Gel Viscosity Research Articles

Design and development of instant linear gel for coal bed methane gas operations

Linear gel fracturing fluids are expressed with an extensive range of materials/polymers in an aqueous base. Earlier we developed fracturing linear gel with fossil diesel, bio-diesel and also used suspending anti-settling agents and emulsifiers. Here we report on a novel and an efficient method for the preparation of linear gel direct mix with water, guar gum and sodium acetate together instantly. In this research work, we used water instead of diesel without any need to mix anti-settling agents, suspending agents, emulsifiers that resulted in 30 viscosity linear gel. The degradation pattern observed from the breaker test showed that a reduction in gel viscosity depends on time, temperature & breaker concentration. Ammonium per sulphate or Ammonium per oxidisulphate and enzyme-G were used for oxidation purpose to break the gel gradually at a particular static temperature. Observations from experiments revealed that a small concentration of breaker provides rapid break compared to oxidative breakers. This article, designing of fracturing fluids describes how to use the fluid's viscosity generated by the gelling agents like guar gum for CBM operations.

Novel eco-friendly linear gel for oil well recovery through efficient hydrofracturing

The linear gel is prepared by treating bio-diesel with various water samples collected from different water bodies. The new biodiesel based linear gel was employed in the recovery of oil wells through hydrofracturing and pilot tests were conducted for the first time. The viscosity of gel was measured at various bottom hole-circulating temperatures and it was found to vary from 32 to zero dial reading in the range of 45ºC to 60ºC. The gel was observed to break at 45ºC and 60ºC in 120 min. So the final temperature was selected as 60ºC for the application of gel for coal bed methane (CBM) wells. It was observed that higher levels of salinity in water helped in optimum utilization of gel in real-time application.

Tailoring the properties of double-crosslinked emulsion gels using structural design principles: Physical characteristics, stability, and delivery of lycopene

Lycopene is claimed to have numerous physiological benefits, but its poor water solubility, chemical instability, and low bioavailability limit its application in functional foods and health care products. In this study, lycopene-loaded emulsions containing oil droplets with different interfacial structures were prepared and then cross-linked using transglutaminase (TG) and/or calcium ions (Ca2+) to form emulsion gels. The oil droplets were first coated by interfacial layers comprised of whey protein isolate (WPI) and sodium alginate (SA). During emulsion preparation, the SA was added either before or after homogenization to create complex or layer-by-layer coatings, respectively. Subsequently, TG and Ca2+ were used to cross-link WPI and SA to form emulsion gels. The results show that double-crosslinking increased the gel strength and viscosity of the emulsion gels. The layer-by-layer emulsion gels were stronger and more viscous than the complex ones. The photochemical and gastrointestinal stability of lycopene encapsulated within the emulsion gels was higher than that of free lycopene. An MTT toxicity test showed that the emulsion gels exhibited no cytotoxicity to Caco-2 cells. The lycopene-loaded emulsion gels exhibited stronger anti-inflammatory activity on the Caco-2 cells than the control. In addition, the absorption of lycopene by the Caco-2 cells increased after encapsulation. This study provides a new approach of preparing edible soft materials to enhance the application of hydrophobic bioactives (like lycopene) in functional foods.

Improving quality attributes of sweet dumplings by germination: Effect of glutinous rice flour microstructure and physicochemical properties

Current sweet dumplings made by raw waxy rice flour have some unsatisfactory storage and cooking quality such as high cracking rate and too sticky for swallowing. Hence, in order to produce high-quality dumplings, impacts of germination on microstructures and physicochemical characteristics of glutinous rice flours were evaluated, and how these technological properties affected dumpling quality was illustrated. It can be observed that germination reduced the relative crystallinity (from 29.15% to 26.00%) and short-range ordered degree of rice flour, which led to the increasement of swelling power for rice flour, but dramatically decreasing the characteristic viscosity and rigidity of flour paste and gel. And transformations of flour technological properties lowered the water mobility, water loss and cracking rate of sweet dumplings. Moreover, decreases in hardness, gumminess and adhesiveness were found in cooked germinated dumplings, and PCA analysis displayed significant correlations among flour microstructures, physicochemical characteristics, and textural quality of sweet dumplings. This study is beneficial to develop high-quality sweet dumplings through designing the microstructures and functionalities of rice flour with germination.

