Effect Of Glycerol Concentration Research Articles

Production of glutinous rice flour from broken rice via ultrasonic assisted extraction of amylose

In this study, a modified aqueous leaching method by complex formation of amylose with glycerol was employed for reducing the amylose content of starch in broken white rice to less than 2%, so that the resulting starch can be classified to that of glutinous rice flour. By employing ultrasonication in alkaline condition, extraction of amylose could be performed by washing at lower temperature in shorter time compared to the existing aqueous leaching method. The effects of glycerol concentration, alkali concentration, ultrasonication and treatment time on the amylose content of the treated starch were systematically investigated. Under optimum condition, amylose content of broken white rice starch can be reduced from 27.27% to 1.43% with a yield of 80.42%. The changes in the physicochemical properties of the rice flour before and after treatment were studied.

Effect of glycerol concentrations on the mechanical properties of additive manufactured porous calcium polyphosphate structures for bone substitute applications.

This article addresses the effects of glycerol (GLY) concentrations on the mechanical properties of calcium polyphosphate (CPP) bone substitute structures manufactured using binder jetting additive manufacturing. To achieve this goal, nine types of water-based binder solutions were prepared with 10, 12.5, and 15 wt % GLY liquid-binding agent, mixed, respectively, with 0, 0.75, and 1.5 wt % ethylene glycol diacetate (EGD) flow enhancer. The print quality of each of the solutions was established quantitatively using an image processing algorithm. The print quality analysis narrowed down the solutions to three batches containing 1.5 wt % EGD and variable amount of GLY. These solutions were used to manufacture porous CPP bone substitute samples, which were characterized physically to determine shrinkage, porosity, microstructure, and compression strength. The 12.5 wt % GLY, 1.5 wt % EGD solution resulted in the highest mechanical strength after sintering (34.6 ± 5.8 MPa), illustrating similar mechanical properties when compared to previous studies (33.9 ± 6.3 MPa) of additively manufactured CPP bone substitutes using a commercially available binder. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 828-835, 2017.

Microencapsulation of bovine spermatozoa: Cryopreservation microencapsulation of sperm using glycerol

Cryopreservation of spermatozoa has been used to preserve spermatozoa in very low temperatures. Glycerol is intracelullar cryoprotectant usually used in Tris citrate containing 20% egg yolk (TCEY), while TCEY-1.5% alginate was used as encapsulation media. The effect of alginate in microencapsulation process and glycerol concentration on viability spermatozoa (motility (%M), live sperm (%L) and intact apical ridge (%IAR) were studied in two steps. In the first step, the effect of alginate and microencapsulation process was studied. Three treatments of this step were: 1) TCEY add with semen (as control), 2) TCEY-Alginate add with semen, 3) TCEY-Alginate add with semen and microencapsulated, followed by conventional sperm cryopreservation using TCEY 7% glicerol. The second steps were done to evaluate the effect of two glycerol concentrations (5 and 7%) and two duration of equilibration time (3 and 4 hours). Result of these experiments showed, that microencapsulation was significantly alter the percentage of post-thawing motility (%M) and intact apical ridge (%IAR). The motility of microencapsulated sperm vs control was 44.7 and 50.83% respectively, whereas IAR 79.33% and 83.50% on microencapsulated sperm and control. There was evidence that alginate act as extracelullar cryoprotectant by protecting sperm during freezing. The mean of decreasing percentage of %M and %IAR in TCEY-Alginate were lower (15.97 and 6.44%) than control (23.80 and 7.37%). The effect of glycerol concentration and equilibration time on the viability of sperm was not significant different. There was no significant interaction of glicerol and equilibration time on the viability of spermatozoa. In conclution, microencapsulation processes altered the viability of sperm, alginate had an important roles as extracelullar cryoprotectant. Moreover the cryopreservation of microencapsulated sperm might be done using 5 or 7% glycerol in 3-4 hours duration of equilibration time. Key Words: Sperm, Alginate, Microencapsulation, Glycerol, Equilibration Time

Photocatalytic Hydrogen Production from Glycerol-water over Metal Loaded and Non-metal Doped Titanium Oxide

