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Drying is an effective way to solve corn mildew. The heat and humidity flow interface in COMSOL Multiphysics heat transfer module was used to coupling fluid flow, water transport and heat transfer in multiple physical fields, and corn was used as a porous medium for simulation analysis, aiming to find the change rules of temperature field and humidity field. The research shows that the multi‐component model and method should be given priority in practice. The higher the hot air temperature is, the higher the average temperature of corn kernels is, and the faster the relative humidity decreases. The drying rate of corn is the highest at 348 K, and the hot air temperature should be appropriately increased at 333 K denaturation temperature. The higher the wind speed, the better the drying effect of corn kernels, but the improvement of drying effect will decrease with the increase of wind speed. Appropriately increase the wind speed between 2 and 4 m/s to improve the drying efficiency while avoiding excessive energy consumption. The mass transfer resistance of the pericarp cannot be ignored. The drying time of corn kernels closer to the hot air entrance is shorter, and the corn kernels close to the hot air exit are prone to humidity accumulation. Multiple hot air intakes should be set up to reduce the occurrence of uneven drying. Practical applications: Corn is prone to mildew after harvest, resulting in resource waste and economic loss, so it is of great significance to dry corn efficiently. Corn is a typical porous medium, and the research on it can provide the basis for drying other porous medium grains. According to different components, the model of single granule and multi‐granule was established respectively. Use COMSOL Multiphysics simulation software to gain a deeper understanding of the complex physical processes involved in the drying process and provide valuable insights for industrial applications. COMSOL software was used to study the drying condition of corn under the synergic action of multiple physical fields, and effective drying strategies and measures to improve the structure of air drying silo were put forward. [ABSTRACT FROM AUTHOR]

Accurate prediction of outgoing moisture content is the key to achieving energy-saving and efficient technological transformation of drying. This study relies on a grain drying simulation experiment system which combined counter and current drying sections to design corn kernel drying experiments. This study obtains 18 kinds of temperature and humidity variables during the drying process and uses Uninformative Variable Elimination (UVE) method to screen sensitive variables affecting the outgoing moisture content. Subsequently, six prediction models for the outgoing corn moisture content were developed, innovatively incorporating Multiple Linear Regression (MLR), Extreme Learning Machine (ELM), and Long Short-Term Memory (LSTM). The results show that eight sensitive variables have been screened to predict the moisture content of outgoing corn. The sensitive variables effectively reduced the redundancy and multicollinearity of data in the MLR model and improved the coefficient of determination (R2) of ELM and LSTM models by 0.02 and 0.05. The MLR prediction model established based on the full set of temperature and humidity data has an R2 of 0.910 and a root-mean-square error (RMSE) of 0.881%, while the UVE-ELM and UVE-LSTM prediction models achieve a better fitting effect and prediction accuracy. The UVE-LSTM model is set with a batch size of 30, a learning rate of 0.01, and 100 iterations. For the training set of UVE-LSTM, the R2 value is 0.931 and the RMSE value is 0.711%. The UVE-ELM model, with sigmoid as the activation function and 14 neurons configured, runs fast and has the best prediction accuracy. The R2 values of UVE-ELM training set and validation set are 0.943 and 0.946, respectively, and the RMSEs are 0.544% and 0.581%. The models proposed in this study provide data reference and technical support for process optimization and automation control of the corn drying process. [ABSTRACT FROM AUTHOR]

Accurate prediction of outgoing moisture content is the key to achieving energy-saving and efficient technological transformation of drying. This study relies on a grain drying simulation experiment system which combined counter and current drying sections to design corn kernel drying experiments. This study obtains 18 kinds of temperature and humidity variables during the drying process and uses Uninformative Variable Elimination (UVE) method to screen sensitive variables affecting the outgoing moisture content. Subsequently, six prediction models for the outgoing corn moisture content were developed, innovatively incorporating Multiple Linear Regression (MLR), Extreme Learning Machine (ELM), and Long Short-Term Memory (LSTM). The results show that eight sensitive variables have been screened to predict the moisture content of outgoing corn. The sensitive variables effectively reduced the redundancy and multicollinearity of data in the MLR model and improved the coefficient of determination (R2) of ELM and LSTM models by 0.02 and 0.05. The MLR prediction model established based on the full set of temperature and humidity data has an R2 of 0.910 and a root-mean-square error (RMSE) of 0.881%, while the UVE-ELM and UVE-LSTM prediction models achieve a better fitting effect and prediction accuracy. The UVE-LSTM model is set with a batch size of 30, a learning rate of 0.01, and 100 iterations. For the training set of UVE-LSTM, the R2 value is 0.931 and the RMSE value is 0.711%. The UVE-ELM model, with sigmoid as the activation function and 14 neurons configured, runs fast and has the best prediction accuracy. The R2 values of UVE-ELM training set and validation set are 0.943 and 0.946, respectively, and the RMSEs are 0.544% and 0.581%. The models proposed in this study provide data reference and technical support for process optimization and automation control of the corn drying process.

Copyright of Journal of Shenyang Agricultural University is the property of Journal of Shenyang Agricultural University 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.)

Moisture sensors are used for real-time measurement of the moisture content of seeds in modern grain dryers. The electrical properties of grains are dependent on moisture content, density, temperature and structure of materials and also on the frequency of the applied electric field. In the study, a laboratory scale dryer integrated with capacitive sensor has been developed and modeled for shelled corn. The dielectric properties of shelled corn with different moisture content have been measured to find optimal working frequency. Modeling based on the relationship between the moisture content and electrical properties of corn have been done. Changes of moisture content affect the dielectric constant of the grain, which in turn makes variation in capacitance. The dielectric properties of corn have been measured at 1 MHz frequency value. The dielectric properties of corn have been characterized using the curve fitting technique. Corn drying experiments have been carried out in the laboratory scale test installation. Model accuracy has been verified by comparison with the results of drying tests. [ABSTRACT FROM AUTHOR]

