production was favored at higher reaction temperature/pressure (3.62 vs. 2.49 molH2/molGly-converted, at the most severe and mild conditions, respectively), lower WHSV (3.89 vs. 1.27 molH2/molGly-converted, at the lowest and highest space velocity, respectively) and more diluted feedstocks (3.95 vs. 1.44 molH2/molGly-converted, at the most diluted and concentrated freestreams, respectively). A threshold value at 10 wt% glycerol was found for the ratio of dehydrogenation to dehydration liquid products. The post-reaction catalyst was also characterized by several techniques, showing that Co leaching was the major drawback, especially at the mildest operation conditions, while carbonaceous deposits are negligible.

Effect of glycerol concentration and carboxy methyl cellulose on biodegradable film characteristics of seaweed waste

Eucheuma cottonii waste seaweed has high cellulose content. Therefore, it could be potentially used as a raw material for biodegradable films to replace plastic. A plastic film is its moisture resistance, and this property allows plastic films to be used as packaging materials and biodegraded by microbes. This research aims to obtain a concentration of glycerol and Carboxy Methyl Cellulose (CMC) to obtain the best biodegradable film characteristics from E. cottonii seaweed waste. This study was conducted in factorial by using a complete randomized block design with two factors: glycerol concentration and CMC concentration. Each treatment has three levels and three replications (3 × 3). The first factor was glycerol concentration: 0.25% (G1), 0.5% (G2), and 0.75% (G3). The second factor included concentrations of 1% CMC (C1), 2% CMC (C2), and 3% CMC (C3). Then, Tensile Strength (TS), thickness, solubility, and elongation were observed. Functional group analysis was conducted by Fourier-transform infrared spectroscopy and biodegradability test. The results showed that the addition of glycerol concentrations of 0.5 and 0.7% and CMC from 1 to 3% produced tensile strengths of 23–39 MPa. These values are proportional to the tensile strength of Poly Tetra Fluoro ethyne (PTFE) and Poly Propylene (PP) synthetic plastics released by Dotmar Engineering Plastics. The biodegradability test showed that the produced biodegradable films decomposed after 14 days.

Bio‐based sustainable films from the Algerian Opuntia ficus‐indica cladodes powder: Effect of plasticizer content

AbstractThe present study investigated the fabrication and characterization of bio‐based sustainable films composed of a terrestrial plant raw material, namely Opuntia ficus‐indica (OFI) cladodes powder (CP) and a marine seaweed derivative, namely agar (A). The effect of glycerol concentration on the properties of the casted films was evaluated at four different contents, namely 30, 40, 50 and 60 wt%. The films present UV‐blocking properties, as well as moderate mechanical performance, thermal stability, and water vapor transmission rate (WVTR). The results point to an increase in thickness, elongation at break, moisture content, water solubility, and WVTR with increasing glycerol content. On the contrary, Young's modulus, tensile strength, and water contact angle decreased as glycerol concentration increased. The best combination is obtained for the film with 30% glycerol, based on an intermediate compromise between physical, mechanical, thermal, and barrier properties. All these outcomes express the potentiality of the powder obtained from grinding the OFI cladodes as raw material to produce low‐cost films for the development of sustainable packaging materials.

Effect of glycerol concentration on physical and texture properties of edible films prepared from karaya gum

This study formulated edible films based on karaya gum in the presence of glycerol. Physical properties of films were investigated by various methods including texture analysis and differential scanning calorimeter (DSC). The obtained results revealed that glycerol acted as a plasticizer contributing to improve the flexibility, water vapor permeability and heat resistance of karaya films. The best value of tensile strength and puncture force for edible films could be achieved by the combination of karaya gum and glycerol at the concentrations of 4% (w/v) and 10% (w/w), respectively.

