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In this research paper, thin-layer convective drying characteristics for Jamun (Indian Blackberry) slices were analyzed at 50 to 80°C air drying temperatures with an interval of 10°C and an air velocity of 0.5 m/s. During the drying investigation, it was found that it occurred only in a range of falling periods of drying. With drying air temperature increment, the duration of drying was significantly reduced. Moisture removal took place from initially at 83.68 (% wb) to finally around 2.88 (% wb) in the tray dryer. The experimental observations were verified with various drying models of thin-layer. By nonlinear regression analysis, the selected drying model parameters were determined. Between the experimental and estimated moisture ratios, the selected drying models were examined with the help of r-squared (r2), Mean Absolute Percentage Error (MAPE), Chi-square (χ2) and Root Mean Squared Deviations (RMSD). As a result, it was found that the Page model was fitted satisfactorily at 50 and 60°C air drying temperatures while the model developed by Midilli et al was fitted satisfactorily at 70 and 80°C air drying temperatures to characterize Jamun slices with convective drying curves. The effective diffusion of water and activation energy values were estimated as 2.79–7.71×10−9 m2/min and 30.82 kJ/mol respectively for Jamun slices. [ABSTRACT FROM AUTHOR]

Increasing global waste generation is not only a threat but also an opportunity to address energy insecurity and pollution using green valorization techniques. However, this requires pretreatment of waste and byproducts and optimization of drying to obtain high‐quality biofuels. Hence, this study aims to analyze the performance of currently used drying models, the influence of different drying temperatures, drying time, and seed pretreatment on the drying kinetics of two varieties of mango seed. Accordingly, whole seeds and crushed seeds were exposed to five drying temperatures (313–353 K) in a heating furnace. Weight loss was recorded systematically, converted into moisture ratio, and then fitted to four semitheoretical mathematical models, namely: (i) Lewis, (ii) Henderson and Pabis, (iii) Page, and (iv) Avhad and Marchetti models. The fitness of these models was compared using statistical parameters, such as R2, X2, root mean square error (RMSE), mean bias error (MBE), and mean absolute error (MAE). The results showed that seed pretreatment and increasing the drying temperature led to an increase in the rate of moisture evaporation and reduced the time required for drying. Among all models, the Avhad and Marchetti model provided higher R2 values of 0.9994 and 0.9991 for local and hybrid mango at 313 K, and 0.9977, and 0.9970 for local and hybrid crushed mango seeds at 353 K and 313 K, respectively; hence, it showed the best performance. The activation energy (Ea) showed a slight differences for both varieties of mango seed and among pretreatments in all mathematical models. The mean Ea values for local and hybrid mango seeds were 41.18 kJ mol−1 and 46.21 kJ mol−1, respectively. For whole and crushed local and hybrid mango varieties, the mean Ea values were 31.37 kJ mol−1, 40.80 kJ mol−1, 50.99 kJ mol−1, and 51.61 kJ mol−1. The likely reason for this variation might be differences in variety, chemical composition, growing conditions, and cellular structure of the seed varieties. [ABSTRACT FROM AUTHOR]

Determination of the drying properties of agricultural products holds several benefits, such as nutrient preservation, processing and storage. The effect of air temperature on the drying properties and kinetics of bushbuck leaves at 30, 40, 50, 60 and 70 °C temperature was investigated. The drying time declined as the temperature rose, indicating a falling rate drying phenomenon. Drying models such as Henderson and Pabis, Newton, Modified Page, Page, Midilli and others, Logarithmic, and Two-term were applied and fitted to the experimental data's moisture ratio. The non-linear regression fitting method results showed that the Midilli and other models gave the best-fit description for the drying process. The values obtained for the coefficient of determination (R2) were observed to have varied from 0.9948 to 0.9995 for the various drying models evaluated. In contrast, the sum of square error (SSE) and root mean square (RMSE) estimate was observed to vary from 0.0056 to 0.0007 and 0.0310 to 0.0163, respectively. On the estimate for the effective moisture diffusivity (Deff), it was observed that it depends on temperature and extends from 1.33×10−9 to 4.83×10−9 m2/s. The value of the activation energy was 26.05 kJ/mol. From this study, it can be deduced that the Arrhenius model could predict the temperature effect on the drying process of bushbuck leaves.

ABSTRACTIn this investigation, the drying of Stevia rebaudiana leaves was carried out in a lab scale convective hot-air dryer at a varying temperature of 30–80°C to analyze the drying behavior, fit mathematical, Artificial Neural Networks (ANNs), and Adaptive Neuro-Fuzzy System (ANFIS) models to predict the drying kinetics of leaves. Further, dried leaf powders were analyzed for color properties, ascorbic acid and total phenol contents, antioxidant activity, water activity (aw), water solubility index (WSI), hygroscopicity (HG), density (bulk, tapped, and particle), bulk porosity, and flowability indices (Hausner ratio (HR), Carr index (CI), and angle of repose (α)). The results showed that ANFIS model with R2 of 0.9998, offers a more accurate forecast of the drying kinetics of leaves dried in a convective hot-air dryer in comparison to mathematical and ANN modeling. The convective drying significantly (p

By using ultrasonic synergy vacuum far‐infrared drying (US‐VFID), the effects of different conditions on the drying kinetics, functional properties, and microstructure of Codonopsis pilosula slices were studied. The sparrow search algorithm (SSA) was used to optimize the back‐propagation (BP) neural network to predict the moisture ratio during drying. With the increase of ultrasonic frequency, power and radiation temperature, the drying time of C. pilosula was shortened. The drying time of US‐VFID was 25% shorter than VFID, when radiation temperature was 50°C, ultrasonic power was 48 W, and frequency was 28 kHz. The SSA‐BP neural network, the average absolute error prediction was 0.0067. Compared with hot air drying (HAD), the total phenolic content and antioxidant activity of C. pilosula by US‐VFID were increased by 29.47% and 8.67%, respectively, and a reduction in color contrast of 16.19%. The dilation and generation of microcapillary of C. pilosula were more obvious. The study revealed US‐VFID could be used for the selection and process control of agro‐processing methods for C. pilosula products. [ABSTRACT FROM AUTHOR]