Modifications of the TiO2 P25 photocatalyst with metals: Platinum (Pt), Copper (Cu) and nonmetal: Nitrogen (N) doping to produce Hydrogen (H2) from a glycerol-water mixture have been investigated. The metals (Cu and Pt) were loaded into Titanium Dioxide (TiO2 ) surface by employing an impregnation and Photo-Assisted Deposition (PAD) method, respectively. As prepared the metal doped TiO2 photocatalyst was then dispersed into an ammonia solution to obtain N-doped photocatalysts. The modified photocatalysts were characterized by X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), and Ultraviolet-Visible Diffuse Reflectance Spectroscopy (UV-Vis DRS). XRD patterns indicated that the modified TiO2 photocatalysts have a nano-size crystallite range of 16-23 nm, while the DRS analysis showed that the doping of both metal and non-metal into TiO2 photocatalysts could effectively shift photon absorption to the visible light region. The optimum Cu loading of Cu-N-TiO2 was found to be 5%, resulting in a 10 times higher H2 production improvement level when compared to unloaded TiO2, even though this is still considered to be inferior compared to that of a 1% Pt loading, which results in a 34 times higher level than an unmodified TiO2 photocatalyst. The effect of glycerol concentrations on hydrogen production has also been studied. This method offers a promising technology to find renewable and clean energy by using cheap materials and a simple technology.

Edible film production from chia seed mucilage: Effect of glycerol concentration on its physicochemical and mechanical properties

This study investigated the physicochemical and mechanical properties of a novel edible film based on chia mucilage (CM) hydrocolloid. CM (1% w/v) films were prepared by incorporation of three concentrations of glycerol (25%, 50%, and 75% w/w, based on CM weight). As glycerol concentration increased, water vapor permeability (WVP), elongation at break (EB), and water solubility of CM films increased while their tensile strength (TS), and Young's modulus (YM) decreased significantly (p<0.05). CM films containing a high concentration of glycerol were slightly reddish and yellowish in color but still had a transparent appearance. CM films exhibited excellent absorption of ultraviolet light, and good thermal stability. The scanning electron micrographs showed that all CM films had a uniform appearance. This study demonstrated that the chia mucilage hydrocolloid has important properties and potential as an edible film, or coating.

BIODEGRADABILITY AND MECHANICAL BEHAVIOUR OF SUGAR PALM STARCH BASED BIOPOLYMER

A new Sugar Palm Starch (SPS) based biopolymer was successfully developed using glycerol as plasticizer. The effect of glycerol concentration (viz., 15, 20, 30 and 40 by weight percent) to the mechanical properties of plasticized SPS biopolymer was investigated. From this investigation, it was found that the 30% glycerol concentrated biopolymer showed the highest flexural strength and impact with the value of 0.13 MPa and 6.13 kJ/m 2 respectively. Later, the above 30% glycerol biopoly mer was undergone through weathering and biodegradation test. The biodegradability test showed 78.09% of tensile strength lost after 72 h of weathering test ing period. Meanwhile, the weight loss (%) of the s ame biopolymer was 63.58% after 72 h of biodegradation test.

Influence of Glycerol and Temperature on the Rheological Properties of Potato Starch Solutions

Abstract Effects of temperature and glycerol concentration on rheological properties of potato starch solutions were investigated. The flow behaviour (shear stress against shear rate) was fitted to various models: power law, Herschel-Bulkley, Bingham, modified Bingham and Casson models. However, it was found that the Herschel-Bulkley model describes better the flow behaviour observed at various temperatures and glycerol concentrations, for flow behaviour index values between 0.44 and 0.78, typical of pseudoplastic solutions. The effect of glycerol concentration on each of the fitting parameters for Herschel-Bulkley model was well modelled by a second-degree polynomial at various temperatures. The simultaneous influence of glycerol concentration and temperature on shear stress could be represented empirically by a second-degree polynomial function that includes linear coupling between concentration and temperature. Finally, the variation of the consistency coefficient with both temperature and glycerol concentration was well described by an exponential expression, with an activation energy value of 2.78 kJ mol-1. The results indicate that both glycerol content and temperature have the effect of diluting potato starch solutions.

