Effect of succinic acid deamidation-induced modification on wheat gluten

The effect of succinic acid deamidation-induced modification on wheat gluten was investigated in the present study. The changes of surface hydrophobicity, functional properties, secondary structure, and sensibility of proteolysis of modified samples were determined. The solubility of deamidated proteins increased in the isoelectric region of untreated wheat gluten. The isoelectric point of succinic acid deamidated wheat gluten was shifted to a basic pH and existed in the broad pH regions. Foaming property and molecular flexibility of wheat gluten were improved after the modification. The hydrolysis degree of the hydrolysates in proteolysis with flavorzyme and pancreatin increased after succinic acid deamidation. Moreover, succinic acid deamidation-induced modification resulted in little change in molecular weight and secondary structure of the protein. Thus, succinic acid could facilitate unfolding protein conformation. In addition, it could improve protein-water interactions, surface properties, and sensibility of the proteolysis of the deamidated wheat gluten.     

Modification of wheat gluten with citric acid to produce superabsorbent materials

Wheat gluten was reacted with citric acid to produce natural superabsorbent materials able to absorb up to 78 times its weight in water. The properties of the modified gluten samples were characterized using Fourier Transform Infra‐red (FTIR) spectroscopy, thermogravimetric analysis, and water uptake. The reaction between gluten and citric acid was examined for gluten : citric acid ratios of 0.38 : 1 to 0.75 : 1 at temperatures from 100 to 130°C. More citric acid reacted for samples containing higher citric acid concentrations and at higher temperatures. FTIR analyses indicated the presence of carboxylate groups on the modified gluten samples, which resulted in modified samples having higher water uptake values than neat gluten. The sample with a gluten:citric acid ratio of 0.5 : 1 and reaction temperature of 120°C had the largest water uptake value. Also, all modified gluten samples had lower thermal stability than neat gluten. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Food uses of wheat gluten

New separation methods for wheat gluten have increased production and made possible the use of mass wheat as a raw material. This widens the use of gluten in the fields where functional as well as baking properties are important. Solubility, swelling, viscosity and nutritional aspects of gluten are reviewed. The current applications of wheat gluten are mainly in baked products, breakfast foods, and meat analogs. Many chemical modifications of gluten have been developed. Modifications are not in use, but the increased gluten production will bring them into use.     

Effect of succinic acid on the shrinkage of unsaturated polyester resin

Succinic acid was presented as a small molecule low shrinkage additive (LSA) in unsaturated polyester resin (UPR). The effects of succinic acid on the volume shrinkage and the flexural strength of UPR cured at 80 ± 1°C were investigated and compared with those of macromolecule LSAs, including polyvinyl acetate (PVAc), polymethyl methacrylate (PMMA), and polystyrene (PS). The results indicated that the volume shrinkage of succinic acid/UPR specimen was significantly lower than those of specimens with macromolecule LSAs. The flexural strength of succinic acid/UPR specimen was improved. The optimal time of pre‐esterification between succinic acid and the excess dihydric alcohol in UPR was 3.0 h, and the optimal addition of succinic acid was 20 g per 100 g UPR. Compared with 2,2‐dimethyl malonic acid we put forward before, succinic acid was a cheaper and more commercial LSA, which obviously accelerated the pre‐esterification process and presented excellent antishrinkage effect. DSC showed that with the addition of succinic acid, the polymerization of UPR was distinctive. The two‐stage polymerization of UPR glue including the cross‐polymerization of UPR and the homopolymerization of polyester was changed to a one‐stage polymerization with lower exotherm and slower polymerization rate, which was optimal for UPR. FTIR and high resolution magic angle spinning nuclear magnetic resonance (HR/MAS NMR) were applied for the quantitative characterization of pre‐esterification caused by succinic acid. Succinic acid performed better effects on the polymerization of UPR as compared to previous LSAs, and finally the homogeneous micro‐structure of cured succinic acid/UPR formed and was demonstrated by SEM. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41276.     

