Changes In State Of Water Research Articles

Effect of lipid‐mediated moisture status on casein characteristic in two types of milk powders during accelerated storage

AbstractThis study aims to investigate the relationship between casein oxidation and moisture status in the presence of milk fat to clarify the role of fat on water in milk powder. The results showed that at the same water activity (aw), the faster oxidation of whole milk powder (WMP) is attributed to the high proportion of free water and immobilized water in them, indicating that the adsorption of milk fat mainly depended on multilayer water and the entrapped water. In the diffusion‐limited reaction, changes in water state affected more than radicals on casein oxidation. Glass transition temperature (Tg) was also affected by the water state of lipid adsorption. At low aw (<0.4), the water content of WMP and skim milk powder (SMP) was similar, but the Tg of WMP was significantly lower than SMP, especially when aw was 0.33, its Tg was <0. It suggested that water state rather than water content was the main factor affecting Tg. Especially, because the mobile water absorbed by milk fat in WMP reduced Tg, which further led to the acceleration of lactose crystallization, casein oxidative aggregation, and Maillard reaction.

In situ investigation of ice fractions and water states during partial freezing of pork loins and shrimps

Ice fractions and water states in partially frozen muscle foods greatly affect their quality. In the study, a variable temperature nuclear magnetic resonance (VT-NMR) with a liquid nitrogen temperature control system was employed to in situ investigate the relationship between ice fractions and temperatures and changes in water states during partial freezing and thawing of pork and shrimp. Results indicated that changes in ice fractions ranging from −2 ∼ −20 °C could be divided into 3 stages including slow increase, random leap and remarkable leap. More serious damages to the structures related to immobile water occurred in shrimp than in pork, and partial freezing also caused deterioration in muscle fibres related to free water. Additionally, −2 ∼ −3 °C and − 3.5 °C were the appropriate partial freezing temperatures for pork and shrimp, respectively. Therefore, the VT-NMR method possessed great potential for fundamental studies and applications of partial freezing of muscle foods.

Insight into the early hydration characteristics of Portland cement with hydroxyethyl methyl cellulose highlighted by 1H low-field NMR

1H low-field nuclear magnetic resonance (1H NMR) as a non-destructive test method can effectively capture the water state changes in cement pastes. The water changes can in turn reflect the early hydration characteristics of cement pastes. Hydroxyethyl methyl cellulose (HEMC) with different viscosities affects the hydration characteristics of cement by acting on the water in different states. The following experimental results are obtained by testing hydration of cement pastes with HEMC by using 1H NMR test. Incorporating 0.1–3% HEMC with different viscosities all can effectively control the bleeding water phenomenon. HEMC can absorb a part of the water in the cement pastes. Incorporating 2–3% HEMC significantly delays the enrichment of the gel pores water and interlayer water. When the content of HEMC increases from 0% to 3%, the hydration degree of cement pastes tends to decrease. Besides, HEMC with higher viscosity of 15000–40000 mPa·s obviously delays the hydration process of cement pastes compared to HEMC with lower viscosity of 400 mPa·s.

Detection of water content in tomato stems by electrical impedance spectroscopy: Preliminary study

Tomatoes lack drought-resistant genes, rendering seedlings susceptible to slow growth and death during drought stress. To gauge the water deficit in tomato plants, the electrical impedance spectra of tomato seedlings were measured at distinct water content levels (pristine, 92%, 91%, 90%, and 89%). These measurements tracked changes in water state, microstructure, and shear stress during water loss. The results revealed that impedance values and the real and imaginary parts decreased with increasing frequency, displaying a negative correlation with water content. Notably, the absolute mid-frequency slope (F2) exhibited an R2 of 0.9996, serving as an effective variable to characterize water content changes in tomato seedlings. Drought-induced alterations in stem cells shifted the seedling's equivalent circuit from the improved Hayden model to two parallel constant phase element (CPE) models. Concurrently, as water was lost, the proportion of free water diminished while water-binding capacity increased. This shift was accompanied by the wilting of cells, which reduced tissue rigidity, weakened ion conductivity, and altered the ratio of free water to bound water from 36.22 to 5.43. The pot experiment revealed that the F2 could be utilized to monitor the situation of short and sharp water shortages; however, additional research is required to explore its potential for long-term water monitoring. These findings establish a solid theoretical basis for monitoring water content in tomato plants in field settings.

