Changes In Moisture Content Research Articles

Investigating the impact of blanching and salt treatment on the drying kinetics of oyster mushrooms

This study aims to evaluate the effect of drying temperature and drying kinetics of the blanched and salt-treated oyster mushrooms. The drying temperatures were from 40 to 80 °C. Evaluations were done on the moisture content, rehydration ratio, and physical changes. The CHNS and FTIR analyses were conducted under optimized drying conditions. The drying kinetics were evaluated and the result discovered that the best drying condition with a good rehydration ratio (6.3) and good quality was the salt treatment sample dried at 60 °C in 6 h. The drying kinetic was explored in five different kinetics models, and the parabolic model proved to be the best model with the highest R2 (1.000), lowest RMSE (7.0899E-05), and MBE (5.02666E-09). The effective moisture diffusivities obtained were 0.4–1.8 × 10−9 m2/s and the activations energy was 36–45 kJ/mol. The drying and treatment processes significantly impact the intensity of functional groups, carbon, hydrogen, and nitrogen contents. This study provides useful insights into the drying process of oyster mushrooms using oven drying.

Effects of heating media on microstructure and chemical composition of heat-treated Pometia pinnata

Changes of microstructure, crystallization, chemical composition, and equilibrium moisture content (EMC) of heat-treated wood (HTW) were investigated to explore the effects of heating media (saturated steam, superheated steam, air) and heat treatment (HT) temperature on HTWs. The results showed that the saturated steam induced more severe cell wall destruction than the other two media. Although the porosity slightly increased with the increasing HT temperature, superheated steam and air HT still decreased the porosity compared to that of control, whereas saturated steam HT increased the porosity. The HT increased both relative crystallinity and crystal size of HTWs. The increasing HT temperature slightly increased the relative crystallinity but decreased the crystal size. The highest crystallinity (55.0%) was observed after saturated steam HT. Leaching led to the increase of crystal size of HTW treated in saturated steam (about 0.15 nm), while those treated in unsaturated steam and air decreased. The increase in relative amount of lignin and cellulose due to the hemicellulose degradation were the main chemical changes of HTWs. Further lignin condensation reaction only occurred after saturated steam HT. Although saturated steam HT induced increased porosity, its lowest EMC (5.91%) indicated the decrease of hydroxyl groups.

Analysis of Moisture Migration and Microstructural Characteristic of Green Sichuan Pepper (Zanthoxylum armatum) during the Hot-Air Drying Process Based on LF-NMR

To have a deeper understanding on the moisture migration patterns and microstructural changes of Green Sichuan Pepper during the hot-air drying process, the low-field nuclear magnetic resonance (LF-NMR) technology and scanning electron microscopy (SEM) methodology were adopted to analyze the moisture distribution, migration patterns and microscopic structural changes under different drying temperatures (45, 55 and 65 °C). The LF-NMR scanning results showed that the internal moisture of the Green Sichuan Pepper mainly includes bound water, immobilized water and free water, which can be respectively symbolized by the relaxation time ranges of T21 (0.1–10 ms), T22 (10–500 ms) and T23 (500–10,000 ms). The immobilized water accounts for 83.72% of the internal water, resulting in the significant drying difficulty of Green Sichuan Pepper. During the drying process, the content of immobilized water and free water exhibited a decreasing trend, while the bound moisture content initially increased and then decreased. In addition, the LF-NMR analysis showed that the parameters peak area A2 demonstrated a high correlation with the moisture content of Green Sichuan Pepper, enabling the prediction of moisture content changes during the drying process. Additionally, the SEM results showed that the pore degree and pore density on the pericarp surface of Green Sichuan Pepper perform significant changes during the drying process, which might be a good explanation for revealing some commonly recognized drying phenomena on Green Sichuan Pepper hot-air drying. In summary, the findings presented in the present work provide some new insights into the moisture distribution, migration patterns and microstructural changes of Green Sichuan Pepper, which can offer theoretical guidance for optimizing the drying process of Green Sichuan Pepper.