This paper presents a hybrid solar dryer with baffles disposed of on the solar collector. When the levels of solar radiation are low, an electrical heater is used to increase the drying air temperature. A photovoltaic system feeds the electrical heater and the fans, and it is also used to preheat the drying air, increasing the temperature at the inlet of the solar collector. Experimental results of corn drying indicated that the baffles augmented the energy efficiency of the system (from 23.5 to 24.9%) and the temperature rise in the solar collector (from 13.5 to 20.2 °C), reducing the time required for the corn to reach the final desired moisture content. [ABSTRACT FROM AUTHOR]

Drying and storage methods are fundamental for maintaining the grain quality until processing. Therefore, the aim of this study was to evaluate the associations of the drying temperature with storage systems and conditions as a strategy for preserving the quality of maize grain postharvest on laboratory and field scales. An increase in temperature accelerated the reduction in grain moisture, but increased the deterioration. The wetting during the storage period reduced the grain quality. Hermetic and aerated storage systems maintained the chemical quality of the grains. The control with healthy and whole corn dried at 80 °C and stored in silos with natural aeration provided a satisfactory quality, equivalent to those of controlled drying and storage under airtight conditions and at low temperatures. Different conditions of drying and storage of corn on the laboratory and field scales were evaluated, which provides an appropriate management of these operations to maintain the grain quality. [ABSTRACT FROM AUTHOR]

The main objective of this investigation was carried out to study the ability of utilizing greenhouse solar dryers for drying of corn in order to obtain the best quality of dried grains for using it as seeds with the least drying time, and comparing with the natural sun drying method. Thus, contributing to increase the productivity. Corn cv. (Giza 168) was used for the experimental work at initial moisture content of 31.73% on dry basis (d.b). Two different drying methods of corn were tested for drying of ear and shelled corn. The two methods were natural sun drying and solar drying using greenhouse type solar dryers at different air velocities (0.5, 1.0 and 1.5 m/s). The experiments were carried out in rice mechanization center at Meet El- Dyba, Kafr El-Sheikh Governorate, Egypt during September 2016. Experiment included the flowing variables Two different drying methods (Solar drying method using greenhouse type solar dryer and natural sun drying method). Two different conditions of corn (complete ear-shelled corn). Three different air velocity (0.5, 1.0 and 1.5 m/s). High moisture ear and shelled corn was dried by using solar energy for heating air inside a greenhouse and compared with natural sun drying method. The results of quality tests that included standard germination test, vigor test and tetrazolium test for both drying methods for ear and shelled corn recorded high percentages for all treatments except solar drying of ear corn at air velocities 0.5 and 1.0 m/s. The average air temperature inside the solar dryer at air velocities 0.5 and 1.0 m/s reached to 43.9 and 42.4 ˚C respectively. High temperatures killed the germ of corn so the quality tests were reduced. Germination percentage of natural sun dried ear corn was 97 % and for solar dried samples at air velocities 0.5, 1.0 and 1.5 m/s was 79, 81, and 89%, respectively. The corresponding values for shelled corn were 93, 97 and 98 %.and 95 % for natural sun dried ones. The vigor test of dried ear corn recorded 90 for natural sun drying method and 34, 45, and 66% for solar drying at air velocities of 0.5, 1.0 and 1.5 m/s, respectively. The corresponding values for shelled corn were 86, 96 and 97% respectively, and 82 for natural sun dried samples. The recorded drying times were 26, 24 and 28 hours to reduce the moisture content from an initial level of 31.73 to final level of 14.07% (d.b.) for ear corn and for shelled corn were 20, 16 and 24 hours to reduce the moisture content from an initial level of an initial level of 31.73 to final level of 14.07% (d.b.) for ear corn and for shelled corn were 20, 16 and 24 hours to reduce the moisture content from an initial level of 27.23% to 14.12% compared with 46 and 38 hours for ear and shelled corn dried by natural sun drying method. Hourly costs of ear corn drying were 0.95, 0.88, 1.00 and 1.03 L.E/ kg for solar drying at air velocities 0.5, 1.0 , 1.5m/s and natural sun drying respectively. The corresponding values for shelled corn were 0.74, 0.58, 0.89 and 0.96 L.E/ kg.

• Energetic and exergetic analysis of the dryer system are investigated. • The proposed solar dryer is sustainable, since it only uses solar energy. • The most significant input exergy rate is due to the absorber plate. • Three control volumes were used to evaluate the exergetic efficiency. • Thermal and exergetic efficiency are greatly affected by the control volume used. In this study, an energy and exergy analysis of the drying process of corn was developed for a hybrid dryer coupled with a PV system. The differential of the dryer is the fact that the PV system was used to feed an electrical heater and fans and also to preheat the drying air through the use of the PV panel rear side as heat exchanger, increasing the air temperature before the inlet of the solar collector. The performance of solar drying processes is extensively investigated in the literature, but usually the drying chamber is used as control volume in the analysis. The main contribution of this work is the assessment and comparison of the performance of the dryer using three different control volumes in the thermodynamic analysis: only the drying chamber, the drying chamber and the solar collector, referred to as solar dryer and the complete drying set, corresponding to the drying chamber, the solar collector and the PV module. The results indicated that the efficiency values found are greatly affected by the control volume used, with variations of the exergy efficiency ranging from 22.2% to 45.0%, depending on the control volume used. It was found that the higher efficiencies were found selecting the drying chamber as control volume (as usually chosen by most works from literature). For the complete drying set, the individual contributions of the exergy rates were evaluated. It was concluded that the main contribution to the input and output exergy are the heat transfer and the outflow exergy rates, respectively. [ABSTRACT FROM AUTHOR]

Uncontrollable ambient conditions are the main factors limiting the self-adaption control of an industrial drying system. To achieve the goal of accurate control of the drying process, the influence of the ambient conditions on the drying behavior should be taken into consideration when modeling the drying process. Present work introduced an industrial drying system with a loading capacity of 50 t, two artificial neural network prediction models with (IANN) and without (OANN) considering the ambient conditions were established using artificial neural network modeling approach. The ambient conditions on the moisture content (MC), exergy efficiency of the heat exchanger (ηex,h) and specific recovered radiant energy (Er) of the drying process were also investigated. The results showed that the ηex,h and Er increase with the increase of ambient temperature while the drying time decrease with the increase of the ambient temperature. The IANN model has a better prediction performance that that of OANN model. An optimal architecture of 9-2-12-3 artificial neuron network model was developed and the best prediction performance of the artificial neural network (ANN) model were found at a training epoch number of 30, and a momentum coefficient of 0.4, where the coefficient of determination of moisture content, exergy efficiency of heat exchanger, and the specific recovered radiant energy, respectively are 0.998, 0.992, and 0.980, indicating that the model has an excellent prediction performance and can be used in engineering practice. [ABSTRACT FROM AUTHOR]

