Quantification of Distributions of Local Proton Concentrations in Heterogeneous Soft Matter and Non-Anfinsen Biomacromolecules.

A new method to quantitatively analyze heterogeneous distributions of local proton densities around paramagnetic centers in unstructured and weakly structured biomacromolecules and soft matter is introduced, and its feasibility is demonstrated on aqueous solutions of stochastically spin-labeled polysaccharides. This method is based on the pulse EPR experiment ih-RIDME (intermolecular hyperfine relaxation-induced dipolar modulation enhancement). Global analysis of a series of RIDME traces allows for a mathematically stable transformation of the time-domain data to the distribution of local proton concentrations. Two pulse sequences are proposed and tested, which combine the ih-RIDME block and the double-electron-electron resonance (DEER) experiment. Such experiments can be potentially used to correlate the local proton concentration with the macromolecular chain conformation. We anticipate an application of this approach in studies of intrinsically disordered proteins, biomolecular aggregates, and biomolecular condensates.

Enzymatic degradation of pea fibers changes pea protein concentrate functionality.

Pea proteins are gaining increased interest from both the food industry as well as from consumers. Pea protein isolates (PPI) excel at forming meat-like textures upon heating while pea protein concentrates (PPC) are more challenging to transform into highly sought-after foods. PPCs are richer in dietary fibers (DF) and are more sustainable to produce than PPI. In this work, degradative enzymes were used to modify the functionality of PPC-water blends with a focus on texturization upon heating. Three enzyme solutions containing ß-glucanases, hemicellulases, pectinases, xylanase, and cellulases were added to 65 wt% PPC blends. The effect of these enzymatic pretreatments was measured by monitoring the torque in a mixing reactor during blending, differential scanning calorimetry (DSC), high-pressure shear rheology (HPSR), and DF content and size analysis. Four endothermic peaks were detected in the DSC thermograms of PPC, namely at 63 °C, 77 °C, 105 °C and 123 °C. The first three peaks were attributed to phase transition and gelation temperatures of the starches and proteins constituting PPC. No endothermic peaks were measured for PPI blends. Enzyme solutions containing ß-glucanases, hemicellulases, pectinases, and xylanases increased the endothermic energy of all peaks, hinting at an effect on the gelation properties of PPC. The same enzymes decreased the resistance to flow of PPC blends and induced a shift of the weight average molecular weight (Mw) distribution of soluble dietary fibers (SDF) towards smaller values while increasing the fraction of SDF by decreasing the insoluble dietary fiber (IDF) content. The solution containing cellulases did not change the DSC results or the viscosity of the PPC mixture, nor did it affect the IDF and SDF contents. On the other hand HPSR measurements of heated PPC samples up to 125 °C showed that all tested enzyme solutions decreased the complex viscosity of PPC-water blends to values similar to PPI-water blends. We demonstrated that degradative enzymes can enhance the functionality of less refined protein-rich ingredients based on pea and other vegetal sources. Using optimized enzyme blends for targeted applications can prove to be a key changer in the development and improvement of sustainable protein-rich foods.

Bioactive properties and gut microbiota modulation by date seed polysaccharides extracted using ultrasound-assisted deep eutectic solvent.

Polysaccharides are abundant macromolecules. The study extracted date seed polysaccharides (UPS) using ultrasound-assisted deep eutectic solvent extraction to valorize date seeds. UPS were subjected to comprehensive characterization and evaluation of their bioactivity, prebiotic properties, and their potential to modulate the gut microbiome. Characterization revealed UPS's heteropolysaccharide composition with galactose, mannose, fructose, glucose, and galacturonic acid respectively in 66.1, 13.3, 9.9, 5.4, and 5.1%. UPS showed a concentration-dependent increase of radical scavenging and antioxidant activities, evidenced by FRAP, TAC, and RP assays. They also displayed antimicrobial efficacy against E. coli O157:H7, S. typhimurium, S. aureus, and L. monocytogenes. Rheological analysis showed UPS's elastic-dominant nature with thixotropic tendencies. UPS inhibited α-glycosidase, α-amylase, and ACE up to 86%, and reduced Caco-2 and MCF-7 cell viability by 70% and 46%, respectively. UPS favored beneficial gut microbiota growth, releasing significant SCFAs during fecal fermentation.

The European Polysaccharide Network of Excellence (EPNOE) research roadmap 2040: Advanced strategies for exploiting the vast potential of polysaccharides as renewable bioresources.