Experimental Investigations of stabilization of Black cotton soil

Abstract The technique of stabilizing soil aids in achieving the qualities of soil that are necessary for building projects. Black cotton soils, sometimes referred to as swelling soils, are those soil types that have a propensity to expand and contract in response to changes in moisture content. By increasing the strength of the black cotton soil, this experimental investigation on stabilizing the soil with a certain amount of granite dust produces positive results. The maximum dry density and reduced potential for shrinkage and swelling are found in the black cotton soil mixed with 5% granite. The greatest results are obtained with 10% of the granite mix with black cotton soil since this experiment shows a significant decrease in the ideal moisture content.

Expansive clay subgrade soil improvement using municipal solid waste fly ash: Experimental and numerical approach

The expansive soil under investigation has caused damage to lightweight structures due to its swelling and shrinkage characteristics in response to changing moisture content. The study aims to assess the impact of municipal solid waste (MSW) fly ash on the engineering properties of subgrade expansive soils and its influence on pavement structure deformation. The influence of municipal solid waste fly ash on expansive soils was evaluated using laboratory tests and finite element methods. The Abaqus software was used to investigate the effects of MSW fly ash on pavement structure deformation. The input parameters employed for this analysis were elastic modulus, Poisson ratio, load, contact area dimension, and pavement layer thickness. To mitigate this issue, MSW fly ash was used as a stabilizing agent at varying percentages (5 %, 10 %, 15 %, 20 %, 25 %, and 30 % of the dry mass of the soil sample).According to the AASHTO soil classification, the soil is classified as A-7, has a high free swell, a low soaked CBR value, and a high soaked CBR swell, and does not meet the ERA manual standard for subgrade materials. The laboratory tests shown several improvements in the engineering properties of expansive soil when MSW fly ash were mixed. These improvements included a reduction of soaked CBR swelling, free swell index, plasticity index, specific gravity, optimum moisture content. Additionally, the maximum dry density and soaked CBR values increased. Numerical analysis using Abaqus software focused on vertical deformation of the pavement structure. The results showed that as the percentage of MSW fly ash in form 0 % to 25 % of soil dry weight, the vertical deformation of the pavement structure decreased from 0.84 mm to 0.67 mm. This demonstrates that the addition of MSW fly ash reduced the deformation of expansive sub-grade soil and improved the engineering qualities of pavement structure. In conclusion, the study revealed that the use of MSW fly ash as stabilizing agent effectively reduced the deformation of expansive subgrade soil and improved the engineering qualities of pavement structure.

Predicting green tea moisture content during roasting by shape feature

This study investigated the changes in tea moisture content and shape features parameters during the roasting process of roasted green tea under different temperatures(70, 100 and 130 °C), leaf amounts (40, 70 and 100 kg), and cylinder speeds (25, 27.5 and 30 r/min), and developed a moisture content prediction model based on Random forest-Genetic algorithm-Back propagation(RF-GA-BP) neural network. Firstly, based on image processing technology, the shape parameters of tea leaves during the roasting process were automatically extracted, and the random forest algorithm was used to rank their importance to reduce the complexity of the model. Then, the activation function and the number of hidden layer nodes in the network structure were optimized. Finally, the initial weights and thresholds of the neural network were optimized using genetic algorithm to obtain the optimal parameters for constructing a moisture content prediction model during the roasting process. The results indicated that the importance of slightness was the highest, with a value of 0.865. The RF-GA-BP neural network model with mean absolute error, root mean square error, and coefficient of determination of 0.030, 0.036, and 0.915, respectively, was superior to the BP, GA-BP, and RF-BP neural network models, and could better predict the moisture content of tea during the roasting process.

Encapsulation of Peperomia pellucida (L.) kunth leaf extract for postharvest preservation of Malang apple (Malus sylvestris) at ambient storage

This study investigated the efficacy of edible coatings based on encapsulated Peperomia pellucida leaf extract to extend the shelf life of Malang apples. An edible coating was developed by encapsulating P. pellucida leaf extract using a chitosan-STPP matrix. The optimum encapsulation efficiency observed of polyphenols and flavonoids retention was 86.25% ± 0.02 and 83.30% ± 0.04, respectively. It achieved by 2.5% chitosan, 2% STPP, and 3.5% extract in formula. The encapsulated extract was further applied to Malang apples as edible coated using varying dipping times and stored for 15 days at ambient temperature. Evaluation parameters on coated Malang apples included hardness, weight loss, pH, moisture content, and color change. A 1-min dipping time of the encapsulated extract was found to be optimal, effectively reducing physical and chemical alterations and enhancing the shelf-life quality of the apples. Therefore, the edible coating derived from encapsulated P. pellucida leaf extract presents a promising alternative for preserving Malang apples.