Popcorn consumption is becoming increasingly attractive, and the effects of post-harvest operations are essential for the improvement of industrial processes. In this context, the objective of this study was to evaluate the effects of drying temperature on the morphology, technological, and digestibility properties from the isolated starch from red popcorn grains. Red popcorn grains were dried in oven-drying (30 °C) and fixed-bed dryer at 40, 70, and 100 °C. The morphology properties of grains and starch, the technological and digestibility properties of the starch, were evaluated. The drying temperature of 100 °C reduces the extraction yield by 13.14%, changes the internal structure of the popcorn grains and the native morphology of the starch granules, increases the pasting temperature and the gelatinization enthalpy, and reduces digestibility compared to drying temperature of 40 °C, which is more indicated due to reduced drying time. • The drying temperature of the red popcorn was studied in a fixed-bed dryer. • Drying at 100 °C promotes a compacted grain structure and reduces starch extraction. • Starch thermal resistance increases the pasting temperature. • Highest drying time restricted the access of enzymes and reduces the digestibility. • Drying at 40 °C is the best drying condition used. [ABSTRACT FROM AUTHOR]

To keep up with the increasing demand for grain, proper drying and storage of grain is critical. Increasing the efficiency of these systems has been investigated, but there has been very little focus on the phenomena that occur inside a wet bin. This research investigated the influence of mixing and diffusion on the moisture content of maize as it leaves the wet bin. To determine the effect of mixing and diffusion of maize on moisture contents as it exits the wet bin, moisture content was established and dye and diffusion tests were conducted. The results of showed that the mixing and diffusion of the each load directly affect the moisture content in the unload increments. The moisture content profile was divided into four sections. Section I, the unload increments 1–3 are primarily load A only; Section II, unload increments 4–6 are primarily mixing of only load A and B with increasing of load B effect; Section III, Unload increments 7–11 are primarily mixing of only load B and C with increasing of load C effect; Section IV, unload increments 12–13 is affected by funnel flow and load B in a stagnation zone near the wall boundary slightly increases. Highlights • Mixing and diffusion of loads directly affects moisture content in unload stages. • Fully segregated profile and fully homogenous profiles are not accurate models. • Moisture content profile can be divided into four sections. • Dye test shows mixing effect is factor which determines moisture content profiles. [ABSTRACT FROM AUTHOR]

Highlights • Dry grind process was modified to achieve in-situ fiber conversion. • Addition of 30 FPU/g fiber cellulase increased ethanol yield of dry grind process. • Excess cellulase addition decreased ethanol yield compared to conventional process. Abstract Conversion of corn fiber to ethanol in the dry grind process could increase ethanol yields, reduce downstream processing costs and improve overall process profitability. This work investigates the in-situ conversion of corn fiber into ethanol (cellulase addition during simultaneous saccharification and fermentation) during dry grind process. Addition of 30 FPU/g fiber cellulase resulted in 4.6% increase in ethanol yield compared to the conventional process. Use of excess cellulase (120 FPU/g fiber) resulted in incomplete fermentation and lower ethanol yield compared to the conventional process. Multiple factors including high concentrations of ethanol and phenolic compounds were responsible for yeast stress and incomplete fermentation in excess cellulase experiments. [ABSTRACT FROM AUTHOR]

Uncontrollable ambient conditions are the main factors limiting the self-adaption control of an industrial drying system. To achieve the goal of accurate control of the drying process, the influence of the ambient conditions on the drying behavior should be taken into consideration when modeling the drying process. Present work introduced an industrial drying system with a loading capacity of 50 t, two artificial neural network prediction models with (IANN) and without (OANN) considering the ambient conditions were established using artificial neural network modeling approach. The ambient conditions on the moisture content (MC), exergy efficiency of the heat exchanger (ηex,h) and specific recovered radiant energy (Er) of the drying process were also investigated. The results showed that the ηex,h and Er increase with the increase of ambient temperature while the drying time decrease with the increase of the ambient temperature. The IANN model has a better prediction performance that that of OANN model. An optimal architecture of 9-2-12-3 artificial neuron network model was developed and the best prediction performance of the artificial neural network (ANN) model were found at a training epoch number of 30, and a momentum coefficient of 0.4, where the coefficient of determination of moisture content, exergy efficiency of heat exchanger, and the specific recovered radiant energy, respectively are 0.998, 0.992, and 0.980, indicating that the model has an excellent prediction performance and can be used in engineering practice.

Browning of KX7349 maize during drying occurred mainly in the pericarp layer. Browning was caused by oxidation of water soluble matter in the pericarp layer. Moisture content had no significant influence on browning rate. Drying temperature, drying time and drying method (vacuum drying or hot-air drying) had significant influence on the browning rate. Through lab research, a prediction model for the relationship between browning rate and drying air temperature was developed. Total drying time is y=- 13.086+0.289X1+1.045X2, where y is the browning rate(%), X1 is drying temperature(°C), X2 is total drying time(h), the value range of X1 was 30~80, the value range of X2 was 2~10. The concurrent and counter current dryer was applied in Nenjiang to optimize the drying process. The hot air temperature in each drying stage was reduced. When the hot air temperature of the 1st, 2d, 3rd drying stage was reduced to 95°C,75°C,60°C respectively, the browning rate was reduced to 15%~16%. Keeping the hot air temperature constant at each drying stage, by drying twice, the browning rate was reduced to 4%~6%. [ABSTRACT FROM AUTHOR]