Refractance window drying (RWD) is a preferred drying technique due to its suitability for heat-sensitive products. Although this drying technique appears promising, it is yet largely unexplored. In this study, the authors provide a review of the existing milestones on RWD using a sample of 40 articles from 2000 to date to quantify the state of investigations across multiple studies and establish specific areas needing further attention. Results show that experimental analyses constitute about 53–59 % of the reported cases, followed by a literature review 24–28 %. Furthermore, 17 % of the total study cases was observed across all modelling categories, with machine learning (ML) techniques constituting only about 8 %. Driven by the outcome, this study thus utilized three ML techniques to model the moisture ratio (MR) of 1.5–4.5 mm thick yam slices, operated over the range of 65–95 °C temperature in an RWD chamber. Unlike the routine procedures, the yam thickness versus air temperature effects on moisture ratio were investigated to determine the more significant factor as well as the air velocity effect or its lack thereof on MR. To investigate the validity window for the entire dataset, all data points were considered, with a training-testing ratio of 7:3 used in each case. For scenario one, prediction based on the yam thickness effect showed a greater influence on the MR. The air velocities at 0.5–1.5 m/s had little effect on MR as compared to the case where air velocity was ignored (i.e., the control case in this study). Also, model accuracy for all tested samples has been determined to be better than 93 %. Insight from this study is to guide in the future design of RW dryers for direct measurement of the moisture ratio of harvested root tubers at various conditions. [ABSTRACT FROM AUTHOR]

To assess the effects of a two‐step temperature method (TTM) on dehydration parameters, color deterioration of dried samples, and specific energy consumption (SEC), spearmint leaves were dried using infrared (IR) undergoing the TTM. Moreover, 14 mathematical models were compared based on the adjusted correlation coefficient, reduced chi‐square, and root mean square error to estimate drying curves. Changes in the color of the dried product at two‐step temperatures of 70to60°C, 60to50°C, and 50to40°C led to decreases of 2.69,.81, and 3.34 compared to fixed temperatures of 70, 60, and 50°C, respectively. On the other hand, the specific energy consumption (SEC) increased by 5.43, 10.92, and 22 MJ.g−1 H2O at 70to60°C, 60to50°C, and 50to40°C compared to 70, 60, and 50°C, respectively. To interpret the results from another point of view, three basic objectives of shortening drying time, reducing energy consumption, and raising the quality of the dried product are achieved in the TTM. For instance, the drying time and energy consumption are reduced at a two‐step temperature of 70to60°C compared to the fixed temperature of 60°C, along with a decrease in the color change compared to the fixed temperature of 70°C. The results indicated that Midilli et al. model resulted in the best fitness in explaining the IR drying behavior of spearmint leaves. Practical applications: During the falling rate period in drying process and especially at higher temperatures and powers, there is a potential for a decrease in the quality of the dried product, and even the risk of thermal runaway due to excessive temperature increase. Certainly, at lower powers and temperatures, the quality of the dried product can be enhanced. However, in this situation, the duration of the process and the energy consumed, which are two crucial factors in the drying process, increase, leading to financial losses for the producer. In the two‐step temperature method (TTM), due to the temperature reduction during the critical period of falling rate, the quality of the dried product improves by considering the processing time and energy consumption. [ABSTRACT FROM AUTHOR]

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Drying is a universal method applied for food preservation. To date, several models have been developed to evaluate drying kinetics. In this study, lychee was dried employing a hot air dryer, and the drying kinetics was evaluated by comparing the Newtonian model, Henderson and Pabis model, Page model, and Logarithmic model. However, temperature and relative humidity, the key driving forces for drying kinetics, are not considered by these models. Thus, an integrated drying model, as a function of temperature and relative humidity, was developed to predict the hot air-drying kinetics and mass transfer phenomena of lychee followed by the calibration and validation of the model with independent experimental datasets. The model validation consisted of Nash- Sutcliffe model coefficient (E), coefficient of determination (R2) and index of agreement (d) and all of them were found close to 1 indicating perfect model fit. Besides, the developed model was applied for process optimization and scenario analysis. The drying rate constant was found as a function of temperature and relative humidity that was high at high temperature and low relative humidity. Interestingly, temperature showed a higher effect on the drying rate constant compared to relative humidity. Overall, the present study will open a new window to developing further drying model of lychee to optimize quality its quality parameters.

ABSTRACTIn this study, grape juice was concentrated through a microwave vacuum-assisted technique. The concentrate was prepared at different powers (30, 50, 80 W) and vacuum pressures (35, 50, 70 kPa) for different time intervals to optimize the processing conditions. The highest evaporation rate (5.32 g/100 g min) and the lowest moisture ratio (0.18) were observed at a higher level of microwave power (80 W) and vacuum pressure (70 kPa). Moreover, different mechanistic models were used to predict the values of the moisture ratio. Among them, the Midilli (R2 = 0.999, SSE = 1.970 × 10−8, RPD = 0.012%) model best fits the experimental values. The effective diffusivity (1.69 × 10−14 m2/s), activation energy (1.56 W/kg), and extraction yield (69.30%) possessed maximum values at 80 W and 70 KPa. While concentrate had exhibited higher antioxidant activities (77.2%) than fresh juice (25.28%) at 30 W. Overall results indicated that the microwave-vacuum technique had significantly reduced the processing time and energy requirement.

This investigation was performed on the drying modelling of white sapote slices that were influenced by drying methods and pre-drying treatments. The experimentation was performed by two factors: drying techniques and pre-drying treatments. The drying techniques included oven-, solar- and open sun-driers, whereas the pre-drying pretreatments were blanching, sodium metabisulfite, sodium-chloride and control. Behaviours of the drying were plotted with the moisture ratio vs time of drying, moisture content (% db) vs time of drying, and drying rate (g of water/100 g dm/hr) versus drying time (t). At the commencement of the drying progression, the drying rate was increased steadily and reduced through the advancement of drying model parameters a and n (empirical constants) and k (drying rate constant) were determined. Their combinations were optimised to suit the requirements of the minimal value of the sum of square deviation on the expected data values (model values). The models were evaluated with the regression coefficient (R2) and chi-square (χ2), resulting in values of 0.95–0.99 and 0.000132 to 0.00511, respectively. Henderson and Pabis's model demonstrated the highest coefficient R2 values (0.99) for oven-dried drying techniques. Also, the Page model gave the highest R2 value (0.99) for sodium metabisulphite pretreatments. It can be concluded that the Henderson and Pabis model is best suited for oven drying among the drying techniques. In contrast, the Page model best fits sodium metabisulphite among the pre-drying treatments. Hence, Henderson and Pabis, and Page models might describe the drying characteristics of the white sapote fruit slices based on respective drying methods and pre-drying treatments.

