Relaxation Time Of Water Research Articles

Estimation of subvoxel fat infiltration in neurodegenerative muscle disorders using quantitative multi-T2 analysis.

MRI's T2 relaxation time is a valuable biomarker for neuromuscular disorders and muscle dystrophies. One of the hallmarks of these pathologies is the infiltration of adipose tissue and a loss of muscle volume. This leads to a mixture of two signal components, from fat and from water, to appear in each imaged voxel, each having a specific T2 relaxation time. In this proof-of-concept work, we present a technique that can separate the signals from water and from fat within each voxel, measure their separate T2 values, and calculate their relative fractions. The echo modulation curve (EMC) algorithm is a dictionary-based technique that offers accurate and reproducible mapping of T2 relaxation times. We present an extension of the EMC algorithm for estimating subvoxel fat and water fractions, alongside the T2 and proton-density values of each component. To facilitate data processing, calf and thigh anatomy were automatically segmented using a fully convolutional neural network and FSLeyes software. The preprocessing included creating two signal dictionaries, for water and for fat, using Bloch simulations of the prospective protocol. Postprocessing included voxelwise fitting for two components, by matching the experimental decay curve to a linear combination of the two simulated dictionaries. Subvoxel fat and water fractions and relaxation times were generated and used to calculate a new quantitative biomarker, termed viable muscle index, and reflecting disease severity. This biomarker indicates the fraction of remaining muscle out of the entire muscle region. The results were compared with those using the conventional Dixon technique, showing high agreement (R = 0.98, p< 0.001). It was concluded that the new extension of the EMC algorithm can be used to quantify abnormal fat infiltration as well as identify early inflammatory processes corresponding to elevation in the T2 value of the water (muscle) component. This new ability may improve the diagnostic accuracy of neuromuscular diseases, help stratification of patients according to disease severity, and offer an efficient tool for tracking disease progression.

Effect of cooking methods and polysaccharide addition on the cooking performance of cubic fat substitutes

This study examined the effect of two different cooking methods (grilling and frying) and konjac glucomannan (KGM) addition on the cooking yield, water distribution, color, texture, oral tribology, sensory characteristics, and thiobarbituric acid (TBA) content of cubic fat substitutes (CFS). Grilled samples displayed higher yellowness and lightness values and cooking yield. Low-field nuclear magnetic resonance analysis showed that the fixed water relaxation time gradually decreased at a higher KGM level, indicating that KGM changed the distribution and migration of internal water. The relaxation time and amplitude of the grilled samples were slightly higher, indicating a slightly lower fixed water level. The textural and sensory evaluation showed that the overall sensory score of the fried cubic fat substitutes and pork backfat exceeded that of the grilled samples. A higher KGM content improved the hardness, springiness, and chewiness of the cubic fat substitutes to improve the texture and taste. The thiobarbituric acid reactive substance (TBARS) value of all the cubic fat substitutes was significantly lower than in the pork backfat, while these values were slightly higher when fried than when grilled. Scanning electron microscopy (SEM) revealed that KGM addition rendered the network structure more compact, denser, and similar to that of pork backfat. This study provided a theoretical basis for cooking cubic fat substitutes and research involving properties such as the cooking yield and water distribution after cooking.

A method for measuring dielectric relaxation of water by NIR spectroscopy: Applicability and application to measurement of water diffusion coefficient

AbstractDeterioration of biomaterial is subject to the interaction between biomolecules and water, which is often of special interest to the realization of long‐term preservation. In previous study, we reported the relationship between dielectric rotational relaxation time and the ν2 + ν3 NIR combination band of water as well as the theory behind it using saccharide solutions as examples and proposed a method accordingly which takes advantages of the infrared microscope to measure the dielectric relaxation time of water in biomaterials. In this work, we examined protein, polypeptide, sugar alcohol and some shelf‐stable vegetables to further discuss its applicability and limit. We also proved that this method can be used for measuring water diffusion coefficient and showed example of how the diffusion coefficient can be used to predict water distribution during drying process at a significantly enhanced spatial resolution relative to other techniques.Practical applicationsMolecular mobility of water determines many properties of biomaterials and can be characterized by different spectroscopies. This paper examined the applicability of a method of calculating the dielectric relaxation time of water using NIR spectrum on different solutions and proved that this method may also be used for calculating the diffusion coefficient of water, a parameter subject to molecular mobility and crucial in the drying process. This paper also provided example of the application of this method in the calculation of water distribution during drying process. The high spatial resolution of infrared microscope relative to other techniques may enable the measurement of water dynamics in biomaterials in a much quicker way and smaller scale.