Structural and functional properties of collagen from tilapia scales pretreated by heat‐assisted ionic liquids

AbstractThis paper explores the structural and functional properties of collagen from tilapia scales pretreated by heat‐assisted ionic liquids (ILs). Results show that the solubility of collagen was significantly influenced by the type and concentration of ILs. With the increase of IL concentration, a remarkable decrease in solubility of collagen was seen. Fluorescence spectra show that heat and IL pretreatments induced the exposure of chromophores. Changes in sodium dodecyl sulfate–polyacrylamide gel electrophoresis indicated that subunits of collagen regenerated from most of the IL solvent systems were not destroyed. The functional properties of regenerated collagen were evaluated by gel strength, viscosity, water‐binding capacity, and emulsifying capacity. Results show that all heat‐assisted ILs pretreatments improved the gel strength and viscosity, and the highest gel strength and viscosity were both obtained in the collagen pretreated by heat‐assisted [EMIM]Cl. Heat‐assisted [BMIM]BF4 pretreatment exhibited the lowest water‐binding capacity. Heat‐assisted [BDMIM]Cl pretreatment indicated superior effect on improving emulsifying capacity than other pretreatments due to its ability to break most of the hydrogen bonds in collagen molecules, resulting in the formation of new re‐aggregates with higher solubility and more hydrophobic groups.

Quality of gelatin from tilapia (Oreochromis niloticus) by-products and its effects as edible coating on fish sausage during chilled storage

Gelatin is a hydrolysed collagen that can be used as raw material for edible coatings to protect perishable foods such as fish sausage. This study aims to examine the quality of gelatin from tilapia by products (skin, scale, bone) and determine the best source of fish gelatin as edible coating on quality of tilapia sausage during chilled storage. The process of made skin gelatin was demineralized with acetic acid while scale and bone were demineralized by hydrochloric acid. Gelatin was examined for yield, gel strength, and viscosity. After edible coatings were applied to the sausages by dipping method, the sausages were stored in the refrigerator at ±5°C for 21 days. Quality deterioration of sausages during storage were measured by sensory value, moisture content, TPC, gel strength and color. The results showed that the highest gelatin yield was obtained from tilapia scales, which was 6.87% while the yield of skin and bone were 4.33% and 1.47% respectively. The best material for edible coating was bone gelatin with gel strength and viscosity which were 325 bloom and 7.10 cP respectively. The application of sausage, where the appearance and texture of sensory value were still acceptable until 21st days of storage. Sausages with edible coating from tilapia bone also showed the highest gel strength about 2514,99-3716,05 g.cm.

Composition of carbopol 940 and HPMC affects antibacterial activity of beluntas (Pluchea indica (L.)) leaves extract gel

Indonesia is a country known for its source of biological wealth, one of which is beluntas leaves. Beluntas leaves have the potential to be an antibacterial, so it is appropriate to be formulated in the form of medicinal preparations, especially gels. This study aims to find out the influence of variations between carbopol gel base 940 and Methylcellulose Hydroxypropyl (HPMC) on the physical properties of gel preparations beluntas leaf extract ( Pluchea indica (L.), and know the influence of gel of extract of beluntas leaves on antibacterial activity. The extract is obtained by the maceration method using ethanol solvent 96%. Each formula uses 15% of the extract of beluntas leaves. Gels are made in four gel base variations namely F0 (0.5% carbopol, 1% HPMC), FI (1% carbopol, 1.5% HPMC), FII (1.5% carbopol, 2.5% HPMC), and FIII (2% carbopol, 3% HPMC). Gels evaluated for their physical properties include organoleptic, viscosity, pH, homogeneity, scattering power, adhesion and Freeze-thaw cycling . Then the gel tested antibacterial activity against bacteria Staphylococcus aureus and Pseudomonas aeruginosa by cup-plate diffusion method . The data obtained were analyzed with One Way Anova and LSD with a 95% confidence level. The results showed that beluntas leaf extract gel meets the organoleptic requirements, homogeneity, good gel adhesion (> 4sec), good gel viscosity (2000-50.000 cps), and good gel pH (4.5-6.5). However, the gel does not meet the requirements of good scattering power (5-7 cm) and Freeze-thaw cycling. Based on the test results that have been done with some of the parameters above, The best composition of carbopol 940 and HPMC in the beluntas leaf extract gel which has antibacterial activity against Staphylococcus aureus and Pseudomonas aeruginosa is 1% carbopol and 1.5% HPMC. The antibacterial activity of the formula is categorized as strong.