효소 가수분해 향상을 위해 고압조건에서 Glycerol 수용액을 사용한 폐지의 전처리

Pretreatment of wastepaper using aqueous glycerol under high pressure was studied to enhance the enzymatic hydrolysis. The pretreatment was conducted over a wide range of conditions including temperatures of <TEX>$150{\sim}170^{\circ}C$</TEX>, sulfuric acid concentrations of 0.5~1.5%, and reaction times of 30~90 minutes. After the effect of glycerol concentration on the pretreatment performance was investigated, 70% glycerol was selected. As glycerol concentration was increased, higher digestibility was achieved due to higher lignin removal. The optimum condition was found to be around <TEX>$160^{\circ}C$</TEX>, 1%, and 60 minutes. At this condition, 60% and 35% of hemicellulose and lignin, respectively, were removed, while only 5% of cellulose was lost. The enzymatic digestibility was 76%, meaning that 73% of the glucan present in the initial substrate was recovered as glucose after enzymatic hydrolysis. Also, it was found that the temperature and acid concentration than the reaction time were more strongly related to the compositional removals and enzymatic digestibility.

Flexural and Impact Properties of Biopolymer Derived from Sugar Palm Tree

The effect of glycerol concentration (15 w/w%, 20 w/w%, 30 w/w% and 40 w/w%) to the flexural and impact properties of plasticized sugar palm starch (SPS) was investigated in this present paper. Prior to the testing, the sugar palm starch extracted from the interior part of sugar palm stem was mixed with common glycerol (was used as a plasticizer) to form a novel biopolymer. The flexural and impact test were carried out according to ASTM D790 and ASTM 256 respectively. From this investigation, it is found that the 30% glycerol concentrated SPS biopolymer showed the highest flexural strength and flexural modulus with the value of 0.13 MPa and 87.54 MPa respectively. For the impact analysis, it is also found that same biopolymer showed the highest impact strength which is 6.13kJ/m2.

Effect of glycerol concentration on edible film production from cress seed carbohydrate gum

In this study an edible film plasticized with glycerol was successfully prepared from cress seed gum (CSG). The physical, optical, water vapor permeability (WVP) and mechanical properties of CSG films incorporated with three levels of glycerol (25%, 35%, and 50% w/w) as plasticizer were determined. Dynamic mechanical thermal analysis was used to determine the glass transition temperature. WVP of the films was found to increase as the glycerol content increased from 25% to 50% w/w in the formulation, resulted in improvement of films flexibility and significantly lower tensile strength and higher elongation at break. The color measurement values showed that increasing the glycerol concentration in polymer matrix caused the b and L values increased while ΔE value decreased. The electron scanning micrograph indicated smooth and uniform surface morphology without signs of phase separation between the film components. The results of the present study demonstrated that CSG can promisingly be used in producing edible films with improved quality characteristics.

Effect of glycerol concentration and temperature on the rheological properties of cassava starch solutions

Abstract Glycerol/starch (G/S) solutions were prepared at different concentrations, with a weight ratio of G/S=0.0, 0.1, 0.2, 0.3, 0.4 and 0.5, and rheological properties were analyzed at 30, 40, 50, 60 and 70°C. Power law dependency of the apparent viscosity as a function of the shear rate is the most appropriate model for describing the rheological behavior of cassava starch solutions as a function of glycerol concentrations. All solutions showed a pseudoplastic behavior; the flow index (n) did not show significant changes as a function of temperature and glycerol concentration. However, the apparent viscosity (μa) and the consistency coefficient (K) did show strong variations with temperature and glycerol content. The temperature variation of both μa and K were better fitted to an exponential model type exp(Ea /RT), logμa(K) vs. 1000/T. The activation energy of the K data for the solution without glycerol (G/S=0.0) was 13.64 KJ/mol, and it decreased with increasing the content of glycerol in the solutions, becoming 6.14 KJ/mol for G/S=0.5. On the contrary, the activation energy for the μa data increased when increasing the glycerol concentration. The effect of glycerol concentration was also modeled using polynomial and exponential fittings.

