Water Mobility Research Articles

Effect of different hydrocolloids on the physicochemical, printing, and digestion properties of 3D printed purple sweet potato

This study investigated the influence of different hydrocolloids, namely hydroxypropyl methylcellulose, xanthan gum, guar gum, flaxseed gum, and κ-carrageenan gum on the physicochemical, printing, and digestion properties of 3D printed purple sweet potato (PSP). Aside from κ-carrageenan gum, addition of these hydrocolloids could improve the 3D printing performance of PSP. Addition of hydrocolloids significantly altered the water mobility and rheological characteristics of PSP. The tanδ (G”/G’) values of PSP-hydrocolloid mixtures were strongly related to their 3D printability. The hydrogen bonds in PSP-hydrocolloid samples were weakened compared to PSP-H2O. In comparison to other hydrocolloids, the addition of guar gum significantly decreased the level of starch digestion in PSP during in vitro digestion. The release of phenolics and anthocyanins was highly correlated with the extent of starch digestion. The variations in interactions between hydrocolloids and phenolics affected the release of individual phenolics from PSP during gastrointestinal digestion and colonic fermentation. PSP-guar gum exhibited a significantly higher content of phenolics released after colonic fermentation than the other PSP-hydrocolloid samples. Overall, this study provided theoretical guidance for addition of hydrocolloids into plant-based food materials to enhance their 3D printing performance and modulate their release of intrinsic bioactives as well as digestion of starch during gastrointestinal digestion and colonic fermentation.

Interplay of legacy irrigation and nitrogen fertilizer inputs to spatial variability of arsenic and uranium within the deep vadose zone

The vadose zone is a reservoir for geogenic and anthropogenic contaminants. Nitrogen and water infiltration can affect biogeochemical processes in this zone, ultimately affecting groundwater quality. In this large-scale field study, we evaluated the input and occurrence of water and nitrogen species in the vadose zone of a public water supply wellhead protection (WHP) area (defined by a 50-year travel time to groundwater for public supply wells) and potential transport of nitrate, ammonium, arsenic, and uranium. Thirty-two deep cores were collected and grouped by irrigation practices: pivot (n = 20), gravity (n = 4) irrigated using groundwater, and non-irrigated (n = 8) sites. Beneath pivot-irrigated sites, sediment nitrate concentrations were significantly (p < 0.05) lower, while ammonium concentrations were significantly (p < 0.05) higher than under gravity sites. The spatial distribution of sediment arsenic and uranium was evaluated against estimated nitrogen and water loading beneath cropland. Irrigation practices were randomly distributed throughout the WHP area and presented a contrasting pattern of sediment arsenic and uranium occurrence. Sediment arsenic correlated with iron (r = 0.32, p < 0.05), uranium negatively correlated to sediment nitrate (r = −0.23, p < 0.05), and ammonium (r = −0.19 p < 0.05). This study reveals that irrigation water and nitrogen influx influence vadose zone geochemistry and mobilization of geogenic contaminants affecting groundwater quality beneath intensive agricultural systems.

Unicellular cyanobacteria degrade sulfoxaflor to its amide metabolite of potentially higher aquatic toxicity

Sulfoxaflor (SFX) is a fourth-generation neonicotinoid used widely in modern agriculture. Due to its high water solubility and mobility in environment, it is expected to occur in water environment. Degradation of SFX leads to formation of corresponding amide (M474), which in the light of recent studies may be much more toxic to aquatic organisms than the parent molecule. Therefore, the aim of the study was to assess the potential of two common species of unicellular bloom-forming cyanobacteria (Synechocystis salina and Microcystis aeruginosa) to metabolize SFX in a 14-day-long experiment, using elevated (10 mg L−1) and predicted highest environmental (10 μg L−1) concentrations. The results obtained support the occurrence of SFX metabolism in cyanobacterial monocultures, leading to release of M474 into the water. Differential SFX decline in culture media, followed by the presence of M474, was observed for both species at different concentration levels. For S. salina, SFX concentration decreased by 7.6% at lower concentration and by 21.3% at higher concentration; the M474 concentrations were 436 ng L−1 and 514 μg L−1, respectively. Corresponding values for M. aeruginosa were 14.3% and 3.0% for SFX decline; 282 ng L−1 and 317 μg L−1 for M474 concentration. In the same time, abiotic degradation was almost non-existent. Metabolic fate of SFX was then studied for its elevated starting concentration. Uptake of SFX to cells and amounts of M474 released to water fully addressed the decrease in SFX concentration in M. aeruginosa culture, while in S. salina 15.5% of initial SFX was transformed to yet unknown metabolites. The degradation rate of SFX observed in the present study is sufficient to produce a concentration of M474 that is potentially toxic for aquatic invertebrates during cyanobacterial blooms. Therefore, there is a need for more reliable risk assessment for the presence of SFX in natural waters.

