The moisture relations of spray dried skimmed milk

Experimental study and mathematical model for soya bean drying in thin layer

Based on our own research conducted on a purpose-built plantation, the production capacity of reed canary grass (Phalaris arundinacea L.) was assessed depending on the age of the plantation and the date of the biomass harvest. The aim of this study was to assess the influence of the harvest date and plantation age on the yield, chemical composition, and calorific value of reed canary grass intended for energy purposes. The biomass on the plantation was cut twice during the growing season (summer/winter). The obtained biomass was analyzed for its ash content and selected elements, i.e., nitrogen, phosphorus, potassium, calcium, magnesium, sodium, sulfur, and chlorine. The total moisture, calorific value in working condition, and combustion heat were also assessed. The two-cut harvest system allowed us to obtain 3.85 t∙ha−1 of biomass from reed canary grass in the first year of cultivation. The highest biomass yields were obtained in the third and sixth years of cultivation and amounted to 8.50 and 8.75 t∙ha−1, respectively. Regardless of the age of the plantation, the biomass yield harvested in the summer period was always higher than the yield obtained from the winter harvest. The contents of some elements in the biomass also depended on the age of the plantation and the harvest date. The biomass of reed canary grass obtained from the summer harvest of the annual plantation was characterized by a high content of nitrogen (1.97% d.m.), potassium (2.35% d.m.), and phosphorus (0.31% d.m.) compared to the content of these elements in the biomass obtained from the three- and six-year plantations. In the case of sodium, the highest content (0.072% d.m.) was found in the biomass obtained from the summer harvest of the three-year plantation, and the lowest was obtained from the winter harvest of the six-year plantation (0.037% d.m.). The average sulfur content was the highest in the biomass obtained from the annual plantation, regardless of the harvest date (0.20% d.m.—summer harvest and 0.21% d.m.—winter harvest). On the other hand, the lowest amount of sulfur was contained in the biomass obtained from the winter harvest of the six-year plantation (0.12% d.m.). Only the magnesium content (from 0.09% d.m. to 0.14% d.m.) in the biomass remained at a similar level, regardless of the age of the plantation or the harvest date. The calcium content was the highest in the biomass obtained from the winter harvest of the annual plantation (0.35% d.m.), and the lowest was obtained from the six-year-old plantation, also from the winter harvest. In addition, the moisture and ash content of the obtained biomass depended on the age of the plantation and the harvest date. The highest moisture content (12.50%) was characteristic of the biomass harvested in the summer period from the one-year plantation. On the other hand, the lowest moisture content was found for the biomass harvested in the winter period from the six-year plantation. The highest ash content was obtained from biomass harvested in the summer period from the one-year plantation (75 g∙kg−1 d.m.) and the three-year plantation (69 g∙kg−1 d.m.). The lowest ash content was obtained from the winter harvest from the six-year plantation (45 g∙kg−1 d.m.). The highest calorific value of 16.0–16.2 MJ∙kg−1 d.m. was obtained for biomass harvested in the sixth year of the study (irrespective of the harvest date). The value of the combustion heat was also dependent on the age of the plantation and the date of the biomass harvest. The highest value for the combustion heat of 17.5 MJ∙kg−1 d.m. was obtained for biomass harvested in the winter period from the six-year plantation

The diffusion of moisture in paper is a complex phenomenon with pore diffusion dominating at low moisture contents and diffusion through fibres dominating at high moisture contents. Vapor diffusion through the pore space depends on the topology of the pore connections. Recently available three dimensional digital reconstructions of the pore space using X Ray Micro computed tomography (XμCT) enable us to determine the impact of the pore and fibre tortuosities and connectivity to moisture diffusion in an explicit manner. In this study, moisture diffusion was simulated through XμCT reconstructions of paper structures using a hybrid random walk algorithm that was developed to allow simultaneous diffusion in both the pore and fibre spaces with differential ‘intrinsic diffusivities’. The algorithm is specifically applied to simulate simultaneous diffusion under low and high relative humidity conditions where diffusion occurs predominantly through one medium i.e. pore space and high humidity conditions where both media (i.e. fibre and pore spaces) are highly conductive. The ‘intrinsic diffusivity’ of moisture through fibres was determined by using numerical simulation and experimental results. This intrinsic diffusivity a fundamental fibre characteristics is found to be independent of refining level but depends only the fibre moisture content under the conditions studied. The algorithm also allowed the determination of the anisotropy in diffusivity. One interesting result is that the anisotropy in diffusion is most significant at low moisture contents when diffusion through the pore space dominates. At high relative humidities (i.e. at high moisture contents), fibre conduction provides an alternative diffusion path, homogenizing diffusion to a large extent. As a result, diffusion becomes more isotropic with increased moisture contents in paper.