An experimental analysis of the drying behaviour of gooseberry slices dried in the open sun is described in this article. Gooseberries brought from the local market were cut approximately semi-circular in cross-section, with an average length of 20–25 mm and a thickness of 3–5 mm. Using the hot air dryer method, the moisture content (MC) of gooseberry slices in their initial condition was estimated to be 87.81% wet-basis. The drying data revealed a steady reduction in MC with time, indicating the lack of a consistent rate drying phase. To fit the drying data, ten mathematical models were used. The selected models were analysed using a multi-regression methodology in an Excel-solver equation. The optimal drying model was chosen based on the values of the coefficient of determination (R2), reduced chi-square (χ2) and root mean square error (RMSE). The logarithmic model was chosen as the best drying model for open sun drying of gooseberry slices as it had the highest R2 (0.99758980) and the lowest values of χ2 (0.00017191) and RMSE (0.01255328) of all the models tested. Multi-regression analysis resulted in the development of a thin layer drying equation that can be used to forecast moisture ratio (MR) at a specific drying period. The estimated value of effective diffusivity was found to be within its value for various agro-products.

Low-temperature drying (withering) is the first stage in black tea processing. Determination of appropriate end moisture content of green tea leaf as well as temperature and relative humidity (RH) maintained during withering eventually aid the final quality of the processed tea. Therefore, the tea leaf withering (partial drying) properties were evaluated in an environmental chamber using mathematical models. The temperatures and RH considered were 25, 30, 35 °C and 80, 85, 90%, respectively. A total of nine combinations of temperature and RH were considered by keeping one parameter constant. The conditions were taken adhering to that of the climatic conditions of Assam, India. The withering data from experiments were fitted into five drying models using the curve fitting method. The Page model gave better predictions with an R2 value of 0.9989 at 30 °C temperature and 90% RH. The total phenolic and flavonoid contents of the tea leaf samples were evaluated. The best results were 50.60 ± 0.02 mg GAE.g-1 (GAE - gallic acid equivalent) and 22.47 ± 0.01 mg QCE.g-1 (QCE - quercetin equivalent) at 30 °C withering temperature.

The delightful pungency, aromatic compounds and phytochemicals in some spices make them indispensable in local food systems and native medicine, hence, driving a robust market in many parts of the world. The understanding of their drying characteristics is very important for processing and adding value, and a thin layer drying study is a proven method for achieving this. In this study, changes in the moisture content, moisture ratio, drying rate and effective diffusivity of alligator peppers, ginger and turmeric were investigated at three drying temperatures 50, 60, and 70 °C following standard procedures. Five models were proposed to simulate the drying process. Non-linear regression was used to establish the coefficient of determination (R2), sum of square error (SSE) and root mean square error (RMSE) for each model to determine the model of the best fit. The Page model gave the best fit for ginger while the logarithmic model was best fitted for alligator peppers and turmeric. The effective diffusivity ranged from 1.79-3.08 × 10-9, 8.44-9.74 × 10-9, and 4.06-6.49 × 10-9 m2.s-1 for alligator peppers, ginger and turmeric, respectively. The activation energy ranged from 16.5-22 kJ.mol-1.K-1 for the three spices. These findings promise improvement in the drying, processing and handling of spices, thereby boosting the obtainable income from the value chain.

The drying process reduces the moisture of the pineapple resulting in a decrease in the humidity ratio to inhibit microbial growth and the enzyme level for spoilage prevention. Therefore, it is significant to understand the drying kinetics to control the process efficiently. This study developed the moisture ratio equation. The thin hollow cylinder of pineapple pieces was prepared for drying. The crossflow dehydrator was fabricated. It could adjust the airflow speeds and temperatures. The separation of variables was the method to solve the moisture transport equation of a pineapple piece for obtaining the moisture ratio. The moisture ratio equation fitted with experimental data with an average coefficient of determination (R2) varying from 0.91 to 0.99 presented various diffusion coefficients. Therefore, the diffusion coefficient function depended on both air temperature and Reynolds number was obtained. When substituting it into the moisture ratio equation, the novel moisture ratio function depended on the airflow velocity, temperature, drying time, and pineapple piece geometry was proposed with R2 of 0.97. In addition, various diffusion coefficients were fitted with Arrhenius's equation by linear regression. Therefore, the novel energy activation, which varied by Reynolds number, was proposed. It had an R2 of 0.9981. All proposed empirical models are unique guidance tools to improve drying efficiency, minimize energy consumption, and minimize postharvest losses in the future.

Low-temperature drying (withering) is the first stage in black tea processing. Determination of appropriate end moisture content of green tea leaf as well as temperature and relative humidity (RH) maintained during withering eventually aid the final quality of the processed tea. Therefore, the tea leaf withering (partial drying) properties were evaluated in an environmental chamber using mathematical models. The temperatures and RH considered were 25, 30, 35 °C and 80, 85, 90%, respectively. A total of nine combinations of temperature and RH were considered by keeping one parameter constant. The conditions were taken adhering to that of the climatic conditions of Assam, India. The withering data from experiments were fitted into five drying models using the curve fitting method. The Page model gave better predictions with an R² value of 0.9989 at 30 °C temperature and 90% RH. The total phenolic and flavonoid contents of the tea leaf samples were evaluated. The best results were 50.60 ± 0.02 mg GAE·g-1 (GAE - gallic acid equivalent) and 22.47 ± 0.01 mg QCE·g-1 (QCE - quercetin equivalent) at 30 °C withering temperature. [ABSTRACT FROM AUTHOR]

Background. Asparagus root (Asparagus officinalis L.) is one of the herbaceous by-products with potential for making value-added products because of its excellent nutritional properties and flavor/fragrance. In order to maintain its quality, drying is suggested as a suitable technique for this purpose. Several drying methods were set up to investigate and select the one which had a high reliability of drying parameters and could be widely applied in the processing of dried vegetable products. Materials and methods. Thin-layer drying at six temperature degrees (40°C, 50°C, 60°C, 70°C, 80°C, and 90°C), solar system, and sun drying were investigated to study the kinetics of moisture ratio change in asparagus roots. Eight common drying kinetic models (Haghi and Angiz II, Henderson Pabis, Logarithmic, Newton, Page, Parobolic, Peleg, and Wang and Singh) were applied to choose the most fitting. The moisture diffusion efficiency and activation energy were determined by Fick's diffusion equation. Results. Rising drying temperature accelerated the drying speed, and the Page model was indicated as the best fit for the experimental data among the remaining drying models. The moisture diffusivity values varied from 9.11 x 10-12 to 1.27 x 10-11 m²/s for the thin-layer drying method and 1.2 x 10-11 and 9.55 x 10-11 m²/s for the solar system and sun drying models, respectively. The efficiency of moisture diffusivity depended on investigating drying models, which was described using the Arrhenius's equation with an activation energy of 30.91 kJ/mol. Conclusion. The page model is the most suitable for describing the drying process of asparagus, with high reliability between the experimental data and estimated data from this model when drying asparagus at 70°C (R²= 0.9996). [ABSTRACT FROM AUTHOR]

