Carrageenan Fiber Prepared by a New Process Route of Ba^(2+)Ion Pre-Crosslinking in the Spinning Solution

Ba^(2+)pre-crosslinked carrageenan fiber(Ba/CAF)was prepared by adding a small amount of Ba^(2+) to the carrageenan(CA)solution as the spinning solution.Ba/CAF-n/A,Ba/CAF-n/B and Ba/CAF-n/C were prepared with ethanol solution(combine A),high concentration BaCl_(2)solution(combine B)and low concentration BaCl_(2)solution(combine C),as coagulation bath and stretch bath,respectively.The combination of coagulation bath and stretch bath suitable for Ba^(2+) pre-crosslinking wet spinning was screened.The results showed that Ba^(2+) can induce the birefringence of the CA molecular chain,and the Ba^(2+) pre-crosslinking effect is the best when the CA mass fraction is 8.0 wt%.From the perspective of production safety,fiber performance and spinning cost,the coagulation bath of 3.5 wt%BaCl_(2)solution and stretch bath of 1.7 wt%BaCl_(2)solution,that is,combination C with low concentration BaCl_(2)solution,is the best choice.Ba/CAF-8.0/C was obtained under the best conditions.The linear intensity,water absorption and flame retardancy study showed that the breaking strength of Ba/CAF-8.0/C is as high as 1.61 cN/dtex,the water absorption was 649.2%and 574.3%,in deionized water and normal saline,respectively,and the LOI value reached 32.

Immobilization of microorganisms using carrageenan gels coated with chitosan and application to biodegradation of 4-chlorophenol

A new cell immobilization method based on the replacement of KCl by KCl+chitosan as the gelling agent was developed. The experimental results showed that through addition of chitosan into gelling agent, the mechanical strength and the thermal stability of the carrageenan gel were greatly improved. The new immobilization method was used to entrap a chlorophenol degrading microorganism. The immobilized microbial cells were applied for chlorophenol biodegradation. The experiments demonstrated that immobilized cells exhibit a higher bioactivity in the degradation of chlorophenol than free cells.

De novo sequencing and comparative analysis of three red algal species of Family Solieriaceae to discover putative genes associated with carrageenan biosysthesis

Betaphycus gelatinus, Kappaphycus alvarezii and Eucheuma denticulatum of Family Solieriaceae, Order Gi-gartinales, Class Rhodophyceae are three important carrageenan-producing red algal species, which pro-duce different types of carrageenans, beta （β）-carrageenan, kappa （κ）-carrageenan and iota （ι）-carrageenan. So far the carrageenan biosynthesis pathway is not fully understood and few information is about the So-lieriaceae genome and transcriptome sequence. Here, we performed the de novo transcriptome sequencing, assembly, functional annotation and comparative analysis of these three commercial-valuable species using an Illumina short-sequencing platform Hiseq 2000 and bioinformatic software. Furthermore, we compared the different expression of some unigenes involved in some pathways relevant to carrageenan biosynthe-sis. We finally found 861 different expressed KEGG orthologs which contained a glycolysis/gluconeogenesis pathway （21 orthologs）, carbon fixation in photosynthetic organisms （16 orthologs）, galactose metabolism （5 orthologs）, and fructose and mannose metabolism （9 orthologs） which are parts of the carbohydrate me-tabolism. We also found 8 different expressed KEGG orthologs for sulfur metabolism which might be impor-tantly related to biosynthesis of different types of carrageenans. The results presented in this study provided valuable resources for functional genomics annotation and investigation of mechanisms underlying the biosynthesis of carrageenan in Family Solieriaceae.

Formulation Development of a Carrageenan Based Delivery System for Buccal Drug Delivery Using Ibuprofen as a Model Drug

Solvent cast films are used as oral strips with potential to adhere to the mucosal surface, hydrate and deliver drugs across the buccal membrane. The objective of this study was the formulation development of bioadhesive films with optimum drug loading for buccal delivery. Films prepared from κ-carrageenan, poloxamer and polyethylene glycol or glycerol, were loaded with ibuprofen as a model water insoluble drug. The films were characterized using texture analysis (TA), hot stage microscopy (HSM), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), x-ray powder diffraction (XRPD), high performance liquid chromatography (HPLC) and in vitro drug dissolution. Optimized films were obtained from aqueous gels containing 2.5% w/w κ-carrageenan 911, 4% w/w poloxamer 407 and polyethylene glycol (PEG) 600 [5.5% w/w (non-drug loaded) and 6.5% w/w (drug loaded)]. A maximum of 0.8% w/w ibuprofen could be incorporated into the gels to obtain films with optimum characteristics. Texture analysis confirmed that optimum film flexibility was achieved from 5.5% w/w and 6.5% (w/w) of PEG 600 for blank films and ibuprofen loaded films respectively. TGA showed residual water content of the films as approximately 5%. DSC revealed a Tg for ibuprofen at -53.87。C, a unified Tm for PEG 600/poloxamer mixture at 32.74。C and the existence of ibuprofen in amorphous form, and confirmed by XRPD. Drug dissolution at a pH simulating that of saliva showed that amorphous ibuprofen was released from the films at a faster rate than the pure crystalline drug. The results show successful design of a carrageenan and poloxamer based drug delivery system with potential for buccal drug delivery and showed the conversion of crystalline ibuprofen to the amorphous form during film formation.

