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Gel Strength (gel + strength)
Selected AbstractsRheological characteristics of suwari and kamaboko gels made of surimi from Indian major carpsJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 9 2002Thazhakot V Sankar Abstract The gel strength, compressibility and folding characteristic of suwari (set) and kamaboko (set and cooked) gels prepared from rohu (Labeo rohita), catla (Catla catla) and mrigal (Cirrhinus mrigala) surimi were examined to understand the occurrence of suwari and modori phenomena in surimi from major freshwater carps. Suwari setting of gels did not take place at lower temperatures. Suwari gels showed good gel strength at 50,°C for rohu and at 60,°C for catla and mrigal after 30,min setting time. Incubation for 60,min decreased the gel strength at 60,°C for rohu and catla. Setting at 25,°C followed by cooking at 90,°C increased the gel strength. Increased setting temperature, however, decreased the gel strength of cooked gels. Gel strength and compressibility data were supported by folding characteristics. © 2002 Society of Chemical Industry [source] Changes in functional properties of shark (Isurus oxyrinchus) cartilage gelatin produced by different drying methodsINTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 8 2009Ki-Seok Kwak Summary Fish gelatins extracted from shark (Isurus oxyrinchus) cartilage were dried by three different methods: freeze drying, hot-air drying and spray drying; and their functional properties were investigated. Freeze-dried gelatin was found to have the strongest gel strength, while gelatins made at high temperatures formed weaker gels. The 135-kPa gel strength of freeze-dried gelatin was relatively high. While foam formation ability of the freeze-dried gelatin was the highest, its foam stability was the lowest. In addition, spray-dried gelatin had the best emulsion capacities. Dynamic viscoelastic properties of shark cartilage gelatins prepared by these drying methods were closely correlated with their gel strength. Elasticity modulus (G'; Pa) and loss modulus (G"; Pa) of the freeze-dried gelatin had higher values than those prepared by hot-air drying and spray drying; viscoelastic properties of the freeze-dried gelatin were maintained longer than those of other drying methods. [source] Development of a healthy low-fat fish sausage containing dietary fibreINTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 2 2008Carlos Cardoso Summary In order to develop a healthy low-fat fish sausage containing dietary fibre (DF), three fundamental changes were made to an ordinary pork sausage recipe: incorporation of 4% (w/w) of Swelite® (a DF obtained from inner pea), different levels of pork meat replacement (0%, 50% and 100%) by hake mince and the combination of varying amounts of Fibruline® (a DF obtained from chicory root) and hake mince (Fibruline: additional hake mince, 2.6:5.2, 5.2:2.6 and 7.8:0.0, % w/w) as a substitute for pork fat. It was found that the addition of Swelite to pork sausage favoured greater gel strength and hardness. On the contrary, increasing levels of pork meat replacement by hake reduced the sausages' gel strength and hardness. Finally, sausages without pork fat showed promising textural and colour parameters. High-Fibruline sausages were less cohesive and chewable than pork fat sausages (control), but also exhibited a greater gel strength. Low-Fibruline ones presented almost all textural properties similar to the control, with exception of hardness and gumminess. Therefore, regarding some key textural parameters, it was possible to produce low-fat fish sausages similar to the ordinary pork sausages. [source] The suitability of muscle of Cirrhinus mrigala in the formation of gel: a comparative electrophoretic study of six tropical carp meatsINTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 1 2008Rupsankar Chakrabarti Summary The annual inland fish production in India is 3.2 million tonnes and above. Aquaculture is around 80% of total inland fish production. The enhanced aquaculture production demands alternate processing methods for better utilisation of the farmed fish. Cirrhinus mrigala is one of the dominated species among cultured Indian major carps, but rated with lowest price. Fish meat with good gel-forming capacity is a prerequisite in the production of fast-moving fabricated analogue product. Cirrhinus mrigala had the highest gel strength, i.e. 435 gcm of its fresh meat in comparison with other carps. Apart from the highest protein and salt-soluble protein nitrogen content in fresh C. mrigala meat, this article also reports that the presence of the darkest thick band of myosin heavy chain and actin in the polyacrylamide gel electrophoresis pattern of salt-soluble extract of