The Effect of Glycerol Concentrations on the Post‐thaw In Vitro Characteristics of Cryopreserved Sex‐sorted Boar Spermatozoa

The objective of this study was to optimize protocols for the cryopreservation of sex-sorted boar spermatozoa. In the experiment 1, we evaluated the effects of a standard boar sperm cryopreservation procedure (3% final glycerol concentration) on the in vitro characteristics of sex-sorted sperm frozen at low sperm concentrations (20 × 10(6) sperm/ml; S20 group). Non-sorted spermatozoa frozen at 1000 × 10(6) (C1000 group) and 20 × 10(6) (C20 group) sperm/ml were used as the freezing control groups. In experiment 2, the effects of different final glycerol concentrations (0.16%, 0.5%, 1.0%, 2.0% and 3.0%) on post-thaw quality of the S20 and C20 groups were evaluated. In both experiments, the samples were evaluated prior to freezing (5°C) and at 30, 90 and 150 min after thawing. Experiment 1 indicated that freezing sperm at low concentrations decreased (p < 0.05) the total motility (TM) and progressive motility (PM) at 90 and 150 min after thawing regardless of whether the sperm were sorted or not. However, the sperm membrane integrity was not affected at any evaluation step. Inexperiment 2, significant effects on the TM and PM because of increased glycerol concentrations in the S20 and C20 groups were observed only at 90 and 150 min after thawing. The samples frozen in 3% glycerol showed lower (p < 0.05) TM and PM values when compared to those frozen in the presence of 0.5% and 1% glycerol. In both experiments, non-sorted control samples displayed higher percentages of spermatozoa with damaged DNA than sorted spermatozoa. In conclusion, the optimization of cryopreservation conditions by decreasing the glycerol concentrations can improve post-thaw motility of sex-sorted spermatozoa frozen at low concentrations.

Substrate preference and oxygen requirement for cyanophycin synthesis by recombinant Escherichia coli

Abstract Cyanophycin (CGP) is a bacterial bioproduct having a straight-chain poly(aspartic acid) as a backbone with arginine pendant groups attached to it. It has many potential industrial applications in the areas of water softening, hydrogel, metal–ion chelation, and nutriceuticals. Biotechnological production of CGP employs as producing strains the recombinant organisms that express heterologous cyanophycin synthase (cph) gene. A systematic study of fermentation parameters influencing CGP synthesis by a recombinant Escherichia coli expressing a cphA of Synechocystis sp. showed that high aeration conditions as provided by 400 rpm stirrer speed and 1.0 L/min air flow in a Sixfors vessel (450 mL culture working-volume) resulted in high yields of cell biomass and crude CGP product. Glycerol substrate was found to yield 1.8-times higher crude CGP than glucose did under similar conditions. With glycerol as substrate, we found that a simplified fermentation scheme consisting of a straight 48-h fermentation at 37 °C (without a 30–37 °C temperature-shifting induction step) yielded compatible or higher amounts of crude CGP as those obtained under various temperature-shifting conditions. By studying the effects of glycerol concentration on CGP yields and analyzing glycerol consumption patterns, we demonstrated that substrate-to-product conversion could be increased by at least 15% and that costly leftover of unused substrate could be alleviated. The results yielded valuable information for optimization of fermentative production of CGP using glycerol that could be obtained as surplus coproduct from biodiesel production.

Effect of glycerol and coating weight on functional properties of biopolymer-coated paper

The effects of glycerol concentration and coating weight on biopolymer-coated paper properties were investigated using response surface methodology. Tests were run on the coated papers to determine water vapor barrier and mechanical properties. Coating weight was the most important parameter affecting water vapor permeability (WVP). Conversely, increasing coating weight led to a decrease in WVP and to an increase in tensile strength (TS) of the resulting coated papers. The papers coated with sodium caseinate (NaCAS) exhibited lower WVP values than those coated with other biopolymers. The TS of the papers coated with hydroxypropylmethylcellulose (HPMC) and chitosan was not affected by the glycerol concentration. HPMC-coated papers were higher in TS and %E than the other coated papers. For all types of coated paper, a maximum level of coating weight and level of glycerol concentration within range of 18.72–26.11% were found to be optimum for minimum WVP and maximum TS and %E.