DESIGN AND DEVELOPMENT OF LULICONAZOLE LOADED MESOPOROUS SILICA NANOPARTICLES AS HYDROGEL FOR MYCOTIC DISEASES

The aim of the present work was to design and synthesize of mesoporous silica nanoparticles as topical hydrogel formulation for inclusion of poorly water soluble antifungal drug like Luliconazole as a drug delivery platform. The SBA-15 was prepared to evaluate its application as a carrier for Luliconazole drug delivery. Its molecular size was suitable for incorporation in to the mesoporous of the SBA-15 materials. The SBA-15 was characterized by FTIR, UV analysis, Particle size, Transmission electron microscopy. The Synthesized Mesoporous silica i.e. SBA-15 was of mean particle size of 15 nm and specific area 283.763m2/g respectively. The results revealed that prepared mesoporous silica have small particle size, high surface area, and enhanced drug dissolution rate. The results obtained showed that Luliconazole was loaded with great efficiency into the SBA-15 which leads to enhanced diffusion of drug. Luliconazole hydrogel formulations improved medication permeation across the skin appropriate polymer was used to produce the formulation (Carbopol 934p and HPMC). The physiochemical parameters of all the established luliconazole formulations were assessed, including gel appearance, pH, viscosity, spreadability, globule size, Zeta potential, and drug content. Many of the above parameters yielded positive outcomes but F1 and F3 batch results was were unacceptable ranges. It can be assumed that the formulation F1 and F3 resulted in improved spreadability, stability, and homogeneity, as well as a stronger drug release analysis.

A Comparison among Lignin Modification Methods on the Properties of Lignin-Phenol-Formaldehyde Resin as Wood Adhesive.

The research aim of this work is to determine the influence of lignin modification methods on lignin–phenol–formaldehyde (LPF) adhesive properties. Thus, glyoxal (G), phenol (P), ionic liquid (IL), and maleic anhydride (MA) were used to modify lignin. The modified lignins were used for phenol substitution (50 wt%) in phenol–formaldehyde adhesives. The prepared resins were then used for the preparation of wood particleboard. These LPF resins were characterized physicochemically, namely by using standard methods to determine gel time, solids content, density, and viscosity, thus the physicochemical properties of the LPF resins synthesized. The panels dimensional stability, formaldehyde emission, bending modulus, bending strength, and internal bond (IB) strength were also measured. MA-modified lignin showed by differential scanning calorimetry (DSC) the lowest temperature of curing than the resins with non-modified lignin and modified with IL, phenolared lignin, and glyoxal. LPF resins with lignin treated with maleic anhydride presented a shorter gel time, higher viscosity, and solids content than the resins with other lignin modifications. Equally, the particleboard panels prepared with LPF resins with maleic anhydride or with ionic liquid had the lowest formaldehyde emission and the highest mechanical strength among all the synthesized resins. The dimensional stability of all panels bonded with modified lignin LPF resins presented no difference of any significance.

Agar Extraction, Physical Properties, FTIR Analysis and Biochemical Composition of Three Edible Species of Red Seaweeds Gracilaria corticata (J. Agardh), Gracilaria dentata (J. Agardh) and Gracilariopsis longissima (S. G. Gmelin)........