C. mrigala might be another possible reason for the highest gel strength in comparison with other carps. Cirrhinus mrigala contained white meat around 90%. This carp could be suitably used in the preparation of high-valued fabricated analogue product. [source] Control of thermo reversible gelation of methylcellulose using polyethylene glycol and sodium chloride for sustained delivery of ophthalmic drugJOURNAL OF APPLIED POLYMER SCIENCE, Issue 2 2010Mrinal Kanti Bain Abstract The effect of molecular weight of polyethyleneglycol (PEG) and sodium chloride (NaCl) on the gelation temperature of methylcellulose (MC) was studied with the objective to develop a MC based formulation for sustained delivery of ophthalmic drug. The gelation temperature of 1% MC was 60 ± 0.40°C. It was found that the gelation temperature of MC was reduced with the addition of 10% PEG and extent of reduction of gelation temperature was depended on the molecular weight of PEG at same PEG concentration of 10%. The gelation temperature of MC was reduced by 10.4 to 5.9°C with the increasing molecular weight of PEG starting from 400 to 20,000 (Mn) depending on the method of determination of gelation temperature. To reduce the gelation temperature of MC close to physiological temperature (37°C), 6% NaCl was added in the different MC-PEG combinations containing different molecular weight of PEG. It was observed that the drug release time increased from 5 to 8 h with the increase in molecular weight of PEG from 400 to 20,000 (Mn) and this was due to the maximum viscosity and gel strength of MC-PEG20000-NaCl ternary combination. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 [source] TEXTURE STABILITY OF HYDROGEL COMPLEX CONTAINING CURDLAN GUM OVER MULTIPLE FREEZE,THAW CYCLESJOURNAL OF FOOD PROCESSING AND PRESERVATION, Issue 1 2009PATRICK D. WILLIAMS ABSTRACT The texture stability of hydrogel complexes containing curdlan gum over multiple freeze,thaw cycles (FTCs) was investigated. The hydrogels formed by curdlan and xanthan gum, locust bean gum, carrageenan or guar gum at various combinations were stored at 4C for 24 h before subjected to five FTCs alternating between,16 (18 h) and 25C (6 h). Xanthan/curdlan hydrogels showed the highest freeze,thaw stability in terms of syneresis, heat stability and adhesiveness. The viscosity of xanthan/curdlan combination was the lowest among all samples studied yet the most stable over the five FTCs, whereas significant changes were observed with locust bean/curdlan hydrogels. The guar/curdlan combination before freeze,thaw treatments exhibited predominant elasticity; however, as the cycles progressed the elasticity decreased. The most stable gel strength was achieved when curdlan was combined with guar or xanthan at 2% (w/v) total concentration, while carrageenan/curdlan gels were the least stable. PRACTICAL APPLICATIONS Texture instability remains the most significant challenge for frozen food products, especially with inevitable post-production temperature fluctuations. Loss of moisture and changes in textural attributes often results in significant reduction of product quality. Precise control of hydrogel complexes that provide texture stabilization over multiple freeze,thaw cycles will enhance the quality of existing products while enabling the development of new ones. [source] PHYSICAL PROPERTIES OF FISH PROTEINS COOKED WITH STARCHES OR PROTEIN ADDITIVES UNDER OHMIC HEATINGJOURNAL OF FOOD QUALITY, Issue 5 2007PANIDA PONGVIRAT CHAI ABSTRACT The texture, color and microstructure of surimi seafood gels were investigated to determine the interaction effects of fish proteins with starches or protein additives under ohmic heating, and to compare ohmically cooked gels with conventional water-bath-cooked gels. Gel properties were affected by the type of additive, concentration and cooking method. The effect of starch on gel texture was more pronounced at low concentrations. Compared to wheat starch, potato starch seemed to slightly improve gel strength; however, it decreased the gel whiteness. All nonfish protein additives resulted in better or equal textural properties of gels, whereas there was a slightly negative effect for gel color. Fast ohmic-cooked gels mostly exhibited higher gel strength than conventionally cooked gels. PRACTICAL APPLICATIONS There is a discrepancy between current gel preparation (slow heating by water bath) and current practice of crabstick manufacturing (fast heating). The use of data generated from slow cooking gel preparation for the manufacture of fast cooking crabstick does not make sense. This study demonstrates how starch and protein additives behave at ohmic heating which mimics the fast cooking crabstick manufacture. [source] Xanthan Enhances Water Binding and Gel Formation of