Though several maize varieties have been developed and introduced over the years in Ghana, farmers still face challenges of access to quality seed maize. Among the major constraints is lack of proper drying systems to quarantee quality of seed produced. Peculiar to most parts of Africa, drying of maize in the open, on bare ground along shoulders of roads is still a common practice in Ghana. In this study, a 5-tonne capacity solar biomass hybrid dryer was developed for drying maize for seed and food/feed in Ghana. Effect of drying air temperature in the dryer on the physiological quality and germination of maize kernels was investigated. Maize grains were dried in the open sun simulating farmers practice and using the dryer at 4 varying levels (L1, L2, L3 and L4) with corresponding heights (0.6m, 1.2m, 1.8m and 2.4m) respectively. Harvested maize at 22.8% moisture content was dried at the varying levels until reaching overall mean moisture content of 12.8 ± 0.2% (wb). Results showed that, drying air temperatures in the dryer increased in accordance with height with lowest mean temperature of 44.4 ± 4.6°C recorded at L1 and mean maximum of 52.8 ± 5.4 °C at L4. The increase in drying temperature at L4 increased kernel stress crack index by an average of 14% and reduced germination by 33%. However, drying temperatures at L1-L3 and in the open sun had no significant effect (p > 0.05) on the germination potential of maize grains. This satisfies the dryer's potential to be used for drying maize grains for high quality seed production on commercial scale. [ABSTRACT FROM AUTHOR]

This study investigated the potential of using the underutilized fresh maize in the preparation of porridge to contribute toward complementary feeding of children, and reductions in pre‐harvest losses. Fresh maize was harvested at different stages of maturity, blanched, smoked, and sun dried before milling into flours that were blended with soy flours for preparation of test porridges. The test flours were analyzed using the Association of the Official Analytical Chemists (AOAC) methods to determine their nutrient composition before preparation of the porridges. A trained consumer panel of 12 people, mothers and nursery school children tasted the porridges to rank acceptability and preference. Analysis of nutritional data showed that the test flours contained similar amounts of proteins, fats, and carbohydrates as the commonly used dried maize–soy flour blends. All the test porridges were generally accepted by the mothers and children due to the unique smoky and roasted aroma, brown color and the sweeter flavor even without the addition of sugar. Grainy texture and the presence of residues were the only unacceptable attributes in some of the test porridges. In conclusion, fresh maize–soy floor blends can be potentially used in complementary feeding of children at home and school as an alternative to other traditional maize flours. Optimization and fortification can help make the flours nutrient‐dense and most appropriate for child feeding at scale. This study investigated the nutritional content of fresh maize flours dried by sun and smoke drying and sensory acceptability of fresh maize –soy blends by mothers and children. Nutritionally, fresh maize flours were similar to field dried maize. Fresh maize‐Soy blends were equally accepted by mothers and children [ABSTRACT FROM AUTHOR]

The objective of the study was to investigate the influence of high power ultrasound on a laboratory-scale fluidized bed shelled corn dryer. The drying time, moisture content variation, specific energy consumption, and quality parameters including ultimate compressive strength, toughness, shrinkage and color of corn kernels were investigated. Furthermore, artificial neural network (ANN) simulation models were developed for predicting the drying variables. Machine vision techniques were used to determine color and shrinkage as qualitative indices. Results showed that the lower frequencies had better penetrations at lower temperatures and cause a significant reduction in drying time. In addition, the ultrasound application led to reduction of ultimate compressive strength and toughness of the dried samples although ultrasound has nonthermal character as the subsidiary factor, it plays an important role in shrinkage and color specification. Based on error analysis results, the prediction capability of ANN model is found to be reasonable for the developed models. Application of ultrasound significantly decreased the specific energy consumption of drying process at the optimal drying condition. [ABSTRACT FROM AUTHOR]

Unsafe moisture content at loading and the climatically uncontrolled nature of traditional storage structure (gombisa) together with ventilation dependent on wind alone, results in mycoflora growth and development on maize in the system. Therefore, this paper was aimed to develop and test a photovoltaic driven ventilation system fitted to a gombisa for natural air in-bin drying of on-cobs-maize and increase the shelf life of the stored product. A modified gombisa was constructed from locally available materials in Germany. An appropriate fan type and size, humidistat set at 70% and two 20 Wp photovoltaic panels were utilized for ventilation purpose, fan control and to power the fan, respectively. In total 1.76 m3 of on-cobs-maize with an average moisture content of 0.22 on d.b. (kg/kg) were also used for the study. Data was collected on solar irradiance, photovoltaic voltage, current, inlet duct air velocity and temperature and relative humidity inside the storage system. Similarly, moisture content of on-cobs-maize, ambient temperature and relative humidity data was also collected for both experiments. The result for the temperature and relative humidity trends revealed higher variability and fluctuation for ambient compared with inside the modified gombisa. Ventilation of on-cobs-maize for 10-12 days resulted in a reduction of moisture content (d.b.) to almost 0.14 (kg/kg) which generally is considered safe for mould growth conditions. A computational fluid dynamics simulation result revealed the uniformity of the drying of on-cobs-maize using the ventilation system fitted to the modified gombisa. Secondary data of solar irradiance obtained from Jimma area, Ethiopia compared to the current experiment show higher energy availability, demonstrating high potential to apply ventilation and drying system to the region. Storing maize inside modified gombisa plays a role in protecting the stored product from outside weather conditions. Also, monitored temperature, relative humidity and energy output showed the system was able to bring the product to safe moisture content for storage without mould development. This promising research result needs to be tested and validated in tropical regions of the world. [ABSTRACT FROM AUTHOR]

A computational fluid dynamics model was developed to simulate the corn drying process in a solar cabinet dryer. Incident solar radiation was modeled using a dual-band spectrum to simulate the absorption of shortwave radiation by corn and account for the greenhouse effect caused by glazing materials. The performance of the dryer was simulated at fair and overcast weather conditions. The model allowed visualization of temperature, humidity, and air velocity profiles in the dryer. The model was validated with experimental results, which showed an overprediction of temperature (8.5%) and humidity (21.4%). The experimental humidity profile suggests that there was stagnation in the airflow of the dryer, which was accurately predicted by the model. The model was used to simulate the dryer’s performance under overcast conditions, and the predicted moisture removal was 32% less than the simulated fair-weather case. [ABSTRACT FROM AUTHOR]