柠檬酸交联对谷朊纤维稳定性能的影响

以谷朊粉为原料,利用湿法纺丝方法制备谷朊纤维,并用柠檬酸对谷朊纤维进行交联处理,制备出交联谷朊纤维。通过比较谷朊粉、谷朊纤维、交联谷朊纤维在热稳定性、水解稳定性、大分子分子量及其构象等方面的差异,分析了柠檬酸交联对谷朊纤维的影响。结果表明,柠檬酸交联处理可提高谷朊大分子的分子量,改变蛋白质大分子的二级结构,从而改善了谷朊纤维的热稳定性和水解稳定性。     

柠檬酸交联对谷朊纤维稳定性能的影响

以谷朊粉为原料,利用湿法纺丝方法制备谷朊纤维,并用柠檬酸对谷朊纤维进行交联处理,制备出交联谷朊纤维。通过比较谷朊粉、谷朊纤维、交联谷朊纤维在热稳定性、水解稳定性、大分子分子量及其构象等方面的差异,分析了柠檬酸交联对谷朊纤维的影响。结果表明,柠檬酸交联处理可提高谷朊大分子的分子量,改变蛋白质大分子的二级结构,从而改善了谷朊纤维的热稳定性和水解稳定性。     

Effect of hydrolysis and denaturation of wheat gluten on adhesive bond strength of wood joints

In this study the adhesive bond strength of different wheat gluten modifications and the relationship between molecular weight and adhesive strength was examined. Guanidine hydrochloride and sodium hydroxide were used as denaturation and dispersing agent. Additionally wheat proteins were hydrolyzed by alkaline conditions and enzymes. Effects of different treatments were observed by viscosity measurements and gel electrophoresis. Wood lap joints were prepared with modified proteins and tensile shear strength was tested under dry and wet conditions. In situ hardening of different formulations was analyzed by means of DMA with two‐layered specimens in a three‐point bending test set‐up. Higher solubility had no positive effect on dry bonding strength and wet bonding strength was even reduced. Depending on the degree of hydrolysis, significant improvement of adhesive bond strength was observed. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Modification of vital wheat gluten with phosphoric acid to produce high free swelling capacity

Wheat gluten reacts with phosphoric acid in the presence of urea to produce natural superabsorbent gels. Fourier Transform Infra‐red (FT‐IR) spectroscopy and two‐dimensional gel electrophoresis (2DE) reveal chemical changes from the reaction. Temperatures above 120°C and dry conditions create the opportunity for reaction. FT‐IR analyses confirm the formation of esters, carbamates, and phosphoramides on the gluten samples. 2DE protein composition topographies indicate a shift in the isoelectric point (pI) to lower values along with extensive inter‐protein linkages. A free swelling capacity (FSC) in excess of 85× the mass of the converted gluten is obtainable using a conservative vacuum‐assisted method to recover and quantify the properties of the wet gel. Other methods produce FSC values nearly twice as high. FSC for acid‐treated gluten is lower for solutions containing solutes than the FSC for deionized water. Native gluten produces FSC values that are about 2% of those for treated gluten, but these values are less sensitive to the presence of ionic solutes and increase slightly in the presence of aqueous ethanol up to a mole fraction of 0.25.. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 39440.     

Study of wheat gluten plasticization with fatty acids

The plasticizing effect on wheat gluten of a series of saturated fatty acids with different carbon chain length (from 6 to 10 carbons) was investigated. Plasticized materials were obtained by mixing in a counter-rotating batch mixer. The wheat gluten plasticization with the saturated fatty acids was shown to be thermodependent. Differential scanning calorimetry enabled the determination of the compatibility limits between wheat gluten and the fatty acids. Plasticizing effect, as judged from the shift of the temperature of the glass to rubbery transition, was determined by dynamic mechanical thermal analysis. As results showed a series effect on several times, it was thus possible to approximate the plasticizing effect of the different saturated fatty acids with a unique Couchman-Karasz equation. The molecular size distribution of the plasticized gluten was analyzed by size-exclusion high performance liquid chromatography (SE-HPLC). Mixing of plasticized wheat gluten induced variable and complex changes in the protein size distribution and resulted in a predominant polymerization, indicating a gluten reactivity in the presence of the fatty acids. The water vapor permeability of films obtained by pressure molding from the mixed plasticized samples showed improved barrier properties in comparison with films from wheat gluten plasticized with glycerol. The use of saturated fatty acids open thus new ways for the plasticization and the improvement of properties of gluten based biodegradable plastics.     