Renewable hydrogen generation by steam reforming of glycerol over zirconia promoted ceria supported catalyst

The study focuses on hydrogen production from steam reforming of glycerol over nickel based catalyst promoted by zirconia and supported over ceria. Catalyst was prepared by the wet-impregnation method and characterized by BET surface area analysis, X-ray diffraction technique and scanning electron microscopy (SEM) analysis. The performance of the catalyst was evaluated in terms of hydrogen yield, selectivity and glycerol conversion at 700 °C in a tubular fixed bed reactor. The effect of glycerol concentration in feed, space time ( W/ F AO), temperature and time on stream (TOS) was analyzed for the catalyst Ni–ZrO 2/CeO 2 which showed the complete conversion of glycerol and high H 2 yield that corresponds to 3.95 mol of H 2 out of 7 mol. Thermodynamic analysis was also carried out using Aspen HYSYS for system having glycerol concentration 10 wt% and 20 wt% and experimental results were compared with thermodynamics. Kinetic study was carried out for the steam reforming of glycerol over Ni–ZrO 2/CeO 2 catalyst using the power law model. The values of activation energy and order of reaction were found to be 43.4 kJ/mol and 0.3 respectively.

Biosynthesis of Ethanol and Hydrogen by Glycerol Fermentation Using &amp;lt;i&amp;gt;Escherichia coli&amp;lt;/i&amp;gt;

Production of high value products from glycerol via anaerobic fermentation is of utmost importance for the biodiesel industry. The microorganism Escherichia coli (E. coli) K12 was used for fermentation of glycerol. The effects of glycerol concentration and headspace conditions on the cell growth, ethanol and hydrogen production were investigated. A full factorial experimental design with 3 replicates was conducted in order to test these factors. Under the three headspace conditions tested, the increase of glycerol concentration accelerated glycerol fermentation. The yields of hydrogen and ethanol were the lowest when glycerol concentration of 10 g/L was used. The maximum production of hydrogen was observed with an initial glycerol concentration of 25 g/L at a final concentration of hydrogen was 32.15 mmol/L. This study demonstrated that hydrogen production negatively affects cell growth. Maximum ethanol yield was obtained with a glycerol concentration of 10 g/L and was up to 0.40 g/g glycerol under membrane condition headspace. Statistical optimization showed that optimal conditions for hydrogen production are 20 g/L initial glycerol with initial sparging of the reactor headspace. The optimal conditions for ethanol production are 10 g/L initial glycerol with membrane.

129 IMPROVEMENT OF BOAR SPERM CRYOSURVIVAL BY THE OPTIMIZATION OF CRYOPRESERVATION CONDITIONS

One of the most important limiting factors for the efficient commercial application of frozen–thawed semen on pig artificial insemination programs is the significant and consistent inter-boar variability in sperm cryosurvival. The objective of the present study was to evaluate the effectiveness of different cryopreservation conditions (CCs) for freezing and thawing boar spermatozoa, and to determine their suitability for individual boars, with particular reference to those that showed an intrinsic poor sperm cryosurvival. Using a split-ejaculate technique, single ejaculates from 53 boars were suspended in lactose-egg yolk extender containing 2 or 3% final glycerol concentration, packaged in 0.5-mL straws, cooled at rates of 10, 40, or 60�C min-1 using a programmable cell freezer, and stored in liquid nitrogen; the frozen samples were warmed at ≈1200�C min-1 (37�C water bath for 20 s) or ≈1800�C min-1 (70�C for 8 s). The cryopreservation condition including 2% glycerol, 40�C min-1 of cooling, and ≈1200�C min-1 of warming was considered as the control. Frozen–thawed sperm were evaluated at 30 and 150 min post-thawing for sperm motility (CASA system), plasma membrane integrity (SYBR-14 and propidium iodide), and acrosome membrane integrity (FITC-peanut agglutinin and propidium iodide). Data were analyzed using 2 different ANOVA mixed models. Whereas cooling rate had no influence (P ≥ 0.05), glycerol concentration and warming rate, both independently, affected (P ≤ 0.05) all post-thawing sperm assessments. No interaction (P ≥ 0.05) among effects was detected for any of the sperm parameters assessed. Evaluating the combined effect of glycerol concentration and warming rate, the highest post-thaw sperm quality was achieved from the semen samples frozen with 3% of glycerol and thawed at ≈1800�C min-1. Significant differences (P ≤ 0.05) among ejaculates (boars) to support the different CCs were shown in all post-thaw sperm assessments. Three different (P ≤ 0.05) ejaculate (boar) populations, defined by PATN analysis (PATN software package, CSIRO, Canberra, Australia), were identified according to post-thaw sperm assessments in semen samples frozen and thawed using control CC (populations so-called 'good', 'moderate', and 'bad' sperm freezers). Different (P ≤ 0.05) susceptibility in the tolerance of spermatozoa to support the different CCs was found among the ejaculate populations. Whereas spermatozoa from ejaculates considered as 'good' freezers are relatively unaffected (P ≥ 0.05), those from 'moderate' and, mainly, 'bad' freezers are very sensitive (P ≤ 0.05) to the modifications in the CCs. In conclusion, slight modifications in the CCs — glycerol concentration and warming rate for thawing — can improve the sperm cryosurvival of some ejaculates (boars), the improvement being particularly larger in those ejaculates (boars) classified as ' bad' sperm freezers. This work was supported by CICYT (AGF2005-00760), Madrid, Spain.