Steady and transient state behavior of a gasification process under fixed-bed downdraft configuration

Gasification is a thermochemical process that has gained significant interest in the field of biomass energy conversion. Despite the level of technological maturity of the process, the dynamic variation of the process as a result of changes in both the properties of the gasifying agent and biomass has not been analysed in sufficient depth. Therefore, the present study characterizes the process dynamically as a function of step-type changes in rice husk biomass moisture content and gasifying airflow. To identify stability conditions and the range for inducing disturbances, steady-state tests were carried out using a 32-factorial design. The experimental results demonstrate that within the tested range of airflow, the gasification process operates in the oxygen-limited zone. Despite increasing the airflow from 20 to 40 standard liters per minute (SLPM) and driving the reaction towards the combustion zone, the high temperatures achieved resulted in the gas reaching a peak Lower Heating Value (LHV) of 2.6 MJ/Nm3 and a gas power of 2.6 kW, with a Cold Gas Efficiency (CGE) of 62%. In contrast, the effect of biomass moisture content was negligible due to the thermal inertia of the reactor and the natural variation of the process. Dynamic evaluation revealed that the oxidation temperature and gas concentration were the variables that took the longest to return to stability after air disturbances. It took approximately 1200 s for the hydrogen (H2) concentration to stabilize, while the gas power required about 300 s. No clear results were observed regarding the impact of the dynamic disturbance in moisture content, which varied between 12.3% w.t and 21.5% w.t.

Optimization of measurement and calculation methods for viscoelastic creep strain and mechanical adsorption creep strain during conventional drying process of Pinus sylvestris

The traditional measurement method for viscoelastic creep strain and mechanical adsorption creep strain has relatively low accuracy, making it difficult to ensure the data accuracy of specimen strain measurements. In this study, 50-mm-thick Pinus sylvestris sawn timber was used as the research object. Along the thickness direction of the test material, the relationship between the free shrinkage coefficient and the moisture content of the test material was studied to optimize the measurement methods of viscoelastic creep strain and mechanical adsorption creep strain during drying process. The results showed that the optimized measurement method for viscoelastic creep strain, which compensates for dimensional change caused by moisture content changes during the creep recovery phase, was applied to different layers in the thickness direction of the test material. The average relative error at the end of the drying stage was reduced 20.1% compared to the traditional method. For the mechanical adsorption creep strain in different layers of the test material’s thickness, the optimized measurement method, based on the free shrinkage size calculated from the free shrinkage coefficient and moisture content, reduced the average relative error 59.1% compared to the traditional method.

Effect of Osmotic Dehydration in Tomato Juice on Microstructure of Garlic and on Drying Using Different Methods

This study investigates the effects of osmotic dehydration on garlic clove halves using a low-pH osmotic solution with ascorbic acid, concentrated tomato juice, and basil extract (45° Brix). Samples, both dehydrated and fresh, were subjected to various drying methods. Physical properties, such as CT scan analysis, texture profile analysis (TPA), porosity, and density, were examined. Additional parameters like energy consumption, specific energy consumption, moisture content, water activity, and color change were evaluated. Osmotic dehydration reduced moisture content by over 7.5%. The specific energy consumption for microwave vacuum drying (MVD) was 95 kJ/g for osmotically dehydrated samples compared to 118 kJ/g for non-dehydrated samples. Drying times decreased by 24 min for MVD and 15% for microwave convective drying (MCD). The Weibull model best fit the drying kinetics, with R2 values above 0.99 and RMSE below 0.03 for all methods. TPA tests showed no significant impact of osmotic dehydration on hardness, though drying methods significantly affected hardness, ranging from 49 N to 707 N. Color change was higher for osmotically dehydrated samples, reaching 37.09 for OD-CD compared to 29.78 for CD.