Polysaccharides are among the most abundant bioresources on earth and consequently need to play a pivotal role when addressing existential scientific challenges like climate change and the shift from fossil-based to sustainable biobased materials. The Research Roadmap 2040 of the European Polysaccharide Network of Excellence (EPNOE) provides an expert's view on how future research and development strategies need to evolve to fully exploit the vast potential of polysaccharides as renewable bioresources. It is addressed to academic researchers, companies, as well as policymakers and covers five strategic areas that are of great importance in the context of polysaccharide related research: (I) Materials & Engineering, (II) Food & Nutrition, (III) Biomedical Applications, (IV) Chemistry, Biology & Physics, and (V) Skills & Education. Each section summarizes the state of research, identifies challenges that are currently faced, project achievements and developments that are expected in the upcoming 20 years, and finally provides outlines on how future research activities need to evolve.

A novel approach for the protein determination in food-relevant microalgae.

Microalgae are gaining interest as food ingredient. Assessments of functional and nutritional properties are necessary to forward their implementation. In this study, protein content and composition of eight commercially available microalgae biomasses were determined and compared to conventional food proteins. A novel procedure for the determination of the true protein content was proposed: Multiplication of proteinic nitrogen with a sample-specific nitrogen-to-protein conversion factor kA. The proteinic nitrogen was derived from the difference of total nitrogen minus non-protein nitrogen. The average kA for microalgae was 5.3 and considerable variation between different microalgae biomasses were detected. In addition, the content of non-protein nitrogen varied between 3.4% and 15.4%. The amino acid profiles of Chlorella samples were nutritionally superior to the tested plant proteins but indicated lower protein interaction tendency, potentially limiting their structuring functionality. In contrast, Auxenochlorella contained lower amounts of indispensable amino acids while showing comparable interaction potential to plant proteins.

Vegan shrimp alternative made with pink oyster and lion's mane mushrooms: Nutritional profiles, presence of conjugated phenolic acids, and prototyping.

The increasing demand for seafood is responsible for many environmental impacts, especially caused by aquaculture. Shrimp accounts for a substantial part of seafood production and therefore also for negative effects associated with it. This work aimed to develop a mushroom-based shrimp analogue with a texture similar to shrimp using the fruiting bodies of pink oyster mushroom (Pleurotus djamor) and lion's mane (Hericium erinaceus). Three flushes of pink oyster mushrooms and a first flush of lion's mane mushroom were analysed regarding their nutritional composition and whether they are suitable shrimp alternatives. The two mushrooms are rich in proteins (∼32% and ∼26% w/w for the first flush of pink oyster and lion's mane, respectively). The protein content of pink oyster mushroom decreased and the dietary fibre content increased across the different flushes. The antioxidants in the mushrooms were extracted using different methods, whereby aqueous extracts mostly excelled in terms of antioxidant activity. Hydrolysis confirmed the presence of conjugated p-coumaric acid in both mushrooms and possibly conjugated caffeic acid in pink oyster. Texture analysis results of the prototypes were close to the values of fried shrimp. However, although the sensory qualities of the final prototypes were perceived as similar to shrimp, further improvements in the recipe are necessary to make the prototypes indistinguishable from shrimp.

Modeling the antimicrobial effects of olive mill waste extract, rich in hydroxytyrosol, on the growth of lactic acid bacteria using response surface methodology.

The objective of this study is to assess the inhibitory effects of an aqueous extract from olive oil mill waste (alperujo) on the growth of a lactic acid bacteria (LAB) cocktail consisting of various strains of Lactiplantibacillus pentosus and Lactiplantibacillus plantarum species. For this purpose, response surface methodology was employed using two independent variables (pH levels 3.5-5.55; hydroxytyrosol concentration ranging from 0.93-2990 ppm). The response variable was the average inhibition per treatment on the LAB cocktail (expressed as a percentage). The developed model identified significant terms, including the linear effect of hydroxytyrosol and pH, their interaction, and the quadratic effect of pH. Maximum inhibition of the LAB cocktail was observed at progressively higher concentrations of hydroxytyrosol and lower pH values. Therefore, complete inhibition of LAB in the synthetic culture medium could only be achieved for concentrations of 2984 ppm hydroxytyrosol at a pH of 3.95. These findings suggest that extracts derived from "alperujo" could be utilized as a natural preservative in acidified foods with a bitter flavor and antioxidant requirements.

Pulse EPR spectroscopy and molecular modeling reveal the origins of the local heterogeneity of dietary fibers.