The Effect of Glycerol Concentration on Biocomposite Bacterial Cellulose-Chitosan Characterization as Dura Mater Artificial

Bacterial cellulose and chitosan have been widely developed for biomaterial applications, one of which is used as a dura mater artificial. In designing dura mater artificial, there are several criteria that must be met, one of which is mechanical that can be seen through tensile strength and elongation value. In previous study, the mechanical properties of biocomposite bacterial cellulose-chitosan still too rigid and did not meet the standard. This research was conducted to determine the effect of the addition of glycerol concentration to the physical and biological of bacterial cellulose-chitosan membrane. Bacterial cellulose membranes with the addition of glycerol concentration of 0%; 0,25%; 0,5% and 0,75% were dried with oven and immersed for 6 hours in 0.5% chitosan solution. Characterization was performed by functional group, morphology, tensile strength, swelling, degradation and cytotoxicity test. Based on the results, it can conclude that biocomposite bacterial cellulose-chitosan-glycerol showed suitable characteristics as a dura mater artificial.

Effects of some material parameters on lignin biopolymer liquefaction by microwave heating

A kraft lignin was liquefied in solution reagents such as polyethylene glycol (PEG) and glycerol under microwave heating. The effects of glycerol concentration, molecular weight of PEG and lignin mass were investigated on lignin liquefaction process through microwave irradiation. For this purpose, the prepared polyols were characterized by gel permeation chromatography, Fourier transform infrared spectroscopy, proton nuclear magnetic resonance and carbon-13 nuclear magnetic resonance techniques. Further, the hydroxyl value (OHV) of polyols was determined by titration method. The results indicated that addition of glycerol increased liquefaction yield and OHV of polyols due to its role as co-solvent in liquefaction process and as a microwave absorber. Glycerol could be used up to 30 wt%, though the beneficial amount of glycerol was obtained as 20 wt%. In another run, it was observed that PEG with a molecular weight of 400 g/mol was an efficient solvent in liquefaction process, which introduced the highest amount of OHV in lignin polyol. A study on the effect of lignin mass was carried out with sufficient amount of glycerol and PEG400 as liquefaction reagents. The results revealed that with further increase in lignin/solvent weight ratio, the molecular weight of polyol increased while its OHV was reduced. Therefore, there was a limiting range in addition of lignin due to insufficient liquefaction solvent in causing enhanced condensation reaction during the liquefaction process. Finally, the polyol with sufficient amounts of testing components was nominated as an optimal polyol with the highest OHV (630 mg KOH/g) and suitable liquefaction yield.

Development of edible packaging film from banana peels and effect of glycerol concentration on the film properties

Edible film from banana peel was developed with incorporation of varying levels of glycerol (5, 10, 15 and 20%) as plasticizers. Different parameters including thickness of the edible film, moisture content of the film by hot air oven method, tearing strength, density, water absorption, solubility, water vapor transmission rate(WVTR) and color were studied. The study shows the best result at 10% glycerol concentrations.

Effect of Glycerol Concentration and Light Intensity on Growth and Biochemical Composition of Arthrospira (Spirulina) Platensis: A Study in Semi-Continuous Mode with Non-Aseptic Conditions

In this study, Arthrospira platensis was grown in the presence of different glycerol concentrations (0.5–9 g/L) under three light intensities (5, 10 and 15 Klux) in semi-continuous mode and under non-axenic conditions. The aim of this study was to investigate the growth performance, the biomass biochemical composition and any interactions between A. platensis and bacteria that would potentially grow as well on glycerol. The results here show that glycerol did not have any positive effect on biomass production of A. platensis. In contrast, it was observed that by increasing glycerol concentration the growth performance of A. platensis was restricted, while a gradual increase of bacteria population was observed, which apparently outcompeted and repressed A. platensis growth. Chlorophyll fluorescence measurements (Quantum Yields) revealed that glycerol was not an inhibiting factor per se of photosynthesis. On the other hand, cyanobacterial biomass grown on glycerol displayed a higher content in proteins and lipids. Especially, protein productivity was enhanced around 15–35% with the addition of glycerol compared to the control. In distinction, carbohydrate and photosynthetic pigments (phycocyanin and chlorophyll-α) content decreased with the increase of glycerol concentration. The results here suggest that A. platensis did not utilize glycerol for biomass production but most probably as metabolic energy carrier towards synthesis of proteins and lipids, which are more energy consuming metabolites compared to carbohydrates. The study revealed that the addition of glycerol at amounts of 0.5–1.5 g/L could be a strategy to improve protein productivity by A. platensis.