Physio-biochemical Changes during Adventitious Root Formation in Gmelina arborea Roxb. Bud Sprout Cuttings

Changes in the endogenous moisture content and biochemical viz., soluble sugar), phenols, o-phenol and peroxidase activity at different stages of adventitious rooting in auxin-treated (5 mM IBA) and non-treated miniature bud sprout cuttings of Gmelina arborea Roxb. were investigated at 0 h, 24 h, 3 days, 7 days, 2 weeks and 3 weeks of planting to elucidate the process of adventitious root formation at physio-biochemical level. Simultaneously adventitious rhizogenesis parameters viz., proportion of live green sprouts (%), callusing (%) and rooting (%) were recorded. Two weeks after planting, the marked difference for adventitious rhizogenesis was noticeable between treated and non-treated sprout cuttings. More than 20% rooting and 75% callusing were recorded in treated sprout cuttings. In contrast, only 7.4% non-treated sprout cuttings exhibited callusing. At the end of Week 3, more than 90% rooting was observed in treated sprout cuttings while it was absent in non-treated ones. All biochemicals exhibited changes in the first 24 h, indicating early incidence of consequential process(s), which influenced the differential response of cuttings to adventitious rhizogenesis in auxin-treated and non-treated state. Overall, the results indicate two possible phases of adventitious rhizogenesis – Phase I of Induction -the initial phase exhibiting low endogenous moisture and o-phenol but elevated phenol and peroxidase activity and Phase II of Initiation – the later phase coinciding with higher endogenous moisture and low phenol content and peroxidase activity. Both phases appear to be separated by an intervening unstable duration (Gap Phase of Stabilization) which may vary among different types of cuttings/species.

Assessment of three-dimensional large-scale deformations during drying of hydrogels via a structure from motion photogrammetry

A low-cost, efficient and accurate structure from motion (SfM) photogrammetry is used to reconstruct the complex morphologies of unevenly deforming hydrogels during the drying process. The primary setups comprise a camera and rotary platform, which are low-cost and works stably for most drying conditions. The dynamic three-dimensional (3D) reconstruction of cylindrical hydrogel samples is achieved by SfM through the generation of point clouds, and the 3D morphologies are calculated by a Poisson reconstruction algorithm based on these point clouds. The accuracy of SfM in quantitatively measuring large-scale deformation is validated, and its applications in drying studies are explored. The results show that as drying proceeds, the maximum measurement deviation of the hydrogel volume between SfM and the traditional buoyancy force method is 1.93% at a volume shrinkage of 69%, confirming the accuracy of the current method for measuring large-scale drying shrinkage. Based on SfM, the temporal evolution of the cross section of the hydrogel is obtained. Comparing to conventional drying experiments that assess the dryness of deformed materials based on overall moisture content changes, SfM enables the evaluation of localized complete drying by quantitative analysis of deformation parameter variations.

Structure and Digestibility of Spray‐Dried Corn Starch: Influence of Post‐Treatments

AbstractResistant starch (RS) has being attracted attention due to its health benefits. In this study, combination of spray drying and post‐treatments is adopted to prepare post‐treated spray‐dried corn starch (PSDCS) with high content of RS. Effect of post‐treatment conditions on structural and digestive properties of the PSDCS is investigated. Relative humidity can alter the ordered structures of the PSDCSs due to changes in equilibrium moisture content. When fixing relative humidity at 33%, improvements in short‐range structure and long‐range crystalline structure of the PSDCS obtained at alternant temperature of 4/30 °C (12 h/12 h) are better than those of the PSDCSs obtained at other temperatures. The highest content of RS (29.97%) is found in the PSDCS obtained at 4/30 °C, which is approximately 3.3 times of native corn starch and 5.6 times of spray‐dried corn starch. These findings demonstrate feasibility of preparation of starch products with lower digestibility using spray drying combined with post‐treatments and lay the groundwork for the production and application of products with high content of RS.