Three species of red algae Gracilaria corticata (J. Agardh), Gracilaria dentata (J. Agardh) and Gracilariopsis longissima (S.G. Gmelin), Steentoft, L. M; Irvine and Farnham (formerly Gracilaria verrucosa (Hudson) were collected from four different sites (Buleji, Hawks Bay, Manora and Paradise Point) of Karachi coast. The G. corticata was the dominant species and the highest yield of agar was compared to other studied species. The physical properties such as gel temperature, melting temperature, density, viscosity and gel strength showed large variations. Interestingly, the gel temperature, melting temperature, density, and gel strength had the highest value in G. corticata samples collected, while gel viscosity recorded the highest value in G. dentata samples. Intensive spectroscopic FTIR analysis was determined in all three species of G. corticata, G. dentata and G. longissima. The bands at 414.7/cm to 3917.2/cm represents stretching and bending vibrations of alcohol O-H, amine N-H, alkane C-H, alkyne C=C, nitriles C=N, carboxyl C=O, nitro aromatic N=O, alkane C-C, nitro methane C-N, aliphatic amines C-N, sulfoxides S=O, alkene C-H alkyl halide C-Cl, C-I groups. The ash content of all studied species (G. corticata, G. dentata and G. longissima) was in the range of 20-30%, while the carbohydrate content was in the range of 22-24%. The results of this study suggested the utilization of our natural resources present in Karachi coast. This could be achieved by determining the quantity and quality of agar in the edible species of Gracilaria/Gracilariopsis.

Understanding the fermentation factors affecting the separability of fermented milk: A model system study

The demand for high-protein fermented milk products is globally increasing. The effect of added starter culture, cutting pH and fermentation temperature on separability, i.e., how well curd and whey separate, were evaluated in a model system aiming to resemble Greek-style yoghurt. Skim milk was fermented with three commercial starter cultures at 39 °C or 43 °C to a pH of 4.45 or 4.60. Stirred fermented gels were concentrated to produce high-protein (~10%) fermented milk. The starter culture influenced the microstructure as well as the association (interactions) between exopolysaccharides (EPS) with the surface of the protein aggregates. The high association of EPS increased the viscosity and gel strength of the fermented model gels and decreased the zeta potential, the amount of whey removed as well as the protein and total solids concentration in the white mass. Increased fermentation temperature (from 39 °C to 43 °C) resulted in increased particle size and zeta potential values when EPS-producing starter cultures were applied. Cutting pH did not influence the separability of fermented stirred gels. The presence of EPS and pronounced association with protein increased the particle size, negative surface charge and structural rigidity, establishing a more stable system with reduced separability.

Study of the use of Gracilaria sp from the Karawang Area and Ulva lactuca as raw material making of Nori

Nori is processed seaweed in the form of dried sheets, generally consumed by Japanese and Korean people. The seaweed used as raw material is Porphyra sp which generally grows in Japan and Korea, so Indonesia has to import more and more nori. Porphyra seaweed is the raw material for making imported nori. Porphyra is not found in Indonesia because the seaweed lives in a subtropical climate. Therefore, it is necessary to look for alternative raw materials besides Porphyra. Indonesian waters have various types of seaweed, one of which is Ulva lactuca seaweed. Ulva Lactuca is one of the red algae plants and belongs to the class Chlorophyceae, shaped like sheet talus like lettuce. Ulva Lactuca has similar characteristics to Porphyra seaweed in terms of texture and color besides that Ulva Lactuca is rich in acrylic acid which functions as an antibiotic, is a source of protein, folic acid, and several types of minerals such as: Ca, K, Mg, Na, Cu, Fe, Zn. Apart from the type of Ulva Lactuca, there are also types of Gracilaria verrucosa often found in Karawang waters. Gracilaria produced in these waters has quite high gel strength and viscosity. The advantages of these properties are expected to improve the quality of the nori products produced. For this reason, in this applied research a study was conducted to make nori with a combination of Gracilaria sp and Ulva sp. Ulva sp (sea lettuce) used is Ulva Lactuca in Pangandaran waters. The manufacturing process begins with washing the seaweed and soaking the seaweed for 6 hours. Ulva Lactuca soaked in NaCl solution with a weight ratio of seaweed: water: salt = 2: 60: 5, soaking seaweed Gracilaria sp. in a solution of rice vinegar with a weight ratio of seaweed: water: rice vinegar = 2: 60: 1. Experiments were carried out in 4 weight ratios of Gracilaria sp. that is different, namely: sample 1 = 100% Ulva lactuca, sample 2 = 97.15% Ulva lactuca: 2.85% Gracilaria sp., Sample 3 = 98% Ulva lactuca: 2% Gracilaria sp., and sample 4 = 99% Ulva lactuca: 1% Gracilaria sp.