The study was carried out to optimize the drying conditions of shrimp in the hot air‐assisted microwave drying system using response surface methodology. The drying experiments were performed using a Box–Behnken design with air temperature (50–70°C), air velocity (.5–1.5 m/s), and microwave power level (600–1000 W) as independent variables and drying time, water activity, and rehydration ratio as independent variables. The obtained response variables were fitted into the various regression equations to predict a suitable model. The methodology of desired function was applied to indicate 61.74°C air temperature, 922.61 W microwave power, and 1.0 m/s air velocity which offered a reduced drying time of 2.8 h, the water activity of.424 and improved rehydration ratio of 2.51, respectively with a desirability value of.949. The moisture content, drying efficiency, shrinkage, and total color change were determined for the samples obtained under optimized conditions and were observed as 16.5% (w.b), 35.71%, 14.14%, and 16.95 ± 2.14, respectively. Scanning electron microscopy analysis of dried shrimp showed the formation of pores of diameters ranging from 3.17 to 10.6 μm. The process parameters optimized under the study for hot air‐assisted microwave drying can be used for the production of good‐quality dried shrimps. Practical applications: Generally, fish and fish products are dried in the open sun or solar dryers in most developing countries. The traditional methods offer the least process controls with maximum energy and manpower demand to meet the ever‐growing industry requirements with increased awareness of the safety and quality of the dried products. The hot air‐assisted microwave (HAMW) drying system developed under the study could have complete control over the process parameters without compromising the quality of the dried product. The study suggests the HAMW drying system as a potential means of drying technique for large‐scale commercial production of dried shrimps. [ABSTRACT FROM AUTHOR]

This work presents the study of the moisture ratio and carotenoid compounds in dried mamey (Pouteria sapota) using non-invasive spectroscopic techniques. The drying behavior of mamey at 64 °C by a homemade solar dryer is analyzed by fitting the experimental data to four different mathematical drying models. In addition, this result is compared with other drying techniques, namely by heat chamber with natural convection at temperatures of 50 °C and 60 °C. The results show that the Lewis model is the one that best fits the experimental moisture ratio curve of mamey. On the other hand, Near-Infrared and Terahertz spectroscopic techniques are used to estimate the moisture ratio, since water absorption is most sensitive at these frequencies. Fourier Transform Infrared-attenuated total reflectance and Raman spectroscopy are performed to detect the carotenoid compounds in dried mamey. This compound has important applications in the food industry and health benefits. To our knowledge, there are few studies on the dehydration of Pouteria sapota as well as its characterization using spectroscopic techniques for the detection of moisture ratio and carotenoid content; therefore, this study can be useful in agriculture and food sectors when detailed information about the cited parameters is needed. [ABSTRACT FROM AUTHOR]

The physicochemical properties and color of dried seed mucilage (gums) depend on the condition and method of drying. So, in this study, the effects of infrared (IR) dryer system parameters such as IR power (150, 250, and 375 W), distance of mucilage from lamp surface (4, 8, and 12 cm), mucilage thickness (0.5, 1.0, and 1.5 cm) on drying kinetics and color indexes (L*a*b*) of basil seed mucilage (BSM) were examined in an IR dryer system. IR drying kinetic of BSM was modeled using mathematical approach. Thus, experimental moisture ratio data were fitted to 8 various empirical models. It was found that Page model has the best fit to show the kinetic behavior and acceptably described the IR drying behavior of BSM with the highest correlation coefficient values and the lowest standard error values. The average effective moisture diffusivity (Deff) increased from 1.69 × 10−9 to 9.21 × 10−9 m2/s with increasing lamp power from 150 W to 375 W, while it was decreased from 7.93 × 10−9 to 2.65 × 10−9 m2/s and 7.81 × 10−9 to 1.82 × 10−9 m2/s with increasing the distance of mucilage from 4 to 12 cm and the reduction of mucilage thickness from 1.5 to 0.5 cm, respectively. The increasing in IR radiation power has a positive influence on the lightness (increasing L* index) of dried BSM and it reduced color changes index (ΔE) from 13.04 to 11.51. The results showed that IR drying method has great industrial potential in saving processing time as well as energy with better maintenance of color and quality of dried BSM.

Wheatgrass is a valuable source of nutrients and phytochemicals with therapeutic properties. However, its shorter life span makes it unavailable for use. So, storage-stable products must be developed through processing in order to enhance its availability. Drying is a very important part of the processing of wheatgrass. Thus, in this study, the effect of fluidized bed drying on the proximate, antioxidant, and functional properties of wheatgrass was investigated. The wheatgrass was dried in a fluidized bed drier at different temperatures (50, 55, 60, 65, 70 °C) using a constant air velocity of 1 m/s. With increasing temperature, the moisture content was reduced at a faster rate, and all drying processes took place during the falling rate period. Eight mathematical models under thin layer drying were fitted into the moisture data and were evaluated. The Page model was the most effective in explaining the drying kinetics of wheatgrass, followed by the Logarithmic model. The R2, chi-square, and root mean squared value for Page model was 0.995465–0.999292, 0.000136–0.0002, and 0.013215–0.015058, respectively. The range of effective moisture diffusivity was 1.23–2.81 × 10−10 m2/s, and the activation energy was 34.53 kJ/mol. There was no significant difference in the proximate composition of was seen at different temperatures. The total phenolic content (117.16 ± 0.41–128.53 ± 0.55 mgGAE/g), antioxidant activity (33.56 ± 0.08–37.48 ± 0.08% (DPPH), and FRAP (1.372 ± 0.001–1.617 ± 0.001 mgAAE/g) increased with the rise in temperature. A significant increase was observed in functional properties, except for the rehydration ratio, which decreased with rising temperature. The current study suggests that fluidized bed drying improves the nutritional retention of wheatgrass with good antioxidant activity and functional properties that can be used to make functional foods. [ABSTRACT FROM AUTHOR]