Role of membrane transport of water and glycerol in the freeze tolerance of the rice stem borer, Chilo suppressalis Walker (Lepidoptera: Pyralidae)

Overwintering larvae of the rice stem borer, Chilo suppressalis accumulate glycerol and are freezing tolerant to about −25 °C. However, non-diapausing larvae cannot accumulate glycerol and are killed by freezing. We compared the extent of tissue damage, the effects of glycerol concentration, and the transport of glycerol and water in fat body tissues from these larvae at selected freezing temperatures. Tissues from overwintering larvae, but not non-diapausing larvae, survive when frozen at −20 °C with 0.25 M glycerol, but the protection afforded by glycerol is offset by the water-channel inhibitor mercuric chloride. Glycerol in higher concentration (0.75 M) affords some protection even to the fat body of non-diapausing larvae. Radiotracer assays of overwintering larvae show that water leaves the tissues during freezing while glycerol enters, and that mercuric chloride disrupts this process. Transport is also disrupted after lethal freezing at −35 °C. Therefore, membrane transport of water and glycerol is involved in the avoidance of freezing injury to fat body cells of the rice stem borer, apparently by mediating the replacement of water with glycerol in freezing-tolerant tissues.

Three-factor response surface optimization of the production of intracellular dextran dextrinase by Gluconobacter oxydans

The production of intracellular dextran dextrinase (DDase) by Gluconobacter oxydans ATCC 11894 was studied in fermentations with various carbon and nitrogen sources. Glycerol and mycological peptone resulted in highest enzyme yields. The effect of glycerol concentration, mycological peptone concentration and initial pH on DDase production was investigated by means of a five-level three-factor central composite rotatable design (CCRD). Only the peptone concentration showed a significant linear main effect on enzyme production. Optimum fermentation parameters were 20.59 g/l of glycerol, 6.67 g/l of mycological peptone and an initial pH of 6.14. The predicted DDase yield was 0.207 U/ml, whereas an actual experimental value of 0.208±0.025 U/ml was obtained.

Three-factor response surface optimization of the production of intracellular dextran dextrinase by Gluconobacter oxydans

The production of intracellular dextran dextrinase (DDase) by Gluconobacter oxydans ATCC 11894 was studied in fermentations with various carbon and nitrogen sources. Glycerol and mycological peptone resulted in highest enzyme yields. The effect of glycerol concentration, mycological peptone concentration and initial pH on DDase production was investigated by means of a five-level three-factor central composite rotatable design (CCRD). Only the peptone concentration showed a significant linear main effect on enzyme production. Optimum fermentation parameters were 20.59 g/l of glycerol, 6.67 g/l of mycological peptone and an initial pH of 6.14. The predicted DDase yield was 0.207 U/ml, whereas an actual experimental value of 0.208±0.025 U/ml was obtained.