Optimizing human diet by including dietary fibers would be more efficient when the fibers' chain interactions with other molecules are understood in depth. Thereby, it is important to develop methods for characterizing the fiber chain to be able to monitor its structural alterations upon intermolecular interactions. Here, we demonstrate the utility of the electron paramagnetic resonance (EPR) spectroscopy, complemented by simulations in probing the atomistic details of the chain conformations for spin-labeled fibers. Barley ß-glucan, a native polysaccharide with linear chain, was utilized as a test fiber system to demonstrate the technique's capabilities. Pulse dipolar EPR data show good agreement with results of the fiber chain modeling, revealing sinuous chain conformations and providing polymer shape descriptors: the gyration tensor, spin-spin distance distribution function, and information about proton density near the spin probe. Results from EPR measurements point to the fiber aggregation in aqueous solution, which agrees with the results of the dynamic light scattering. We propose that the combination of pulse EPR measurements with modeling can be a perfect experimental tool for in-depth structural investigation of dietary fibers and their interaction under such conditions, and that the presented methodology can be extended to other weakly ordered or disordered macromolecules.

Interaction of barley ß-glucan with food dye molecules - An insight from pulse dipolar EPR spectroscopy.

The interactions between dietary fibers (DFs) and small molecules are of great interest to food chemistry and nutrition science. However, the corresponding interaction mechanisms and structural rearrangements of DFs at the molecular level are still opaque due to the usually weak binding and the lack of appropriate techniques to determine details of conformational distributions in such weakly organized systems. By combining our previously established methodology on stochastic spin-labelling of DFs with the appropriately revised set of pulse electron paramagnetic resonance techniques, we present here a toolkit to determine the interactions between DFs and small molecules, using barley ß-glucan as an example for neutral DF and a selection of food dye molecules as examples for small molecules. The proposed here methodology allowed us to observe subtle conformational changes of ß-glucan by detecting multiple details of the local environment of the spin labels. Substantial variations of binding propensities were detected for different food dyes.

Genome-wide association study of lipase and esterase in wholegrain wheat flour (Triticum aestivum L.).

Lipase activity is one of the main causes of the lipid rancidity in wholegrain wheat flour, leading to its short shelf life. Genetically diverse wheat germplasm offers potential for the selection of wheat cultivars with low lipase activity for stable wholegrain end use. This study evaluated 300 European wheat cultivars harvested in 2015 and 2016 on the genetic association of lipase and esterase activities in wholegrain wheat flour. Esterase and lipase activities in wholegrain flour were measured photometrically with p-nitrophenyl butyrate and p-nitrophenyl palmitate as substrates, respectively. Both enzyme activities showed wide ranges among all cultivars within each year, with differences up to 2.5-fold. The two years showed low correlations between each other, indicating a large environmental impact on the enzyme activities. Cultivars 'Julius' and 'Bueno' were suggested to be better suited for stable wholegrain products, as they had consistently low esterase and lipase activities compared to the other cultivars. A genome-wide association study revealed associations with single nucleotide polymorphisms in genes located on the high-quality wheat genome sequence of the International Wheat Genome Sequencing Consortium. Eight and four candidate genes were tentatively proposed to be associated to esterase and lipase activity, respectively, in wholegrain flour. Our work shows esterase and lipase activities from a new perspective, that combines reverse genetics to understand the underlying causes. This study outlines the possibilities and limitations to improve lipid stability of wholegrain wheat by genomics-assisted breeding methods, thereby offering new opportunities to optimize the quality of wholegrain wheat flour and wholegrain products.

Ferric Pyrophosphate Forms Soluble Iron Coordination Complexes with Zinc Compounds and Solubilizing Agents in Extruded Rice and Predicts Increased Iron Solubility and Bioavailability in Young Women.