Drying kinetics of lemon fruits undergoing microwave-drying was investigated, furthermore, mathematical drying models were statistically analyzed to simulate drying kinetics fitted to the obtained experimental moisture ratio results. The investigation was conducted under three levels of microwave power of 550, 770 and 1100 W. The variations in lemon moisture content (M.C.) were recorded versus time until reaching to 14.28%, 12.99% and 11.73% d.b. and 14.15%, 11.60% and 12.86% d.b. for whole fruit without and with 1% NaOH pretreatment, respectively, at previously power levels, respectively. Meanwhile, for slices, the M.C. (at the same previously power levels, respectively) reached (12.86%, 14.15% and 15.47% d.b.), (16.82%, 12.86%, and 14.15% d.b.) and (12.86%, 14.15%, and 15.47% d.b.) for thicknesses of 4, 5 and 6 mm, respectively. The whole lemon fruit with preated-1% NaOH recorded highest percentages of: total crude fats (1.782%), total soluble sugar (6.88%), citric acid (6.62%) and ascorbic acid (46.05 mg/100g) compared to other treatments. [ABSTRACT FROM AUTHOR]

In this investigation, the drying of Stevia rebaudiana leaves was carried out in a lab scale convective hot-air dryer at a varying temperature of 30–80°C to analyze the drying behavior, fit mathematical, Artificial Neural Networks (ANNs), and Adaptive Neuro-Fuzzy System (ANFIS) models to predict the drying kinetics of leaves. Further, dried leaf powders were analyzed for color properties, ascorbic acid and total phenol contents, antioxidant activity, water activity (aw), water solubility index (WSI), hygroscopicity (HG), density (bulk, tapped, and particle), bulk porosity, and flowability indices (Hausner ratio (HR), Carr index (CI), and angle of repose (α)). The results showed that ANFIS model with R2 of 0.9998, offers a more accurate forecast of the drying kinetics of leaves dried in a convective hot-air dryer in comparison to mathematical and ANN modeling. The convective drying significantly (p <.05) effected the L*, a*, b*, hue angle and chroma values of dried leaves. Increase in the drying temperature from 30 to 80°C resulted in a decrement of 50.90% in aw, 10.10% in tapped density, while enhancement of 23.26% in WSI, 32.93% in HG, 54% in particle density, and 10.59% in bulk porosity of dried leaf powder. Notably, ascorbic acid and antioxidant activity decreased with rising temperatures, while total phenols enhanced up to 50°C. The bulk density of dried samples remained largely unchanged with increasing temperature, while the flowability of the Stevia powder improved. Thus, these findings provide valuable insights for producers regarding the drying characteristics and properties of Stevia leaf powder. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the drying kinetics of capers at different temperatures and to examine the morphological changes of capers during the drying and rehydration processes. Computer‐aided image processing and Artificial Neural Network models (ANN) were used to analyze the shrinkage and moisture ratio of capers (drying) and the expansion of capers (rehydration). Lewis, Page, Fick's law, and logarithmic models were investigated to describe the conventional drying kinetics of capers at 50, 60, and 70°C; the logarithmic model was shown to be the best describing model (r2: 0.9996, 0.9996 and 0.9981, respectively). Effective diffusivities varied between 1.91 × 10−10 and 2.62 × 10−10 m2/s for the temperature range. The activation energy was 14.572 kJ/mol. Image processing revealed that diameter reduction rates were 1 × 10−4 mm/s for 50 and 70°C and 7 × 10−5 mm/s for 60°C. ANN was applied using multilayer perceptron models with three layers (input: ANN1, hidden: ANN2, and output: ANN3) which were sufficiently valid for predicting the experimental parameters (r2: 0.9992, 0.9915, and 0.8484, respectively). All morphological properties were reduced with drying, and shrinkage of capers was increased proportionally with the moisture content. The Global Sensitivity Analysis recognized treatment time as the most influential parameter affecting the moisture ratio and the caper diameter changes. Practical applications: One of the major problems for humans has been to improve food preservation techniques for long‐term storage. The major scope of industry is the drying of fruits and/or vegetables to produce dried foods with high quality and a long shelf life. To the best of our knowledge, drying of capers regarding the drying kinetics, modeling and quality changes has not been published to date. In this study, goal was to better understand drying kinetics and geometric changes that occur to capers during the dehydration and rehydration processes at various drying temperatures. Quantitative information regarding geometrical changes to capers was supplied by the image processing of the acquired pictures, which enabled rapid monitoring of physical changes during dehydration and rehydration. The remarked kinetic model, ANN model, and Quantitative information regarding geometrical changes are valuable information for researchers studying on drying of food and large‐scale dryer designers. [ABSTRACT FROM AUTHOR]

Researchers have carried out the kinetics of various agro products for open sun drying, but research articles still need to address such analysis for cotton seeds. Open sun drying of cotton seeds has been experimentally investigated and presented in this paper. Shorting of cotton seeds was carried out to collect appropriate samples in current research work. Cotton seeds were found to have a nearly ovoid shape with an average radius of 2 to 2.5 mm. The initial moisture content of cotton seeds was estimated to be 14.65% wet-basis using the hot air oven method. During drying, the reduction in the mass of cotton seeds was measured at every one-hour time interval. From this data, it was observed that drying occurred with a falling rate period. Drying data were fitted with 10 mathematical models available in the literature. Multi-regression analysis in Excel-solver equation was performed to obtain values of constants and coefficients of these models. Coefficient of determination (R2), reduced chi-square (χ2) and root mean square error were taken as criteria for the selection of the best drying model. The diffusion approach and models by Verma et al. were chosen as the most suitable drying models for open sun drying of cotton seeds. Effective diffusivity was estimated and found within the range suggested in the literature. [ABSTRACT FROM AUTHOR]

The delightful pungency, aromatic compounds and phytochemicals in some spices make them indispensable in local food systems and native medicine, hence, driving a robust market in many parts of the world. The understanding of their drying characteristics is very important for processing and adding value, and a thin layer drying study is a proven method for achieving this. In this study, changes in the moisture content, moisture ratio, drying rate and effective diffusivity of alligator peppers, ginger and turmeric were investigated at three drying temperatures 50, 60, and 70 °C following standard procedures. Five models were proposed to simulate the drying process. Non-linear regression was used to establish the coefficient of determination (R²), sum of square error (SSE) and root mean square error (RMSE) for each model to determine the model of the best fit. The Page model gave the best fit for ginger while the logarithmic model was best fitted for alligator peppers and turmeric. The effective diffusivity ranged from 1.79–3.08 × 10–9, 8.44–9.74 × 10–9, and 4.06–6.49 × 10–9 m² ·s–1 for alligator peppers, ginger and turmeric, respectively. The activation energy ranged from 16.5–22 kJ·mol–1·K–1 for the three spices. These findings promise improvement in the drying, processing and handling of spices, thereby boosting the obtainable income from the value chain. [ABSTRACT FROM AUTHOR]

