Changes In Moisture Content Research Articles

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.

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

AbstractThe 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.

Storage study on compositional analysis of quinoa and ragi based snacks

This research focuses on examining compositional changes in quinoa and ragi seed-based snack products (Khakhara, Mathari, Laddu, and Cookies) during storage, aiming to provide comprehensive insights into their nutritional stability. The study addresses parameters such as total ash, total moisture, protein, fat, carbohydrates, energy, crude fiber, iron, and calcium content. The background underscores the significance of understanding alterations in these snacks’ composition during storage, and the purpose is to assess their implications for nutritional value and quality. Methodologically, the investigation thoroughly analyzes the specified parameters over the storage period. The principal results reveal dynamic changes in total ash, moisture, protein, fat, carbohydrates, energy, crude fiber, iron, and calcium content, shedding light on the evolving nature of these popular snacks during storage. This study contributes to the field by highlighting the need for strategies to enhance the shelf life and nutritional stability of quinoa and ragi-based snacks. The major conclusions drawn underscore the importance of further research to comprehend the driving factors behind these compositional changes. Acknowledging research limitations, the study recognizes the necessity for ongoing investigations to unravel underlying mechanisms. In terms of practical implications, the findings suggest a potential impact on the nutritional quality of these snacks, urging the development of strategies to mitigate such effects. Socially, the study’s insights into popular snack products contribute to broader discussions on food quality, nutrition, and health. In summary, this research advances our understanding of compositional changes in stored snacks and prompts further exploration for practical and societal advancements in the field.

Terahertz time-domain spectroscopy imaging combined with convolutional long short-term memory neural network for In situ moisture reduction prediction of particle foods during pulsed fluidized bed drying

Fluidized bed drying (FBD), as a novel dehydration method, has been widely applied in drying various heat-sensitive high-value food products, in which the pulsed fluidized bed drying (PFBD) technique addresses the ineffective fluidized limitation of the traditional FBD when dealing with cohesive products. However, achieving in situ real-time monitoring of dynamic product moisture content (MC) change during both FBD and PFBD without sampling is still challenging. This paper presents an innovative integration of a whisk-broom terahertz time-domain spectroscopy (THz-TDS) imaging system with a fluidized bed dryer, facilitating in situ, real-time monitoring of MC reduction of products without process pausing for sampling. The reliability, and robustness of the established system and prediction models were tested by drying peppercorn and sweetcorn under various drying settings, including different temperatures, flow patterns, and durations. Implementing the convolutional neural networks (CNN) and long short-term memory (LSTM) for correlating terahertz time-domain image data with reference datasets in this research provided reliable MC reduction prediction results for the mixture dataset from peppercorn and sweetcorn drying. The successful application of this combined sensing and analytical method presents a promising approach for enhancing industrial processing control and expands the utility of THz-TDS in the agriculture and food industrial fields.

Modifying Expansive Soil Characteristics with Xanthan Biopolymer Integration

Abstract: Expansive soils pose significant challenges in various engineering projects due to their tendency to swell and shrink with changes in moisture content. Traditional stabilization methods often come with environmental and economic drawbacks. This research paper explores the potential of xanthan biopolymer, a polysaccharide of microbial origin (Xanthomonas Campestris), as a sustainable and effective alternative for altering the engineering properties of expansive soils. Through laboratory experiments and analysis, the paper investigates the influence of xanthan biopolymer on key soil properties such as swelling behaviour, shear strength, and permeability. The findings provide insights into the feasibility and efficacy of using xanthan biopolymer for soil stabilization, offering a promising avenue for sustainable geotechnical engineering practices.

Effects of vegetation restoration on the temporal variability of soil moisture in the humid karst region of southwest China

Study regiona typical humid karst region of southwestern China. Study focusTemporally stable soil moisture variability (SMV) helps clarify stress on vegetation growth. In the humid karst region of southwest China, large-scale vegetation restoration has affected the soil moisture. However, most studies here have focused on changes in the soil moisture content, and changes in the SMV have not been considered. New hydrological insights for the regionIn this study, changes to the SMV after vegetation restoration were analyzed using two indicators: the soil moisture coefficient of variation(SMCV) and soil moisture memory(SMM). The results showed that the SMCV decreased by an average of 22.3 % and the SMM increased by an average of 17.2 % in the Karst region of southwest China. the SMV had significantly decreased after vegetation restoration, and the overall decrease was larger on 15-day, monthly, and yearly scales and smaller on the weekly scale.When the effects of different vegetation types were considered, SMV greatly decreased in forestland and grassland on the 15-day and monthly scales, in shrubland on the annual scale, and in sparse woodland on the 15-day, monthly, and annual scales. Four geomorphic regions in particular showed large reductions in the SMV: the karst basin, peak cluster depression, peak forest plain, and non-karst region. In addition, changes in SMV after vegetation restoration have a significant positive influence on geochemical and climatic factors and a non-significant negative influence on geological structure factors. Among them, the significant influence factors of CaO content and MgO content are greater than SiO2 content by 0.71 and 0.63. precipitation and temperature are greater than vapor pressure difference by 0.51 and 0.4. Overall, vegetation restoration was found to make the SMV in the humid karst region more stable.

Stabilization of Black Cotton Soil using Fly Ash

Using expansive soil at construction sites poses significant challenges due to its tendency to shrink and swell. To mitigate these issues and make expansive soil suitable for construction, proper treatment is necessary. Black cotton soils, which are expansive and have low bearing capacity, contain Montmorillonite clay mineral responsible for their shrinkage and swelling properties. Changes in moisture content can exacerbate the swelling behavior of black cotton soil. The goal of stabilization is to enhance the usability of black cotton soil for construction by adding Fly Ash (FA). Soil is a unique material, and by incorporating certain admixtures, it can be stabilized with varying percentages of Fly Ash (5%, 10%, 15%, 20%).

Morphological changes and color development during cookie baking-Kinetic, heat, and mass transfer considerations.

Color and shape are important quality attributes in baked goods, particularly cookies. Composition and processing conditions determine and influence color development and morphological changes in these baked goods. The objective of this study was to systematically evaluate the evolution of color and shape during baking to determine useful correlations that can be implemented during the assessment and modeling of the baking process. Cookies (AACC-I standard protocol 10-53.01) were baked at 185, 205, and 225°C. Moisture content, water activity, surface temperature, characteristic dimensions (radius and thickness), and color indexes (lightness, redness, blueness, and browning index [BI]) were monitored at different locations on the cookie surface and baking times. Relationships among the tested conditions were explored using correlation analysis. The cookies' dimensions and color indexes were strongly correlated with changes in moisture content over time, and those relationships were characterized using empirical models. The temperature dependence of the kinetic parameters of the changes in lightness and BI was also described and deemed independent of the location on the cookie surface. This study provides insights into the influence of heat and mass transfer on the physical and physicochemical changes of cookies during baking. The kinetic and secondary models developed in this study can serve as important components for establishing a comprehensive approach for coupling heat transfer, mass transfer, and reaction kinetics to estimate and optimize cookie-baking processes. PRACTICAL APPLICATION: The findings from this study provide valuable information for better understanding the morphological changes and color developments during the cookie-baking process. The quantitative data and models generated in this study will allow identifying baking conditions for better quality development.