Water-holding properties and electrochemical characterization of the soil under the Grand Deliverance Hall of the Chongshan Temple, Taiyuan City, China: providing the basis for preventing groundwater erosion in historic buildings

Many historic buildings are at serious risk of deterioration due to changes in the moisture content of the soil under the buildings. Based on the typical deterioration problems of the Grand Deliverance Hall and the cultural relics in the hall, this study analyzes and concludes that the main factor affecting the generation and development of deterioration is groundwater erosion through environmental monitoring and geotechnical engineering investigation. The impact of changes in moisture content on the water-holding properties and pore distribution of the soil under the cultural-relics buildings was further assessed. Then, combined with the soil property, our study provides a novel and effective way to monitor and reflect the water-holding properties of the soil using electrochemical detection. The connected pore resistance and matrix suction decrease with the increase in the moisture content, both showing a power function law. Changes in moisture content cause changes in the thickness of the double electric layer, which in turn affects the connected pore resistance and matrix suction of soil. The greater the connected pore resistance, the greater the matrix suction and the water holding capacity. Finally, based on the research of this study and the conservation ideology of cultural relics that respects the original and minimizes intervention, protection recommendations to prevent groundwater erosion are proposed in order to provide guidance for future research.Graphical

Rolling table centrifuge modelling of partially saturated granular material to inform on instability during solid bulk cargo transport

The response of partially saturated granular cargoes during maritime transportation has resulted in the capsize and sinking of 27 bulk carriers at sea and the loss over 90 seafarers’ lives in the last decade. The partially saturated granular material response to energy imparted during cargo loading, ship engine vibrations and vessel rolling motions from sea states causes a change in state of the granular cargo, which can lead to vessel instability and ultimately capsize. However, the mechanisms driving the response of partially saturated granular cargos within a bulk carrier hold are not well understood. This paper presents results from an experimental study of rolling table centrifuge model tests on a partially saturated silica sand to contribute to improved understanding of the response of granular cargoes during maritime transport. Observed settlement, pore pressure, moisture content and density changes during and/or following a sequence of large amplitude rolling motions are presented. The results indicate that for the conditions considered, a progressive upwards migration of pore water during rolling led to creation of a free surface of water above the granular sample that was left in a denser, lower moisture content sample compared to its initial state. Sloshing of free water on top of even a competent cargo during rolling motions of the ship can contribute to loss of ship stability and ultimately capsize.

Modeling the Moisture Content and Dry Matter Loss in Dynamic Woody Biomass Storage Piles with Variable Extraction

The urgent need to mitigate climate change has spurred significant interest in renewable energy sources. This paper explores the storage and processing of woody biomass for biofuel production, considering the dynamic nature of biomass piles in real-world scenarios. A model has been developed to analyze moisture content changes and dry matter loss in woody biomass stored in piles prior to processing, taking into account varying extraction methods and environmental conditions. Case studies that examine the effects of different unpiling methods (FIFO, LIFO, and homogeneous) on moisture content and dry matter loss under various feedstock arrival rates and weather conditions are presented. Results indicate that unpiling methods significantly impact moisture content, with LIFO typically resulting in higher moisture content due to the utilization of fresher feedstock. Dry matter loss increases with pile size and time, emphasizing the importance of accurate modeling for assessing carbon emissions and feedstock quality. Furthermore, the model highlights the importance of process loading order and extraction methods in biomass storage, suggesting potential cost benefits associated with decreased moisture content. The difference between different extraction methods could vary the moisture content in the feedstock reaching the biofuel process by as much as 37.6%, however dry matter loss varies minimally for realistic pile changes. Overall, this research contributes to a better understanding of biomass storage dynamics and informs sustainable biofuel production practices.

Modeling of a heat-integrated biomass downdraft gasifier: Influence of feed moisture and air flow

A model for a heat-integrated biomass downdraft gasifier is developed and used to study the influence of changes in biomass moisture content and gasifier air flow. This one-dimensional steady-state model accounts for pyrolysis, combustion and gasification reaction kinetics as well as transport phenomena occurring within the gasifier and heat integration system. The gasifier is divided into four zones for solving the ordinary differential equations (ODEs), because each zone has different geometry for the reactor or heating system. The material and energy balance ODEs are solved as a boundary value problem (BVP), ensuring that conditions for the producer gas at the bottom of the reactor match the conditions of the countercurrent annulus gas, which is used for heating. The model also accounts for the preheating of the biomass using exhaust gas from an associated engine used to generate electricity from the producer gas. The model predicts the process gas temperature, flow rate and composition and was validated using two experimental runs with different control inputs. The model predictions show good agreement with the data. Simulations with the highest feed moisture result in lower reactor temperatures and simulations with the highest air flow result in the highest reactor temperatures.