A bottom-up evaluation on cryoprotective potentials of gelatine from fish scale

The potential health risks and high cost of current cryoprotectants have emphasised the need to develop antifreezes with high safety and low expense. Gelatine is a promising alternative to these cryoprotectants due to its inherent structural attributes and high availability. In this study, the feasibility of three types of gelatines (gelatine A, B and P) as cryoprotectants in terms of the secondary structure and gel properties related to antifreeze performance was comprehensively investigated. Sodium dodecyl sulphate–polyacrylamide gel electrophoresis analysis patterns suggested that gelatine A had the lowest structural stability upon freeze–thaw (F–T) treatments, which was confirmed by the presence of low-molecular-weight fragments. The two-dimensional correlation infrared spectroscopy indicated that gelatine P had the greatest stability and highest sensitivity to F–T treatments according to changes in the polyproline type II helix structure. Gelatine B showed the lowest gel strength and viscosity compared with the two other gelatines when subjected to the same F–T cycles, which may be ascribed to the loose and inhomogeneous microstructure of gelatine B due to its impaired molecular structure. Gelatine P may be the promising antifreeze used for cryoprotection of the frozen food via the further modifications. This work may provide some valuable guidelines for the development of novel cryoprotectants from the perspective of bottom-up strategies.

Synthesis and Aqueous Solution Properties of Shape-Shifting Stimulus-Responsive Diblock Copolymer Nano-Objects

We report the synthesis of poly(N-(2-acryloyloxyethyl)pyrrolidone)-poly(4-hydroxybutyl acrylate) (PNAEP85-PHBAx) diblock copolymer nano-objects via reversible addition–fragmentation chain transfer (RAFT) aqueous dispersion polymerization of 4-hydroxybutyl acrylate (HBA) at 30 °C using an efficient two-step one-pot protocol. Given the relatively low glass transition temperature of the PHBA block, these nano-objects required covalent stabilization prior to transmission electron microscopy (TEM) studies. This was achieved by core crosslinking using glutaraldehyde. TEM analysis of the glutaraldehyde-fixed nano-objects combined with small-angle X-ray scattering (SAXS) studies of linear nano-objects confirmed that pure spheres, worms or vesicles could be obtained at 20 °C in an acidic aqueous solution by simply varying the mean degree of polymerization (x) of the PHBA block. Aqueous electrophoresis, dynamic light scattering and TEM studies indicated that raising the dispersion pH above the pKa of the terminal carboxylic acid group located on each PNAEP chain induced a vesicle-to-sphere transition. 1H NMR studies of linear PNAEP85-PHBAx nano-objects indicated a concomitant increase in the degree of partial hydration of PHBA chains on switching from pH 2-3 to pH 7-8, which is interpreted in terms of a surface plasticization mechanism. Rheological and SAXS studies confirmed that the critical temperature corresponding to the maximum worm gel viscosity could be tuned from 2 to 50 °C by adjusting the PHBA DP. Such tunability is expected to be useful for potential biomedical applications of these worm gels.

Experiment on the profile control effect of different strength gel systems in heterogeneous reservoir

Polymer gel has attracted extensive attention as an effective agent for profile control as development enters middle and late stage. However, formation heterogeneity and the unclear mechanism of gel profile with different strength severely limits the displacement effect. In this work, microstructure and viscosity of polymer gels with different concentrations were characterized. The injection behavior experiments were carried out to calculate breakout pressure and plugging rate. The core flooding experiments were performed to obtain the remaining oil saturation field and recovery rate. The results illustrated that the gel viscosity increased and the plugging ability enhanced as the polymer concentration increased; Meanwhile, type C was determined as the best strength for displacement in heterogeneous formation; From oil displacement results, the gel fluidity decreased and blocking formed in high permeability reservoir, which forcing subsequent water divert to the low permeability reservoir. As a result, the swept volume expanded and the oil recovery enhanced. The fruitful works throw light on the mechanism of gel profile control and provide strong technical support for enhanced oil recovery in heterogeneous formation.