Effect of glycerol concentrations and temperatures on epidermal growth factor protein expression in preserved canine amniotic membrane.

Amniotic membrane has been widely applied as a biological graft in both medical and veterinary practice. In ophthalmology, epidermal growth factor (EGF) in human amniotic membrane (HAM) promotes corneal epithelial cell proliferation and migration, thus it facilitates corneal wound healing. In dogs, with limited cryopreserved HAM availability, different cold glycerol preserving protocols have been developed for the storage canine amniotic membrane (CAM). This study aimed to study protein expression of EGF in CAM preserved with different concentrations of glycerol and storage temperatures, using enzyme-linked immunosorbent assay. CAM preserved in 50% glycerol and 99.5% glycerol and kept at 4 and - 20°C for 7-30days were compared. We found that preserving membrane with 50% glycerol at - 20°C has significantly higher EGF protein expression compared with that at 4°C (p < 0.05). There was a trend that the storage in 50% glycerol achieved higher EGF protein expression than 99.5% glycerol at both 4°C and - 20°C. In conclusion, 50% glycerol at - 20°C was the best condition to preserve CAM in our study. Therefore, there is likely an alternative method to maintain level of EGF protein expression in preserved CAM.

Efeito do glicerol como plastificante nas propriedades funcionais de filmes de proteína de soja e óleo essencial de orégano

Neste trabalho, avaliou-se o efeito da concentração de glicerol nas propriedades de filmes de proteína de soja (IPS) incorporados de óleo essencial de orégano (OEO). As concentrações de glicerol testadas foram de 20, 25 e 30 g de glicerol/100 g de IPS, e a concentração de OEO utilizada foi de 3% (m/m) em relação à solução filmogênica. O aumento na concentração de glicerol com a presença de OEO promoveu diminuição no módulo de Young, resistência à tração e aumento no alongamento à ruptura e permeabilidade ao vapor de água. Entretanto, em alta concentração de glicerol e OEO o filme mostrou migração aparente desses compostos. Filmes de IPS com OEO apresentaram atividade antimicrobiana frente a E. coli e S. aureus, e significativa atividade antioxidante (medida pelos métodos DPPH e ABTS), independentemente da concentração de glicerol. Os filmes apresentados são uma opção promissora de embalagens ativas ambientalmente corretas para serem utilizadas na conservação de alimentos.

Effects of glycerol concentrations on the bioproduction of PGHX by Agrobacterium HX1126

PGHX is a polymer of β (1-3)-galactose which posses the gel-forming property. As previously reported in the flask culture experiment, the crude PGHX (24.9 g/L, 48.2% in yield) with the maximum gel strength of 957 g/cm2 can be generated. However, PGHX produced in the stirred bioreactor had no gel-forming property when using the same medium. Hence, the effects of different glycerol concentrations on both the yield and the gel-forming property of PGHX were investigated and the reason for gel-forming property losing was explored. We proposed a new strategy for the production of PGHX with enhanced gel formation in the stirred bioreactor by mediating both the concentration of carbon source and the duration of fermentation. As a result, we managed to obtain the crude PGHX (22 g/L, 42.4% in yield) with the maximum gel strength of 438 g/cm2 at 56 h in the bioreactor. This strategy would help the enhancement of PGHX yield in the industrial production.

