谷朊蛋白的改性及应用

近20年来,利用动植物等可再生资源代替当前广泛使用的石化材料成为热门研究方向,是消除污染、保护环境、实现绿色化学、推进人类社会与环境和谐发展的唯一途径.谷朊蛋白是谷类淀粉加工的副产物,是植物代谢产生的天然植物蛋白,一种生物可降解、可再生的天然高分子.由于其独特的粘弹性、延伸性、薄膜成型性和热凝固性等,越来越受到人们的重视,不仅拓宽了在食品工业中的应用领域,还可作为价格适宜、性能优良的高分子材料应用于其它领域.本文介绍了有关谷朊蛋白的组成、近年来国内外改性原理和方法,及其潜在的应用.     

Application of deep eutectic solvents in the extraction and separation of target compounds from various samples

Deep eutectic solvents, as a new type of eco‐friendly solvent, have attracted increasing attention in chemistry for the extraction and separation of target compounds from various samples. To summarize the application of deep eutectic solvents, this review highlights some of the unique properties of deep eutectic solvents and deep‐eutectic‐solvent‐based materials, as well as their applications in extraction and separation. In this paper, the available data and references in this field are reviewed to summarize the application developments of deep eutectic solvents. Based on the development of deep eutectic solvents, the exploitation of new deep eutectic solvents and deep‐eutectic‐solvent‐based materials are expected to diversify into extraction and separation.     

Exploring novel poly(thiophene‐3‐yl‐amine) through facile self acid assisted‐polycondensation

Aromatic moieties of benzene and pyridine as side chains for poly(thiophene‐3‐yl‐amine) are rationally designed and synthesized by facile self acid‐assisted polycondensation (SAAP). Nitrogen atom is the key atom to form ammonium cation which guarantees SAAP success while other aromatic moieties are chosen carefully to attach on N atom to functionalize poly(thiophene‐3‐yl‐amine) matrix. Our results indicate that thiophene‐3‐yl‐amine is an excellent platform to construct plenty of functionalized monomers candidates for SAAP. Our study would push SAAP or AAP scope forward and pave the way to explore much more polythiophene derivatives. Furthermore, DFT calculation is carried out to deep understand AAP mechanism. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 4003–4012     

Ionic Liquid Lignosulfonate: Dispersant and Binder for Preparation of Biocomposite Materials

Ionic liquid lignins are prepared from sodium lignosulfonate by a cation exchange reaction and display glass transition temperatures as low as ?13 °C. Diethyleneglycol‐functionalized protic cations inhibit lignin aggregation to produce a free‐flowing “ionic liquid lignin”, despite it being a high‐molecular‐weight polyelectrolyte. Through this approach, the properties of both lignin and ionic liquids are combined to create a dispersant and binder for cellulose+gluten mixtures to produce small microphases. Biocomposite testing pieces are produced by hot‐pressing this mixture, yielding a material with fewer defects and improved toughness in comparison to other lignins. The use of unmodified lignosulfonate, acetylated lignosulfonate, or free ionic liquid for similar materials production yields poorer substances because of their inability to maximize interfacial contact and complexation with cellulose and proteins.     

ACQ‐to‐AIE Transformation: Tuning Molecular Packing by Regioisomerization for Two‐Photon NIR Bioimaging

The traditional design strategies for highly bright solid‐state luminescent materials rely on weakening the intermolecular π–π interactions, which may limit diversity when developing new materials. Herein, we propose a strategy of tuning the molecular packing mode by regioisomerization to regulate the solid‐state fluorescence. TBP‐e‐TPA with a molecular rotor in the end position of a planar core adopts a long‐range cofacial packing mode, which in the solid state is almost non‐emissive. By shifting molecular rotors to the bay position, the resultant TBP‐b‐TPA possesses a discrete cross packing mode, giving a quantum yield of 15.6±0.2 %. These results demonstrate the relationship between the solid‐state fluorescence efficiency and the molecule's packing mode. Thanks to the good photophysical properties, TBP‐b‐TPA nanoparticles were used for two‐photon deep brain imaging. This molecular design philosophy provides a new way of designing highly bright solid‐state fluorophores.     

Recognition and Sensing of Creatinine

Current methods for creatinine quantification suffer from significant drawbacks when aiming to combine accuracy, simplicity, and affordability. Here, an unprecedented synthetic receptor, an aryl‐substituted calix[4]pyrrole with a monophosphonate bridge, is reported that displays remarkable affinity for creatinine and the creatininium cation. The receptor works by including the guest in its deep and polar aromatic cavity and establishing directional interactions in three dimensions. When incorporated into a suitable polymeric membrane, this molecule acts as an ionophore. A highly sensitive and selective potentiometric sensor suitable for the determination of creatinine levels in biological fluids, such as urine or plasma, in an accurate, fast, simple, and cost‐effective way has thus been developed.     