The effect of water repellence and antecedent soil moisture on wetting front stability and infiltration rate are reported for a seasonally water repellent topsoil. The effect of water repellence on infiltration was determined by comparing the in situ infiltration of water to that of a 7M ethanol solution. Wetting front stability was measured during infiltration of water into repacked, wettable and water repellent soils, within a Hele‐Shaw chamber. Water repellence restricted in situ movement of water through large macropores (>500 μm), which decreased intrinsic permeability by 1 to 2 orders of magnitude. In repacked soils, water repellence caused the development of unstable wetting fronts and reduced infiltration from 240 mm h−1 to 101.7 mm h−1. Infiltration into wettable soils at moisture contents near field capacity was expected to result in rapid infiltration and stable wetting fronts. However in repacked soils, wetting front instability developed, and infiltration rates were 190% lower when air and/or water movement through the base of the chamber was restricted. Infiltration into in situ soil was also slower at high antecedent soil moisture. The hydraulic conductivity of the 7M ethanol solution decreased significantly from 112.3 mm h−1 in dry water repellent conditions, to 35.6 mm h−1 in wettable soils at high antecedent moisture contents. Consequently the previously reported development of wetting front instability and reduced infiltration into in situ wettable soils at high moisture contents were confirmed and attributed to difficulty displacing existing soil water during infiltration of new water.

Tensile and shear properties of fingernails as a function of a changing humidity environment

In most species, arrest of growth and a decrease in water content occur in seeds and pollen before they are dispersed. However, in a few cases, pollen and seeds may continue to develop (germinate). Examples are cleistogamy and vivipary. In all other cases, seeds and pollen are dispersed with a variable water content (2-70%), and consequently they respond differently to environmental relative humidity that affects dispersal and maintenance of viability in time. Seeds with low moisture content shed by the parent plant after maturation drying can generally desiccate further to moisture contents in the range of 1-5% without damage and have been termed 'orthodox'. Pollen that can withstand dehydration also was recently termed orthodox. Seeds and pollen that do not undergo maturation drying and are shed at relatively high moisture contents (30-70%) are termed 'recalcitrant'. Since recalcitrant seeds and pollen are highly susceptible to desiccation damage, they cannot be stored under conditions suitable for orthodox seeds and pollen. Hence, there are four types of plants with regard to tolerance of pollen and seeds to desiccation. Orthodoxy allows for dispersal over greater distances, longer survival, and greater resistance to low relative humidity. The advantage of recalcitrance is fast germination. Orthodoxy and recalcitrance are often related to environment rather than to systematics. It has been postulated that certain types of genes are involved during presentation and dispersal of pollen and seeds, since molecules (sucrose, polyalcohols, late embryogenic abundant proteins, antioxidants, etc.) that protect different cell compartments during biologically programmed drying have been detected in both.

Aims: The study aimed to design and develop a greenhouse solar corn dryer that provides an efficient, sustainable, and cost-effective drying solution. The consistent use of traditional and conventional open sun drying (OSD) for agricultural products and yield necessitates the development of an innovation that can maintain quality, expedite the drying process, and potentially replace these techniques by utilizing renewable energy. Study Design: The study employed a Research and Development Design and an experimental quantitative approach to analyze variables and data. Place and Duration of Study: Situated in Brgy. Anlugan, Cabanglasan, Bukidnon and lasted from January 28, 2025, to March 26, 2025. Methodology: First, the sketch and construction of the greenhouse solar dryer (GSD) were done in the locale of the study. Then, to commence the corn drying process, 2 sacks were bought for each method and repeated to conduct 2 trials, totaling up to 8 sacks of corn kernels with high moisture content. Necessary research instruments were used to measure the following parameters: moisture content, temperature, relative humidity, cost, and time. Lastly, samples of corn were randomly taken and filled into bags for testing of aflatoxin levels. Results: There was a significant difference between the performance of the GSD compared to the OSD in terms of moisture content, as P = 0.001. for both trials. Furthermore, there was no significant difference in the relative humidity measured from both methods, yet the GSD managed to store more heat compared to the OSD. Furthermore, aflatoxin levels measured through the ELISA test showed that the former contained samples that were food-grade compared to the traditional method. Lastly, through calculated costs and efficient hours of drying, the GSD was cheaper and took less time compared to the latter. Conclusion: The developed design has the potential to replace the traditional practice of open sun drying, yet it requires more enhancements and further trials to evaluate and potentially replace this method for the benefit of local farmers.