Spin-lattice relaxation time in water/graphene-oxide dispersion.

We present the results of the calculations of the spin-lattice relaxation time of water in contact with graphene oxide by means of all-atom molecular dynamics simulations. We fully characterized the water-graphene oxide interaction through the calculation of the relaxation properties of bulk water and of the contact angle as a function of graphene oxide oxidation state and comparing them with the available experimental data. We then extended the calculation to investigate how graphene oxide alters the dynamical and relaxation properties of water in different conditions and concentrations. We show that, despite the diamagnetic nature of the graphene oxide, the confining effects of the bilayers strongly affect the longitudinal relaxation properties of interfacial water, which presents a reduced dynamics due to hydrogen bonds with oxygen groups on graphene oxide. This property makes graphene oxide an interesting platform to investigate water dynamics in confined geometries and an alternative contrast-agent for magnetic resonance imaging applications, especially in view of the possibility to functionalize graphene oxide from theranostic perspectives.

Molecular dynamics study of water rotational relaxation in saccharide solution for the development of bioprotective agent

Saccharides are often used as bio-protective agent owing to their unique interactions with the solvent water to change the water dynamics which dominate biomolecule deterioration. In this work, we present some basic laws for controlling water rotational relaxation time by performing molecular dynamics (MD) simulations of saccharide solutions. It is revealed that the water rotational relaxation time in saccharide solution is exponentially proportional to its residence time. Interestingly, the larger the solute dipole moment, the smaller the prerequisite residence time to obtain a tenfold retardation of the water relaxation time (the decuple-retarding period), which means the higher the increasing rate of the relaxation time vis-à-vis the residence time. We also find that water residence time exhibits a Gaussian distribution for various sugar solutions. This random walk of water within the solution further suggests that the larger ratio of the hydration layer volume to the overall water accessible space results in a longer residence time, thus a longer relaxation time distribution. We finally conclude that the protective agent with a large specific surface area and a large dipole moment is effective to retard the water rotational relaxation.

The effect of propylene glycol addition on the flavour compounds retention of peppermint powders

AbstractCompared with peppermint oil, natural peppermint has more ingredients, a layered fragrance, and a green colour. It has been widely used as a nutritional additive, herbal tea, food flavouring or colouring. In this work, the retention of volatile flavour compounds of peppermint powders was enhanced by propylene glycol, a reagent that enhances hydrogen bonds and moisture absorption. The levels of influence of propylene glycol content on the retention of different volatile flavour compounds, moisture absorption and water distribution were evaluated by GC–MS, dynamic water absorption instrument (DVS), and low‐field nuclear magnetic resonance (LF‐NMR), respectively. GC–MS analysis showed that the volatile substances of peppermint powders (PMs) without propylene glycol were reduced to 22 kinds after storage for 90 days, and the total amount of volatile substances remained at 40.94%; PG2 with 2% propylene glycol had the best flavour retention. After 90 days of storage, the residual percentage of volatile flavour compounds of PG2 was approximately 72.56%, which was significantly increased compared with that of PM. The DVS results suggested that all the peppermint powders adopted a type III moisture absorption isotherm, and they all had multilayer adsorbed water. PG2 had the best moisture retention capacity and the highest hygroscopic hysteresis, while PG4 with a high propylene glycol content had a relatively poor moisture retention capacity. Similarly, LF‐NMR analysis showed that PG2 had a higher proportion of bound water and lower relaxation times T21 and T22 under different humidity conditions, indicating that it had the strongest water binding capacity. The correlation analysis showed that there was a significant positive correlation between the residual volatile compounds of peppermint powders and the peak area of bound water A21. The higher the proportion of strongly bound water in peppermint particles was, the more residual volatile substances were identified in peppermint particles. These results show that peppermint particles supplemented with propylene glycol can significantly improve the flavour retention ability of peppermint powders. In short, the results could be applied to the storage stability and quality control of peppermint products.