Effect of Glycerol Concentration and Heating Treatment on Delignification and Bioethanol Production of Sago Dregs

Effect of Glycerol Concentration and Heating Treatment on Delignification and Bioethanol Production of Sago Dregs

Use of a Plasticizer for Physical Stability Prediction of Amorphous Solid Dispersions

Utilizing glycerol as a plasticizer, an accelerated physical stability testing method of amorphous solid dispersions (ASDs) was developed. The influence of glycerol concentration on the glass transition temperature and α-relaxation time (a measure of molecular mobility) of amorphous ketoconazole, celecoxib, and the solid dispersions of each prepared with polyvinylpyrrolidone was investigated. By temperature scaling (Tg/T), the effects of glycerol concentration and temperature on the relaxation time were simultaneously evaluated. Glycerol, in a concentration dependent manner, accelerated crystallization in all of the systems without affecting the fragility. In celecoxib-PVP ASDs, the drug crystallization was well coupled to molecular mobility and was essentially unaltered at glycerol concentrations up to 2% w/w. The acceleration in crystallization brought about by glycerol expedited the determination of the coupling between molecular mobility and crystallization. As a result, we were able to predict the ph...

Effects of glycerol concentration on the motility of equine spermatozoa after thawing

The aim of this study was to evaluate the effect of different glycerol concentrations on stallion sperm motility after thawing. For statistical analysis 228 ejaculates were used. The semen was filtrated to remove gel fraction; macroscopic and microscopic evaluation was done. After evaluation the ejaculates were centrifuged, the supernatant was removed and the spermatozoa were re-suspended in French diluent with different concentrations of glycerol (2.0; 2.5; 4.0 and 6.0%). The choice of concentration of glycerol for a particular ejaculate was completely random. The spermatozoa were packed into 0.5 ml straws and placed for 2 h in a fridge (4 °C). Then the straws were placed in liquid nitrogen vapor (-80 to -100 °C) and after 10 min plunged into liquid nitrogen and stored at -196 °C for at least 48 h. The selected straws were individually thawed in a 38 °C water bath for 30 s prior to post-freezing analysis. Two progressive motilities using phase contrast microscopy (magnification × 400) were recorded: motility II immediately after thawing and motility III after 2 h incubation in a 38 °C water bath. The Spearmen/Kendall rang correlation test was selected to prove whether there is a correlation between the selected indices (glycerol concentration and motility II and motility III). Nonparametric multiple group analysis (Steel-Dwass test) was applied for finding the differences between groups. The Spearman/Kendall rang correlation proved a relationship between motility II and glycerol concentration. It can be stated that in this study the best glycerol concentration for freezing equine spermatozoa is with a concentration of 4.0% glycerol.

Anaerobic Degradation of Pure Glycerol for Electricity Generation using a MFC: The Effect of Substrate Concentration

Alternative glycerol treatment and valorization, could be a promising solution, contributing to the biodiesel production economy. Thus, the potential of electricity generation from pure glycerol, using a two-chamber microbial fuel cell (MFC), was evaluated. The effect of glycerol concentration in a range of 0.5–5.2 g COD L−1 on MFC performance was examined. In order to achieve a stable MFC performance and a high power density, special attention was paid during the acclimation phase of the anaerobic consortium, which was performed using glucose, instead of glycerol, as substrate. The best performance of the cell was observed at a glycerol concentration of 3.2 g COD L−1. At this concentration, the Coulombic efficiency (CE) was 34.1 %, the chemical oxygen demand (COD) removal efficiency was approximately 99 % and the maximum power density was 65.4 mW m−2. Further increase of glycerol concentration to 5.2 g COD L−1 did not enhance the MFC performance, since the power density remained at 63.4 mW m−2, while the CE and the COD removal efficiency decreased to 22.1 and 81 %, respectively. The experimental results showed that glycerol is a suitable and promising substrate for power generation, using a simple two-chamber MFC and that acclimation of anaerobic sludge using glucose as substrate, is a suitable procedure for securing a stable MFC performance, even at high glycerol concentrations.