Higher Gel Strength Research Articles

Formulation, Characterization and Release Behaviour of Metformin Hydrochloride Modified Release Tablet by Using Hydrophilic Polymers

Amongst the many public health problems, the diabetes mellitus is considered as a chronic life-style related disease which is now growing as an epidemic in both developed as well as developing countries. The current study is about formulation of metformin hydrochloride tablet to confirm their sustained release property by using various polymers. The tablets are prepared by granulation techniques using binding solution containing polyvinyl pyrolline K30. The possible interaction between the pure metformin hydrochloride and polymers are identified by Fourier transform-infrared spectroscopy. Tablets were formulated with different polymers like Hydroxy propyl methyl cellulose K100 and sodium carboxymethyl cellulose. Matrix prepared with high concentration of HPMC K100 polymer retards the drug release up to 6 h at 59 %, but the formulation 2 (F2) showed 72.72% of drug release in 6 h. The release of drug from the F2 formulation was found to be prolonged drug release when compared to other formulations. Hence our study conclude that the HPMC K100 polymer containing formulation showed good sustained release property owing to the high gel strength and well high viscosity nature of the polymer.

Interaction between Negatively Charged Fish Gelatin and Cyclodextrin in Aqueous Solution: Characteristics and Formation Mechanism.

The effect that ratios of fish gelatin (FG) to α/β/γ cyclodextrins (α, β, γCDs) had on the phase behavior of a concentrated biopolymer mixture were comparatively investigated. This showed that the formed biopolymer mixture had the highest gel strength at ratios of FG–CD = 90:10. FG could interact with CDs to form stable soluble complexes with lower values of turbidity, particle size and ζ-potential. All of the FG–CD mixture solutions exhibited pseudo-plastic behaviors, and FG–αCD samples had the highest viscosity values than others. The addition of CDs could unfold FG molecules and make conformation transitions of FG from a random coil to β-turn, leading to the environmental change of hydrophobic residues and presenting higher fluorescence intensity, especially for βCDs. FTIR results revealed that the formation of intermolecular hydrogen bonds between FG and CD could change the secondary structure of FG. These findings might help further apply FG–CD complexes in designing new food matrixes.

The structural, thermal, pasting and gel properties of the mixtures of enzyme-treated potato protein and potato starch

To understand the interactions between enzyme-modified potato proteins and potato starch, herein transglutaminase or peroxidase was used to create covalent crosslinked structure of potato protein. The mixtures of native or enzyme-treated protein and potato starch in different proportions were prepared and the structural and physicochemical characteristics were studied. The results revealed that the new covalent and/or noncovalent linkages formed after enzyme modification of potato protein. Compared with the mixtures of native protein and starch, the mixtures of enzyme-treated protein and starch had larger shear resistance (breakdown value decreased by about 2–100 times) and higher gel strength (G′ and G″), but smaller thermal stability (312.3–307.3, 309.1 °C) and lower peak viscosity (decreased by 1.5–4 times). In conclusion, transglutaminase or peroxidase accelerated the formation of cross-networked structure in potato protein, which increased the interaction with starch, hence greatly improving the gel properties of the mixture of protein and starch.

Gracilaria gracilis (Gracilariales, Rhodophyta) from Dakhla (Southern Moroccan Atlantic Coast) as Source of Agar: Content, Chemical Characteristics, and Gelling Properties.

Agar is a sulfated polysaccharide extracted from certain marine red algae, and its gel properties depend on the seaweed source and extraction conditions. In the present study, the seaweed Gracilaria gracilis (Gracilariales, Rhodophyta) from Dakhla (Moroccan Atlantic Coast) was investigated for its agar content, structure, and gel properties. The agar yields of G. gracilis were 20.5% and 15.6% from alkaline pretreatment and native extraction, respectively. Agar with alkaline pretreatment showed a better gelling property supported by higher gel strength (377 g·cm−2), gelling (35.4 °C), and melting (82.1 °C) temperatures with a notable increase in 3,6-anhydro-galactose (11.85%) and decrease in sulphate (0.32%) contents. The sulfate falling subsequent to alkaline pretreatment was verified through FT-IR spectroscopy. The 13C NMR spectroscopy showed that alkaline-pretreated agar has a typical unsubstituted agar pattern. However, native agar had a partially methylated agarose structure. Overall, this study suggested the possibility of the exploitation of G. gracilis to produce a fine-quality agar. Yet, further investigation may need to determine the seasonal variability of this biopolymer according to the life cycle of G. gracilis.