Role of delignification in water state changes during water absorption and air drying of wood characterized with LF-NMR

ABSTRACT Delignification, recently much used in wood modification and functional material preparation, is closely related to wood-water interactions. To attain more information on the role of delignification in wood, this study characterized the water state changes during water-absorption and air-drying process with LF-NMR. By adjusting delignification time, lignin was removed about 15%, 34%, and 61%, respectively. Water absorption increased after delignification, and free water was generated more and faster than bound water. This was because delignification changed wood-water interaction environments suggested by SEM and FTIR analysis. Specifically, delignification increased hygroscopic polysaccharide percentage and sorption site concentration. New pore generation and enlargement after delignification provided more water exchanging paths and accommodation. Besides, delignified wood had higher and faster moisture decrease, and wood air drying was facilitated because of enriched water exchanging paths and higher initial moisture gradient difference in water-saturated delignified wood. Therein, free water decreased more and faster than bound water. The T 2s of bound water and free water were both shortened after delignification, indicating water had tighter intermolecular interaction with delignified wood. The study provided new insight for understanding the role of lignin in water state changes during wood-water interactions and may facilitate better preparation of functional material and wood modification.

Effect of freeze-thaw pretreatment combined with variable temperature on infrared and convection drying of lotus root

The effects of freezing temperature, times of freeze-thaw (FT) pretreatment combined with variable temperature on infrared and convection drying of lotus root were studied. The FT pretreatment improved the drying rate (from 0.0188 to 0.0261 min−1), reduced the total energy consumption (from 4.77 to 3.73 kW h/kg), and resulted in a more porous structure of the final product with low shrinkage rate (from 83.39 to 73.04%), reduced hardness (from 41.67 to 24.49 N) and with a crisp texture (from 0.36 to 0.17 s). The inflection point of the change in state of water was determined using low field NMR during drying. Effect of the drying conditions on the quality of final products was also monitored. Variable temperature drying not only effectively solved the problem of color deterioration, but also promoted faster drying rate with reduced energy consumption and a better quality product.

Vacuum-steam pulsed blanching (VSPB) softens texture and enhances drying rate of carrot by altering cellular structure, pectin polysaccharides and water state

As a new type of blanching technology, vacuum-steam pulsed blanching (VSPB) has higher blanching efficiency and quality, but the mechanism of this technology on texture softening and drying enhancement is still unclear. In this study, the mechanism was revealed from texture, pectin, nanostructure, cell ultrastructure, calcium, and water state. Results revealed that VSPB treatment reduced the hardness and chewiness, increased water-soluble pectin, decreased sodium‑carbonate-soluble and chelate-soluble pectin concentration, and resulted in depolymerization and degradation of pectin nanostructure. However, transmission electron microscopy showed that blanching damaged the cell wall structure and the integrity of the middle layer. Scanning electron microscope - Energy dispersive X-ray spectroscopy measurement observations indicated that lipid droplets containing calcium ions were formed under the action of VSPB. In addition, low field nuclear magnetic resonance showed that the redistribution of moisture in carrot was facilitated by VSPB. The findings reveal the mechanism of texture softening and drying rate enhancement driven by blanching. Industrial relevanceThermal blanching is an essential thermal treatment for many fruits and vegetables processing. Hot water blanching and steam blanching are the two most frequently employed blanching methods due to simple to establish and easy to operate. However, hot water and steam blanching holds several disadvantages, e.g., hot water blanching requires a huge amount of water and generates an excessive amount of wastewater, particularly loss of water-soluble nutrients during blanching due to leaching and diffusion, while for steam blanching, the existence of air and water vapor among the piled materials leads to low blanching efficiency and un-uniform heating. VSPB is an innovative steam blanching method. In the VBSP process, the air and water vapor are expelled by the vacuum pump to facilitate steam deep penetration in the materials, particularly the piled materials, so as to improve blanching efficiency and uniformity. Previous study indicated VSPB could soften texture and reduce the drying time of carrot, but the mechanism was not clear. The current work reveal that VSPB softens texture and enhances drying rate of carrot via micro-, ultra-structure modification, pectin polysaccharides degradation and changes of water state. The findings have important implications for understanding and controlling the blanching triggered texture formation and drying enhancement.