BACKGROUND: Co-extrusion of ferric pyrophosphate (FePP) with solubilizers, citric acid/trisodium citrate (CA/TSC), or ethylenediaminetetraacetic acid (EDTA) sharply increases iron absorption. Whether this can protect against the inhibition of iron absorption by phytic acid (PA) is unclear. Sodium pyrophosphate (NaPP) may be a new enhancer of iron absorption from FePP. OBJECTIVES: Our objectives were to 1) investigate the ligand coordination of iron, zinc, and solubilizers in extruded rice and test associations with iron solubility and absorption, 2) assess whether co-extrusion of FePP + CA/TSC rice can protect against inhibition of iron absorption by PA; 3) determine the effect of zinc oxide (ZnO) compared with zinc sulfate (ZnSO4), and 4) quantify iron absorption from FePP + NaPP rice. METHODS: We produced labeled 57FePP rice cofortified with ZnSO4 and EDTA, CA/TSC or NaPP, and FePP + EDTA rice with ZnO. We used electron paramagnetic resonance (EPR) to characterize iron-ligand complexes. We measured in vitro iron solubility and fractional iron absorption (FIA) in young women (n = 21, age: 22 ± 2 y, BMI: 21.3 ± 1.5 kg/m2 geometric mean plasma ferritin, 28.5 µg/L) compared with ferrous sulfate (58FeSO4). FIA was compared by linear mixed-effect model analysis. RESULTS: The addition of zinc and solubilizers created new iron coordination complexes of Fe(III) species with a weak ligand field at a high-spin state that correlated with solubility (r2 = 0.50, P = 0.02) and absorption (r2 = 0.72, P = 0.02). Phytic acid reduced FIA from FePP + CA/TSC rice by 50% (P < 0.001), to the same extent as FeSO4. FIA from FePP + EDTA + ZnO and FePP + EDTA + ZnSO4 rice did not significantly differ. Mean FIAs from FePP + EDTA + ZnSO4, FePP + CA/TSC + ZnSO4, and FePP + NaPP + ZnSO4 rice were 9% to 11% and did not significantly differ from each other or from FeSO4. CONCLUSION: Rice extrusion of FePP with solubilizers resulted in bioavailable iron coordination complexes. In the case of FePP + CA/TSC, PA exerted similar inhibition of FIA as with FeSO4. FePP + NaPP could be a further viable solubilizing agent for rice fortification. This study was registered at clinicaltrials.gov as NCT03703739.

An Updated Review on Prebiotics: Insights on Potentials of Food Seeds Waste as Source of Potential Prebiotics.

Prebiotics are a group of biological nutrients that are capable of being degraded by microflora in the gastrointestinal tract (GIT), primarily Lactobacilli and Bifidobacteria. When prebiotics are ingested, either as a food additive or as a supplement, the colonic microflora degrade them, producing short-chain fatty acids (SCFA), which are simultaneously released in the colon and absorbed into the blood circulatory system. The two major groups of prebiotics that have been extensively studied in relation to human health are fructo-oligosaccharides (FOS) and galactooligosaccharides (GOS). The candidature of a compound to be regarded as a prebiotic is a function of how much of dietary fiber it contains. The seeds of fruits such as date palms have been reported to contain dietary fiber. An increasing awareness of the consumption of fruits and seeds as part of the daily diet, as well as poor storage systems for seeds, have generated an enormous amount of seed waste, which is traditionally discarded in landfills or incinerated. This cultural practice is hazardous to the environment because seed waste is rich in organic compounds that can produce hazardous gases. Therefore, this review discusses the potential use of seed wastes in prebiotic production, consequently reducing the environmental hazards posed by these wastes.

Site-selective and stochastic spin labelling of neutral water-soluble dietary fibers optimized for electron paramagnetic resonance spectroscopy.

Use of spin labels to study structures of polymers has been widely spread in polymer science. However, for the studies of neutral water-soluble dietary fibers (DFs), labelling efficiencies in past studies have only been sufficient for application of continuous wave electron paramagnetic resonance spectroscopy (CW-EPR), but still insufficient for some advanced methods such as pulse EPR. Thus, in this paper, two spin labelling strategies, namely, site-selective mono-spin-labelling and stochastic multi-spin-labelling, were examined on linear cereal ß-glucan, as well as linearly branched arabinoxylan and galactomannan. The effects of both methods in DF properties were evaluated. For the mono-labelling pathway, labelling efficiency could reach up to 46 %. In the stochastic labelling strategy, a degree of substitution (DS) up to 150 % could be reached, whereas optimized conditions for this strategy were achieved at DS = 3 % to obtain DFs whose bioactivity properties were still preserved while spin labelling efficiency was still sufficient for CW and pulse EPR experiments.

The Cu(ii) - dietary fibre interactions at molecular level unveiled via EPR spectroscopy.