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.

Reduced Washing Cycle for Sustainable Mackerel (Rastrelliger kanagurta) Surimi Production: Evaluation of Bio-Physico-Chemical, Rheological, and Gel-Forming Properties.

Although dark muscle is currently the most important obstacle in marketing high-quality Indian mackerel (Rastrelliger kanagurta) surimi, reducing washing remains a challenge for long-term surimi production from this species. Herein, the impact of washing cycles (one (W1), two (W2), and three (W3) cycles) with a 1:3 mince to water ratio on the bio-physico-chemical properties, rheology, and gelling ability of mackerel surimi was evaluated. The yield, Ca2+-ATPase activity, TCA-soluble peptide, and myoglobin contents of surimi decreased as the number of washing cycles increased, while lipid removal, reactive SH content, and surface hydrophobicity of surimi increased. Surimi generated by W2 and W3 provided the same rheological patterns and Fourier-transform infrared spectroscopy (FTIR) spectra as unwashed mince, with the highest gel strength and whiteness, as well as the lowest expressible drip, thiobarbituric acid reactive substances (TBARS), and fishy odor. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) demonstrated the presence of polymerized proteins stabilized by disulfide and other interactions. Using a scanning electron microscope, several concentrated dense areas and distributed pores generated by myofibrillar proteins gel networks were found. Surimi from W2 and W3 appeared to be of similar overall quality, however W2 had a larger yield. As a result of the evaluation of bio-physico-chemical, rheological, and gel-forming capabilities, as well as product yield, W2 may be the best option for producing high-quality surimi from Indian mackerel in a sustainable manner.

Experimental study on an oil‐based polymer gel for lost circulation control in high‐temperature fractured formation

AbstractAiming at the lack of plugging agent for oil‐based drilling fluid leakage in fractured formation, an oil‐based gel‐plugging agent with high structural strength and strong thermal stability was synthesized based on monomer polymerization and crosslinking. According to the preparation experiment, when the total concentration of methyl methacrylate (MMA) and butyl acrylate (BA) is 30% and the ratio is 6:4, the oil‐based gel solution can be completely gelatinized from 80 to 200°C, which has high gel strength and controllable gelation time. The effects of total concentration of BA and MMA, the ratio of BA and MMA, synthesis temperature, oil‐based drilling fluid invasion, shear effect, and fiber concentration on gelling performance were systematically studied. Fourier transform infrared molecular structure analysis showed that the oil‐based gel contained benzene ring group and ester characteristic group. From the rheological properties of oil‐based gel with 30% gelling agent at 160°C, it could be seen that the elastic modulus G′ of 10 Hz is 232 kPa, which is much larger than the storage modulus G″ is 99 kPa, which reflects the solid properties and has good elasticity and high strength. The displacement experiment of sand filling pipe and dynamic and static plugging experiment of high temperature and high pressure shows that the oil‐based gel has high bearing capacity in fractures and sand filling pipe. The bearing pressure is 3.01 MPa in 6 mm fractures, and the bearing pressure gradient is 0.602 MPa/cm.

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.

Characteristics of Soy Protein Prepared Using an Aqueous Ethanol Washing Process.

Currently, the predominant process for soy protein concentrate (SPC) production is aqueous ethanol washing of hexane-extracted soy meal. However, the use of hexane is less desired, which explains the increased interest in cold pressing for oil removal. In this study, cold-pressed soy meal was used as the starting material, and a range of water/ethanol ratios was applied for the washing process to produce SPCs. Washing enriched the protein content for the SPCs, regardless of the solvent used. However, we conclude that washing with water (0% ethanol) or solvents with a high water/ethanol ratio (60% and above) can be more advantageous. Washing with a high water/ethanol ratio resulted in the highest yield, and SPCs with the highest protein solubility and water holding capacity. The water-only washed SPC showed the highest viscosity, and formed gels with the highest gel strength and hardness among all the SPCs at a similar protein concentration. The variations in the functionality among the SPCs were attributed to protein changes, although the effects of non-protein constituents such as sugar and oil might also be important. Overall, the aqueous ethanol washing process combined with cold-pressed soy meal created SPCs comparable to commercial SPC in terms of composition, but with varied functionalities that are relevant for novel soy-food developments.

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.

Production and Physicochemical Characterization of Gelatin and Collagen Hydrolysates from Turbot Skin Waste Generated by Aquaculture Activities.