On-farm, in-bin drying of corn is weather dependent process that requires a careful selection of drying strategy in a locality to prevent reduction in the grain quality. This study simulated drying and storage of corn using different fan control methods and assessed the impact of infrared heat treatments to decontaminate corn of harmful molds spores. Fan operation considered included running the fan continuously, only at night (NANO), only during the day (NADO), at a set window of equilibrium moisture content of natural air, and when supplemented with heating of ambient air. The drying was investigated at various initial moisture contents (16 to 22%, wet basis), air flow rates (1.11 to 4.46 m3 min−1[air] t−1 [corn]) and corn harvesting start dates (August 15-November 15). To prevent aflatoxin contamination, freshly-harvested corn should be dried within 10 days to MC below 15% if prevailing relative humidity exceeds 86%. [ABSTRACT FROM AUTHOR]

Abstract: Maize drying is an important process, especially for storage and conservation. For this study, the experimental stage was carried out using a forced convection dryer with air heated at different temperature conditions (306.05–441.85 K) and flow (0.13–0.256 m3/hr), totalizing 15 drying curves. Then the performances of the classic drying kinetics methodology and the approach proposed in this paper, in which the increase in moisture content of the product with time was represented combining exponential models and neural networks based on wavelets, were compared. Good performance was obtained in predictions using the proposed approach. One of the main differentials of the methodology adopted was the obtainment of a model that has a global predictive capacity, within the range of tested operating conditions, which can be used in predicting drying curves for different operating conditions. Practical applications: The drying process is also one of the most widely used methods for preserving food, and has the advantage of reducing the costs of storage and transport because of the low volume and weight of the end product. During the last years, this topic has attracted a broad industrial interest, resulting in many research studies investigating the drying process. Usually, with regard to the classic approach for modeling of the drying process, the kinetics of drying curves obtained in different operating conditions is affected separately, that is, the parameters are estimated independently, resulting in different regression problems. With the classical approach, in general, it is not possible to obtain a comprehensive prediction model with regards to operating conditions. We have proposed an alternative modeling method. Aiming to obtain a modeling tool with an overall predictive ability, an approach for drying kinetics prediction that combines exponential models and neural networks was proposed. The proposed modeling method was able to predict drying curves for different operating conditions. [ABSTRACT FROM AUTHOR]

This study aimed at assessing the influence of corn variety, harvesting date and drying temperature on the composition and the in vitro digestion of dry matter, starch and crude protein of mature corn grain. Two corn grains varieties harvested at two different dates after physiological maturity (at two different moisture contents) were analyzed for their composition and dried in a fluidized-bed dryer between 54 and 130 °C. The corn varieties differed in their chemical composition while the harvesting date had only a significant impact (p < 0.05) on the neutral detergent fibre content. The dried samples were then submitted to a sequential in vitro pepsin-pancreatin digestion. Crude protein digestibility is influenced by corn variety and decreases when drying temperature and moisture content increase. The in vitro digestibilities of dry matter and starch increase in the same trend even if they are differently affected by the drying temperature according to the moisture content level. At higher moisture content, the increase in the in vitro digestibility of dry matter and starch follow a linear trend (R 2 > 0.97). It appears that the drying temperature, the harvesting date and the corn varieties may significantly affect the digestion of corn grain major components with possible implication on animal performance. [ABSTRACT FROM AUTHOR]

Copyright of Revista Brasileira de Engenharia Agricola e Ambiental - Agriambi is the property of Revista Brasileira de Engenharia Agricola e Ambiental 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.)

Freshly harvested corn at moisture content of 24% wet basis (w.b.) was intermittently dried with infrared (IR) at intensities 2.39, 3.78, and 5.55 kW/m2 for 30, 50, and 180 s to safe storage-moisture content of 13% (w.b). Microbial load reduction, energy use and corn sensory and pasting qualities were evaluated. Experiments were carried out at product-to-emitter gap size of 450 mm. Increasing IR intensity from 2.39 to 5.55 kW/m2 resulted in average microbial load reductions of 2.6 and 2.9 log CFU/g at 180 and 30 s of intermittent IR heating, respectively. IR treatments reduced corn paste viscosity and stress cracks ( p < .05), but insignificantly impacted corn color ( p > .05). Drying corn to storage-moisture content with IR intensities 2.39 and 5.55 kW/m2, required 7.5 and 15.0 MJ/kg of water removed, respectively. Accelerated, Scaled-up IR drying and decontamination was achieved without affecting the corn quality; optimized treatments could potentially improve throughput and energy efficiency. Practical applications Freshly harvested, high moisture content corn must be dried within short duration to about 12-14% (w. b.) to prevent mold growth and preserve the overall corn quality. This research presents the following practical applications: Scaled up infrared (IR) treatment of corn with efficacy to significantly reduce drying time (9 to 22 min depending on infrared intensity and intermittent IR drying duration to dry freshly harvested corn at moisture content 23-13% wet basis)., Capability of using intermittent IR heating to combine corn drying and decontamination in a single step while maintaining the quality of finished product., Potential of IR heating to inactivate heat resistant, mycotoxin-producing mold spores that are liable to survive conventional drying methods. [ABSTRACT FROM AUTHOR]

The drying status and quality aspects in terms of physical, nutritional, functional properties and microbial status of three common maize varieties (900M gold, pioneer 92 and kavri) dried in different drying complexes are presented in this paper. Total drying varied from18-20 h for drying of freshly harvested maize varieties in the complexes where sun drying method was used. The overall calculation reveled that drying cost in the mills ranged from US$11.5 to US$14.75 per ton of fresh maize (1 US$ equals 80 BDT). The dimensions of the maize varieties as length, width and thickness were found to be ranged from 12.62±0.34 to 14.54±0.32, 9.56±0.24 to 10.60±0.35, 6.38±0.28 to 7.3±0.41 mm, respectively. The 900M gold variety gave the highest bulk density of 575.84±3.8 kg m-3. The highest crude protein (8.75%±0.10%) and water solubility index (1.90±0.02 gm gm-1 of gel) were found in the dried samples of 900 M gold variety at 14% moisture content. The highest ash, fat and starch content were 2.01%±0.02%, 3.97%±0.09% and 76.33%±0.88%, respectively in pioneer 92 varieties at 14% moisture content. The highest microbial load was found at higher moisture dried grain (14%) than lower moisture dried samples. The quality of dried grain was found to be affected with the variation in final moisture content during storage. Therefore, maize should be dried at moisture content less than 14% to maintain quality and to keep free from microbial infestation for its future use as food and feed. [ABSTRACT FROM AUTHOR]