While dietary fibres have a reputation of a healthy food component, the interaction between nutrients and neutral fibers is non-covalent, and its characterization is challenging for most analytical techniques. Here, on the example of barley ß-glucan (BBG) and paramagnetic Cu(ii) ions we demonstrate the performance of different Electron Paramagnetic Resonance (EPR) methods in the fibre studies. EPR techniques were tested on two spin probe systems with different affinity in the interaction with dietary fibres - Cu(OAc)2 salt, which weakly dissociates under physiological conditions and CuSO4 salt, which easily dissociates, so that in the latter case Cu(ii) can be considered as a 'free' ion, only chelated by water molecules. The Cu(ii)-BBG interaction was determined by pulse EPR relaxation measurements, but this interaction appears not strong enough for continuous wave EPR detection. The capability of the fibres for Cu(ii) absorption was successfully analyzed by comparison of the results from the pulse dipolar spectroscopy with numerical simulations. The local distribution of sugar hydrogen atoms around the Cu(ii) ion has been determined by electron spin echo envelope modulation (ESEEM) and electron-nuclei double resonance (ENDOR) techniques.

Estimation of Iron Availability in Modified Cereal ß-Glucan Extracts by an in vitro Digestion Model.

For cereal-based foods rich in dietary fibers, iron bioavailability is known to be poor. For native cereal ß-glucan extracts, literature has demonstrated that the main factor impacting the bioavailability is phytic acid, which is often found in association with dietary fibers. During food processing, ß-glucan can undergo modifications which could potentially affect the equilibrium between phytic acid, fiber, and iron. In this study, an in vitro digestion was used to elucidate the iron dialysability, and hence estimate iron availability, in the presence of native, chelating resin (Chelex)-treated, oxidised, or partially hydrolysed oat and barley ß-glucan extracts (at 1% actual ß-glucan concentration), with or without phytase treatment. It was confirmed that pure, phytic acid-free ß-glucan polysaccharide does not impede iron availability in cereal foods, while phytic acid, and to a smaller extent, also proteins, associated to ß-glucan can do so. Neither Chelex-treatment nor partial hydrolysis, 2,2,6,6-tetramethylpiperidine 1-oxyl (TEMPO) or NaIO4 oxidation significantly influenced the phytic acid content of the ß-glucan extracts (ranging 2.0-3.9%; p > 0.05). Consequently, as long as intrinsic phytic acid was still present, the ß-glucan extracts blocked the iron availability regardless of source (oat, barley) or Chelex-treatment, partial hydrolysis or NaIO4-oxidation down to 0-8% (relative to the reference without ß-glucan extract). Remarkably, TEMPO-oxidation released around 50% of the sequestered iron despite unchanged phytic acid levels in the modified extract. We propose an iron-mobilising effect of the TEMPO product ß-polyglucuronan from insoluble Fe(II)/phytate/protein aggregates to soluble Fe(II)/bile salt units that can cross the dialysis membrane. In addition, Chelex-treatment was identified as prerequisite for phytase to dramatically diminish iron retention of the extract for virtually full availability, with implications for optimal iron bioavailability in cereal foods.

A microcalorimetric and microscopic strategy to assess the interaction between dietary fibers and small molecules.

The interaction between small molecules and neutral soluble dietary fiber is one of the proposed mechanisms determining the bioavailability of these components in the small intestine. However, the weak nature of these interactions makes it difficult to find an analytical method sensitive enough to detect them. Here, we probed the molecular interaction between galactomannan, arabinoxylan, and ß-glucan with gallic acid, cinnamic acid, acetylsalicylic acid, and acetaminophen, using advanced analytical methods, namely isothermal titration calorimetry (ITC) and in the form of gold-nanoparticles, transmission electron microscopy (TEM). The results obtained from ITC analysis were fully consistent with the results obtained from TEM. In short, the interaction of these fibers and small molecules was mainly entropically driven, hence involving hydrophobic type association and possible conformational changes of the polysaccharide. However, the enthalpy contribution (hydrogen interaction) is also significant, especially regarding interactions with the acetylsalicylic acid molecule.

Process-Induced Changes in the Quantity and Characteristics of Grain Dietary Fiber.

Daily use of wholegrain foods is generally recommended due to strong epidemiological evidence of reduced risk of chronic diseases. Cereal grains, especially the bran part, have a high content of dietary fiber (DF). Cereal DF is an umbrella concept of heterogeneous polysaccharides of variable chemical composition and molecular weight, which are combined in a complex network in cereal cell walls. Cereal DF and its distinct components influence food digestion throughout the gastrointestinal tract and influence nutrient absorption and other physiological reactions. After repeated consumption of especially whole grain cereal foods, these effects manifest in well-demonstrated health benefits. As cereal DF is always consumed in the form of processed cereal food, it is important to know the effects of processing on DF to understand, safeguard and maximize these health effects. Endogenous and microbial enzymes, heat and mechanical energy during germination, fermentation, baking and extrusion destructurize the food and DF matrix and affect the quantity and properties of grain DF components: arabinoxylans (AX), beta-glucans, fructans and resistant starch (RS). Depolymerization is the most common change, leading to solubilization and loss of viscosity of DF polymers, which influences postprandial responses to food. Extensive hydrolysis may also remove oligosaccharides and change the colonic fermentability of DF. On the other hand, aggregation may also occur, leading to an increased amount of insoluble DF and the formation of RS. To understand the structure-function relationship of DF and to develop foods with targeted physiological benefits, it is important to invest in thorough characterization of DF present in processed cereal foods. Such understanding also demands collaborative work between food and nutritional sciences.