Rising trends in fish filleting are increasing the amount of processing by-products, such as skins of turbot, a flatfish of high commercial value. In line with circular economy principles, we propose the valorization of turbot skins through a two-step process: initial gelatin extraction described for the first time in turbot, followed by hydrolysis of the remaining solids to produce collagen hydrolysates. We assayed several methods for gelatin extraction, finding differences in gelatin properties depending on chemical treatment and temperature. Of all methods, the application of NaOH, sulfuric, and citric acids at 22 °C results in the highest gel strength (177 g), storage and loss moduli, and gel stability. We found no relation between mechanical properties and content of pyrrolidine amino acids, but the best performing gelatin displays higher structural integrity, with less than 30% of the material below 100 kDa. Collagen hydrolysis was more efficient with papain than alcalase, leading to a greater reduction in Mw of the hydrolysates, which contain a higher proportion of essential amino acids than gelatin and show high in vitro anti-hypertensive activity. These results highlight the suitability of turbot skin by-products as a source of gelatin and the potential of collagen hydrolysates as a functional food and feed ingredient.

Xanthan gum inclusion optimizes the sol-gel and mechanical properties of agar/konjac glucomannan system for designing core-shell structural capsules

Core-shell structural capsules can encapsulate various food ingredients (e.g., nutrients), thus being highly potential for the design of many food products. This work reports how the gum (xanthan, locust bean or gellan) inclusion tailors the practical features of agar/konjac glucomannan (KGM) system for fabricating the core-shell structural capsules. The rheological and textural analyses revealed that xanthan gum inclusion could simultaneously increase the sol-gel transition point and gel strength (ca. 1.6 times higher) of agar/KGM system. The composite gels were dehydrated to generate shell materials. The materials including xanthan or locust bean gum showed stronger chain interactions than did that including gellan gum, accompanied by weakened crystalline features for the different shell materials. Again, compared to the agar/KGM counterpart, the shell materials including xanthan gum could display a similar tensile strength (close to 50 MPa) but an evidently increased elongation at break (ca. 2.5 times higher). Then, these agar/KGM based systems were used to prepare core-shell structural capsules. The capsules based on agar/KGM/xanthan gum materials exhibited the highest roundness and breaking stress. Regarding this, the increased sol-gel point reduced the time required for droplet hardening (to generate core-shell gel balls); such fact, together with the higher gel strength, weakened the deformation of gel balls and thus increased the roundness and breaking stress of capsules (resulting from drying of gel balls).

Chitosan–dipeptide hydrogels as potential anticancer drug delivery systems

A novel chitosan–dipeptide hydrogel was fabricated through a combination of self-assembly of 9-fluorenylmethoxycarbonyl-modified diphenylalanine (Fmoc–FF) and its electrostatic interaction with glycol chitosan (GCS). Hydrogel strength and stability depended on its composition. The highest gel strength was observed at a Fmoc–FF mass fraction (ϕFF) of 0.85, whereby the highest combined strength of the two interactions was achieved. As the ϕFF increased above 0.6, gel stability decreased in buffered solution at pH 7.46. The incorporation of doxorubicin (DOX) as a cationic model drug significantly increased the stability of the complex hydrogels. DOX-loaded hydrogels exhibited slow DOX release, probably due to the drug's strong binding to Fmoc–FF via electrostatic attraction and the high gel stability. These hydrogels also exhibited excellent thixotropic features that facilitated the development of injectable self-healing drug delivery systems. Notably, DOX release was significantly accelerated as the pH of the medium decreased from 7.46 to 5.5 and 4.0, possibly due to hydrogel components' protonation. The DOX-loaded hydrogel exhibited notable cytotoxicity against A549 human lung cancer cells, which suggests the newly developed hydrogel to be a promising candidate vehicle for the localized and controlled drug delivery in cancer therapy.

Nutritional and Rheological Features of Lentil Protein Isolate for Yoghurt-Like Application.

The substitution of animal protein with proteins of plant origin is a viable way to decrease the negative impact caused by animal husbandry on the environment. Pulse consumption has been widely promoted as a nutritious contribution to protein supplementation. In this study, an emulsion of lentil (Lens culinaris) protein isolate is fermented with lactic acid bacteria (LAB) to manufacture a yoghurt alternative and the techno-functional properties compared to a dairy- and a soy-based product with similar protein contents. The yoghurt-like products are subjected to large and small deformation analysis, quantification of fermentable oligosaccharides, disaccharides, monosaccharides and polyols (FODMAP), water holding capacity tests, protein profile analysis and the gel structure is visualised by confocal laser scanning microscopy (CLSM). The lentil yoghurt alternative shows good water holding capacity, high firmness and consistency values in large deformation analysis, with cohesiveness and viscosity not significantly different from that of dairy yoghurt. The high gel strength and rigidity of the lentil yoghurt gels measured by small deformation analysis is well-reflected in the dense protein matrix in the CLSM graphs. FODMAP content of the lentil yoghurt is very low, making it suitable for consumption by irritable bowel syndrome (IBS) patients. Our results show that lentil protein isolate is an excellent base material for producing a plant-based yoghurt alternative.