Quality assessment and analytical quality by design-driven RP-HPLC method development for estimation of Gymnemagenin in Gymnema sylvestre

Gymnemic acids are the group of phytocompounds from Gymnema sylvestre known to possess hypoglycemic activity. Quantitative estimation of Gymnemic acid in terms of Gymnemagenin is essential for the standardization of G. sylvestre. In the present work, methodology combining reversed-phase HPLC with an Analytical Quality by-design approach was utilized for quantitative analysis of Gymnemagenin in G. sylvestre leaves. The quality assessment was performed by evaluating various pharmacognostic parameters as per WHO guidelines. Initially, the Analytical Target Profile and Critical Quality Attributes were identified. The method was optimized using 22 full factorial designs with a concentration of orthophosphoric acid in the aqueous phase (X1) and mobile phase ratio (X2) selected as an independent variable and, tailing factor (R1) and theoretical plates (R2) chosen as dependent variables. The optimized chromatographic conditions were identified with mobile phase, Methanol and Water (0.1% OPA) in the ratio of 85:15 v/v with flow rate of 0.8 mL/min and detection wavelength of 210 nm. Further, the amount of Gymnemagenin in crude G. sylvestre leaves and its extract was found to be 5.108% and 6.23% w/w respectively. The quality evaluation parameters were found to be within the given standard limit. Finally, it can be concluded that the combination of the HPLC method with the AQbD approach resulted in a more precise and accurate method for quantification of total Gymnemic acids in terms of Gymnemagenin. The developed method involves advantages such as efficient separation, well-defined peaks, and reduced analytical time and can be successfully applied for the analysis of Gymnemagenin in different Gymnema species and their herbal products.

Tissue structural analysis for internal browning sweet potatoes using magnetic resonance imaging and bio-electrochemical impedance spectroscopy

Occurrence of internal browning in sweet potato tuber has recently been confirmed, and its chemical and bacterial characteristics have been reported. However, the structural characteristics of such tissues are unknown. We investigated the tissue structural characteristics inside a browning sweet potato through magnetic resonance imaging (MRI) and bio-electrochemical impedance spectroscopy (BIS) and the relationship was discussed. The high-resolution proton density-weighted (PDW) and proton spin–spin relaxation time (T2)-weighted (T2W) images of cutting out samples obtained from micro-imaging revealed changes in the physical structure surrounding the browning tissues. The T2 distribution maps of the same browning samples assumed the changes in the water distribution and water mobility, which generally changes under the influence of solutes, such as metabolites, starch, protein, and metal ions. BIS further confirmed the variation in the distribution of electrolytes in the tissues. MRI may provide a non-destructive assessment of the internal browning of whole sweet potatoes.

Feasibility of Mini sipIT Behavioral Intervention to Increase Urine Volume in Patients With Kidney Stones

To determine the feasibility and acceptability of mini sipIT, a context-sensitive reminder system that incorporates a connected water bottle and mobile app with text messaging, for kidney stone patients who have poor adherence to increasing fluid intake for prevention. Patients with a history of kidney stones and urine volume <2L/d participated in a 1-month single-group feasibility trial. Patients used a connected water bottle and received text message reminders when fluid intake goals weren't met. Perceptions of drinking behavior, intervention acceptability, and 24-hour urine volumes were obtained at baseline and 1-month. Patients with a history of kidney stones were enrolled (n = 26, 77% female, age=50.4 ± 14.2years). Over 90% of patients used the bottle or app daily. Most patients perceived that mini sipIT intervention helped them to increase their fluid intake (85%) and reach their fluid intake goals (65%). There was a significant increase in average 24-hour urine volume after the 1-month intervention compared to baseline (2006.5 ± 980.8 mL vs 1352.7 ± 449.9 mL, t (25)= 3.66, P = .001, g= 0.78), with 73% of patients having higher 24-hour urine volumes at the end of the trial. Mini sipIT behavioral intervention and outcome assessments are feasible for patients and may lead to significant increases in 24-hour urine volume. Digital tools in combination with behavioral science may improve adherence to fluid intake recommendations for kidney stone prevention, however, rigorous efficacy trials are necessary.