Transglutaminase-Treated Porcine Myofibrillar ProteinsJOURNAL OF FOOD SCIENCE, Issue 3 2010Yongbiao Shang ABSTRACT:, In this study, the effect of xanthan on dynamic rheological properties, textural profile, and water binding of transglutaminase (TG)-treated myofibrillar protein (MP) gels was investigated. In experiment 1, MP suspensions (40 mg/mL protein, 0.6 M NaCl) at pH 6.45 with or without 0.05% xanthan were treated with 0%, 0.1%, 0.2%, 0.3%, 0.4%, and 0.5% TG; in experiment 2, MP suspensions (40 mg/mL protein, 0.6 M NaCl) at pHs 6.13, 6.30, 6.45, 6.69 with or without 0.05% xanthan were treated with 0.3% TG. Treated samples were analyzed with differential scanning calorimetry for thermal stability and oscillatory rheometry and Instron penetration tests for gelation properties. The TG treatments lowered the transition temperature (Tm) of MP by as much as 6 °C (P,< 0.05) but increased apparent enthalpy of denaturation. However, there was no detectable thermal stability difference between MP samples with or without xanthan. The shear storage modulus (G,) of MP gels increased markedly upon treatments with ,0.3% TG, and the presence of xanthan further enhanced the gel strength (P,< 0.05). The addition of 0.05% xanthan decreased cooking loss of TG-treated MP gels by 17% to 23% when compared with gels without xanthan at all pH levels evaluated (6.13 to 6.67). Thus, the combination of TG and xanthan offered a feasible means to promote cross-linking and gelation of MP while reducing cooking losses. [source] Characteristics of Sarcoplasmic Proteins and Their Interaction with Surimi and Kamaboko GelJOURNAL OF FOOD SCIENCE, Issue 1 2009A. Jafarpour ABSTRACT:, This study examined the effect of adding common carp sarcoplasmic proteins (Sp- P) on the gel characteristics of threadfin bream surimi and kamaboko while maintaining constant moisture and myofibrillar levels. Based on the temperature sweep test, which is involved in heating of surimi gel from 10 to 80 °C to monitor the viscoelastic properties, at temperature range of 40 to 50 °C, the decrease level (depth of valley) in storage modulus (G,) thermograph was in proportion to the concentration of added Sp- P. Storage modulus (G,) showed greater elasticity after adding Sp- P compared with the control without Sp- P. Furthermore, the breaking force and distance and consequently gel strength of the resultant kamaboko were improved significantly (P > 0.05). Thus, added Sp- P did not interfere with myofibrillar proteins during sol,gel transition phase but associated with textural quality enhancement of resultant kamaboko; however, addition of Sp- P from the dark muscle of the carp decreased the whiteness of the resultant surimi. Furthermore, according to the SEM micrographs, the gel strength could not be associated with either the number of polygonal structures/mm2 or the area of the polygonal structures in the kamaboko gel microstructure. [source] Alternative Techniques for Producing a Quality Surimi and Kamaboko from Common Carp (Cyprinus carpio)JOURNAL OF FOOD SCIENCE, Issue 9 2008A. Jafarpour ABSTRACT:, The demand for surimi and kamaboko is increasing in the world at the same time as the supply of the fish traditionally used has declined. In an effort to increase the range and hence supply of fish used, factors increasing the quality of surimi and kamaboko from common carp were investigated. The best surimi and kamaboko characteristics were produced by a modified conventional method (MCM) rather than traditional method (TM), alkaline-aided method (AAM), and pH modified method (PMM). MCM processing used centrifugation instead of decanting and filtering to optimize dewatering and remove the sarcoplasmic proteins (Sp-P). The temperature sweep test, at the end of sol,gel transition stage (at 75 °C), showed significantly (P < 0.05) greater G, for the kamaboko from MCM than that from other methods tested. Furthermore, the greatest and the least gel strengths were obtained with MCM and TM kamaboko, respectively. The protein recovery was about 67%, 74%, 87%, and 92% for TM, AAM, MCM, and PMM, respectively. TM and MCM resulted in the removal of Sp-P as determined by SDS-PAGE. The superiority of MCM kamaboko gel characteristics was supported by scanning electron micrographs (SEM) of the gel, which showed a significantly (P < 0.05) greater number of polygonal structures than for the TM kamaboko, which had the fewest and largest polygonal structures. The pH-shifting methods improved the textural quality of the resultant kamaboko compared with TM. However, a simple modification (centrifugation compared with decanting) by MCM in the surimi process can further improve the quality of the surimi and kamaboko gels. Furthermore, because it removed Sp-P and still preserved gel strength, it suggests that