Measurement of crude oil emulsion instability using magnetic resonance and magnetic resonance imaging

Emulsion stability is important in many environmental and industrial applications. Unstable emulsions tend to have a layered structure which will evolve in space and time. Magnetic Resonance (MR) is a nondestructive method that can be used to study emulsion instability based on relaxation times (T1, T2), and/or diffusion (D). The bulk transverse relaxation lifetime (T2) is the most useful parameter for analysis. Since breaking of emulsions creates different layers and phases, spatially resolved T2 data is more valuable than bulk whole sample data. Previous literature studies were principally based on bulk T1, T2 or self-diffusion measurements without spatial resolution. In this study, for the first time, spatially resolved T2 distributions were used to examine oil and water behavior during emulsion breaking.Diluted bitumen was used as the oil phase in a synthetic emulsion. Measurements undertaken included spatially resolved T2 distribution measurements and T1-T2 relaxation correlation measurements. The results reveal changes in the relaxation times of oil and water caused by changes in the dynamics of the water and oil during emulsion breaking. In each layer of the sample, comparing peak T2 values with bulk T2 values of different components gives an insight into phase environments. Water and oil content in each layer was resolved by using peak areas of the T2 distribution. The results of T2 distribution imaging were consistent with optical microscopy images, which showed W/O emulsions in the oil dominant region and complex W/O/W emulsions in the water dominant region of the sample. With the above information one can obtain full spatial and temporal information on evolving phases as well as kinetics of phase dynamics in emulsion breaking.

NMR Surface Relaxivity in a Time-Dependent Porous System.

We demonstrate an unexpected decay-recovery behavior in the time-dependent ^{1}H NMR relaxation times of water confined within a hydrating porous material. Our observations are rationalized by considering the combined effects of decreasing material pore size and evolving interfacial chemistry, which facilitate a transition between surface-limited and diffusion-limited relaxation regimes. Such behavior necessitates the realization of temporally evolving surface relaxivity, highlighting potential caveats in the classical interpretation of NMR relaxation data obtained from complex porous systems.

Dielectric Relaxation Studies on the Hydration Dynamics of Ionic, Non-Ionic and Zwitterionic Surfactants in Aqueous Acetate Buffer Solution

Dielectric relaxation studies of acetate buffer solutions of Sodium Dodecyl Sulphate (SDS- anionic), Cetyl Trimethyl Ammonium Bromide (CTAB- cationic), Tween 80 (TW-80-non-ionic), Betaine Anhydrous (BA- zwitterionic) surfactants have been examined in the frequency region between 1GHz and 25GHz for various concentrations of surfactants at the temperatures of 283, 288, 293 and 298K using time domain dielectric spectroscopy. The obtained corrected loss spectra of all the amphiphiles except betaine anhydrous in acetate buffer solution depicted peaks near 1-2GHz and 15GHz, respectively. For betaine anhydrous, expected peak was not observed in the 1-2GHz frequency region. The peak ascertained near 15GHz, and another peak about 1-2GHz was accorded to free water relaxation and bound water reorientation of the surfactant micelles, and has acquired the reliance of temperature with concentration in detail. Single Debye and Cole-Cole function was employed to compute the relaxation times of free water and bound water, respectively. The Arrhenius plot was used to calculate the enthalpy and entropy for the micelle forming surfactants.