Optimization of genistein solubilization byκ-carrageenan hydrogel using response surface methodology

κ-Carrageenan was explored to improve genistein solubility by matrix retention.The corresponding maximum value in the efficiency of retention(Re)(50.48 mg/100 mg)was achieved when variables were set as:pH 4.76,temperature 52.12◦C and genistein concentration 0.27 mg/mL.The coefficient of determination(R2)of the response surface regression model presented in this study was 0.9848.The evidences from XRD,DSC and FT-IR attested the amorphous form of genistein in hydrogel matrix.Importantly,the solubility of genistein in hydrogel amorphous form(16.84–34.42g/mL)was much higher than that of its free crystalline form(1.89–6.09g/mL)over 30–90◦C.©2013 Beijing Academy of Food Sciences.Production and hosting by Elsevier B.V.All rights reserved.

Oligo-carrageenan kappa increases C, N and S assimilation, auxin and gibberellin contents, and growth in Pinus radiata trees

Oligo-carrageenans （OCs） obtained from pure carrageenans extracted from marine red algae stimulate growth by enhancing photosynthesis and basal metabolism in tobacco plants and Eucalyptus trees. In addition, OCs stimulate secondary metabolism, increasing the level of metabolites involved in defense against pathogens. In this work, we analyzed the effect of OC kappa on the increase in height, in activities of basal metabolism enzymes in- volved in carbon, nitrogen and sulphur assimilation, ribu- lose 1,5 biphosphate carboxylase/oxygenase （rubisco）, glutamate dehydrogenase （GDH） and O-acetylserine thiol- lyase （OASTL）, and in the level of growth-promoting hormones, the auxin indole acetic acid （IAA） and the gibberellin GA3, in pine （Pinus radiata） trees treated with OC kappa at concentrations of 1 and 5 mg mL-1 and cultivated for 9 months without additional treatment. Pines treated with OC kappa at 1 mg mL-1 showed a similar increase in height but displayed a higher increased in total chlorophyll, activities of rubisco, GDH and OASTL and level of IAA and GA3 than those treated with OC kappa at 5 mg mL-1. Thus, OC kappa stimulates growth and basal metabolism and increases the level of growth-promoting hormones in pine trees, mainly at 1 mg mL-1.

Dietary Supplementation of <i>κ</i>-Carrageenan to Improve the Physio-Chemical and Functional Properties of White Bread

Fiber intake improves gut health and prevents non-communicable diseases. The current study investigates the substitution of carrageenan in white bread and evaluates its effect on the physiochemical and structural characteristics of bread. The 100% wheat flour was used as control and the test sample contained 4% carrageenan. The physio-chemical analysis showed that carrageenan-substitution improved the hydration properties of the flour (WHC—1.33 g/g;SC—3.50 ml/g). Carrageen substituted bread had reduced the loaf volume. The fiber content in carrageenan-substituted bread was noticeably higher (9.4 g%) than control (3.5 g%). Crude lipid (4.6 g%) and protein (7.0 g%) content improved with carrageenan-substitution. The mineral contents (Na, K, Mg, Ca, Fe, and Zn) were increased in carrageenan-breads. The texture profile analysis showed a decreased hardness (H1—92.3 N, H2—62.5 N) and improved springiness (5.3 mm) in carrageenan-bread.

Preparation and Properties of Carrageenan-g-Poly(Acrylic Acid)/Bentonite Superabsorbent Composite

A novel biopolymer-based superabsorbent hydrogel composite based on kappa-carrageenan (κC) have been prepared via graft copolymerization of acrylic acid (AA) in the presence of bentonite powder using methylenebisacrylamide (MBA) as a crosslinking agent and ammonium persulfate (APS) as an initiator. The hydrogel structure was confirmed using FTIR spectroscopy and the morphology of the samples was examined by scanning electron microscopy (SEM). The affecting variables onto graft polymerization (i.e. AA, MBA and APS concentration, as well as the bentonite amount) were systematically optimized to achieve a hydrogel with swelling capacity as high as possible. The results of Brunauer–Emmett–Teller (BET) analysis showed that the average pore diameter of the synthesized hydrogel was 11.5 nm. The effect of various salt media and solutions with different pHs on the swelling of the superabsorbent was also studied.