Formulation and Evaluation of Hydrogels containing Liposomes Entrapped with Antifungal Agent

Background: The main aim of the present study was to formulate and evaluate prolonged release Fluconazole liposomal gel for the transdermal delivery. Fluconazole, α-(2.4-diflurofenil)-α-(1H-triazole-1-methyl)-1H-1, 2, 4-triazole-1-ethanol, is a class of antifungal of triazole. It shows the action against species of Candida sp., and it is specified in cases of or pharyngeal candidiasis, esophageal, vaginal, and deep infection. Materials and Method: Fluconazole liposomal gel was prepared by thin film hydration method using phosphatidyl choline and cholesterol. Liposomes were characterized for entrapment efficiency, particle size, and surface charge. Liposomes were then dispersed into a Carbopol gel base to form liposomal gel and evaluated for drug content, pH, spreadability, viscosity and in-vitro drug release. Results: The results indicated that concentration of cholesterol in the formulations affected the particle size and entrapment efficiency. When the concentration of cholesterol increased particle size was also increased but decrease in entrapment efficiency. The viscosity of Fluconazole liposomal gel decreases with increasing rate of shear. Hence it was showed that with non-Newtonian flow. In-vitro diffusion studies were carried out using cellophane membrane, results showed that liposomal gel formulation F1 (91.36%) showed highest cumulative percent of drug release and formulation F8 (76.98%) showed lowest cumulative percent of drug release. Conclusion: Therefore, Fluconazole liposomal gel sustained the drug release for the longer duration, hence decreases the number of application of drugs and also improves patient compliance.

Improved Gel Properties of Whey Protein-Stabilized Emulsions by Ultrasound and Enzymatic Cross-Linking.

This study investigated the effects of high-intensity ultrasound (HUS) and transglutaminase pretreatment on the gelation behavior of whey protein soluble aggregate (WPISA) emulsions. HUS pretreatment and TGase-mediated cross-linking delayed the onset of gelation but significantly increased (p < 0.05) the gel firmness (G′) both after gel formation at 25 °C and during storage at 4 °C. The frequency sweep test indicated that all gels had a similar frequency dependence at 4 and 25 °C, and the elasticity and viscosity of the WPISA-stabilized emulsion gel were significantly enhanced by HUS pretreatment and TGase-mediated cross-linking (p < 0.05). HUS and TGase-mediated cross-linking greatly improved the textural properties of WPISA-stabilized emulsion gels, as revealed by their increases in gel hardness, cohesiveness, resilience, and chewiness. HUS pretreatment and TGase-mediated cross-linking significantly increased the water-holding capacity but decreased the swelling ratios of the gels (p < 0.05). Interactive force analysis confirmed that noncovalent interactions, disulfide bonds, and TGase-induced covalent cross-links were all involved in the formation of gel networks. In conclusion, the combination of HUS and TGase-mediated cross-linking were beneficial for improving the gelation properties of WPISA-stabilized emulsion as a controlled release vehicle for potential food industrial applications.

Rheological properties and interactions of fish gelatin-κ-carrageenan polyelectrolyte hydrogels: The effects of salt.

This study mainly explored the effects of low-concentration salts (0.1, 0.5 mM NaCl and Na2 SO4 ) on the gel, rheological and structural properties of fish gelatin (FG)-κ-carrageenan (κC) polyelectrolyte hydrogels. The results showed that κC could increase the gel strength, hardness, and chewiness of the FG-κC polyelectrolyte hydrogels, while the addition of salts had a negative effect. The rheological behaviors showed that the addition of salts reduced the apparent viscosity, gel, and melting points of the FG-κC polyelectrolyte hydrogels. Compared with NaCl, Na2 SO4 -treated FG-κC had lower gel strength, hardness, viscosity, gelation, and melting points, while the addition of salts increased the fluorescence intensity by unfolding FG molecules. The secondary structure analysis results showed that the addition of NaCl and Na2 SO4 decreased α-helix and β-sheet contents of FG-κC by destroying the hydrogen bond of FG-κC.