丁二酸生产工艺技术进展

简述了丁二酸的发展现状,介绍了目前丁二酸的主要生产方法,包括电化学法、顺酐催化加氢法和生物发酵法,并指出丁二酸的发展前景。     

Clarification of succinic acid fermentation broth by ultrafiltration in succinic acid bio–refinery

BACKGROUND: Succinic acid is an important precursor chemical for the synthesis of high value‐added products. In this work, ultrafiltration was first investigated to clarify succinic acid fermentation broth by integrating fermentation and separation and removal processes of the product in situ. Four different ultrafiltration membranes (PES 100 kDa, PES 30 kDa, PES 10 kDa and RC 10 kDa) were used in this work. RESULTS: Results indicate that ultrafiltration is feasible for clarifying succinic acid fermentation broth. Almost all the microorganism cells (99.6%) were removed from the fermentation broth. Proteins were also removed effectively by all the membranes studied. The removal rate was 79.86% for PES 100 kDa, 86.43% for PES 30 kDa, 86.83% for PES 10 kDa, and 80.06% for the RC 10 kDa. After ultrafiltration, a clearer permeate was obtained compared with that from centrifugation. CONCLUSION: Membranes operating at high flux are always susceptible to rapid fouling. Compared with molecular weight cut‐offs (MWCO), membrane material has a significant influence on the flux. Membrane flux measured in this study shows industrial potential of this technology in treatment of succinic acid fermentation broth. © 2012 Society of Chemical Industry     

Novel biocomposites based on wheat gluten and rubber wood sawdust

Rubber wood sawdust (RWS) was used as a reinforcement for wheat gluten based bioplastics. The RWS content was varied from 0, 5, 10, 15–20 wt %. Effects of the RWS content on the morphology, water absorption, mechanical, thermal, and biodegradation properties of the wheat gluten based bioplastic were investigated. An addition of RWS caused an improvement of the tensile strength and water resistance of the wheat gluten based bioplastics. Scanning electron micrograph of the wheat gluten/RWS composites with a 10 wt % of RWS revealed a good dispersion and uniform embedding of the RWS within the wheat gluten matrix. Agglomeration of RWS was observed when the RWS loads were increased (15 and 20 wt %). The biodegradation process of the composites depended on the amount of RWS. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43705.     

Effect of some polymeric materials on the corrosion behaviour of tin in succinic acid solution

The anodic behaviour and corrosion of tin in various concentrations (0.05–0.7M) of succinic acid were studied using cyclic voltammetry. The potentiodynamic anodic polarization curves exhibit active/passive transition. The active dissolution of tin involves one anodic peak. The cathodic curve exhibits one cathodic peak corresponding to the reduction of the passive layer. The ratio of the anodic charge/cathodic charge is more than unity indicating that the passive layer is very thin and the dissolution products are mainly soluble species. Additions of some polyethylene glycols to the succinic acid solution decrease the anodic peak current and shift the peak potential in the negative direction. These changes depend on the concentration and molecular weight of the polyethylene glycol added. The effect of the inhibitors decreases in the following order: (PEG)₆₀₀₀ > (PEG)₄₀₀₀ > (PEG)₁₂₀₀. The inhibition efficiency decreases with increase in temperature, suggesting physical adsorption.     