The effect of the fatty acid composition of fried oil on the oil-absorbing capacity of tofu puffs

The influence of the fatty acid composition of fried oil on the oil-absorbing capacity of tofu puffs was examined. Two edible vegetable oils and three blends of different oleic acid and linoleic acid ratios were analyzed before and after frying, along with the rheological properties, fatty acid composition, acid value, peroxide value, and p-anisidine value. As well as the moisture content, oil content, and microstructure changes of the tofu puffs, were evaluated. The results revealed that the viscosity of all fried oils increased after short-time thermal exposure, while the acid value, peroxide value, and p-anisidine value also increased. The blend oil, with an oleic acid and linoleic acid ratio of 1:1, demonstrated good oxidation stability and low viscosity. The tofu puffs fried with this blend oil had lower oil content and weak adhesion, attributed to their microstructure. The development of special frying oil with good stability based on fatty acid composition provides a theoretical basis for the production of low-oil frying food.

Metabolomics analysis, combined with enzyme and in-vitro simulation system analysis, provide new insights into the browning resistance mechanism of goji berries（Lycium barbarum. L)

Enzymatic browning is one of important factor causing quality deterioration of Goji berries (GB). To understand the enzymatic browning process of GB and its mechanism, changes of L*, a*, b* values, and the total color difference and whiteness index during the air contact storage were evaluated. Then changes of moisture content, total phenolics and the activities of the key browning enzymes, peroxidase (POD), Polyphenol oxidase (PPO), phenylalanine ammonia-lyase (PAL) and Superoxide dismutase (SOD), were determined during storage. Finally, the chemical constituents of GB were determined by targeted metabolomics and HPLC, and the possibility that these constituents were endogenous substrates of key enzymes for browning were evaluated. The results show that brightness and reddish-yellowness diminished are the general characteristics of GB discoloration. The activity of browning related enzymes (POD, PPO, PAL) was consistent with that of phenolics and flavonoids, which increased first and then decreased during storage. The content of chlorogenic acid decreased most rapidly under the action of the enzyme, which degraded 75% within 5min, followed by ferulic acid and rutin. Therefore, it is suggested that chlorogenic acid is the main endogenous substrate of GB enzymatic browning. In conclusion, these studies provide experimental basis for the browning mechanism of GB.

Chemo-mechanical ageing of paper: effect of acidity, moisture and micro-structural features

A multi-scale modeling framework is proposed for the prediction of the chemo-mechanical degradation of paper, with the particular aim of uncovering the key factors affecting the degradation process. Paper is represented as a two-dimensional, periodic repetition of a fibrous network unit cell, where the fibers are characterized by a moisture-dependent chemo-hygro-mechanical constitutive behavior. The degradation of paper occurs primarily as a result of the hydrolysis of cellulose, which causes a reduction of the degree of polymerization and a consequent decrease of the effective mechanical properties, ultimately leading to fiber embrittlement and a loss of material integrity. The interplay between the acidity of the paper, the ambient environmental conditions, and its chemo-mechanical degradation behaviour is a complex process. In the model, these interactions are accounted for by determining the coupled temporal evolution of the degree of polymerization, the acidity of the paper, and the moisture content, from which the time-dependent tensile strength of the paper is calculated. The internal stresses developing in the fibrous network under a change in moisture content lead to brittle fiber fracture once they reach the fiber tensile strength. The successive breakage of individual fibers results in damage development in the fibrous network, altering its effective constitutive properties. The temporal evolution of the effective hygro-mechanical properties of the fibrous network is calculated by employing asymptotic homogenization. For obtaining accurate model input, the strength and stiffness properties of individual fibers and the degree of polymerization of paper samples are measured at different ageing times by carrying out dedicated experiments. Subsequently, a series of numerical simulations is performed to analyze the chemo-mechanical degradation process of paper, highlighting the influence of the time-evolving acidity and moisture content. The numerical study further considers the effects of micro-structural features (i.e., the anisotropy of the fibrous network orientation and the fiber longitudinal elastic modulus) on the macroscopic degradation response of paper. The results of this work may help conservators of cultural heritage institutions determining optimal environmental conditions to limit or delay the time-dependent degradation of valuable historical paper artefacts.