In this study, grape juice was concentrated through a microwave vacuum-assisted technique. The concentrate was prepared at different powers (30, 50, 80 W) and vacuum pressures (35, 50, 70 kPa) for different time intervals to optimize the processing conditions. The highest evaporation rate (5.32 g/100 g min) and the lowest moisture ratio (0.18) were observed at a higher level of microwave power (80 W) and vacuum pressure (70 kPa). Moreover, different mechanistic models were used to predict the values of the moisture ratio. Among them, the Midilli (R2 = 0.999, SSE = 1.970 × 10−8, RPD = 0.012%) model best fits the experimental values. The effective diffusivity (1.69 × 10−14 m2/s), activation energy (1.56 W/kg), and extraction yield (69.30%) possessed maximum values at 80 W and 70 KPa. While concentrate had exhibited higher antioxidant activities (77.2%) than fresh juice (25.28%) at 30 W. Overall results indicated that the microwave-vacuum technique had significantly reduced the processing time and energy requirement. [ABSTRACT FROM AUTHOR]

In this study, the effects of infrared (IR) dryer system parameters such as IR power, the distance of mucilage from lamp surface, mucilage thickness on drying kinetics and, color indexes (L*, a*, b* and ΔE) of wild sage seed mucilage (WSSM) were investigated in an IR dryer system. Experimental moisture ratio (MR) data were fitted to 7 various empirical thin-layer models. It was found that the Page model has the best fit to show the kinetic behavior and acceptably described the IR drying behavior of WSSM with the lowest mean square error (MSE), root mean square error (RMSE), mean absolute error (MAE), and standard error (SE) values and the highest correlation coefficient (r) value. The values of MSE, RMSE, and MAE for all experiments were in the range of 0.1×10-3-1.1×10-3, 1.04×10-2-3.25×10-2 and 8.7×10-3-27.1×10-3, respectively. The average effective moisture diffusivity (Deff) increased from 4.61×10-9 m2s-1 to 15.8×10-9 m2s-1 with increasing lamp power from 150 W to 375 W, while it was decreased from 14.4×10-9 m2s-1 to 5.16×10-9 m2s-1 and 13.2×10-9 m2s-1 to 4.31×10-9 m2s-1 with increasing the distance of mucilage from 4 to 12 cm and the reduction of mucilage thickness from 1.5 to 0.5 cm, respectively. Increasing in IR radiation power has a positive influence on the yellowness (increasing 19.78% in b* index) of dried WSSM. Also, it increased the color changes index (ΔE) from 16.05 to 17.59.

This study was conducted to investigate the effect of acetylation on equilibrium moisture content (EMC) of Nigerian-grown rubberwood and its effect on colour change in exposure of rubberwood to surface degradation through accelerated weathering. The samples were modified to two levels of acetylation, which yielded weight percent gain (WPG) of 7 % and 10 % after 8hr (8-hr Acetyl) and 48hr of acetylation (48-hr Acetyl), respectively. Accelerated weathering of unmodified (Ref) and acetylated wood was done using QUV-Accelerated Weathering Tester for four weeks. The unmodified and acetylated samples (weathered and unweathered) were oven-dried and conditioned in climate rooms at different relative humidity of 50 %, 65 % and 95 %, with samples being moved to each room after 14 days. Results showed that acetylation led to a significant decrease in equilibrium moisture content of rubberwood. After weathering, there was a decrease in EMC of rubberwood due to removal of hemicelluloses alongside the degraded lignin, and a slight increase in EMC of the acetylated wood. In terms of colour change, photo-bleaching of the acetylated samples was higher (10.46 for 48-hr Acetyl) after four weeks of weathering compared to the unmodified samples (6.43). Hence, the outcome of this study has shown that, although acetylation is effective in minimizing moisture ingress into wood, it resulted in photo-bleaching of the weathered samples. Additional surface coating is recommended to serve as a protective layer, preventing partial washing out of the acetyl groups, minimize photo-bleaching during weathering and prolong the aesthetic value of the wood especially in outdoor applications such as wall cladding and façade.

Sun‐drying has proven to be the most sustainable technique for preserving food and agricultural products. However, conventional sun‐drying has limited drying capacity and can lead to significant losses in product quality. Greenhouse and indirect solar drying are advanced drying methods with improved product quality. In this article, the natural convection greenhouse dryer and natural convection indirect solar dryer were developed to study date palm fruits' drying characteristics (Phoenix dactylifera L.) in terms of moisture ratio and convective heat transfer coefficients. At the same time, the thermal performance of drying units was examined in terms of energy efficiency. The greenhouse dryer's higher convective heat transfer coefficient reduced drying time, and the indirect solar dryer's energy efficiency was obtained. The experimental data were fitted in various drying models, of which the Lewis model was found to be best fitted. The experimental errors were analyzed in terms of percent uncertainties. The drying costs of dried date palm fruits under greenhouse dryer and indirect solar dryer were found to be INR ₹ 22.37/kg (US$ 0.30/kg) and INR ₹ 30.14/kg (US$ 0.40/kg), respectively. Drying units could be a sustainable way of product drying, particularly in the rural areas where advanced drying mechanisms are still unavailable (1 USD = 74.8 INR as on 03 Feb, 2022). [ABSTRACT FROM AUTHOR]