Aqueous two‐phase systems based on deep eutectic solvents and their application in green separation processes

As a new environmentally friendly separation technology, deep eutectic solvent based aqueous two‐phase systems are extensively applied in various fields. Herein, we review recent advances in this field and highlight the possible directions of future developments. This article focuses on the effects of deep eutectic solvent and inorganic salts on the phase equilibrium, the microstructure of deep eutectic solvent based aqueous two‐phase systems, the applications of deep eutectic solvent based aqueous two‐phase systems in separation (proteins, biopolymers, saponins, and organic acids), and removal and recovery technologies for deep eutectic solvent from aqueous two‐phase systems.     

Development of deep eutectic solvents applied in extraction and separation

Deep eutectic solvents, as an alternative to ionic liquids, have greener credentials than ionic liquids, and have attracted considerable attention in related chemical research. Deep eutectic solvents have attracted increasing attention in chemistry for the extraction and separation of various target compounds from natural products. This review highlights the preparation of deep eutectic solvents, unique properties of deep eutectic solvents, and synthesis of deep‐eutectic‐solvent‐based materials. On the other hand, application in the extraction and separation of deep eutectic solvents is also included in this report. In this paper, the available data and references in this field are reviewed to summarize the applications and developments of deep eutectic solvents. Based on the development of deep eutectic solvents, an exploitation of new deep eutectic solvents and deep eutectic solvents‐based materials is expected to diversify into extraction and separation.     

Effect of frozen storage on molecular weight, size distribution and conformation of gluten by SAXS and SEC-MALLS

In this study, the effects of frozen (-18 °C) storage time on molecular weight, size distribution, conformation, free amino groups and free sulfhydryl groups of gluten were studied by small-angle X-ray scattering (SAXS), multi-angle laser light scattering (MALLS) in conjunction with a size exclusion chromatography (SEC) and spectrophotometrically. The results showed that the gluten dissolved in 50 mM acetic acid appeared to be similar to quasi-spherical of the chain conformation and the slope of the conformation plot decreased during the storage. Both the molecular weight and radius of gyration of the frozen gluten decreased with the storage time showing a depolymerization in the high molecular weight fraction of gluten (10(5) Da ~ 10(9) Da). Therefore, at constant molecular weight the change of the chain conformation did not show a clear correlation with the storage time. The free amino groups content changed little and the free sulfhydryl groups content of the gluten increased from 9.8 μmol/g for the control to 12.87 μmol/g for 120-day-stored gluten, indicating that the water redistribution and ice recrystallization lead to the breakage of the disulphide bonds and may be one of the reasons for the depolymerization of gluten polymer.     

Detoxification of gluten by means of enzymatic treatment

Celiac disease (CD) is an inflammatory disease of the upper small intestine in genetically predisposed individuals caused by glutamine- and proline-rich peptides from cereal storage proteins (gluten) with a minimal length of nine amino acids. Such peptides are insufficiently degraded by gastrointestinal enzymes; they permeate the lymphatic tissue, are bound to celiac-specific, antigen-presenting cells, and stimulate intestinal T-cells. The typical clinical pattern is a flat small intestinal mucosa and malabsorption. Currently, the only therapy is a strict, lifelong gluten-free diet. Recent research has shown that gluten and gluten peptides can be degraded by prolyl endopeptidases from different sources. These peptidases can either be used to produce gluten-free foods from gluten-containing raw materials, or they have been suggested as an oral therapy for CD, in which dietary gluten is hydrolyzed by coingested peptidases already in the stomach, thus preventing CD-specific immune reactions in the small intestine. This would be an alternative for CD patients to the gluten-free diet. Furthermore, microbial transglutaminase could be used to detoxify gluten either by selectively modifying glutamine residues of intact gluten by transamidation with lysine methyl ester or by crosslinking gluten peptides in beverages via isopeptide bonds so that they can be removed by filtration.     

Expanding Anti‐Stokes Shifting in Triplet–Triplet Annihilation Upconversion for In Vivo Anticancer Prodrug Activation

A strategy to expand anti‐Stokes shifting from the far‐red to deep‐blue region in metal‐free triplet–triplet annihilation upconversion (TTA‐UC) is presented. The method is demonstrated by in vivo titration of the photorelease of an anticancer prodrug. This new TTA system has robust brightness and the longest anti‐Stokes shift of any reported TTA system. TTA core–shell‐structured prodrug delivery capsules that benefit from these properties were developed; they can operate with low‐power density far‐red light‐emitting diode light. These capsules contain mesoporous silica nanoparticles preloaded with TTA molecules as the core, and amphiphilic polymers encapsulating anticancer prodrug molecules as the shell. When stimulated by far‐red light, the intense TTA upconversion blue emission in the system activates the anticancer prodrug molecules and shows effective tumor growth inhibition in vivo. This work paves the way to new organic TTA upconversion techniques that are applicable to in vivo photocontrollable drug release and other biophotonic applications.     