Changes in water state, distribution, and physico‐chemical properties of preserved kumquats during different processing methods

AbstractChanges in water state, glass‐transition temperature (Tg), microstructure, and some quality attributes of preserved kumquats after osmotic dehydration under atmospheric pressure or vacuum conditions followed by hot‐air drying were investigated. Low‐field nuclear magnetic resonance results showed that there was less immobilized water content in kumquats under vacuum impregnation with sugar (VSKs) versus that of kumquats under atmospheric pressure osmosis with sugar (ASKs). The freedom of water in kumquats under atmospheric pressure osmosis with sugar and then hot air‐drying (VS‐ADKs) was lower than that of kumquats under vacuum osmosis with sugar and then hot air‐drying (AS‐ADKs). Magnetic resonance imaging results revealed the water release. Sucrose intake produced a more pronounced depressing influence on the Tg of VSKs than on that of the Tg of ASKs. The Tg of VS‐ADKs were lower than that of AS‐ADKs. Scanning electron microscopy displayed that the VSKs samples presented relatively compact tissue, but the ASKs exhibited the rupture of the cell cavities. The VS‐ADKs showed the more compact lamellar structure but the AS‐ADKs showed more loose fragments. The lightness of color in VSKs significantly decreased, while the redness and yellowness in ASKs diminished. High hardness and gumminess values were identified in VSKs and VS‐ADKs. Correlation analyses showed that hardness was positively correlated with T23 either in the ASKs or in the VSKs.Practical ApplicationChanges in water state, glass‐transition temperature (Tg), microstructure, and some quality attributes of preserved kumquats after osmotic dehydration under atmospheric pressure or vacuum conditions followed by hot‐air drying were investigated. Low‐field nuclear magnetic resonance, magnetic resonance imaging, differential scanning calorimetry, scanning electron microscopy and so on were used as the intuitive and efficient methods. The differences in two immerse methods and the effects of drying on the properties of preserved kumquats were elucidated. These results were helpful to the control and assessments about the processing of preserved kumquats.

Structuring and Phase Formation in Silica Gel in Water Fluids of Different Densities

The effect of the density of water fluid in the range of ~10–3–0.25 g cm–3 on the structuring of amorphous silica gel was studied at 380°C that exceeds the temperature of critical point of water. It was shown that a decrease in the specific surface area (Ssp) is observed already at the lowest density. As the latter increases, Ssp decreases further, and starting from the density of ~0.01 g cm–3, the formation of crystalline silica phases (cristobalite, keatit) was observed in the sample. Based on the observed regularities in the change in the morphology and crystallinity of SiO2, as well as on the data on the variations in the properties of the water fluid with temperature and pressure below and above the critical point, it was concluded that the increase in the structuring rate with an increase in the density of the water fluid is more likely due to the kinetic factor (mass action law) than with a change in the physical state of water (intermolecular interaction forces action). Using the obtained samples of treated silica gel as a support for the NaWMn/SiO2 catalysts it was shown that their efficiency in the oxidative coupling of methane decreases with increasing degree of crystallinity of the support. However, when supports that have undergone processing in the water fluid of relatively low densities (<0.05 g cm3) were used, the catalysts were more active and selective than the one prepared using the untreated silica gel.

Quality changes of frozen mango with regard to water mobility and ice crystals during frozen storage

AbstractQuality changes of mango with regard to water mobility and ice crystals were studied at different storage temperatures for 6 months. Mangoes were stored in the glassy state (T [−80 and − 60°C] &lt; Tg′ and Tg′ &lt; T [−49°C] &lt; Tg″), partially freeze‐concentrated state (Tg′′ &lt; T [−38°C] &lt; Tm′), and rubbery state (T [−18°C] &gt; Tm′). Results indicated that the most samples stored at −80 and − 60°C had no significant difference in the water mobility, freezable water, drip loss, and vitamin C after the same storage period. The Tg′ and Tg″ showed a different effect on the quality stability of frozen mangoes. In the glassy state, changes in water state, freezable water, and ice crystal size of frozen samples were slower, resulting in lower rate of quality changing (L* value, hardness, and vitamin C) than other conditions from 0 to 6 months.Practical applicationsThis study demonstrated the correlation between the water mobility and ice crystals of mango revealing the mechanism of physical and chemical changes in samples stored at different states during frozen storage. Compared to the partially freeze‐concentrated and rubbery state storages, the glassy state storage reduced the rate of the quality change in mangoes over time. Therefore, glassy state storage (below Tg″) has great potential for the food processing industry because it can improve frozen storage strategies and extend the shelf life of frozen mango during long‐term storage.