2-D Magnetic Resonance Tomography With an Inaccurately Known Larmor Frequency Based on Frequency Cycling

When using magnetic resonance tomography (MRT) for imaging 2-D or 3-D water-bearing structures in a subsurface, the transmitting frequency must be the same as the Larmor frequency. Due to the inhomogeneity and noise interference in a geomagnetic field, it is difficult to determine the precise Larmor frequency using a magnetometer, resulting in unknown frequency offsets and inaccurate estimations of water content and relaxation time ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$T_{2}^{*}$ </tex-math></inline-formula> ). To solve the 2-D MRT imaging problem in the case of an unknown frequency offset, a frequency cycling method is proposed in this article. This method takes the estimated Larmor frequency as the center, uses two frequencies with the same offset for transmitting, then combines the acquired MRT signals to obtain frequency-cycled data, and finally uses the off-resonance kernel function for inversion. Based on MRT forward modeling and QT inversion, we conduct synthetic data experiments on a complex model with three water-bearing structures and test the 2-D imaging results of the frequency-cycled data. The results show that the water content and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$T_{2}^{*}$ </tex-math></inline-formula> distribution obtained by the inversion of the frequency-cycled data can accurately reflect the water-bearing structure, which is better than the results of the assumed on-resonance case. In addition, the phase correction method presented in this article significantly improves the accuracy of 2-D MRT estimated aquifer properties under low resistivity conditions. Finally, the validity and accuracy of the frequency cycling method are verified by comparing the inversion results of the data with known drilling data collected in field measurements.

Effects of fat-to-lean ratio and cooking time on the water distribution, nutritional quality and fatty acid composition of traditional Chinese pork meatballs

ABSTRACT This study examined the effects of two fat-to-lean ratios (7:3 and 6:4) and five cooking times (30 min, 60 min, 90 min, 120 min and 150 min) on water migration in and the nutritional quality and fatty acid composition of traditional Chinese pork meatballs. Accordingly, this work has established a quality control reference for the industrial-scale research and development of pork meatball production. Low-field nuclear magnetic resonance was used to determine the distribution and migration of water in pork meatballs during the cooking process, and gas chromatography–mass spectrometry was used to determine the fatty acid composition of pork meatballs. The results show that the water in pork meatballs migrated and thus became more strongly bound as the cooking time increased. The relaxation time of water in pork meatballs with a fat-to-lean ratio of 7:3 was significantly higher than that of water in pork meatballs with a fat-to-lean ratio of 6:4 (P < .05). The length of cooking time did not have a significant effect on the protein or fat content of pork meatballs (P > .05). When the pork meatballs were cooked for 150 min, the calorie value of pork meatballs with a fat-to-lean ratio of 7:3 was significantly greater than that of pork meatballs with a fat-to-lean ratio of 6:4. The hardness and tenderness of pork meatballs with a fat-to-lean ratio of 7:3 were significantly lower than those of pork meatball with a fat-to-lean ratio of 6:4 (P < .05), but the elasticity and chewiness of the former were greater than that of the latter. During cooking, the improvement in the thiobarbituric acid reactive substances (fat oxidation) value of pork meatballs with a fat-to-lean ratio of 6:4 was greater than that of pork meatballs with a fat-to-lean ratio of 7:3. The main fatty acids in both types of pork meatballs were oleic acid (C18:1 n9c), linoleic acid (C18: 2), palmitic acid (C16:0) and stearic acid (C18:0), with oleic acid (C18:1n9c) being predominant. These results show that in terms of taste and textural requirements, and unsaturated fatty acid content, pork meatballs with a fat-to-lean ratio of 7:3 and a cooking time of 150 min can best meet the texture preferences and nutritional needs of consumers.

Effects of Different Salt Ion Concentrations in Immersion Vacuum Cooling on the Qualities of Spiced Chicken Drumsticks.