Dispersion of low concentration of particulate or fibrillated protein fillers into plant protein melts and their impact on the elasticity and tenderness gap of plant-based foods

The development of plant-based foods has emerged as a promising strategy to decrease meat consumption. Using predominantly globular plant proteins challenges the crafting of cohesive, viscoelastic, and anisotropic structures similar to animal meat. In this study, we investigated the effect of incorporating low concentrations (<1%, w/w) of the polar gelatin or the non-polar zein on the mechanical properties of high moisture meat analogue prototypes. These proteins were studied in both particulate (bulk) and nano-fibrillated forms. Building on our previous work, soy protein (68% protein) and mung bean protein (81% protein) concentrates were chosen based on their distinct protein purity and high propensity to rearrange into new ordered secondary structural elements upon extrusion. Gelatin and zein were incorporated into the extrusion process via aqueous dispersion in particulate form or previously converted into nanofibers (210–440 nm diameter) using food-grade electrospinning. The incorporation of both fillers (either particulate or fibrillate) decreased the elasticity and Warner-Bratzler Shear Force (WBSF, known to be inversely correlated to meat tenderness) of mung bean extrudates. However, the addition of 0.1% fibrillated gelatin or particulate/fibrillated zein increased up to 44% or 22% the WBSF of soy extrudates, respectively. In all cases, the incorporation of fillers caused dramatic concentration-dependent changes in the secondary structures (FTIR) of soy proteins and the water mobility (LF-NMR) of extrudates. This work highlights the potential of multifunctional fillers and the combination of top-down (extrusion) and bottom-up (fibrillation) approaches to reduce the tenderness gap between animal meat and structured foods made with less-refined plant-protein fractions.

Eggshell composition of Amazon turtle (Podocnemis expansa) is altered after incubation in substrates containing glyphosate and fipronil formulations

Besides its crucial role during embryo development, eggshells are an essential bioindicator of environmental contaminants. However, the effects of contaminant exposure during incubation on the eggshell composition remain poorly known for freshwater turtles. Accordingly, we tested the effects of incubating the eggs of Podocnemis expansa in substrates containing glyphosate and fipronil formulations on the eggshell's level of mineral and dry matter, crude protein, nitrogen, and ethereal extract. Eggs were incubated in sand moistened with water contaminated with glyphosate Atar 48 at concentrations of 65 or 6500 μg/L, fipronil Regent 800 WG at concentrations of 4 or 400 μg/L, or the combination of 65 μg/L glyphosate and 4 μg/L fipronil and 6500 μg/L glyphosate with 400 μg/L fipronil. Exposure to the tested pesticides, alone or in association, altered the chemical composition of the eggshell of P. expansa, reducing the eggshell's moisture and crude protein content and increasing levels of ethereal extract. These changes may cause significant deficiencies in the mobilization of water and nutrients to the embryo, affecting the development and reproductive success of P. expansa.

Trenched and diked contours for sustainable agricultural utilization in changing world; soil hydrological, geomorphological, and physical perspectives from over 70 years of implementation in the Northern Negev