Graft Photopolymerization of Styrene to Wheat Gluten Protein in Dimethyl Sulfoxide

To determine the suitability of dimethyl sulfoxide (DMSO) as a solvent for photo polymerization, solutions of wheat gluten protein (0.28-0.93% by weight) and styrene (4.13-12.65% by weight) in DMSO were irradiated by a 200.W high-pressure mercury arc lamp from 3 min up to 1 hr. Graft copolymers of gluten styrene resulted that contained styrene residues ranging from 2 to 23% by weight. When gluten protein was photolyzed in DMSO alone, a significant amount of sulfur from the solvent was incorporated; however, styrene successfully competed with the solvent for free radical sites. The rate of grafting was directly related to both the concentration of gluten and of styrene. Also, the ratio of grafted polystyrene to gluten in the graft polymer indicated that the grafts were composed of small units of polystyrene.     

Gluten and celiac disease--an immunological perspective

Gluten, a complex protein group in wheat, rye, and barley, causes celiac disease (CD), an autoimmune enteropathy of the small intestine, in genetically susceptible individuals. CD affects about 1% of the general population and causes significant health problems. Adverse inflammatory reactions to gluten are mediated by inappropriate T-cell activation leading to severe damage of the gastrointestinal mucosa, causing atrophy of absorptive surface villi. Gluten peptides bind to the chemokine receptor, CXCR3, and induce release of zonulin, which mediates tight-junction disassembly and subsequent increase in intestinal permeability. Proinflammatory cytokine IL-15 also contributes to the pathology of CD, by driving the expansion of intra-epithelial lymphocytes that damage the epithelium and promote the onset of T-cell lymphomas. There is no cure or treatment for CD, except for avoiding dietary gluten. Current gluten thresholds for food labeling have been established based on the available analytical methods, which show variation in gluten detection and quantification. Also, the clinical heterogeneity of celiac patients poses difficulty in defining clinically acceptable gluten thresholds in gluten-free foods. Presently, there is no bioassay available to measure gluten-induced immunobiological responses. This review focuses on various aspects of CD, and the importance of gluten thresholds and reference material from an immunological perspective.     

Influence of Farming System and Forecrops of Spring Wheat on Protein Content in the Grain and the Physicochemical Properties of Unsonicated and Sonicated Gluten

The potential for enhancing the spring wheat protein content by different cultivation strategies was explored. The influence of ultrasound on the surface and rheological properties of wheat-gluten was also studied. Spring wheat was cultivated over the period of 2018–2020 using two farming systems (conventional and organic) and five forecrops (sugar beet, spring barley, red clover, winter wheat, or oat). The obtained gluten was sonicated using the ultrasonic scrubber. For all organically grown wheat, the protein content was higher than for the conventional one. There was no correlation between the rheological properties of gluten and the protein content in the grain. Gluten derived from organically grown wheat was more elastic than those derived from the conventional one. Sonication enhanced the elasticity of gluten. The sonication effect was influenced by the forecrops. The most elastic gluten after sonication was found for organic barley and sugar beet. The lowest values of tan (delta) were noted for conventional wheat and conventional oat. Cultivation in the monoculture gave gluten with a smaller susceptibility to increase elasticity after sonic treatment. Sonication promoted the cross-linking of protein molecules and induced a more hydrophobic character, which was confirmed by an increment in contact angles (CAs). Most of the organically grown wheat samples showed a lower CA than the conventional ones, which indicated a less hydrophobic character. The gluten surface became rougher with the sonication, regardless of the farming system and applied forecrops. Sonication treatment of gluten proteins rearranged the intermolecular linkages, especially disulfide and hydrophobic bonds, leading to changes in their surface morphology.     

Analytical methods for detection of gluten in food--method developments in support of food labeling legislation

The current essential therapy of celiac disease is a strict adherence to a gluten-free diet. Besides food products that are naturally gluten-free, "very low gluten" and "gluten-free" bakery products have become available. The availability of immunochemical and other analytical methods to determine gluten markers in foods is of utmost importance to ensure the well being of gluten-sensitive individuals. The aim of this review was to evaluate if currently available methodologies are suitable to meet the requirements of food labeling standards for individual gluten source declaration, in order to achieve policy objectives. Codex Alimentarius and European Union (EU) legislation and gluten detection methodologies applicable at present have been summarized and compared. In 2009, the European Commission issued Regulation No. 41/2009 concerning the composition and labeling of foodstuffs suitable for people intolerant to gluten. This review constitutes a basis to investigate the possibility to develop a proteomic-based method for the specific detection of gluten-containing cereals in food products, especially at or around the limits specified in EU legislation.     