Effects of Ethanolic Extract of Kiam Wood/Cashew Bark and Commercial Phenolic Compounds Oxidized Under Alkaline Condition on Gel Property of Gelatin from Cuttlefish Skin

The effect of ethanolic extracts of kiam wood (EKW) or cashew bark (ECB) and commercial phenolic compounds oxidized under alkaline condition (pH 9) on gel properties of gelatin extracted from cuttlefish skin was investigated. All the oxidized compounds increased gel strength (GS) of gelatin, in which the highest value was noticed for gels containing oxidized catechin (CH-G) and gallic acid (GA-G) (P<0.05). Among the ethanolic extracts, the gel added with EKW (EKW-G) had higher GS than that containing ECB gel (ECB-G) (P<0.05). Both extracts yielded gels with similar GS to those added with oxidized ferulic and tannic acids (P>0.05). Lightness and free amino group content of gels were decreased with the addition of oxidized compounds, regardless of their types. Gels added with oxidized compounds showed lower solubility and amino group content as compared to the control, indicating the formation of nondisulphide covalent bonds in the gel matrix. The treated samples showed a gel network with thicker strands and larger voids, compared with the control gel. Overall, oxidized EKW extract had a similar impact on the gel properties of gelatin to the oxidized phenolic compounds, especially catechin and gallic acids.

Effect of chitosan as adsorben to bacto agar quality from Gelidium sp.

Gelidium sp. is a seaweed that produces agar with a high gel strength. Bacto agar must have a high purity, so it needs a right purification method. One of the ways by adsorption process using chitosan. The aim of this research was to determine the influence of chitosan as an adsorbent and the optimum condition of its adsorption process. Bacto agar was extracted with water at 90°C. An alkali and acid pretreatment were added in the extraction process in order to increase thephysico-chemical properties of the agar gels. The agar extract was adsorbed by chitosan with various concentration of chitosan (0.5; 0.75; and 1%) and adsorption time (0, 30, and 60 minutes). The characteristic of bacto agar include moisture content, ash content, acid-insoluble ash content, sulphate content, gel strength, viscosity, syneresis, gelling and melting points, analysis of its molecular structure by FTIR and SEM. Bacto agar resulted in this research were tested as a bacterial culture medium using Total Plate Count (TPC) method. The best chitosan treatment process was obtained in bacto agar at 0,75% and 0 minute of adsorption which is had the physico-chemical properties that met the criteria of commercial bacto agar with 3.50% of bacto agar yield, 14.61% moisture content, 4.02% ash content, 0.93% acid-insoluble ash content, 1.34% sulphate content, 1054.96 g/cm2 gel strength, 60 Cp viscosity, 4.62% syneresis, 65 °C and 20.75 °C of melting and gelling points respectively. The microbial analysis shows that bacto agar can be used as a bacterial culture medium.

SIFAT PASTA PATI MILLET (Pennisetum glaucum (L.) R. Br.) TERMODIFIKASI HEAT MOISTURE TREATMENT UNTUK PEMBUATAN SOHUN

Improve the consumption of millet to vermicelli promoted for food diversification. Millet starch less stable of stirring and heating. Starch modification can improve the quality. In this research to evaluate pasting character of millet starch modified by heat moisture treatment which suitable for vermicelli. Heat moisture treatment conditioned at 25% moisture content and heating 100, 130 and 150 0C for 3, 5 and 7 hours with oven. Crystalline and starch paste properties of modified starch were analyzed and then selected to vermicelli. The suitable starch for vermicelli which stable paste of stirring and heating and high gel strength. The results show modified starch with 100 °C for 7 hours has an ideal for vermicelli. Shown by lower peak viscosity and viscosity breakdown (2951 cP and 71 cP), high final viscosity (3695 cP).Keyword : Heat moisture treatment, millet starch, RVA, pasting properties

Influence of collagen and some proteins on gel properties of jellyfish gelatin.