AbstractTrenched and diked contours (TDC) are used in hilly arid regions worldwide to reduce runoff and soil erosion. The TDC is based on three parts: ‘runoff contributing area’, trench, and adjacent soil dike on the hillslope contours. Surveys over the Northern Negev indicate the hydrological interrelation between the inter‐dike surface and the dike. This study hypothesized that all the TDC parts are hydrologically interrelated. The objective is to analyze the soil's physical properties that influence the interrelation from dike construction until maturation and the influences of these interrelations on soil fertility, salinity, and stability. TDC systems, also known as ‘Shikim’, were constructed by the KKL‐JNF (Karen Kayemet L'Israel. The Jewish National Foundation) all over the hills of the Northern Negev, the semiarid region of Israel, from the 1950s until present, which gives the ability to analyze the dynamic of water flows inside the TDC s along their existence. The findings indicate three hydrological interrelations, (i) From the ‘runoff contributing area’ into the trench, which differs between the planted and un‐planted types; (ii) From the trench into the dike; (iii) and water migration in the ‘dike’ medium. Along the TDC maturation, the intensity of biological influences on these interrelations increases, leading to increased water mobilization to the trench (planting strip) and into the dike medium. The water migration in the ‘dike’ leads to forming of a soil bed adequate for sustainable agricultural utilization in its' downslope face. The finding of this study will maximize the agricultural utilization of the TDCs and their profitability.

Water usability as a descriptive parameter of thermodynamic properties and water mobility in food solids

A classic problem in preservation is the microbes can grow in low-moisture foods. In this paper, the water sorption, and thermodynamic properties of glucose/WPI solid matrices were measured, while their molecular mobility was analyzed and associated with the microbial growth of D. Hansenii at various aw and 30 °C. Although the sorption isotherms, Tg, and relaxation processes of studied matrices were affected by aw and WPI, the microbial growth showed highly dependent on water mobility rather than aw. Hence, we introduced water usability (Uw), derived from the mobility difference between system-involved water and liquid pure water explicating from the classical thermodynamic viewpoint, to describe the dynamic changes of water mobility in glucose/WPI matrices. Despite to aw, the yeast growth rate was enhanced at high Uw matrices concomitantly with a rapid cell doubling time. Therefore, the proposed Uw provides a better understanding of the water relationships of microorganisms in food preservation.

Highly Stable Polymer-Enhanced Pickering Foams for Hydraulic Fracturing Applications

Foams have been used as fracking fluids for decades, but their thermodynamic instability has always restricted subsurface applications, particularly in harsh reservoir conditions. Therefore, this study comprehensively investigated the role of commonly used stabilizers in foaming behaviors, including the surfactant (APG), nanoparticle (CNCs), and polymer (XG), and their stabilizing behavior at the interface was also explored using molecular dynamics (MD) simulations. Our findings indicated that the 0.5% XG-enhanced Pickering foam (0.5% APG + 1.0% CNCs) would be an exceptional fluid for fracking applications. The formation of APG–CNC–XG gel-like networks among bubbles significantly improved the stability of this liquid foam, and the liquid half-life could be extended by nearly 24 h, while the foam can last for several days at 80 °C. Using MD simulations, we showed that the coexistence and intramolecular interactions among APG, CNCs, and XG molecules generate a stronger hydrogen bonding network in the thin film, significantly reducing water mobility, corresponding to the experimental observations. To explore the potential of foams as fracking fluids, the sand-carrying capacity of two types of foams was also evaluated; the polymer-enhanced Pickering foam was able to suspend the sands for more than a day without participation. In the lab fracturing test, despite requiring a higher breakdown pressure, the polymer-enhanced Pickering foam reduces water consumption by almost 20%. Moreover, the highly viscous foam also induced the wing-shaped fracture with a wider width along the hole. The deep insights gained from this study will advance the application of foams as the fracking fluid in unconventional oil/gas reservoirs.

Effect of soluble dietary fibre from barley on the rheology, water mobility and baking quality of wheat flour dough

Incorporation of dietary fibre in a bread recipe is a technological challenge. Therefore, the aim was evaluating the impact of substitution of wheat flour with extracted soluble dietary fibre from barley (BDF) at two levels (4.0% and 8.0%) on dough and bread characteristics. The percent water absorption and mixograph peak mixing time increased for both BDF substitution levels, while T22 relaxation time reduced significantly. In addition, 4.0 and 8.0% BDF substitution levels resulted in a 20.6% and 33.4% reduction in freezable water (FW) content, respectively, and increased G′ and G″ values. In creep tests, BDF dough showed reduced creep compliance values and recoverable strain percentages. BDF limits the water availability in dough for the other biopolymers as reflected in more β-sheet structures, reduced water mobility and lower FW content. The reduction in water availability results in impaired development of an elastic gluten network and an increased resistance to deformation, eventually translating in higher crumb hardness and lower loaf volume. These insights can serve as basis for targeted interventions to recipes and processing to counteract the adverse effects of BDF on bread properties. This study also revealed that 4.0% BDF substitution of wheat flour does not adversely affect bread quality.