The objective of this research was to investigate the effect of heating rate at different moisture contents on starch retrogradation and gelatinization process. Starch retrogradation was not influenced by either moisture content (water/starch ratio of 0.7 or 2.0) or heating rate (5°C/min, 20°C/min, or 40°C/min). In order to further understand the effects of heating rate on starch–water interactions, starch suspensions at a water/starch ratio ranging from 0.7 to 3.0 were heated at 5, 15, or 25°C/min by using a DSC to different final temperatures and rescanned. The deconvoluted G and M1 endotherms and the corresponding additional unfrozen water (AUW) were determined. The results showed that the G and M1 endotherms merged at higher heating rates and at higher moisture contents as expected. A significant interaction was observed between moisture content and heating rate. The results suggest that the gelatinization process is governed by moisture content at the lower heating rate (5°C/min) and by heating rate at the higher heating rates (15 or 25°C/min). Results from the AUW data suggest that the M1 component of gelatinization dominated at moisture content below water/starch ratio of 1.5 and at 5°C/min heating rate. However, at moisture contents above water/starch ratio 1.0, an interaction was observed between moisture content and heating rate. The data suggest that at higher moisture content (>1.5 water/starch ratio) and at higher heating rate (≥15°C/min), there is still a kinetic limitation to the complete melting of the M1 endotherm.

Bamboo, a renewable resource, has broad applications in construction, furniture, and other sectors. However, its dimensional stability and mechanical properties under varying humidity conditions pose challenges. This study aims to investigate the effects of microwave-compression treatment on the mechanical properties, water resistance, and chemical composition of bamboo at various moisture contents, and to elucidate the mechanisms underlying these changes. In the experiment, bamboo samples with moisture contents of 10%, 30%, and 50% were subjected to microwave-compression, and their mechanical properties, water resistance, chemical composition, and microstructure were subsequently analyzed. The results indicate that bamboo with low moisture content (10%) exhibited the best modulus of elasticity (MOE) and modulus of rupture (MOR), while bamboo with higher moisture contents (30% and 50%) showed significant declines in mechanical properties, although dimensional stability improved. Chemical analysis revealed that microwave-compression treatment resulted in the reorganization of lignin and hemicellulose, enhancing the chemical stability of bamboo, while X-ray diffraction (XRD) analysis indicated an increase in crystallinity at higher moisture contents. Overall, the study demonstrates that microwave-compression treatment can optimize the mechanical properties and dimensional stability of bamboo, particularly with moderate moisture contents. The results show that microwave-compression treatment can improve the structural performance of bamboo, especially under low-humidity conditions.

Wood chips that are used as a fuel for biomass boiler houses in Latvia are mainly obtained from logging, therefore, their quality and content are very variable. In addition to wood, wood chips may contain sawdust, bark, fir needles, sand, and soil. The quality of wood chips is determined by its composition. For the best biomass boiler efficiency, the fuel moisture is determined not to exceed 50% and ash content not to exceed 5%. In practice wood chip composition analysis shows that the moisture content varies from 25% to 58%, while the content of ash varies from 2.5% to 5.2%. High moisture content in wood chips decreases the fuel net calorific value more than high ash content. It should be noted that higher ash content and moisture increase the boiler house operating costs, because the efficiency decreases that can result as an increase of the heat energy trade price. Using a flue gas condenser, there is a possibility to recover some heat losses caused by leaving water vapor in the flue gas, but anyway, the moisture decreases the efficiency of burning. The heat production efficiency of 3.1 MW wood chip boiler used for centralized district heating and hot water producing is determined using existing statistics data and measurements and evaluated taking into account the boiler operating capacity, produced heat energy, amount of wood chips used for firing and fuel quality parameters, such as moisture and ash content, calorific value. The influence of the wood chip composition on the boiler house efficiency is studied. The boiler house operation was monitored since 16th November 2020 till 21st January 2021. The monitored period was divided in 5 shorter periods to be able to compare the heat generation system efficiency under the influence of various wood chip parameters. The results showed that the specific boiler house efficiency was the lowest (70%) in the period, when the ash content of the fuel was high (average 5.30%), the moisture level was low (average 24.30%). The highest efficiency (94%) was identified, when the average ash content was 3.2% and the average moisture content 47.68%.