The effect of two process conditions (fermentation time (B) and mix ratio (A)) on the dry mixture of maize (M) and sorghum (S) powder (ogi) was investigated. Five mix ratios (1 (M50:S50), 2 (M60:S40), 3 (M70:S30), 4 (M80:S20), 5 (M90:S10)), and five fermentation times (6, 12, 18, 24 and 30 h) were considered. The drying was done at 50 °C in a convective fabricated cabinet dryer. It took about 2 hours for the drying to be completed. After drying, all samples were analysed for the output parameters (carbohydrate, crude fibre crude protein, fat content, vitamin C and magnesium content). The results showed that the interaction of all the levels of the two process conditions did not change the mean values of the carbohydrate, crude protein and magnesium contents of the dried fermented product (ogi powder). Various combinations of all the levels of the two process conditions did not cause the value of the carbohydrate, crude fibre, crude protein, fat, vitamin C and magnesium content to be higher than 83.5%, 0.6%, 3.2%, 1.2%, 3.0%, and 3.85 mg/100g respectively. [ABSTRACT FROM AUTHOR]

In the United States, more than 200 maize processing plants use multiple-effect evaporators to remove water from thin stillage and steepwater during dry grind and wet milling processes, respectively. During the dry grind process, unfermentables are centrifuged and the liquid fraction, thin stillage, is concentrated in multiple effect evaporators. Evaporator fouling occurs during thin stillage concentration and may be from deposition of proteins, fat, fiber, and/or carbohydrates on evaporator surfaces. Studies on evaporator fouling from maize processing streams are limited and fundamental causes are not well understood. Therefore, the overall objective was to investigate effects of compositional variation on evaporator fouling during thin stillage concentration. Effects of total solids during evaporator concentration, removal of post fermentation oil, corn oil and glycerol addition, and overall plant operation were studied. Thin stillage had lower fouling rates compared to evaporator concentrates. Addition of postfermentation corn oil (0.5 to 1.0% added) increased thin stillage fouling rates, but at higher oil concentration (1.5% added), rates decreased. At 10% solids content in evaporator concentrates, oil recovery had no influence on fouling rates. Glycerol addition (1%) to thin stillage increased fouling rates. Simultaneous plant shutdown and evaporator cleaning decreased subsequent fouling rates. [ABSTRACT FROM PUBLISHER]

In some special harvesting conditions of corn grains, the seeds have humidities between 25% ... 30%, and they are subjected to the drying operation in order to be safetly stored. Corn seeds subjected to drying, behave differently according to their condition and the operation parameters of the drying technology. Corn seeds do not support aggressive drying conditions characterized by non-uniform temperatures and rates of the drying agent, when passing through the product layer. The purpose of the paper is to establish the optimal operating parameters for the drying process to maximize the technological effect and to conserve the quality of the corn seeds. In the investigations, corn seeds with four initial humidities were dryed in a layer thickness of 150 mm. During the investigations, was studied the influence of the drying agent's velocity and temperature on the protein content and germination of the seeds. The drying process for corn seeds was carried out using four velocities and five temperatures of the drying agent. To achieve the goal, a laboratory dryer for agricultural products was designed and built. Experimental research results show that both the protein content as well as the germination capacity of corn seeds were affected by temperatures of the drying agent higher than 50°C. The optimal drying variant of corn seeds, regardless the initial moisture content, was obtained for the drying agent's velocity of 2.5 m/s and the temperature of 50°C. For temperatures of the drying agent higher than 50°C, the protein content and seed germination capacity decreased up to 5.46% and 88%, respectively. [ABSTRACT FROM AUTHOR]

Grain filling rate (GFR) and grain drying rate (GDR) are important for maize final yield determination and adaptability. To identify marker-trait associations and candidate genes, a diverse maize population consisting of 290 inbred lines was used and a genome-wide association study was conducted with 201 SSR markers. GFR and GDR of all stages showed broad phenotypic variations and a total of 33 and 20 excellent lines were selected out for GFR and GDR in the five heterosis groups. Furthermore, 50 significant associations were detected within 30 different markers, of which, 33 and 17 of all associations were respectively corresponding to GFR and GDR of all periods in all environments. Interestingly, two candidate genes of sus1 and pdk1 functioning in starch synthesis were possibly linked to two detected markers of umc1771 and mmc0241 for GFR. Additionally, wx1 matching phi027 for GFR at 20 days encoding a protein was also predicted to relate to starch synthesis. Therefore, those results provide useful information for our understanding on genetic basis in the control of GFR and GDR as well as tools for marker-assisted selection in maize breeding. [ABSTRACT FROM AUTHOR]

Corn starch was modified with lysine by dry heat treatment and to investigate how they can affect the pasting and structural properties of the treated starches. Dry heating with lysine reduced the pasting temperature and resulting in viscosity increase. The particle size of heated starch–lysine mixture increased, suggesting that starch granules were cross-linked to lysine. After dry heating, the onset temperature, peak temperature and conclusion temperature of corn starch–lysine mixture were lower than those of other starches. The degree of crystallinity decreased for the starch after dry heat treatment while these heated starch samples still have the same X-ray diffraction types as the original starch. [ABSTRACT FROM AUTHOR]