Sp-P are not required for gel strength. [source] Water Vapor Permeability of Mammalian and Fish Gelatin FilmsJOURNAL OF FOOD SCIENCE, Issue 4 2006R.J. Avena-Bustillos ABSTRACT:, Water vapor permeability of cold- and warm-water fish skin gelatins films was evaluated and compared with different types of mammalian gelatins. Alaskan pollock and salmon gelatins were extracted from frozen skins, others were obtained from commercial sources. Water vapor permeability of gelatin films was determined considering differences on percent relative humidity (%RH) at the film underside. Molecular weight distribution, amino acid composition, gel strength, viscoelastic properties, pH, and clarity were also determined for each gelatin. Water vapor permeability of cold-water fish gelatin films (0.93 gmm/m2hkPa) was significantly lower than warm-water fish and mammalian gelatin films (1.31 and 1.88 gmm/m2hkPa, respectively) at 25 °C, 0/80 %RH through 0.05-mm thickness films. This was related to increased hydrophobicity due to reduced amounts of proline and hydroxyproline in cold-water fish gelatins. As expected, gel strength and gel setting temperatures were lower for cold-water fish gelatin than either warm-water fish gelatins or mammalian gelatins. This study demonstrated significant differences in physical, chemical, and rheological properties between mammalian and fish gelatins. Lower water vapor permeability of fish gelatin films can be useful particularly for applications related to reducing water loss from encapsulated drugs and refrigerated or frozen food systems. [source] Comparison of Texture of Yogurt Made from Conventionally Treated Milk and UHT Milk Fortified with Low-heat Skim Milk PowderJOURNAL OF FOOD SCIENCE, Issue 6 2004W. Krasaekoopt ABSTRACT: The textures of yogurt made from ultra-high temperature (UHT) treated and conventionally treated milks at high total solids were investigated. The yogurt premixes, fortified with low-heat skim milk powder to 16%, 18%, and 20% total solids, were UHT processed at 143°C for 6 s and heated at 85°C for 30 min using the conventional method. The onset of gelation was delayed in the UHT-processed milk compared with conventionally heated milk. During fermentation, the viscosity of yogurt made from UHT-treated milk at 20% total solids was close to that of yogurt made from conventionally treated milk with 16% total solids. However, after storage for , 1 d, the yogurt made from UHT-treated milk had lower viscosity and gel strength than the yogurt made from conventionally treated milk. The solids level had no influence on yogurt culture growth. [source] Physicochemical and Sensory Characteristics of Fish GelatinJOURNAL OF FOOD SCIENCE, Issue 2 2000S.-S. Choi ABSTRACT: The physicochemical differences between pork and fish gelatin and the effect of melting point on the sensory characteristics of a gelatin-water gel were investigated. Gelatin gel strength (measured as Bloom) and melting point of gelatin gels were measured, and quantitative descriptive analysis sensory tests were performed. The dependence of the gelatin gel strength and the melting point of fish gels on gel concentration, maturation time, maturation temperature, pH, and the influence of NaCl and sucrose were similar to those for pork gelatin. The flavored fish gelatin dessert gel product had less undesirable off-flavor and off-odor and a more desirable release of flavor and aroma than the same product made with an equal Bloom, but higher melting point, pork gelatin. [source] Effect of mixing method on rheological properties of alginate impression materialsJOURNAL OF ORAL REHABILITATION, Issue 7 2002K. Inoue The apparent viscosity of alginate impression paste prepared by three mixing methods (hand-mixing technique (HM), semiautomatic instrument (SM) and automatic mixing instrument (AM)), and the gel strength and surface depression of the respective set materials were measured. The materials used were eight commercially available products mixed at a temperature of 23 ± 0.5 °C and allowed to set. The AM had a high mixing speed, which reduced the working time 4.4,31.5%, compared with HM. This was the result of an increase in paste temperature during mixing. In the case of impression materials mixed with the AM, the gel strength and the surface depression at the gel fracture increased significantly, in accordance with Fisher's protected least significant difference (PLSD) analysis. This phenomenon is caused by a decrease of air bubbles in the set material. [source] GELLING BEHAVIOR OF RICE FLOUR DISPERSIONS AT DIFFERENT CONCENTRATIONS OF SOLIDS AND TIME OF HEATINGJOURNAL OF TEXTURE STUDIES, Issue 3 2008ALKA KAPRI ABSTRACT Rice flour dispersions, under suitable conditions of processing, can form a gel. The effect of concentration of solids (10,18%) and time (0,75 min) of processing on textural attributes, and viscoelasticity were investigated along with sensory attributes. The textural attribute determined is gel strength, while viscoelasticity was determined in terms of mechanical spectra like storage modulus (G,), loss modulus (G,), complex viscosity (,*) and loss factor (tan ,) during a frequency sweep varying from 0.01 to 40 Hz at a constant stress of 25 Pa. Microstructural observation indicates the swelling of starch granules in the beginning of heating, while damaged granule and leached-out materials are visible at the end of the gelling process. Desirability function analysis has been applied to obtain a rice gel with acceptable textural attributes; a solid concentration of 15.2% and a heating time of 75 min can lead to the development of a gel with a satisfaction level of 0.6. PRACTICAL APPLICATIONS Rice flour gels in the form of hard-set gels, porridges and spreads are popular in several parts of the world particularly for feeding of infants and children. The application of the present study lies in understanding the role of major processing variables on the quality attributes and viscoelasticity of a product, characterization of cooked gels and for developing rice flour-based food gels. The findings may also be extended for the development of other cereal-based gels. [source] Participation of cysteine protease cathepsin L in the gel disintegration of red bulleye (Priacanthus macracanthus) surimi gel pasteJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 3 2010Yaqin Hu Abstract BACKGROUND: Endogenous proteases, among them cysteine-type proteases, are reported to contribute to gel disintegration, resulting in kamaboko of poor quality. Severe gel disintegration occurs in red bulleye surimi gel paste. The objective of this study was to clarify the participation of cysteine protease cathepsin L in the gel disintegration of red bulleye surimi. The surimi was made into kamaboko with and without cathepsin L inhibitors. To confirm its hydrolysis action, crude cathepsin L was also extracted and added to the surimi to make kamaboko. RESULTS: The gel strength of kamaboko obtained by both one-step (50 °C, 2 h) and two-step (50 °C, 2 h + 80 °C, 20 min) heating was very low in the absence of inhibitors. Protease inhibitors E-64 and leupeptin were found to enhance the gel strength considerably. Sodium dodecyl sulfate polyacrylamide gel electrophoresis revealed that the hydrolysis of kamaboko was promoted by crude cathepsin L and inhibited by E-64 and leupeptin. The gel strength of two-step heated kamaboko was increased from 12 to 110 and 130 g cm,2 by E-64 and leupeptin respectively at a concentration of 0.2 g kg,1 surimi. CONCLUSION: Endogenous cathepsin L of red bulleye surimi participates in gel disintegration during kamaboko processing. It does so by degrading the myosin heavy chain of actomyosin and consequently hindering the gelation of red bulleye surimi. Copyright © 2009 Society of Chemical Industry [source] Rheological characteristics of suwari and kamaboko gels made of surimi from Indian major carpsJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 9 2002Thazhakot V Sankar Abstract The gel strength, compressibility and folding characteristic of suwari (set) and kamaboko (set and cooked) gels prepared from rohu (Labeo rohita), catla (Catla catla) and mrigal (Cirrhinus mrigala) surimi were examined to understand the occurrence of suwari and modori phenomena in surimi from major freshwater carps. Suwari setting of gels did not take place at lower temperatures. Suwari gels showed good gel strength at 50,°C for rohu and at 60,°C for catla and mrigal after 30,min setting time. Incubation for 60,min decreased the gel strength at 60,°C for rohu and catla. Setting at 25,°C followed by cooking at 90,°C increased the gel strength. Increased setting temperature, however, decreased the gel strength of cooked gels. Gel strength and compressibility data were supported by folding characteristics. © 2002 Society of Chemical Industry [source] Physicochemical properties of the thermal gel of water-washed meat in the presence of the more soluble fraction of porcine sarcoplasmic proteinANIMAL SCIENCE JOURNAL, Issue 1 2007Yuji MIYAGUCHI ABSTRACT We investigated the physicochemical properties of the thermal gel of water-washed pork meat (WWM) in the presence of the soluble fraction of porcine sarcoplasmic protein (SP) obtained with ammonium sulfate at 75 percent saturation. Two precipitated fractions of SP were obtained at 0,50 percent and 50,75 percent saturation, named SP-f1 and SP-f2, respectively, and the soluble fraction obtained at 75 percent saturation, SP-f3, was used. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis showed that SP-f3 contained mainly glyceraldehyde-3-phosphate dehydrogenase (GAPDH), while SP-f1 and SP-f2 had other SPs such as phosphorylase b, enolase, actin and phosphoglycerate mutase. The gel strength of WWM was greater when SP-f3 rather than one of various animal proteins such as bovine plasma (BP), egg white, or whey protein isolates (WPI), was added and SP-f3 had a gel-enhancing effect as good as that of polyphosphate (PP). The gel strength of WWM with added SP-f3 increased significantly with NaCl at 0.15 mol/L or more, but not in the absence of NaCl (0 mol/L). The effect of SP-f3 was evident at neutral pH and maximum gel strength was obtained at a pH above 6.0. Differential scanning calorimetric (DSC) analysis showed that an endothermic peak corresponding to myosin heads in WWM shifted to a lower temperature with the addition of SP-f3, as in the case of PP, though there was no such shift in the presence of other animal proteins (BP, egg white and WPI), suggesting that SP-f3 increases the gel strength of WWM through the dissociation of actomyosin similar to PP. Scanning electron microscopy (SEM) revealed wall-like structures among the protein strands in the WWM gel matrix in the presence of SP-f3. The results of DSC and SEM indicated that the formation of a gel network in meat products is reinforced with GAPDH in SP after the interaction between GAPDH and myofibrillar protein. [source] Alternative Techniques for Producing a Quality Surimi and Kamaboko from Common Carp (Cyprinus carpio)JOURNAL OF FOOD SCIENCE, Issue 9 2008A. Jafarpour ABSTRACT:, The demand for surimi and kamaboko is increasing in the world at the same time as the supply of the fish traditionally used has declined. In an effort to increase the range and hence supply of fish used, factors increasing the quality of surimi and kamaboko from common carp were investigated. The best surimi and kamaboko characteristics were produced by a modified conventional method (MCM) rather than traditional method (TM), alkaline-aided method (AAM), and pH modified method (PMM). MCM processing used centrifugation instead of decanting and filtering to optimize dewatering and remove the sarcoplasmic proteins (Sp-P). The temperature sweep test, at the end of sol,gel transition stage (at 75 °C), showed significantly (P < 0.05) greater G, for the kamaboko from MCM than that from other methods tested. Furthermore, the greatest and the least gel strengths were obtained with MCM and TM kamaboko, respectively. The protein recovery was about 67%, 74%, 87%, and 92% for TM, AAM, MCM, and PMM, respectively. TM and MCM resulted in the removal of Sp-P as determined by SDS-PAGE. The superiority of MCM kamaboko gel characteristics was supported by scanning electron micrographs (SEM) of the gel, which showed a significantly (P < 0.05) greater number of polygonal structures than for the TM kamaboko, which had the fewest and largest polygonal structures. The pH-shifting methods improved the textural quality of the resultant kamaboko compared with TM. However, a simple modification (centrifugation compared with decanting) by MCM in the surimi process can further improve the quality of the surimi and kamaboko gels. Furthermore, because it removed Sp-P and still preserved gel strength, it suggests that Sp-P are not required for gel strength. [source] Development of a robust hydrogel system based on agar and sodium alginate blendPOLYMER INTERNATIONAL, Issue 2 2008Ramavatar Meena Abstract BACKGROUND: As part of an ongoing research and development programme of our laboratory on functional modification of seaweed polysaccharides for preparing hydrogels with improved properties, we report herein the preparation of a robust hydrogel system based on grafting of agar and sodium alginate blend (Agar/Na-Alg) with acrylamide (AAm) to obtain the copolymer Agar/Na-Alg- graft -PAAm. RESULTS: A robust hydrogel system with superior absorbency and pH resistance has been developed based on a PAAm-grafted seaweed polysaccharide blend of Agar/Na-Alg. The blend (Agar/Na-Alg) and grafted product (Agar/Na-Alg- graft -PAAm) were evaluated using Fourier transform infrared spectroscopy, X-ray diffraction, thermogravimetric analysis, swelling capacity, rheology and scanning electron microscopy. The swelling capacity of the grafted copolymer exhibited an enhancement over that of the blend from 14 to 24 g g,1 in acidic medium. The blend and grafted copolymer produced hydrogels with lower gelling points of 31 and 29 °C and gel strengths were 170 and 120 g cm,2, respectively. CONCLUSION: This study constitutes an example of value addition of seaweed polysaccharides targeting new applications. The copolymer hydrogel may be useful in health, personal care and agricultural applications. Copyright © 2007 Society of Chemical Industry [source] | |||||||||||||