Aqueous electrospinning of wheat gluten fibers with thiolated additives

The molecular weight distribution (MWD), rheology and electrospinning of a series of wheat gluten (WG) mixtures with poly(vinyl alcohol) (PVA), dithiothreitol (DTT), and thiolated poly(vinyl alcohol) (TPVA) in water/1-propanol (1/1) were investigated by size-exclusion chromatography, steady-shear viscosity measurements and scanning electron microscopy. Thiolated additives reduce disulfide bonds between protein subunits and thus increase WG solubility. Accordingly, Newtonian behavior is observed for pure components and PVA/WG, and shear-thinning for DTT/WG and TPVA/WG. Concentration, viscosity and additive type affect WG electrospinnability. At higher concentrations, PVA/WG fibers are thicker than WG ones, whereas DTT/WG and TPVA/WG fibers are thinner and beadless. While at low concentrations both DTT/WG and TPVA/WG generate poor fibers, lowering TPVA thiolation level results in better fibers, unobtainable with DTT. Thus, although using only the lower end of the WG MWD, reasonably good fibers can nonetheless be obtained with an inexpensive aqueous system and very low additive amounts.     

Chemical lipophilization of soy protein isolates and wheat gluten

Chemical modification of soy protein isolate and wheat gluten can be used to investigate the influence of the chemical composition and the structure of the proteins on the final product properties and to adjust these properties to meet specific demands. Proteins were lipophilized by adding different levels of lauroyl chloride to aqueous protein dispersions. At optimum reaction conditions, incorporation rates of lauroyl chains to the protein were 400 and 300 μmol/g proteins for soy protein isolate and wheat gluten, respectively. The study showed that it was possible to lipophilize proteins in an aqueous medium, even with the protein significantly high in concentration.     

无隔膜电化学合成丁二酸清洁工艺研究

通过对合成丁二酸新电化学体系的研究,设计了无隔膜电解装置,开发出了低能耗、高收率、无污染的丁二酸电化学合成高效清洁工艺.产品总收率可达98.5％,吨产品直流耗电量小于1 500 kW·h,母液可循环利用.     

氧化还原电位调控对Actinobacillus succinogenes 厌氧发酵产丁二酸的影响

对氧化还原电位调控在产琥珀酸放线杆菌厌氧发酵产丁二酸过程中的代谢产物分布的作用进行了研究。在血清瓶发酵培养过程中,筛选出对发酵过程无抑制作用的氧化剂铁氰化钾和还原剂二硫苏糖醇作为发酵体系的氧化还原电位调节剂。在3L发酵罐上利用铁氰化钾和二硫苏糖醇调节发酵体系氧化还原电位值在-100～-450mV,结果表明-350mV为菌体生长和产丁二酸的最佳电位,丁二酸生产速率由0.75g/(L·h)提高到1.18g/(L·h),产物丁二酸与副产物乙酸的质量浓度比由2.5提高到3.9。     

Improving wheat gluten materials properties by Kraft lignin addition

The industrial production of wheat gluten (WG)-based biomaterials implies to improve their actual mechanical properties as well as to reduce their water sensitivity. In this study, the effect of Kraft lignin (KL) content on the processability and on the physical properties of WG materials was investigated. WG plasticized with glycerol was blended with KL, and processed into materials by mixing and thermomolding. Materials were characterized by dynamic mechanical thermal analysis, tensile test, and water absorption measurements. The introduction of KL in plasticized WG resulted in an increase of the material glass transition temperature (T_g) and in a strong decrease of the rubbery storage modulus, which will favor industrial processing. The increase in T_g did not follow a simple mixing rule, demonstrating specific interaction between KL and WG. The resulting materials effectively showed improved properties when compared with pure WG-based materials: they exhibited higher tensile strength and lower water sensitivity in ambient conditions. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

电解合成丁二酸的研究进展

综述了国内外电解合成丁二酸的方法,详细介绍了电解反应过程中阴极材料、阳极材料、电解槽结构和隔膜材料的发展趋势.分析结果表明铅及铅合金阴极凭借其自身的优势,仍然是工业生产所采用的最主要的阴极材料;最适合的阳极材料是钛基氧化钌、铱或钽铱钛合金;而且无需使用任何形式的隔膜;未来最具有应用前景的研究方向是Ti或Ti/TiO2阴极.