The study of process kinetics may aid the design and optimization of drying systems. This paper evaluated the influence of drying temperature (40, 60 and 80 °C) on the moisture content, drying rate, density, shrinkage and breakage of maize dried in two different dryers: oven and silo dryer. In both dryers, the temperature increase reduced drying time, final moisture content and shrinkage of the grains, however increased breakage. Drying rate was higher in the oven (6.4×10−4±2.3×10−4s−1 versus 5.4×10−4±1.2×10−4s−1), while shrinkage (15.2±4.7 % versus 24.4±5.6 %) and density increase (16.6±5.9 % versus 33.4±5.8 %) were more intense in the silo. There was a large release of husk in the silo dryer and the moisture content was slightly smaller in the lower layers respective to the upper ones. [ABSTRACT FROM AUTHOR]

Uncertainties in mathematical modelling of water transport in cereal grain kernels during drying and storage are mainly due to implementing unreliable values of the water diffusion coefficient and simplifying the geometry of kernels. In the present study an attempt was made to reduce the uncertainties by developing a method for computer-aided identification of the water diffusion coefficient and more accurate 3D geometry modelling for individual kernels using original inverse finite element algorithms. The approach was exemplified by identifying the water diffusion coefficient for maize kernels subjected to drying. On the basis of the developed method, values of the water diffusion coefficient were estimated, 3D geometry of a maize kernel was represented by isoparametric finite elements, and the moisture content inside maize kernels dried in a thin layer was predicted. Validation of the results against experimental data showed significantly lower error values than in the case of results obtained for the water diffusion coefficient values available in the literature. [ABSTRACT FROM AUTHOR]

This study introduces sensor psychrometrics, as opposed to the physically constrained static gravimetric experimentation, for the characterisation of cobed maize drying. Simultaneous spreadsheet integration and Solver analytics were used to interpret the digital drying curve from sensor-sampled psychrometric data. The results were validated gravimetrically at dryer settings of 37, 43, and 53°C. The ear drying curves were reproduced with a goodness-of-fit consistency of 0.997–0.999 across the different calibration settings. The new methodology, presented along with its uncertainty, exploits advances in computing and instrumentation to digitize empirical drying, moving experimentation beyond the rigid confines of the lab to the desktop. [ABSTRACT FROM PUBLISHER]

The objective of this study was to evaluate the effects of particle size and drying methods of corn on growth performance of weaned piglets. Crossbreed weaned piglets (n = 192; Duroc × Landrace × Large White) were assigned to one of four treatments (2 × 2 factorial arrangement). All piglets were fed corn–soybean meal diets and treatments were (1) hot air-dried and coarsely ground corn, (2) hot air-dried and finely ground corn, (3) sun-dried and coarsely ground corn and (4) sun-dried and finely ground corn. The results showed that finely ground corn (FGC) improved the performance of piglets. Additionally, the apparent total tract digestibility (ATTD) of gross energy (GE) and ether extract (EE) were increased by FGC, but the drying methods did not affect the performance of piglets or ATTD. Furthermore, smaller particle size significantly decreased the intestinal permeability, which was also not influenced by drying methods. FGC increased the total number of white blood cells, but not other blood parameters. Finally, the level of serum interleukin-1 was decreased by fine grinding and that of serum tumour necrosis factorαwas decreased by sun drying. Conversely, these characteristics of weaned piglets can hardly have been affected either by the corn drying method or its interaction with grinding methods. [ABSTRACT FROM AUTHOR]

Many thin layer drying models have been developed for constant inlet conditions. During deep bed drying, drying air conditions vary with position in the bed and also vary with time, so models developed for thin layers under constant conditions are not valid for deep bed drying analysis. A new thin layer drying rate model (called the two-layer model) is presented which allows for varying air conditions. The model was applied to corn by retro-fitting the model to Page's mode as fitted by Li and Morey (1984). The model was then incorporated into a deep bed simulation, and the results compared with pilot plant drying data. During drying experiments, constant air conditions and varying air conditions were both tested. For constant conditions, all models gave reasonable agreement, but for varying drying conditions, the diffusion model showed an ability to respond better to changes. [ABSTRACT FROM AUTHOR]

Moisture content uniformity is one of critical parameters to evaluate the quality of dried products and the drying technique. The potential of the hyperspectral imaging technique for evaluating the moisture content uniformity of maize kernels during the drying process was investigated. Predicting models were established using the partial least squares regression method. Two methods, using the prediction value of moisture content to calculate the uniformity (indirect) and predicting the moisture content uniformity directly, were investigated. Better prediction results were achieved using the direct method (with correlation coefficients RP = 0.848 and root-mean-square error of prediction RMSEP = 2.73) than the indirect method (RP = 0.521 and RMSEP = 10.96). The hyperspectral imaging technique showed significant potential in evaluating moisture content uniformity of maize kernels during the drying process. [ABSTRACT FROM AUTHOR]

Subsequent processing of Ogi Slurry into various products often requires heat application. Drying pattern and thermo physical properties of Ogi slurry produced from four maize varieties were therefore investigated at soaking period of 24, 48, 72 and 96 hours. The drained Ogi slurries from all the maize varieties were oven dried at temperature (65±3°C). Moisture content (%), Moisture ratio, drying rate (kg/min.), thermal conductivity (Wm-1 K-1), specific heat capacity (kJkg-1°C) and thermal diffusivity(m²/s) were determined. Initial moisture content was in the range 44.0- 48.2% for C3Y, 42.0-51.8% for B2Y, 42.0-49.8% for A4W and 45.0-50.2% E9W. Drying rate decreased from 4.48 to 0.041667 kg/minutes, 4.18 to 0.02416 kg/min, 4.48 to 0.062 and 0.027 kg/minutes for Ogi produced from maize varieties E9W with increase in drying time. Similar trend were observed for Ogi Slurries produced from other maize varieties. The values obtained for specific heat of Ogi slurries were in the range of 1.7-2.38 kJ/kg°C, 1.4-2.95, 2.21-3.51 kJ/kg°C and 1.68-2.34 kJ/kg°C for C3Y, B2, A4W and E9W, respectively. The values for thermal diffusivity ranged from 1.67-2.20 × 10-7), 1.11 -2.2.14 × 10-7, 1.59-2.67×10-7, 1.78-2.73 × 10-7 for C3Y, B2, A4W and E9W, respectively. Soaking period had no significant effect (p>0.05) on the drying pattern and thermal properties of Ogi. [ABSTRACT FROM AUTHOR]