Ice Adhesion Evaluation of PTFE Solid Lubricant Film Applied on TiO2 Coatings

Ice formation affects the performance of many industrial components, including aircraft wings, spacecraft, and power transmission cables. In particular, ice build-up on airplane components increases drag and fuel consumption. A large number of studies have been carried out to reduce ice adhesion by developing passive methods such as icephobic coatings and active ice removal approaches such as mechanical vibrations or chemical-based solutions. Despite remarkable recent breakthroughs in the fabrication of icephobic coatings, passive ice removal solutions require higher durability to resist cyclical mechanical ice detachment treatments. Functionalized TiO2 coatings, applied using the suspension plasma spray (SPS) technique, have been shown to be robust and to have dual-scale characteristics in an ice accretion analysis. In this study, the icephobicity and mechanical durability of a novel duplex coating consisting of polytetrafluoroethylene (PTFE) solid lubricant films on TiO2-coated substrates were evaluated. Notably, various amounts of PTFE were applied on top of the TiO2 coating to identify the ideal quantity required to obtain optimal icephobic properties. Ice was generated in an icing wind tunnel, and the amount of accreted ice was evaluated to assess the anti-icing properties. Wettability parameters, including static water contact angle and contact angle hysteresis, were measured to determine the water mobility and surface energy. Ice shear adhesion to the PTFE-TiO2 duplex coating was measured using a custom-built test rig. The mechanical durability was assessed by measuring the ice shear strength for almost twenty icing–deicing cycles, and after five cycles, the roughness parameters and images taken from the surface of the samples were compared. The combination of PTFE solid lubricant film and TiO2 coating reduced ice adhesion by 70%–90% compared to that of a bare aluminum substrate (reference material). Additionally, the results showed that the application of a uniform layer of PTFE solid lubricant film on dual-scale TiO2 coating significantly reduced ice adhesion and maintained mechanical durability for 25 deicing cycles, making this combination a promising candidate for deicing approaches.

Development of Efficient Analytical method for the multicomponent analysis of Pravastatin Sodium and Nebivolol Hydrochloride in Bulk Drug by RP-HPLC

Cardiovascular diseases are managed through multi drug regimens. For better patient compliance and cost effectiveness, desired therapeutic efficacy is achieved through combination of more than two drugs in single dosage form. Nebivolol Hydrochloride is β1 receptor blocker and Pravastatin sodium exhibits its pharmacological action through inhibition of cholesterol synthesis. Both drugs are therapeutically compatible and can be administered in single dose formulation. A review of the literature found that there was no effective strategy for the selected drug combination. As a result, an attempt was made to establish a simple, efficient, sensitive, specific, and rapid method for simultaneously estimating Pravastatin sodium and Nebivolol hydrochloride in bulk drugs using RP-HPLC.Column C-18 (Shim-pack) 250 x 4.6 mm, particle size 5 m, mobile phase acetonitrile and water in the ratio 20:80 at 257 nm were found to be the optimal chromatographic conditions. Pravastatin sodium and Nebivolol hydrochloride had retention times of 2.092 and 3.623 minutes, respectively, with average percentage recovery of 99.38% and 99.54%, respectively.The proposed technique was found to be in accordance with the guidelines of the International Conference on Harmonization (ICH).