Rheological and DSC Studies on the Interaction between κ-Carrageenan and Cellulose Nanocrystals (CNC)

Rheometer and differential scanning calorimetry （DSC） have been used to probe the mechanism of gelation in gels formed by mixture of k-carrageenan and cellulose nanocrystals （CNC）. The results indicated that an association occurred between CNC chains and aggregated k-carrageenan helices.

Antibacterial Activity of Polyethylenimine/Carrageenan Multilayer against Pathogenic Bacteria

The multilayer of polyethylenimine (PEI) and carrageenan (k, i, l) formed by layer-by-layer assembly was investigated for its antibacterial activity against Enterobacter cloaceae, Staphylococcus aureus and Enterococcus faecalis 29505 for potential use as coating on biomaterial surface. All the multilayers exhibited growth inhibition. PEI/Iota carrageenan multilayer was effective in inhibiting the growth of the E. cloaceae, S. aureus and E. faecalis while PEI/Lambda carrageenan was effective in inhibiting the growth of E. cloaceae. Results of the paper strip test for combined action of carrageenan and PEI showed synergism with regards to bacterial growth inhibition. The multilayers had also contact-killing effect with the test organisms. The multilayer was also characterized by atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS) and biomolecular interaction analysis.

Structural Studies on <i>ι</i>-Carrageenan Derived Oligosaccharides and Its Application

Mild hydrochloric acid hydrolysis of i-carrageenan from Eucheuma spinosum yielded two oligosaccharides of sulfated tetrasaccharide structure. These were characterized by Fourier Transform Infrared Spectroscopy (FT-IR), Nuclear Magnetic Resonance (NMR) and Electrospray Ionization Mass Spectrometry (ESIMS). Both oligosaccharides have structure of b-D-galactopyranose(Galp)4S-(1→4)-α-D-AnGalp2S-(1→3)-b-D-galactopyranose Galp)4S-(1→4)-α-D-AnGalp2S-(1→3). Application of the resulting oligosaccharides on protein delivery system in terms of encapsulation efficiency was performed.

Anti-Inflammatory Effect of Dendrobium Huoshanense Polysaccharides on Carrageenan-Induced Air Pouch Synovitis in Mice

Objective:The purpose was to observe the anti-inflammatory effects of Dendrobium huoshanense polysaccharides(DHPs)on carrageenan-induced sterile air pouch synovitis.Materials and Methods:A total of 30 Institute of Cancer Research(ICR)mice were randomly and equally assigned to the control,carrageenan-induced air pouch synovitis model(model),and carrageenan-induced air pouch synovitis model+DHP(200 mg/kg of body weight)(model+DHP)groups.Mice in the model+DHP group were intragastrically administered 200 mg/kg BW of DHP solution daily for 10 days.Mice in the control and model groups were intragastrically administered the same amount of distilled water.Two hours after intragastric administration on day 10,1 mL of a 1%carrageenan solution in a sterile 0.9%saline solution was injected into the air pouch of mice in the model and model+DHP groups.Six hours later,the mice were sacrificed and 4 mL of ice-cold sterile 0.9%saline solution was injected into the air pouch to fully wash its inner wall.The lavage fluid was collected to observe the color and turbidity of the lavage fluid,as well as the appearance of the backside of the air pouch.The exudate volume,total number of leukocytes,protein content,levels of malondialdehyde(MDA),interleukin-1β(IL-1β),and tumor necrosis factor-alpha(TNF-α),and total superoxide dismutase(T-SOD)activity of the lavage fluid were analyzed.Results:The results showed that pretreatment with DHPs reduced the carrageenan-induced exudate volume(P<0.01),total leukocytes(P<0.05),and protein content(P<0.01)in the air pouch lavage fluid.Furthermore,mice in the model+DHP group had significantly higher(P<0.01)T-SOD activity and lower MDA content(P<0.05),IL-1β(P<0.05),and TNF-α(P<0.01)levels in the air pouch lavage fluid compared with the model group.Conclusion:It is concluded that DHPs partially alleviated carrageenan-induced sterile inflammation,and its mechanism may be related to reducing exudation and scavenging oxygen-free radicals,inhibiting lipid peroxidation,and reducing the level of the proinflammatory factors,such as IL-1βand TNF-α.