The traditional immersion vacuum cooling of meats can result in product defects. To optimize these processes, different salt ion concentrations in the immersion solution (0%, 3%, 5%, and 7%) were assessed, in relation to the cooling rate, cooling loss rate, color, texture, moisture status, and microstructure of chicken drumsticks. The cooling rate at 5% salt ion concentration was the fastest and most similar to the conventional vacuum cooling method, which can reduce the central temperature of drumsticks from 75 to 25 °C in 15 min. Immersion vacuum cooling did not cause weight loss and the 5% salt ion concentration was the best for weight maintenance, which can increase the weight of drumsticks by 2.3%. The L* and b* values first decreased and then increased with increasing salt ion concentrations, but not significantly. Hardness gradually decreased, whereas the low-field nuclear magnetic data showed that the transverse relaxation time of free water (T22) in the drumsticks increased from 200.01 ms to 237.79 ms with increasing salt ion concentrations. Scanning electron microscopy images revealed irregular and smaller pores between the muscle fibers with increasing salt ion concentrations. The 5% salt ion concentration in the immersion solution during vacuum cooling was optimal as it increased the cooling rate and improved the edible quality without cooling loss. Thus, adjusting the salt ion concentration of the immersion solution is a feasible way to improve economic benefits and quality characteristics of meat products.

Calculation of Dynamic Properties of Drug-Added Aqueous Solutions with T1 T2 Relaxation Times

The development of modern spectroscopic methods has facilitated and accelerated structure analysis. The NMR method is the most popular way to perform structural analysis of compounds with very complex structures.D2O is a solvent that is frequently used in NMR analysis of both chemical molecules and many biological molecules such as drugs, proteins, and enzymes. In this paper, the study of residual water in proton drug-added protein solutions was carried out via NMR relaxation. The spin-lattice (T1) and the spin-spin relaxation (T2) times of residual water in drug-added protein solutions were studied depending on temperature by Avance Bruker 400 MHz 1H-NMR Spectrometer, and activation energies (Ea) and rotational correlation times (τ0 and τc) have been determined for T1 and T2 relaxation times.

ПРИМЕНЕНИЕ МЕТОДА ЯМР C ПАРАМАГНИТНЫМ ДОПИНГОМ ДЛЯ ОЦЕНКИ АПОПЛАСТНОГО ПЕРЕНОСА ВОДЫ В КОРНЯХ ИНТАКТНЫХ РАСТЕНИЙ ПРИ ДЕЙСТВИИ АБИОТИЧЕСКИХ СТРЕССОВ

In this work, the methodological approach based on low-field NMR using the GdDTPA paramagnetic complex for the qualitative assessment of water transport along the apoplastic (extracellular) pathway in the roots of intact wheat plants is proposed. This approach consists in measuring the spin-spin relaxation times of the water magnetization in the roots during simultaneous incubation of the roots in a solution of the paramagnetic Gd-DTPA complex and the impact of a stress factor on the plants. During root incubation, this complex spreads only along the root apoplast system and shortens the apoplast water relaxation times. GdDTPA does not penetrate into the cells and, accordingly, does not change the intracellular water relaxation times. Thus, the rate of decrease in the relaxation times of the magnetization of apoplast water, which directly depends on the intensity of water transfer through the apoplast, can be used to determine the relative contribution of water transfer through the root apoplast during stress exposure. A twofold increase in the concentration of carbon dioxide in the aerial parts of plants was used as an abiotic factor presumably influencing the transfer of water along the root apoplast. Using this methodological approach, it was shown that increase in the CO2 concentration in the leaf zone of wheat plants to 800 ppm leads to decrease in the rate of water transfer through the root apoplast by 2–2.5 times compared with the control at ambient CO2 concentration of 400 ppm.

Sodium and quantitative hydrogen parameter changes in muscle tissue after eccentric exercise and in delayed-onset muscle soreness assessed with magnetic resonance imaging.