Highlights: [•] Hardware and software of test rig for batch type fluidized bed dryer are introduced. [•] Uncertainty analyses of measurements during drying of corn and unshelled pistachio nut are performed. [•] Pioneering studies on batch type fluidized bed drying are tabulated. [•] Effects of particle mass, air temperature and velocity on drying performance are researched. [ABSTRACT FROM AUTHOR]

Cronobacter sakazakii is a Gram-negative emerging pathogen regarded as causative agent of meningitis and necrotizing enterocolitis in certain groups of infants. In the previous research, thirty-two local isolates of C. sakazakii were obtained from various dried food products such as from corn starch, suggesting that they are able to survive drying. Some of the isolates were toxic. Green Fluorescent Protein (GFP) have been inserted to C. sakazakii and used as a marker for selective enumeration due to the ability of this protein to fluoresce under UV and to tolerate in ampicillin containing media. The objective of this study was to evaluate the survival, colonization and penetration of two isolates of C. sakazakii from dried food product during maize drying. The maize was challenged with mutants at a concentration of 105-106 CFU/g before drying. Maize drying was performed at temperature of 40, 45 and 50°C for 4, 6 and 8 days until the moisture content reached 14%. The totals of resistant drying mutants were counted every day onto ampicillin containing media by observing under UV light. The survival rate of C. sakazakii during drying was determined by the slope of linier regression from C. sakazakii survival curve. Isolates of FWHd16, the toxic strain of C. sakazakii, were more resistant to heat treatments in comparison to isolates of YRt2a, or the non toxic strain of C. sakazakii. Following fluorescence and scanning electron microscope observation, it is concluded that both isolates were colonizing on maize surface. These mutants were able to penetrate to the inner side of the grain by entering injured surface or pores at the tip cap of maize. [ABSTRACT FROM AUTHOR]

Four male lambs (Katahdin; average live weight 25.9±2.9 kg) with "T" type cannulas in the rumen and proximal duodenum were used in a 4×4 Latin square experiment to evaluate the influence of supplemental dry distillers grain with solubles (DDGS) levels (0, 10, 20 and 30%, dry matter basis) in substitution for dry-rolled (DR) corn on characteristics of digestive function and digestible energy (DE) of diet. Treatments did not influence ruminal pH. Substitution of DR corn with DDGS increased ruminal neutral detergent fiber (NDF) digestion (quadratic effect, p<0.01), but decreased ruminal organic matter (OM) digestion (linear effect, p<0.01). Replacing corn with DDGS increased (linear, p≦0.02) duodenal flow of lipids, NDF and feed N. But there were no treatment effects on flow to the small intestine of microbial nitrogen (MN) or microbial N efficiency. The estimated UIP value of DDGS was 44%. Postruminal digestion of OM, starch, lipids and nitrogen (N) were not affected by treatments. Total tract digestion of N increased (linear, p = 0.04) as the DDGS level increased, but DDGS substitution tended to decrease total tract digestion of OM (p = 0.06) and digestion of gross energy (p = 0.08). However, it did not affect the dietary digestible energy (DE, MJ/kg), reflecting the greater gross energy content of DDGS versus DR corn in the replacements. The comparative DE value of DDGS may be considered similar to the DE value of the DR corn it replaced up to 30% in the finishing diets fed to lambs. [ABSTRACT FROM AUTHOR]

This is a general study about the performance and energy requirement for NA/LT in-bin drying of corn at 10 different locations in Argentina. The goals of this study were to use the PHAST-FDM simulation model and historical weather data to study the performance of four NA/LT in-bin drying strategies for drying corn with different airflow rates (1 to 2 m³ min-1 t-1 ) and from different initial moisture contents (MC) (17 and 20%) in terms of drying time, final moisture content and dry matter loss, among other parameters. Additionally, the electrical and caloric energy consumption was also estimated. The most successful strategy across locations was the intelligent strategy (a model based strategy). The appropriate specific airflow rate was 2 m³ min-1 t-1 in North Argentina and 1 m³ min-1 t-1 in the South Argentina. In some locations with warm weather, no NA/LT in-bin drying strategy succeeded in drying corn with initial MC of 20% or superior under the airflow rates ranges investigated in this study, mostly due to excessive dry matter loss. The location with the coldest weather (Balcarce) resulted with the highest total energy consumption per point of moisture extracted and per ton of grain, (35.5 and 25.1 kWh for 17% and 20% initial MC, respectively). On the contrary, the location with the warmest weather (Saenz Peña) resulted with the lowest total energy consumption, with 9.4 and 10.7 kWh per point of moisture extracted and per ton, for 17% and 20% initial MC, respectively. [ABSTRACT FROM AUTHOR]

As a first objective, this study addresses a novel approach to drying efficiency analysis through transient models based on both the first and second laws of thermodynamics. As a second objective, we developed a numerical meshless scheme based on cubic radial basis functions to solve the associated nonlinear coupled advection-dominated set of partial differential equations. The simulated results showed excellent accuracy when compared with available literature data on drying. Finally, and most significantly, this study presents an original methodology for optimizing dryers based on energy and exergy efficiencies and the associated controllable operational parameters: drying air velocity (flowrate) and temperature. [ABSTRACT FROM PUBLISHER]

Low temperature/natural drying of grain depends strongly on the climate. Being a slow process, experimental determinations are costly and difficult, so that developing a mathematical model and finding a proper method of solution is of great importance. The dryer model is composed of a first-order, hyperbolic partial differential equation (PDE) system, encompassing four dependent variables: grain moisture content, grain temperature, air temperature and air humidity, plus two independent variables: time and position along the bed depth direction. The bed system requires initial and boundary conditions, the latter of the Dirichlet type. In this work the following numerical methods for solving the set of dryer equations were compared: (1) explicit finite differences (2) implicit finite differences and (3) the method of lines. The performance parameters selected for the comparison were (a) drying time and (b) specific energy consumption. The influence of time and length steps of numerical solutions on such parameters was also assessed through indicators such as relative computing (CPU) time, prediction stability and truncation error. The results indicated that the method of lines was the most adequate to solve the compromise between these indicators. [Copyright &y& Elsevier]