A Sequentially Coupled Catchment‐Scale Numerical Model for Snowmelt‐Induced Soil Slope Instabilities

AbstractThe frequency of snowmelt‐induced soil slope instabilities is increasing in some seasonally cold regions because of climate change. Reliable hazard assessment and risk mitigation of snowmelt‐induced landslides require physically‐based prediction models. However, existing models either apply only at the slope scale or assume precipitation as the sole landslide trigger. In doing so, they neglect the complexity and coupled nature of the thermo‐hydro‐mechanical processes leading to slope instability in seasonally cold regions (such as snow accumulation and melting, infiltration and surface runoff, soil saturation, pore water pressure buildup and dissipation). Here, we present a spatially distributed and sequentially coupled numerical model to simulate snowmelt‐induced slope instabilities at the catchment scale. The model accounts for temperature‐dependent changes in the soil hydraulic behavior related to changes in water state by means of a routine implemented in a geographic information system. We verified the performance of the model using a case study of spring snowmelt‐induced soil slope failures that occurred after the 2004 Mid‐Niigata earthquake in Japan. Considering limitations and simplifications, the model was able to predict the triggering condition, magnitude, and spatial distribution of the snowmelt‐induced landslides with a satisfactory degree of accuracy. We believe that the robustness and simplicity of our numerical approach make it suitable for implementation in early warning systems.

Effect of in vitro oxidation on the water retention mechanism of myofibrillar proteins gel from pork muscles

The aim of this study was to investigate the effects of oxidation on the structure of pork myofibrillar proteins (MPs) and the water retention mechanism of MPs gel. In a Fenton reaction system, protein oxidation increases (P < 0.05) with hydrogen peroxide (H2O2) concentration (0, 0.5, 1, 3, 5, 10, and 20 mmol/L). The Brunauer–Emmett–Teller surface area of the proteins gel gradually increased (P < 0.05) from 6.17 m2/g to 14.73 m2/g. Low field nuclear magnetic resonance results showed that immobilized water in the gel gradually decreased but free water content gradually increased (P < 0.05). Gel strength and water holding capacity (WHC) increased and then decreased. The results reveal that moderate oxidation contributes to the compact and uniform pore structure, higher WHC of proteins gel as well. However, excessive oxidation leads to increase pores and changes in water states of gel, leading to lower WHC.

Effects of low-dose γ-irradiation on the water state of fresh Lentinula edodes

Understanding the water state in fresh Lentinula edodes under low-dose irradiation will be helpful to evaluate the freshness and forecast the shelf-life. In this study, the effects of low-dose γ-irradiation (1.0 and 2.0 kGy) on the water state of L. edodes during storage were investigated. Low-field nuclear magnetic resonance results revealed that fractions M22 and M23 constituted the predominant parts among the four water fractions. The results also released that 1.0 kGy-irradiated mushrooms maintained the water state and good appearances. However, 2.0 kGy irradiation caused watery exudate and unfavourable appearance. Moreover, the changes of water state associated with the appearance can be used to assess the freshness and forecast the shelf-life of irradiated L. edodes. Our results suggested that low-dose γ-irradiation (≤1.0 kGy) was a potential preservative method to decrease the water loss, retain the freshness, and extend the shelf-life of fresh mushrooms.

Precursor Models and Early Years Science Learning: A Case Study Related to the Water State Changes

Children’s everyday activities enable them to learn some science even before entering preschool education and children bring these ideas with them when entering education settings. Some of these ideas, or else mental representations, may not be compatible with what is generally accepted by the scientific community. This paper presents the results of an empirical study, focusing on the construction of a precursor model that can support children’s scientific learning, in relation to the phenomenon of change of the state of water. The research included 91 children aged 5–6 which participated in a specifically designed teaching intervention. The intervention lasted approximately 55 min and was conducted at eight stages, during which children’s predictions and explanations for simple cases of change of the state of water were recorded. The analysis of children’s responses suggests that the specific teaching intervention can have a positive effect on children’s thinking in relation to the change of the state of water. A considerable number of pre-schoolers were able to take advantage of their involvement in the teaching intervention and construct a stable precursor model to support the development of their understanding, in relation to the water change of state phenomenon. It appears that precursor models can function in the minds of young children as intermediaries between mental representations of reality and scientific knowledge and prepare children’s thinking, forming the basis for a cognitive path towards cognitive processing and the formation of more complex models. The proposed intervention is compatible with the model used in science education and it is proposed to be used in moderation and should not replace children’s learning through play.

Changes of water state and gel characteristics of Hairtail (Trichiurus lepturus) surimi during thermal processing.