Aqueous RAFT Synthesis of Low Molecular Weight Anionic Polymers for Determination of Structure/Binding Interactions with Gliadin

Gliadin, a component of gluten and a known epitope, is implicated in celiac disease (CeD) and results in an inflammatory response in CeD patients when consumed. Acrylamide‐based polyelectrolytes are employed as models to determine the effect of molecular weight and pendent group on non‐covalent interaction modes with gliadin in vitro. Poly(sodium 2‐acrylamido‐2‐methylpropane sulfonate) and poly(sodium 3‐methylpropyl‐3‐butanoate) are synthesized via aqueous reversible addition fragmentation chain transfer (aRAFT) polymerization and characterized by gel permeation chromatography‐multiangle laser light scattering. The polymer/gliadin blends are examined via circular dichroism, zeta potential measurements, 8‐anilinonaphthalene‐1‐sulfonic acid fluorescence spectroscopy, and dynamic light scattering. Acrylamide polymers containing strong anionic pendent groups have a profound effect on gliadin secondary structure and solution behavior below the isoelectric point, while polymers containing hydrophobic character only have a minor impact. The polymers have little effect on gliadin secondary structure and solution behavior at the isoelectric point.     

Incorporating deep learning with convolutional neural networks and position specific scoring matrices for identifying electron transport proteins

In several years, deep learning is a modern machine learning technique using in a variety of fields with state‐of‐the‐art performance. Therefore, utilization of deep learning to enhance performance is also an important solution for current bioinformatics field. In this study, we try to use deep learning via convolutional neural networks and position specific scoring matrices to identify electron transport proteins, which is an important molecular function in transmembrane proteins. Our deep learning method can approach a precise model for identifying of electron transport proteins with achieved sensitivity of 80.3%, specificity of 94.4%, and accuracy of 92.3%, with MCC of 0.71 for independent dataset. The proposed technique can serve as a powerful tool for identifying electron transport proteins and can help biologists understand the function of the electron transport proteins. Moreover, this study provides a basis for further research that can enrich a field of applying deep learning in bioinformatics. © 2017 Wiley Periodicals, Inc.     

Magnetic molecularly imprinted polymers for recognition and enrichment of polysaccharides from seaweed

New magnetic molecularly imprinted polymers with two templates were fabricated for the recognition of polysaccharides (fucoidan and alginic acid) from seaweed by magnetic solid‐phase extraction, and the materials were modified by seven types of deep eutectic solvents. It was found that the deep eutectic solvents magnetic molecularly imprinted polymers showed stronger recognition and higher recoveries for fucoidan and alginic acid than magnetic molecularly imprinted polymers, and the deep eutectic solvents‐4‐magnetic molecularly imprinted polymers had the best effects. The practical recovery of the two polysaccharides (fucoidan and alginic acid) purified with deep eutectic solvents‐4‐magnetic molecular imprinted polymers in seaweed under the optimal conditions were 89.87, and 92.0%, respectively, and the actual amounts extracted were 20.6 and 18.7 μg/g, respectively. To sum up, the developed method proved to be a novel and promising method for the recognition of complex polysaccharide samples from seaweed.     

Magnetic chitosan functionalized with β‐cyclodextrin as ultrasound‐assisted extraction adsorbents for the removal of methyl orange in wastewater coupled with high‐performance liquid chromatography

Three types of choline chloride based deep eutectic solvents were prepared and used to modify magnetic chitosan. The adsorption capacity of the three deep‐eutectic‐solvent‐modified magnetic chitosan/carboxymethyl‐β‐cyclodextrin for removing methyl orange from wastewater was examined. The different deep eutectic solvents were used to strengthen the adsorption capacity of magnetic chitosan. Deep‐eutectic‐solvent‐modified magnetic chitosan/carboxymethyl‐β‐cyclodextrin materials were characterized by Fourier transform infrared spectroscopy and Brunauer–Emmett–Teller surface area measurements. Among the three deep eutectic solvents, choline chloride/glycerol (1:2) modified magnetic chitosan/carboxymethyl‐β‐cyclodextrin showed the highest adsorption capacity to methyl orange. Therefore, choline chloride/glycerol (1:3, 1:4, 1:5, 1:6) deep eutectic solvents were prepared for the assay, and choline chloride/glycerol‐modified magnetic chitosan/carboxymethyl‐β‐cyclodextrin prepared with choline chloride/glycerol (1:3) (volume: 40 μg, contact time: 30 min, and pH: 6) had the best adsorption capacity over the concentration range of 10–200 μg/mL.