Risk of dengue, Zika, and chikungunya transmission in the metropolitan area of Cucuta, Colombia: cross-sectional analysis, baseline for a cluster-randomised controlled trial of a novel vector tool for water containers

BackgroundArbovirus diseases such as dengue, Zika, and chikungunya are a public health threat in tropical and subtropical areas. In the absence of a vaccine or specific treatment, vector management (in this case the control of the primary vector Aedes aegypti) is the best practice to prevent the three diseases. A good understanding of vector behaviour, ecology, human mobility and water use can help design effective vector control programmes. This study collected baseline information on these factors for identifying the arbovirus transmission risk and assessed the requirements for a large intervention trial in Colombia.MethodsBaseline surveys were conducted in 5,997 households, randomly selected from 24 clusters (neighbourhoods with on average 2000 houses and 250 households inspected) in the metropolitan area of Cucuta, Colombia. The study established population characteristics including water management and mobility as well as larval-pupal indices which were estimated and compared in all clusters. Additionally, the study estimated disease incidence from two sources: self-reported dengue cases in the household survey and cases notified by the national surveillance system.ResultsIn all 24 study clusters similar social and demographic characteristics were found but the entomological indicators and estimated disease incidence rates varied. The entomological indicators showed a high vector infestation: House Index = 25.1%, Container Index = 12.3% and Breteau Index = 29.6. Pupae per person Index (PPI) as an indicator of the transmission risk showed a large range from 0.22 to 2.04 indicating a high transmission risk in most clusters. The concrete ground tanks for laundry –mostly outdoors and uncovered- were the containers with the highest production of Ae. aegypti as 86.3% of all 17,613 pupae were identified in these containers. Also, the annual incidence of dengue was high: 841.6 self-reported cases per 100,000 inhabitants and the dengue incidence notified by the National surveillance system was 1,013.4 cases per 100,000 in 2019. Only 2.2% of the households used container water for drinking. 40.3% of the study population travelled during the day (when Aedes mosquitoes bite) outside their clusters.ConclusionsThe production of Ae. aegypti mosquitoes occurred almost exclusively in concrete ground tanks for laundry (lavadero), the primary intervention target. The baseline study provides necessary evidence for the design and implementation of a cluster randomized intervention trial in Colombia.

Influence of Excipients and Pressing Force on the Impurity Content of N-(4-aminobenzoyl)-L-glutamic Acid in Folic Acid Drugs During Storage

Introduction. Excipients, impurities contained in them, and sorbed water are one of the reasons for degradation of the active pharmaceutical substance (API). Excipients effect should be especially evaluated for moisture-sensitive APIs. Folic acid (FA) is an important vitamin for humans. It hydrolyze in water under the action of UV irradiation and main decomposition product is N-(p-aminobenzoyl)glutamic acid (impurity A). We found an increase in the content of impurity A during FA film-coated tablets storage in PVC-film and aluminum foil packaging in the absence of UV irradiation.Aim. Investigate the effect of excipients and parameters of the production process on the content of impurity A during storage of FA drugs.Materials and methods. The FA tablets containing 1.0 mg of API produced by direct compression technology were the objects of study. The pressing force (PF) was varied from 5 to 15 kN.Results and discussion. We found that content of impurity A in tablets containing 93.0 % lactose monohydrate and obtained with PF above 10 kN exceeded limit value during storage for 300 days. Probably lactose simultaneously acts both as a source of free water and as a catalyst for FA hydrolysis. Since the interaction of lactose and FA occurs in the solid phase, pressing accelerates hydrolysis by increasing the contact area of substances and the mobility of water molecules.Conclusion. We found that lactose monohydrate probably is the main cause of FA hydrolysis in drugs. Independently of the mechanism of its action, an increase in the PF above 10 kN leads to an increase in the rate of FA hydrolysis. This is due to an increase in the mobility of water molecules and the contact area between the excipient and API. We have selected the optimum pressure range (5–10 kN) for tablet mix containing lactose monohydrate and FA.

Molecular insights into nuclear-magnetic-resonance properties of NaCl solution confined within calcite nanopores

Nuclear magnetic resonance (NMR) relaxation time is an important petrophysical property probing fluid dynamics within pores and providing valuable information to understand solid–fluid interactions and ion-related effects. In this study, we investigate NMR and diffusion properties of confined sodium chloride (NaCl) solutions within calcite nanopores via molecular dynamics (MD) simulations. Density profiles, self-diffusion coefficients, and NMR relaxation times were analyzed as a function of pore size, pore geometry, and NaCl concentration. MD results indicate that the presence of NaCl hinders water movement, resulting in reduced self-diffusion coefficients and relaxation times of water. Nevertheless, the influence of NaCl on water mobility is less than the effects caused by confinement and geometry. Strength of oscillations in water and ion density profiles increases when the slit pore size is reduced to 1 nm, suggesting that water-calcite interactions near pore surfaces are stronger in smaller pore sizes. Analysis of dipole–dipole correlation functions and probability distribution of correlation times shows that ions in aqueous solution have an impact on both intra- and intermolecular interactions. A comprehensive comparison of NMR relaxation times of water in both slit and spherical nanopores reveals that spherical models provide a more accurate representation of the confinement effect induced by pore networks within tight rocks. These findings provide a novel quantitative understanding of the impact of confinement, pore geometry, and ion concentration on the translational and rotational dynamics of confined fluids in calcite nanopores.