Performance Evaluation of Polymer Gel Composite Resin Coated Sand Water Shutoff System

Aiming at the problems of low plugging strength and short plugging time of Polymer gel in fractured ultra-low permeability reservoirs, a composite plugging process of Polymer gel and resin coated sand is proposed. This paper evaluates the rheological properties of Polymer gel and the consolidation performance of resin coated sand through laboratory tests. Furthermore, the sand-packed tube was used to compare and evaluate the water blocking ability of Polymer gel and resin coated sand alone and the combined water blocking ability of the two. The results show that the initial viscosity of Polymer gel is very low (20-30cp), the strength after gelation is high (>40000cp), it has certain temperature and salt resistance, and it can still maintain high gel strength after shearing. However, after long-term water flooding, its plugging strength gradually decreases, and its plugging validity period is shorter. The selected resin coated sand has better consolidation effect at reservoir temperature and good plugging ability. After combining the polymer gel with the selected resin coated sand, the plugging strength and validity period of the system have been greatly improved. The research results in this paper can provide new exploration ideas for chemical water shutoff in fractured ultra-low permeability reservoirs.

Characterization and functional properties of gelatin from goat bone through alcalase and neutrase enzymatic extraction.

Background and Aim:Gelatin is a dissolved protein that results from partial extraction of collagen, commonly from pig and bovine skin. There was no study on gelatin production from Kacang goat bones through enzymatic extraction. This study aimed to evaluate the chemical, physical, and functional properties of gelatin from bones of Kacang goat using alcalase and neutrase enzymes.Materials and Methods:Male Kacang goat bones aged 6-12 months and two commercial enzymes (alcalase and neutrase) were used for this study. Descriptive analysis and completely randomized design (one-way analysis of variance) were used to analyze the chemical, physical, and functional properties of gelatin. Kacang goat bone was extracted with four concentrations of alcalase and neutrase enzymes, namely, 0 U/g (AG-0 and NG-0), 0.02 U/g (AG-1 and NG-1), 0.04 U/g (AG-2 and NG-2), and 0.06 U/g (AG-3 and NG-3) with five replications.Results:The highest yield of gelatin extraction with alcalase obtained on AG-3 was 9.78%, and that with neutrase on NG-3 was 6.35%. The moisture content of alcalase gelatin was 9.39-9.94%, and that of neutrase gelatin was 9.15-9.24%. The ash and fat content of gelatin with alcalase was lower than that without enzyme treatment with higher protein content. The lowest fat content was noted in AG-1 (0.50%), with protein that was not different for all enzyme concentrations (69.65-70.21%). Gelatin with neutrase had lower ash content than that without neutrase (1.61-1.90%), with the highest protein content in NG-3 (70.89%). The pH of gelatin with alcalase and neutrase was 6.19-6.92 lower than that without enzymes. Melting points, gel strength, and water holding capacity (WHC) of gelatin with the highest alcalase levels on AG-1 and AG-2 ranged from 28.33 to 28.47°C, 67.41 to 68.14 g bloom, and 324.00 to 334.67%, respectively, with viscosity that did not differ, while the highest foam expansion (FE) and foam stability (FS) were noted in AG-1, which were 71.67% and 52.67%, respectively. The highest oil holding capacity (OHC) was found in AG-2 (283%). FS and OHC of gelatins with the highest neutrase levels in NG-2 were 30.00% and 265.33%, respectively, while gel strength, viscosity, FE, and WHC of gelatins with the highest neutrase levels did not differ with those without enzymes at all enzyme concentrations. B chain was degraded in all gelatins, and high-intensity a-chains in gelatin with alcalase and peptide fraction were formed in gelatin with neutrase. Extraction with enzymes showed loss of the triple helix as demonstrated by Fourier transform infrared spectroscopy.Conclusion:Based on the obtained results, the Kacang goat bone was the potential raw source for gelatin production. Enzymatic extraction can increase the quality of gelatin, especially the alcalase (0.02-0.04 U/g bone) method. This can be used to achieve the preferable quality of gelatin with a higher yield.