In vitro Colon Fermentation of Soluble Arabinoxylan Is Modified Through Milling and Extrusion.

Dietary fibers such as arabinoxylan (AX) are promising food constituents to prevent particular diet-related chronic diseases because of their prebiotic properties. Arabinoxylan fermentation by the gut microbiota depends on the structural architecture of AX, which can be modified during food processing and consequently affect its prebiotic potential, but it is little investigated. Therefore, the aim of this study was to evaluate the effects of naturally occurring and processing-induced structural alterations of the soluble AX of wheat bran and rye flour on the in vitro human colon fermentation. It was found that fermentation behavior is strongly linked to the AX fine structure and their processing-induced modifications. The short-chain fatty acid (SCFA) metabolism, acidification kinetics, bacterial growth, and bacterial composition revealed that wheat bran AX (WBAX) was fermented faster than rye flour AX. Increased levels of bound phenolic acids resulting from processing were identified as the inhibiting factor for AX fermentation kinetics. Bacterial genera promoted by AX varied between AX source and processing type, but also between microbiota. Extruded WBAX promoted butyrate production and growth of butyrate-producing Faecalibacterium in the butyrogenic microbiota while it did not enhance fermentation and inhibited the growth of Prevotella in the propiogenic microbiota. We anticipate that the findings of this study are a starting point for further investigation on the impact of processing-induced changes on the prebiotic potential of dietary fibers prior to human studies.

Pigeon Pea Husk for Removal of Emerging Contaminants Trimethoprim and Atenolol from Water.

The pace of industrialization and rapid population growth in countries such as India entail an increased input of industrial and sanitary organic micropollutants, the so-called emerging contaminants (EC), into the environment. The emission of EC, such as pharmaceuticals, reaching Indian water bodies causes a detrimental effect on aquatic life and ultimately on human health. However, the financial burden of expanding sophisticated water treatment capacities renders complementary, cost-efficient alternatives, such as adsorption, attractive. Here we show the merits of washed and milled pigeon pea husk (PPH) as low-cost adsorbent for the removal of the EC trimethoprim (TMP) and atenolol (ATN) that are among the most detected pharmaceuticals in Indian waters. We found a linear increase in adsorption capacity of PPH for TMP and ATN at concentrations ranging from 10 to 200 µg/L and from 50 to 400 µg/L, respectively, reflecting the concentrations occurring in Indian water bodies. Investigation of adsorption kinetics using the external mass transfer model (EMTM) revealed that film diffusion resistance governed the adsorption process of TMP or ATN onto PPH. Moreover, analysis of the adsorption performance of PPH across an extensive range of pH and temperature illustrated that the highest adsorption loadings achieved concurred with actual conditions of Indian waters. We anticipate our work as starting point towards the development of a feasible adsorbent system aiming at low-cost water treatment.

Effect of Polysaccharide Conformation on Ultrafiltration Separation Performance.

The manifold array of saccharide linkages leads to a great variety of polysaccharide architectures, comprising three conformations in aqueous solution: compact sphere, random coil, and rigid rod. This conformational variation limits the suitability of the commonly applied molecular weight cut-off (MWCO) as selection criteria for polysaccharide ultrafiltration membranes, as it is based on globular marker proteins with narrow Mw and hydrodynamic volume relation. Here we show the effect of conformation on ultrafiltration performance using randomly coiled pullulan and rigid rod-like scleroglucan as model polysaccharides for membrane rejection and molecular weight distribution. Ultrafiltration with a 10 kDa polyethersulfone membrane yielded significant different recoveries for pullulan and scleroglucan showing 1% and 71%, respectively. We found deviations greater than 77-fold between nominal MWCO and apparent Mw of pullulan and scleroglucan, while recovering over 90% polysaccharide with unchanged Mw. We anticipate our work as starting point towards an optimized membrane selection for polysaccharide applications.