The objective of the current study was to assess sodium (23 Na) and quantitative proton (1 H) parameter changes in muscle tissue with magnetic resonance imaging (MRI) after eccentric exercise and in delayed-onset muscle soreness (DOMS). Fourteen participants (mean age: 25 ± 4 years) underwent 23 Na/1 H MRI of the calf muscle on a 3-T MRI system before exercise (t0), directly after eccentric exercise (t1), and 48 h postintervention (t2). In addition to tissue sodium concentration (TSC), intracellular-weighted sodium (ICwS) signal was acquired using a three-dimensional density-adapted radial projection readout with an additional inversion recovery preparation module. Phantoms containing saline solution served as references to quantify sodium concentrations. The 1 H MRI protocol consisted of a T1 -weighted turbo spin echo sequence, a T2 -weighted turbo inversion recovery, as well as water T2 mapping and water T1 mapping. Additionally, blood serum creatine kinase (CK) levels were assessed at baseline and 48 h after exercise. The TSC and ICwS of exercised muscles increased significantly from t0 to t1 and decreased significantly from t1 to t2. In the soleus muscle (SM), ICwS decreased below baseline values at t2. In the tibialis anterior muscle (TA), TSC and ICwS remained at baseline levels at each measurement point. However, high-CK participants (i.e., participants with a more than 10-fold CK increase, n = 3) displayed different behavior, with 2- to 4-fold increases in TSC values in the medial gastrocnemius muscle (MGM) at t2. 1 H water T1 relaxation times increased significantly after 48 h in the MGM and SM. 1 H water T2 relaxation times and muscle volume increased in the MGM at t2. Sodium MRI parameters and water relaxation times peaked at different points. Whereas water relaxation times were highest at t2, sodium MRI parameters had already returned to baseline values (or even below baseline values, for low-CK participants) by this point. The observed changes in ion concentrations and water relaxation time parameters could enable a better understanding of the physiological processes during DOMS and muscle regeneration. In the future, this might help to optimize training and to reduce associated sports injuries.

P.62 Increased skeletal muscle extracellular volume fraction in patients with Becker muscular dystrophy assessed by quantitative magnetic resonance imaging

Quantitative magnetic resonance imaging (MRI) is increasingly proposed in clinical trials related to dystrophinopathies, including Becker muscular dystrophy (BMD). Extracellular volume fraction (ECV) is a candidate variable to characterize muscle tissues microstructure. Previous studies have demonstrated that the myocardium of BMD patients presented increased ECV. Given that cardiac muscle shares important structural features with skeletal muscles, we hypothesize that ECV could also be a sensitive biomarker to monitor pathological alterations of the skeletal muscle structure in BMD patients. We established the sensitivity of ECV quantification using magnetic resonance fingerprinting with water and fat separation (MRF T1-FF) as an imaging biomarker of skeletal muscle tissue alterations in BMD, by comparison with fat fraction (FF) and water relaxation time quantification. Data from the thighs of 28 BMD patients and 8 healthy volunteers were acquired. The MRI exam comprised FF mapping, water T2 mapping and water T1 mapping before and after an intravenous injection of a gadolinium-based contrast agent using MRF T1-FF from which ECV was calculated. Mann-Whitney tests, Kruskal-Wallis tests, ROC curves analysis and Spearman-rank correlation tests were performed. ECV was higher in dystrophic patients than in controls (0.20 [0.16 – 0.28] vs 0.07 [0.06 – 0.07], p<.001). In muscles of BMD patients with normal FF, ECV was also higher than in muscles of healthy controls (0.11 [0.10 – 0.13] vs 0.07 [0.06 – 0.09], p<.001). ECV classified dystrophic muscles with high sensitivity and specificity (AUC, 0.98; 95%CI: 0.96-0.99, p <.001), and correlated significantly with FF (ρ = .62, p < .001), water T2 (ρ = .56, p = .002), Walton score (ρ = .58, p = .001) and serum cardiac troponin-T level (ρ = .63, p < .001). In conclusion, muscle ECV measured with MRF represents a promising imaging biomarker for the early detection of skeletal muscle involvement in patients with Becker muscular dystrophy.

Effects of adding different contents of pig rind on physical and chemical properties and sensory qualities of wheat bran chicken sausage