Introduction: Drying of agricultural products is one of the main ways to prevent product spoilage. There are several methods to dry agricultural products, including direct sunlight, hot, sunny weather, microwave, vacuum, and freezer which use different energy sources. Due to constrain of fossil fuels supply, the price of this type of energy is increasing thus the tendency to use renewable energies is increasing (Purohit and Kandapal, 2005; Purohit et al., 2006). In Iran the drying efficiency of solar dryers is low because less solar energy is converted into thermal energy. Therefore, many measures have been taken to increase the efficiency of solar collectors which causes to obtain the dried samples with better quality and lower cost. In this study a combination of tracking system and phase change materials (PCM) are used to increase the efficiency of solar dryer cabinet with three types of collectors including flat plat (FPC), parabolic trough (PTSC) and evacuated tube (ETSC) collectors. Materials and Methods: The dryers used in this study include a cabinet connected to a flat plat, parabolic trough and evacuated tube collectors. In all of the dryers, PCM have been used to maximize solar energy utilization. Moreover to get the maximum solar radiation the tracking system used in FPC and PTSC and a storage tank with fluid pump used in PTSC and ETSC. The air flow rate inside the system was about 0.018 kg.s-1 for all the experiments. The experiments were performed in three continues days from 16 to 18 June 2018, from 8:00 to 24:00. Tomato sample with a thickness of 9 mm was considered for drying process. To describe the drying process of the samples, the moisture ratio versus time was considered. Also, the drying efficiency was defined considering the ratio of energy (thermal and mechanical) consumed to heat the product and extract moisture from the product (Qm) to the total energy used for drying process, including fluid thermal energy (Qf) and mechanical energy (Emec) (Fudholi et al., 2014). In order to evaluate the quality of the dried product at different modes, three quality parameters including color difference, shrinkage and rehydration ratio were considered. Color difference between the fresh and dried samples was evaluated as one of the most important factors that the customer was considered for selection (Magdic et al., 2009). The change in the volume of the dried product compared to the fresh product is defined as shrinkage. Moreover, to evaluate the rehydration ratio the weight of water absorbed by the samples was considered. Results and Discussion: The effect of variations of the intensity of solar radiation on the amount of solar energy taken by the collectors was negligible. The time required to dry tomato slices by the dryer equipped with FPC was longer than the other systems. The results also showed that the highest drying efficiency is related to the dryer with ETSC and it was about 39.02%. The least value is related to the dryer with FPC and it was about 30.12%. Due to the long drying time the use of the fan and the pump increase and the amount of energy consumed to drying the product increases as well. Thus the efficiency of the dryer with FPC decreases. The values of specific energy for the dryer with FPC, PTSC and ETSC were obtained as 7.12, 7.92 and 8.34 MJ/kg, respectively. The results of qualitative evaluation of dried tomato slices showed that the product obtained from the dryer equipped with ETSC, due to the short drying time, the color changes and the shrinkage was suitable in comparison with the other reports. The amount of rehydration ration was the highest as well. Using PCM had no adverse effect on the quality of the dried samples. The results showed that the dryer with ETSC had higher efficiency (about 39.02%) and the quality of the samples was suitable compared to other systems. Using recycling system can improve the thermal efficiency of the solar dryer.

• Drying time reduction of 32–38% achieved. • Microbial quality of dried Bombay duck was within the acceptable limit. • Drying efficiency of 40.67% and collector efficiency of 33.7% obtained. • Energy efficient technology for large sacale drying of Bombay duck. This work investigated the kinetics, modelling and quality of Bombay duck (Harpodon nehereus) dried in the solar-LPG hybrid dryer. The moisture content of the Bombay duck was lowered from 86.4 ± 0.52% to 16.4 ± 0.67% (w.b) within 11 h. The reduction in weight of Bombay duck samples during drying was measured at 1 h interval. LPG backup maintained the desirable drying conditions in the dryer. The drying process was observed to occur under the falling rate period. Effective moisture diffusivity during drying of Bombay duck was determined to be 3.7 × 10 -10 m2/s. Drying parameters were fitted into thin layer drying models. The Page model was a suitable fit for the data under study (R2 = 0.9986, RMSE = 0.01268 and χ2 = 0.000134). The maximum drying and collector efficiency recorded for Bombay duck drying in solar-LPG dryer was 40.67% and 33.7%, respectively. The rehydration ratio and shrinkage of dried Bombay duck were found to be 1.94 and 26.42% respectively. Microbial analysis of dried fish was within the safe limits. Benefit-cost ratio, payback period, NPW, annuity and IRR were also determined to check the economic feasibility of the study. [ABSTRACT FROM AUTHOR]

In this study, the combined infrared-hot air dryer develops and optimize in Agricultural Engineering laboratory, faculty of agriculture, Tanta University, Egypt. Thin-layer modelling of sweet potato slices drying under infrared (IR) and hot-air drying (HAD) were used to estimate the drying coefficients. The initial moisture content of the freshly harvested sweet potato was 79 - 81 % (w. b.). Three different levels of sweet potato slices thickness (1, 3, 5 mm), were pre-treated by dipping into a solution of 0.5 % sodium meta-bisulphite and 1% citric acid for 30 min. Four different levels of infrared radiation (0.861, 0.973, 1.039 and 1.161 kW.m-2) and three different levels of airdrying temperature (45,55 and 65°C) with a constant air velocity of 1.2 m. s-1 were using. The experimental measurements included sweet potatoes slices moisture content, air temperature, radiation intensity, and quality changes of the dried sweet potato. Three different thin layer drying models (Lewis's model and Henderson & Pabis's and Logarithmic model) were examined for describing the changes of moisture content during the drying process. The results show that, the Coefficient of determination R² and Standard error, SE. for The Logarithmic model recorded R²= 0. 99 and SE= 0.122 were considered more proper for describing the drying kinetics and predicting the changes in moisture content of sweet potatoes more than the Henderson and Pabis's were model recorded R²= 0.94 and SE= 0.51 and Lewis's model were recorded R²= 0.96and SE = 0.241. The results show that, the moisture ratio of sample slices decreased when the radiation intensity and the drying air temperature increased. Meanwhile, the drying constant of Logarithmic model (kLog) increased with the increasing of radiation intensity and air-drying temperature and the decreasing of slice thickness. The diameter and thickness shrinkage percentage occurred with all treatments, while slightly increasing with infrared radiation. The rehydration ratio ranged from 3.95 to 5.53. [ABSTRACT FROM AUTHOR]

Copyright of Shipin Kexue/ Food Science is the property of Food Science Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Whole and halved strawberries were dried by using three methods, which were solar tunnel drying, shade drying, and microwave drying (180W, 540W, and 900W) to determine drying characteristic and modelling. The researchers measured solar irradiation at ambient and drying air temperatures and air velocity at specific intervals in various parts of the dryer. How microwave drying (180, 540, and 900 W) affected the drying time and drying ratio of the whole and halved strawberry samples was investigated. In addition, the data on the drying process were applied to 5 different mathematical models, which were Weibull distribution, Midilli et al., Jena and Das and Aghbashlo et al. Equation Models. The researchers compared the performance levels of the models according to correlation coefficient (R2), chi-square value (x2), besides the root mean square error (RMSE) between moisture ratios that were observed and predicted. Furthermore, the Weibull Distribution and Midilli et al. models were found to reveal the ratio of drying in a satisfactory way for all the methods of drying.