Expanding the application range of theκ‑carrageenase OUC‑FaKC16A when preparing oligosaccharides fromκ‑carrageenan and furcellaran

Carrageenan oligosaccharides are important products that have demonstrated numerous bioactivities useful in the food,medicine,and cosmetics industries.However,the specifc structure–function relationships of carrageenan oligosaccharides are not clearly described due to the defciency of high specifc carrageenases.Here,a truncated mutant OUC-FaKC16Q based on the reportedκ-neocarratetrose(Nκ4)-producingκ-carrageenase OUC-FaKC16A from Flavobacterium algicola was constructed and further studied.After truncating the C-terminal Por_Secre_tail(PorS)domain(responsible for substrate binding),the catalytic efciency and temperature stability decreased to a certain extent.Surprisingly,this truncation also enabled OUC-FaKC16Q to hydrolyze Nκ4 intoκ-neocarrabiose(Nκ2).The ofset of Arg265 residue in OUC-FaKC16Q may explain this change.Moreover,the high catalytic abilities,the main products,and the degradation modes of OUC-FaKC16A and OUC-FaKC16Q toward furcellaran were also demonstrated.Data suggested OUC-FaKC16A and OUC-FaKC16Q could hydrolyze furcellaran to produce mainly the desulfated oligosaccharides DA-G-(DA-G4S)2 and DA-G-DA-G4S,respectively.As a result,the spectrum of products ofκ-carrageenase OUC-FaKC16A has been fully expanded in this study,indicating its promising potential for application in the biomanufacturing of carrageenan oligosaccharides with specifc structures.

Expression and Characterization of a Novelλ-Carrageenase Cgl150A_Wa from Wenyingzhuangia aestuarii

λ-Carrageenan is a highly sulfated polysaccharide alternating of 1,4-O-α-D-galactopyranose-2,6-sulfate(D2S,6S)and 1,3-O-β-D-galactopyranose-2-sulfate(G2S).λ-Carrageenases are desirable tools forλ-carrageenan degradation.Based on the genome mining,a novelλ-carrageenase Cgl150A_Wa was cloned from the bacterium Wenyingzhuangia aestuarii and expressed in Escherichia coli.Cgl150A_Wa was an endo-acting enzyme and exhibited its maximum activity at 30℃and pH 8.0.By employing a glycomics strategy that combined ultra-performance liquid chromatography-mass spectrometry analysis and glycoinformatics,Cgl150A_Wa was proven to degradeλ-carrageenan octaose and hexaose,and the major hydrolysis product of Cgl150A_Wa wasλ-carrageenan tetrose.In addition to the typicalλ-carrageenan motifs,the active center of Cgl150A_Wa might tolerate desulfatedλ-carrageenan motifs.Cgl150A_Wa is a potential biotechnological tool for preparingλ-carrageenan oligosaccharides and structural investigation.

Analgesic and anti-inflammatory activity of Cotinus coggygria Scop.extracts in vivo

Objective:To assess the analgesic and anti-inflammatory effects of standardized extract of Cotinus coggygria(C.coggygria)in different animal models.Methods:C.coggygria extracts(25,50,and 100 mg/kg)were administered to rats and mice(n=6)during hot plate,tail-flick,acetic acid-induced writhing,and formalin tests to determine its analgesic efficacy.The anti-inflammatory activity of C.coggygria extracts was evaluated by histamine and carrageenan-induced paw edema,cotton pellet-induced granuloma,and acetic acid-induced peritoneal capillary dye leakage tests.Results:C.coggygria extracts(50 and 100 mg/kg)significantly alleviated thermal and chemical-induced pain in rodents(P<0.05).It also demonstrated notable anti-inflammatory properties by mitigating histamine and carrageenan-induced paw edema,granuloma deposits,and vascular permeability(P<0.05).Moreover,C.coggygria extracts remarkably reduced TNF-α,IL-1β,IL-6,COX-2,and oxidative stress in rat paws(P<0.05).Carrageenan-induced histological aberrations in hind paw tissues were effectively(P<0.05)mitigated by treatment with C.coggygria extracts.Conclusions:C.coggygria Scop.extracts show analgesic and anti-inflammatory effects via inhibition of COX-2 and inflammatory and oxidative mediators.