Chicken sausage is one of the very popular meat products. In order to change the nutritional composition of chicken sausage and increase the content of dietary fiber, we add bran, but it affects the textural properties of chicken sausage. Pork rind is rich in collagen and is a natural and safe food gel. Pork rind content affects the cooking loss, color, TPA, moisture distribution and sensory evaluation results of cooked sausage products. In this study, six different pigskin content treatment experiments were set up: 0 %, 5 %, 10 %, 15 %, 20 %, and 25 %. This research shows that adding pork rind can reduce cooking loss during the sausage heating process. As more pork rind was added, the L* and b* values of minced meat and chicken sausage gradually increased, while the a* value gradually decreased. The chewiness of the sausages in the test group was significantly reduced (p&lt;0.05), except for T1, while the elasticity, recovery, and cohesiveness did not change significantly (p&gt;0.05), and the hardness value increased significantly (p&lt;0.05). The hardness of the sausages increased significantly (except in T5). Compared with the control group, the relaxation times of hydrated water and immobilized water in the treatment group became shorter, while the relaxation times of free water shifted to a longer direction. Sensory evaluation revealed that the hardness score of the T5 group was significantly lower than that of the control group. Based on these results, the sausage quality of the T3 group (pork rind 15 %) was the highest. This study improves the gel properties of bran chicken sausage, provides scientific data support for the application of pork rind in chicken sausage, improving the application value of pork rind.

Screening and collective effects in randomly pinned fluids: a new theoretical framework

We propose a theoretical framework for the dynamics of bulk isotropic hard-sphere systems in the presence of randomly pinned particles and apply this theory to supercooled water to validate it. Structural relaxation is mainly governed by local and non-local activated process. As the pinned fraction grows, a local caging constraint becomes stronger and the long range collective aspect of relaxation is screened by immobile obstacles. Different responses of the local and cooperative motions results in subtle predictions for how the alpha relaxation time varies with pinning and density. Our theoretical analysis for the relaxation time of water with pinned molecules quantitatively well describe previous simulations. In addition, the thermal dependence of relaxation for unpinned bulk water is also consistent with prior computational and experimental data.

Gel properties of okara dietary fiber-fortified soy protein isolate gel with/without NaCl.

Soy protein isolate (SPI) is widely used as an alternative to animal-based protein, and its gelling property is essential for producing plant protein-based foods. Insoluble dietary fiber has been used to improve the properties of protein gels. Effects of partial replacement of SPI by okara dietary fiber (ODF) on the gelling properties of ODF-fortified SPI gels with and without 0.1m NaCl were investigated. The presence of ODF hindered the SPI self-aggregation and reduced the surface hydrophobicity of SPI. The presence of ODF reduced the hydrophobic interaction and improved the proportion of disulfide bonds in the gels. In the microstructure, the swollen ODF promoted the local aggregation of SPI at 0.1m NaCl. Texture profile analysis showed that 5% and 10% ODF improved the SPI gel hardness in the absence of NaCl, whereas only 5% ODF improved the gel hardness at 0.1m NaCl. The results of low-field nuclear magnetic resonance imaging revealed that ODF shortened the T2 relaxation time of the free water in the gel. The gel of ODF-10 had the highest storage modulus. Using an appropriate amount of ODF to replace SPI could improve the quality of SPI gel and increase the dietary fiber content in the product. In addition, the appropriate ratio of ODF/SPI varied in different solution environments. © 2022 Society of Chemical Industry.

Evaluating Physicochemical and Sensory Properties of Functional Yogurt Supplemented with Glycyrrhiza Polysaccharide as Potential Replacement for Gelatin

Glycyrrhiza is a well-known plant resource used for the production of extractum-glycyrrhizae; however, large amounts of Glycyrrhiza residues containing polysaccharides are produced, and these have not been well utilized until now. The aim of this study was to evaluate the Glycyrrhiza polysaccharides obtained from Glycyrrhiza residues as a potential gelatin replacer in yogurt. The incorporation of Glycyrrhiza polysaccharide (GP) at different concentrations accelerated the growth of lactic acid bacteria. Similar to the effect of adding gelatin (GE), GP could suitably improve the water-holding capacity (WHC) and texture of the yogurt. Moreover, the yogurt prepared with GP showed a higher viscosity and shorter transverse relaxation time of mobile water (T23) value than the control group (CG). Moreover, the microstructure analysis indicated that the casein network of yogurt with GP was more compact and cohesive than those of others. Yogurt prepared with 0.1% GPs exhibited the best sensory acceptance. The results indicated that small amounts of GPs can effectively replace gelatin as a thickener in yogurt with good quality.