Yedoma Permafrost Releases Organic Matter with Lesser Affinity for Cu2+ and Ni2+ as Compared to Peat from the Non-Permafrost Area: Risk of Rising Toxicity of Potentially Toxic Elements in the Arctic Ocean.

Pollution of the Arctic Ocean by potentially toxic elements (PTEs) is a current environmental problem. Humic acids (HAs) play an important role in the regulation of PTE mobility in soil and water. The permafrost thaw releases ancient organic matter (OM) with a specific molecular composition into the Arctic watersheds. This could affect the mobility of PTEs in the region. In our study, we isolated HAs from two types of permafrost deposits: the Yedoma ice complex, which contains pristine buried OM, and the alas formed in the course of multiple thaw-refreezing cycles with the most altered OM. We also used peat from the non-permafrost region as the recent environmental endmember for the evolution of Arctic OM. The HAs were characterized using 13C NMR and elemental analysis. Adsorption experiments were conducted to assess the affinity of HAs for binding Cu2+ and Ni2+. It was found that Yedoma HAs were enriched with aliphatic and N-containing structures as compared to the much more aromatic and oxidized alas and peat HAs. The adsorption experiments have revealed that the peat and alas HAs have a higher affinity for binding both ions as compared to the Yedoma HAs. The obtained data suggest that a substantial release of the OM from the Yedoma deposits due to a rapid thaw of the permafrost might increase the mobility of PTEs and their toxicity in the Arctic Ocean because of much lesser "neutralization potential".

Study on the mechanism of various exogenous proteins with different inhibitions on wheat starch digestion: From the distribution behaviors of protein in the starch matrix

This study aimed to compare the effect of various exogenous proteins on wheat starch (WS) digestion and assess the relevant mechanisms based on the distribution behaviors of exogenous proteins in the starch matrix. Rice protein (RP), soy protein isolate (SPI), and whey protein isolate (WPI) all effectively suppressed the rapid digestion of WS but with different modes. RP increased the slowly digestible starch content, while SPI and WPI increased the resistant starch content. Fluorescence images showed that RP aggregated and competed for effective space with starch granules, while SPI and WPI formed continuous network structures among the starch matrix. These distribution behaviors endowed different reductions in starch digestion by influencing the gelatinization and ordered structure of starch. Pasting and water mobility results suggested all exogenous proteins inhibited the water migration and swelling of starch. Simultaneously, X-ray diffraction and Fourier transform infrared spectroscopy analysis showed that exogenous proteins improved the ordered structures of starch. RP had a more significant effect on the long-term ordered structure, while SPI and WPI had a more effective effect on the short-term ordered structure. These findings will enrich the theory of exogenous protein inhibiting starch digestion and inspire the applications in low-glycemic index food.

Impact of glucose oxidase on characteristics of corn dough with different frozen storage times

SummaryWe have studied the impact of different concentrations of GOX on corn doughs' processing characteristics and protein structure. The doughs were frozen for different periods, and the quality of their products, like corn tortillas, was studied. The results showed that adding GOX attenuated the adverse effects of ice crystals produced during the freezing period and improved the dough's viscoelasticity and low‐temperature stability. In addition, GOX further enhanced its water‐holding capacity, limited water mobility, and re‐established the dough's secondary structure. Furthermore, the results demonstrated that GOX improved the texture and delayed the staling rate of corn tortillas prepared with fresh and frozen corn dough. We further concluded that 100 mg kg−1 of GOX exhibited the best improvement effect on the corn dough characteristics and quality of the produced tortillas.