This study examined the changes of water state and gel characteristics of Hairtail surimi during thermal processing including two steps. The results showed that there were four content of water in Hairtail surimi gels. Water-holding capacity (WHC) and T23 relaxation time of water and gel strength increased from 47.01 to 78.97% and from 64.23 to 51.52 ms, respectively, and whiteness decreased from 63.87 to 55.22 during the entire thermal processing. Meanwhile, the texture properties including hardness, gumminess, and chewiness declined from 402.42 to 130.41 g, from 294.39 to103.70 g, and from 233.68 to 43.60 g, respectively, during the first step, and then increased markedly during the second step from 130.41 to 2,301.87 g, from 103.70 to 1,250.99 g, and from 43.60 to 978.51 g, respectively. Furthermore, the WHC and textural profile had positive correlation, and changes in protein secondary structure were interesting, with the α-helices decreasing significantly from 26.40 to 14.12%, while the β-sheet and the random coil structure increasing significantly from 36.28 to 44.03%, and from 10.89 to 14.31%, respectively, and β-turn structure increasing form 26.44 to 27.98% during the first step and then declining markedly during the second step, moreover β-sheet had a fine positive correlation with WHC hardness and chewiness. Overall, dense, porous and compact three-dimensional network gel structure gradually formed. In a word, during thermal processing. WHC of Hairtail surimi increased, and protein secondary structure of protein became orderly, and a fine, dense gel formed during thermal processing. Water is considered as the highest and most important chemical constituent in surimi products. During surimi gelation, water molecules exist as bulk water and motionally restricted water on the protein surface. In order to gain more insights into the surimi heating-induced gelation processing, and improve the surimi gel properties, and give same advice to manufacturing enterprise, this work was conducted to study the structural changes of protein and water state during surimi gelation processing and performed along with the monitoring of the texture, WHC and other physical characteristics of surimi gel, as well as the microstructure of surimi gel.

Water Redistribution within the Microstructure of Cementitious Materials due to Temperature Changes Studied with 1H NMR

Changes of water state within the pore structure of cement paste due to temperature changes are followed by means of 1H nuclear magnetic resonance (NMR) relaxation analysis. The study shows that, with increasing temperature, the signal due to water contained in the smallest C–S–H interlayer spaces decreases while that from the larger gel pores, and to a lesser extent from the capillary pores, increases. On cooling, the opposite behavior is observed with complete reversibility. The observed changes in water populations appear to be instantaneous compared to the rate of temperature change in the samples. These changes are postulated to be responsible for macroscopically observed changes of relative humidity in pores during heating/cooling and are therefore key in understanding thermal deformations of cement-based materials. It is evident that the previous hypothesis of microstructural delayed water transport being responsible for macrostructural delayed thermal deformations can be rejected. Different micros...

「水のすがたとゆくえ」の発話事例の解釈的分析 : 小集団の議論を通した概念変化の様相

「水のすがたとゆくえ」の発話事例の解釈的分析 : 小集団の議論を通した概念変化の様相

Effect of C/N on Water State during Composting of Kitchen Waste and Vegetable Waste Mixture

The objective of this study was to evaluate the effects of the C/N ratio on the water state changes during the composting of kitchen waste (KW) and vegetable waste (VW) mixtures. The C/N ratios in KW and VW were 50.70 and 27.07, respectively, and the VW was added to the KW to amend the C/N ratio. Five composting treatments were used, R1 with 0% KW, R2 with 25% KW, R3 with 50% KW, R4 with 75% KW, and R5 with 100% KW, and the initial C/N ratios increased in the order R1 &lt; R2 &lt; R3 &lt; R4 &lt; R5. As the composting process progressed, the capillary water (CW) and multi-molecular-layer water (MMLW) were changed into entrapped water (EW), and a high C/N ratio could delay the changes in the water state. The percentage of EW and CW significantly positively correlated with the C/N ratio during the composting of KW. The composting process performed better in treatments R2 and R3 than in the other treatments, and it was found that treatments R2 and R3 each had a lag phase of around 4 d until the water states started to change.

The use of vacuum ultraviolet radiation for investigationof water samples with different salt content

The paper gives the results of experimental research in photolysis of water samples using vacuum ultraviolet radiation at the wavelength 185 nm. Differences in the kinetics of formation of hydrogen peroxide for different waters found are explained by changes in the structural state of water, which was confirmed in defining sizes of clusters by the method of dynamic light scattering.

近赤外光の吸光特性を利用した水の相状態（液相，固相）の検出

We have developed a detection method of the state of water using near-infrared light-absorption. In this paper, a new evaluation index of the frozen state of water is proposed. In this case, we focused on the light-absorption characteristics of water. The experimental results showed that the absorption peak shifts to longer wavelength when the water state changes into ice state. To remove the affect of the scattering by bubbles generated in the freezing process and the thickness of the water layer, we have proposed a new evaluation index based on absorbed light intensity ratio at two wavelengths. The index is constant even when the layer thickness changes from 1mm to 3mm and is not also affected by light scattering. This result indicates that the proposed evaluation index can be used as a criterion to detect the liquid phase (water state) or the solid phase (ice state). It has been confirmed that the method using the index is effective for monitoring the water freezing process with supercooling by the experiment.