Carrageenan oligosaccharides and associated carrageenan-degrading bacteria induce intestinal inflammation in germ-free mice

Carrageenans(CGNs)are widely used in foods and pharmaceuticals although their safety remains controversial.To investigate the effects of CGNs and CGN-degrading bacteria in the human colon,we screened for CGN degradation by human fecal microbiota,and for inflammatory response to CGNs and/or CGN-degrading bacteria in germ free mice.Thin-layer chromatography indicated that high molecular weight(MW)CGNs(!100 kDa)remained undegraded in the presence of human fecal microbiota,whereas low MW CGNs,i.e.,k-carrageenan oligosaccharides(KCO,~4.5 kDa)were degraded when exposed to seven of eight human fecal samples,although sulfate groups were not removed during degradation.Bacteroides xylanisolvens and Escherichia coli isolates from fecal samples apparently degraded KCO synergistically,with B.xylanisolvens serving as the primary degrader.Combined treatment of KCO with KCO-degrading bacteria led to greater pro-inflammatory effects in the colon and rectum of germ-free mice than either KCO or bacteria alone.Similarly,p-p38-,CD3-,and CD79a-positive immune cells were more abundant in combined treatment group mice than in either single treatment group.Our study shows that KCO-degrading bacteria and the low MW products of KCO can promote proinflammatory effects in mice,and represent two key markers for evaluating CGN safety in foods or medicines.

不同浓度卡拉胶对汉麻分离蛋白凝胶性质及结构的影响

为阐明不同浓度的卡拉胶(0.4%、0.8%、1.2%、1.6%、2.0%,w/w)对汉麻分离蛋白凝胶特性和结构的影响,以未添加卡拉胶的汉麻分离蛋白凝胶为对照,测定复合凝胶的持水能力、质构、流变特性,同时检测了卡拉胶的加入对复合凝胶水分分布、蛋白结构及分子间作用力的影响。结果表明:添加卡拉胶显著(P<0.05)提高了汉麻分离蛋白凝胶持水能力和凝胶强度,改变了蛋白结构。与对照组相比,0.8%卡拉胶的添加显著(P<0.05)提高凝胶的硬度、弹性模量并降低了凝胶的频率依赖性,并与水分子结合最为紧密,α-螺旋向β-折叠和无规卷曲转变,增加凝胶刚性结构;此时维持凝胶结构的主要作用力由疏水相互作用力向二硫键转变,凝胶网络更加致密,电镜结果证明了这一结论。因此,添加0.8%的卡拉胶可显著(P<0.05)提高汉麻分离蛋白的凝胶性质并改善其结构,为提高汉麻分离蛋白在食品领域的应用提供了理论和实验基础。

响应面法优化草莓混合凝胶3D打印配方

为提高草莓尾果利用率,扩宽草莓加工产品品类,将草莓制浆后与黄原胶、卡拉胶复配成适合3D打印的基料,并利用单因素及响应面优化试验,得到草莓混合凝胶3D打印最优配方。结果表明:不同原料对打印精度的影响大小依次为K-卡拉胶>草莓浆>黄原胶,最佳工艺配方为草莓浆添加量40 g,黄原胶添加量2 g,K-卡拉胶添加量3 g,在此条件下,测得草莓3D打印产品打印精度为98.39%,草莓3D打印产品最符合设置模型(正方体:上边长15 mm、下边长15 mm、高15 mm),此时材料能够很好地挤出且支撑能力最好。

卡拉胶对七彩神仙鱼生长、酶活性和肠道微生物组成的影响

为探究黏合剂卡拉胶对七彩神仙鱼生长、消化酶活性、抗氧化酶活性和肠道微生物组成的影响,在水温(28.0±0.5)℃下,将初始体质量(10.81±2.41)g的七彩神仙鱼饲养在80 L养殖缸中,每缸15尾,投喂添加3%、6%、9%、12%和15%卡拉胶的饲料,以投喂不添加卡拉胶的颗粒饲料和牛心汉堡为对照,养殖56 d。结果表明:3%卡拉胶组七彩神仙鱼质量增加率和特定生长率最高,胃蛋白酶活性和前肠淀粉酶活性显著高于其他组,肝脏丙二醛含量和谷胱甘肽过氧化物酶活性显著低于其他试验组;12%卡拉胶组肝脏超氧化物歧化酶活性显著高于其他试验组。在肠道微生物组成的门水平方面,3%卡拉胶组变形菌门相对丰度显著高于其他组,梭杆菌门的相对丰度减少;在属水平方面,牛心汉堡组不含有乳球菌属,3%卡拉胶组罗姆布茨菌属相对丰度显著高于其他卡拉胶组,牛心汉堡组的鲸杆菌属相对丰度显著高于其他组。添加3%的卡拉胶能够提高七彩神仙鱼的质量增加率和特定生长率,显著提高胃蛋白酶和前肠淀粉酶活性,且不会造成氧化应激,肠道变形菌、罗姆布茨菌和乳球菌的相对丰度增加。在本试验条件下,七彩神仙鱼饲料中卡拉胶的适宜添加量为3%。