Marine gelatin is one of the food proteins used in food and non-food products, offering desirable functionalities such as gelling, thickening, and binding. Jellyfish has been chosen for this gelatin research, in view of the benefits of its main collagen protein and lower fat content, which may reduce the amounts of chemicals used in the preparative steps of gelatin production. To date, the lack of identified proteins in gelatin has limited the understanding of differentiating intrinsic factors quantitatively and qualitatively affecting gel properties. No comparison has been made between marine gelatin of fish and that of jellyfish, regarding protein type and distribution differences. Therefore, the study aimed at characterizing jellyfish gelatin extracted from by-products, that are i.e., pieces that have broken off during the grading and cleaning step of salted jellyfish processing. Different pretreatment by hydrochloric acid (HCl) concentrations (0.1 and 0.2 M) and hot water extraction time (12 and 24 h) were studied as factors in jellyfish gelatin extraction. The resultant jellyfish gelatin with the highest gel strength (JFG1), as well as two commercial gelatins of fish gelatin (FG) and bovine gelatin (BG), were analyzed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The results show that the jellyfish gelatin (JFG1) extracted with 0.1 M HCl at 60°C for 12 h delivered a maximum gel strength of 323.74 g, which is lower than for FG and BG, exhibiting 640.65 and 540.06 g, respectively. The gelling and melting temperatures of JFG1 were 7.1°C and 20.5°C, displaying a cold set gel and unstable gel at room temperature, whereas the gelling and melting temperatures of FG and BG were 17.4°C, 21.3°C, and 27.5°C, 32.7°C, respectively. Proteomic analysis shows that 29 proteins, of which 10 are types of collagen proteins and 19 are non-collagen proteins, are common to all BG, FG, and JFG1, and that JFG1 is missing 3 other collagen proteins (collagen alpha-2 (XI chain), collagen alpha-2 (I chain), and collagen alpha-2 (IV chain), that are important to gel networks. Thus, the lack of these 3 collagen types influences the inferior gel properties of jellyfish gelatin.

Preparation and characterization of konjac glucomannan and gum arabic composite gel

Compounding is a safe method to avoid limitations of a singular gel. Here, composite gels were prepared with konjac glucomannan (KGM) and gum arabic (GA) and evaluated by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), water solubility index (WSI), water absorption index (WAI), texture profile analysis (TPA) and rheological analysis. The gel stratified when GA concentration ≥ 2.5%. FTIR indicated that the interactions of KGM and GA were mainly related to hydrogen bonds and acetyl groups, and the solution separated from gels only included GA and water molecules. The microstructures became denser and contained smaller holes at high GA concentrations as seen by SEM. WSI and WAI both increased with GA increasing. Hardness and springiness dropped when GA concentration increased from 0 to 2.0%, but they increased when GA increased from 2.0% to 4.0%. Rheological analysis showed the gels were non-Newtonian pseudoplastic fluids, with anti-thixotropy (GA ≤ 3.5%) and thixotropy (GA ≥ 4.0%). Furthermore, the gels could be classified as non-covalent gels, with higher gel strength at high GA concentrations. The non-covalent linkages included hydrogen bonding and hydrophobic interaction, and hydrogen bonding held the dominated status. Therefore, KGM and GA have antagonistic and synergistic effects.

Convenient Agarose Preparation with Hydrogen Peroxide and Desulfation Process Analysis.

Agarose is a natural seaweed polysaccharide and widely used in the medicine, food, and biological fields because of its high gel strength, non-toxicity, and electrical neutrality. The sulfate group is one of the main charged groups that affect the performance of agarose. In the present study, a simple, eco-friendly, and efficient method was explored for agarose preparation. After desulfation with hydrogen peroxide (H2O2), the sulfate content of agar reached 0.21%. Together with gel strength, electroendosmosis, gelling and melting temperature, the indicators of desulfated agar met the standards of commercially available agarose. Notably, the desulfated agar can be used as an agarose gel electrophoresis medium to separate DNA molecules, and the separation effect is as good as that of commercially available agarose. Further, the H2O2 desulfation process was analyzed. The addition of a hydroxyl radical (HO•) scavenger remarkably decreased the H2O2 desulfation rate, indicating that HO• has a certain role in agar desulfation. Sulfate content detection indicated that sulfur was removed from agar molecules in the form of sulfate ions (SO42−) and metal sulfate. The band absence at 850 cm−1 indicated that the sulfate groups at C-4 of D-galactose in sulfated galactan were eliminated.