Wheatgrass is a valuable source of nutrients and phytochemicals with therapeutic properties. However, its shorter life span makes it unavailable for use. So, storage-stable products must be developed through processing in order to enhance its availability. Drying is a very important part of the processing of wheatgrass. Thus, in this study, the effect of fluidized bed drying on the proximate, antioxidant, and functional properties of wheatgrass was investigated. The wheatgrass was dried in a fluidized bed drier at different temperatures (50, 55, 60, 65, 70 °C) using a constant air velocity of 1 m/s. With increasing temperature, the moisture content was reduced at a faster rate, and all drying processes took place during the falling rate period. Eight mathematical models under thin layer drying were fitted into the moisture data and were evaluated. The Page model was the most effective in explaining the drying kinetics of wheatgrass, followed by the Logarithmic model. The R2, chi-square, and root mean squared value for Page model was 0.995465–0.999292, 0.000136–0.0002, and 0.013215–0.015058, respectively. The range of effective moisture diffusivity was 1.23–2.81 × 10−10 m2/s, and the activation energy was 34.53 kJ/mol. There was no significant difference in the proximate composition of was seen at different temperatures. The total phenolic content (117.16 ± 0.41–128.53 ± 0.55 mgGAE/g), antioxidant activity (33.56 ± 0.08–37.48 ± 0.08% (DPPH), and FRAP (1.372 ± 0.001–1.617 ± 0.001 mgAAE/g) increased with the rise in temperature. A significant increase was observed in functional properties, except for the rehydration ratio, which decreased with rising temperature. The current study suggests that fluidized bed drying improves the nutritional retention of wheatgrass with good antioxidant activity and functional properties that can be used to make functional foods.

In this novel article, a comparative study has been conducted between analytical and fractional solution of Fick’s first- and second-order of diffusion to model the solar drying process of different products and dryers under different operating parameters. Laplace and Laplace’s inverse transform have been used to obtain the solution in function with two parameters: the order index n and the fractional time index α of the above Fick’s laws, and their parameters have been non-linearly optimised using a grey wolf optimisation (GWO) algorithm. The results showed that the anomalous diffusion phenomenon during the drying process is best described by the fractional‐order model. Values obtained using the model MR12 were in better agreement with the experimental data than the values obtained using the other selected models with very acceptable statistical parameters.

A laboratory experiments were carried out to study and modeling the effect of soil gypsum content on soil shrinkage characteristic curve (SSCC) of gypsiferous shrinkage curve. Soil samples with 100 (G2), 150 (G3), 200 (G4), 250 (G5), 350(G6) g kg-1 gypsum content were prepared by mixing materials from surface soil layer with low gypsum content (G1) 60.6 g kg-1 and sub-surface soil layer with high gypsum content (G7) 433.9 g kg-1. SSCC was measured for each soil sample at the moisture tension of 0,3,6,15,33,100,500,700,1000 and 1500 kPa, the results indicated that SSCC of the studied gypsiferous soils (G1–G7) included only three shrinkage stages. The proportional shrinkage stage formed the bulk part of the SSCC which ranged between 46–84 % for the gypsiferous soils samples G1–G6, the residual shrinkage stage was less than proportional shrinkage stage of the SSCC and ranged between 11–49 % for the gypsiferous soils samples G1–G6, and Zero shrinkage in all samples of gypsum soils. The results showed a significant agreement between the measured and predicated SSCC values calculated. The coefficient of determination ranged between 0.9961 and 0.988 for all studied gypsiferous soils.

In this study, the effects of infrared (IR) dryer system parameters such as IR power, the distance of mucilage from lamp surface, mucilage thickness on drying kinetics and, color indexes (L*, a*, b* and ΔE) of wild sage seed mucilage (WSSM) were investigated in an IR dryer system. Experimental moisture ratio (MR) data were fitted to 7 various empirical thin-layer models. It was found that the Page model has the best fit to show the kinetic behavior and acceptably described the IR drying behavior of WSSM with the lowest mean square error (MSE), root mean square error (RMSE), mean absolute error (MAE), and standard error (SE) values and the highest correlation coefficient (r) value. The values of MSE, RMSE, and MAE for all experiments were in the range of 0.1×10-3 -1.1×10-3, 1.04×10-2 -3.25×10-2 and 8.7×10-3 -27.1×10-3, respectively. The average effective moisture diffusivity (Deff) increased from 4.61×10-9 m 2 s -1 to 15.8×10-9 m ² s -1 with increasing lamp power from 150 W to 375 W, while it was decreased from 14.4×10-9 m 2 s -1 to 5.16×10-9 m 2 s -1 and 13.2×10-9 m ² s -1 to 4.31×10- 9 m ² s -1 with increasing the distance of mucilage from 4 to 12 cm and the reduction of mucilage thickness from 1.5 to 0.5 cm, respectively. Increasing in IR radiation power has a positive influence on the yellowness (increasing 19.78% in b* index) of dried WSSM. Also, it increased the color changes index (ΔE) from 16.05 to 17.59. [ABSTRACT FROM AUTHOR]

Copyright of Wood Industry / Drvna Industrija is the property of Drvna Industrija and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Previous research has shown that the accumulated temperature can describe drying processes as well as crop growth. To describe the mass and heat transfer processes in the rice drying process more accurately, a mathematical model of rice drying was proposed based on the drying accumulated temperature, and the optimal tempering ratio for conventional hot air drying was obtained through data comparison and analysis. First, it was proven that there was an exponential relationship between the moisture ratio and the drying accumulated temperature of rice. Second, by comparing and analyzing the fitting results of seven different drying mathematical models, the model with the highest fitting degree was selected and reconstructed to obtain the drying accumulated temperature–moisture ratio model. Finally, the new model was used to fit the results of two drying experiments without and with tempering, and the tempering characteristics of rice drying were proved by comparing and analyzing the coefficient difference between the two models. The results showed that the optimal tempering ratio was 3. This study thus provides a reference for rice drying process parameters. [ABSTRACT FROM AUTHOR]

Experiments were carried out to assess the utilization of infrared radiation for drying and sterilizing tomato slices using an infrared dryer. To fulfill the objective of this research work, some operating parameters affecting the performance of the infrared dryer were taken into consideration: Three different levels of infrared intensity (0.973, 1.093, and 1.161 kW/m² ), three different inlet air temperatures (40, 50 and 60°C) and three different tomato slices thicknesses (3, 5 and 7mm). The experimental work included the use of the simple exponential model (Lewis's 1921) for describing the drying behavior and predicting the changes in moisture content of tomato slices during the drying process. Evaluation of the infrared dryer was carried out taking into consideration tomato slices moisture ratio and final dried tomato slices quality. The obtained data reveal that the final dried tomato slices quality in terms of ascorbic acid, total phenolic content, lycopene pigment and antioxidant activity were in the optimum region with the use of the infrared dryer under conditions of 0.973 kW/m² radiation intensity, 50 0C air temperature and 5 mm tomato slices thickness. The findings illustrated that the investigated model (Lewis's 1921) could describe the drying behavior of tomato slices satisfactory. [ABSTRACT FROM AUTHOR]