Study of corn kernel breakage susceptibility as a function of its moisture content by using a laboratory grinding method

Molecular dynamics study of pressure effect on glass formation and the crystallization in liquid CuNi alloy

Mechanical properties and thermal and structural changes of poly(vinyl chloride) (PVC)/wood sawdust composites were assessed with respect to the effect of moisture content, varying from 0.33 to 3.00 % by weight in the composite, for three different wood sawdust contents. The swell ratio and texture characteristics of the composite extrudates were also evaluated. Unique explanations were given to describe changes in the composite properties in terms of molecular interactions between PVC, cellulosic sawdust and moisture, such as dipole–dipole interactions, interfacial defects and bonding, fibre swelling, and moisture evaporation. The results suggest that at low moisture content the tensile modulus decreased and elongation at break of the composites increased with moisture content, the effect being reversed for high moisture content. Tensile strength decreased with increasing moisture content up to 1–2 %, and then unexpectedly increased at higher moisture contents. The effect of moisture content on flexural properties of the composite was similar to that on tensile properties. Impact strength of the composites was considerably improved with moisture content at low sawdust contents (16.7 wt%), and was independent of the moisture content at higher sawdust contents (28.6 and 37.5 wt%). A decrease in decomposition temperature with an increase in polyene content was evidenced with increasing moisture content, while the glass transition temperature did not change with varying moisture content. The extrudate swell ratio increased with the shear rate but remained unaffected by moisture content. The bubbling and peeling‐off in the composite extrudate occurred as a result of the evaporation of water molecules and the application of a high shear rate. Copyright © 2004 Society of Chemical Industry

Orange-fleshed sweet potato (OFSP) is a bio-fortified sweet potato with a high beta-carotene content. OFSP deteriorates rapidly due to its high moisture content. Conventional air drying is one of the most common methods employed but has the disadvantage of low rates of moisture removal, hence the longer drying time, which affects the quality of the final product. Pretreatments prevent quality deterioration and hasten the drying rate. This study investigated the effects of different pretreatments on thin-layer drying kinetics and the quality of OFSP slices. Three-mm-thick OFSP slices were pretreated using three different pretreatments: lemon juice, salt solution, and hot water blanching (HWB). Pretreated slices were dried in a solar dryer. Data collection (weight, temperature, relative humidity, and solar radiation) was done at 1-hour intervals. Four mathematical models (Page, Logarithmic, Modified Page, and Henderson and Pabis) were fitted to the experimental data. Also, the quality parameters of vitamin A and rehydration were investigated. The dryer inside temperatures and relative humidity ranged from 26.93–44.53 oC and 36.87%–65.30%, respectively. The moisture content of fresh OFSP slices for both treated and untreated samples was found to be in the range of 291.55–302.24% (dry basis, db), which reduced to 25.25–35.25% (db) after drying. The drying time ranged between 11 and 13 hours. The page model was found to be the best model for untreated samples, with R2 of 0.9948, RMSE of 0.0151, and χ2 of 0.0097, while the logarithmic model best described the drying behaviour of all the pretreated samples because it had the highest values of R2 and the lowest values of RMSE and χ2. Lemon juice-pretreated samples had the best quality parameters (vitamin A retention and rehydration ratio). A maximum rehydration ratio of 1.6765 was obtained for samples pretreated with lemon juice, and a minimum rehydration ratio of 1.1390 was obtained from HWB-pretreted samples. The results, therefore, indicate that lemon juice can be used as a pretreatment for thin-layer drying of OFSP slices. Pretreatments help minimise postharvest losses associated with OFSP, thus contributing to solving food and nutrition insecurity challenges.

Stingless bee honey from Heterotrigona itama exhibits a high moisture content (>27.0%) and therefore, is highly susceptible to undesirable microbial fermentation unless it is reduced to less than 20%. This study aims to reduce the moisture content of honey using a novel method based on passive diffusion and monitor the subsequent changes in several properties of honey. To achieve this, approximately 50 mL of freshly harvested honey samples was placed in clay pots (4 cm diameter × 6 cm height), covered with lids, and stored at temperatures of either 25 ± 1°C, 60% relative humidity (RH), or 35 ± 1°C, 25% RH. The results showed that the moisture content and Aw of honey after storage were significantly reduced (p ≤ .05) from 25.8 to 19.5% and from 0.79 to 0.70, respectively. A similar level of reduction was achieved at 25°C, although this process took 21 days and resulted in some losses of honey solids due to cross‐wall diffusion. The reduction in moisture content also resulted in a decrease in pH and free acidity of honey and an increase in viscosity. The data obtained in this study indicate the feasibility of using clay pots as an alternative method to reduce the moisture content in honey and protect it against fermentative deterioration.Practical ApplicationsStingless bee honey is highly popular in Malaysia and many other countries as it is high in carbohydrates and possesses many health benefits such as antioxidants and antimicrobial properties. However, the honey is susceptible to fermentation as its moisture content often exceeds the level required for microbial stability. Traditionally, the moisture content of stingless bee honey is reduced by drying the honey in shallow trays at elevated temperatures. However, this leads to contamination if the drying is performed under unhygienic conditions. Therefore, this study proposed the application of a passive diffusion method that serves as an effective alternative for moisture reduction in honey. It is anticipated that this method will not only reduce the moisture content but also retain most of its properties when the filtration process is performed under appropriate conditions.