Search

Summary: The objective of this study was to quantify the carbon dioxide (CO2) produced by soybeans stored at 25 °C, with moisture contents (MC) of 12%, 14%, 18% and 22% (wet basis – w.b.), in a dynamic respiration measurement system, as well as to evaluate the accumulated dry matter loss (DML) throughout the stoichiometric relation between glucose and CO2, the safe storage time of stored soybeans and quantify the aflatoxins of the soybeans during storage. Also, the presence of aflatoxins B1, B2, G1 and G2 within soybeans were evaluated. Soybeans with high MC contributed to a significant increase in respiration rate (RR) and, consequently, greater DML during the storage. Compared to the MC of 12% (w.b.), the soybean RR increased 1.3, 2.8 and 19 times for soybeans at 14%, 18% and 22% (w.b.) respectively. Maximum storage time of soybean increased with the decrease of MC. Soybeans stored with 22% (w.b.) obtained high contamination by aflatoxin B1 and B2. [ABSTRACT FROM AUTHOR]

Over the last few decades, the drying process has proven to be a fundamental operation within the food industry, as it prolongs the shelf life and reduces the levels of deterioration of the product. Infrared drying has gained great attention in recent years as it promotes more uniform and energy‐efficient drying. Given the above, this study aimed to perform infrared drying of pear slices at different temperatures, evaluating the drying kinetics, and the thermodynamic analysis. The pear slices 3‐mm thick were dried in an infrared dryer at temperatures between 50 and 100°C until constant mass. Different mathematical models were fitted to the experimental data to represent drying as a function of time. Energy and exergy analysis were performed by applying the first and second laws of thermodynamics. The Henderson and Pabis modified model satisfactorily represented the drying of pear slices. The effective diffusion coefficient increased linearly with increasing temperature, ranging from 1.15 × 10−9 and 5.08 × 10−9 m2/s. From Arrhenius's relations, the activation energy of the drying process of pear slices was 29.87 kJ/mol. The lowest specific energy consumption (10.28 kWh/kg) was observed for higher drying temperature. The drying temperature positively influenced the energy and exergy efficiencies of the process. The efficiency of the first law of thermodynamics varied between 40 and 99%. The increase in the energy required in the dryer, overcomes the destruction of exergy in the equipment. Practical Applications: Infrared radiation drying is a promising high‐efficiency technology. One of the main advantages of this method is the significant reduction in drying time compared with convective drying. For a complete evaluation of the drying system, analysis of the first and second laws of thermodynamics must be applied. Few studies on energy and exergy analysis of infrared dryers are found. A detailed literature review showed that there is no information on energy and exergy analysis of the infrared drying process of pear slices. It is believed that this study will contribute to the pear food industry by providing results from the best drying process in terms of kinetics, energy, and exergy. [ABSTRACT FROM AUTHOR]

One of the ways to enable and preserve the quality of an agricultural product is through its dehydration. Drying by infrared radiation has been gaining great attention from the industry, as it promotes better heating uniformity, conferring better quality characteristics when compared to traditional drying methods. Thus, this study aimed to model the drying kinetics of pequi slices, subjected to drying by infrared radiation. Pequi fruits (Caryocar brasiliense Camb.), harvested manually in different stages of maturation (green and ripe), with initial moisture contents of 1.06 and 2.20 kga kgdm−1, were used for the green and ripe fruits, respectively. The fruits were peeled and cut into slices approximately 40 mm long and 2 mm thick. The slices were subjected to the infrared drying process under the temperatures of 55, 65, 75, 85, and 95°C. During drying, the effective diffusion coefficient was evaluated. Among the mathematical models that were adjusted to the experimental data, the modified Henderson and Pabis model satisfactorily described the period of decreasing drying rate of pequi slices. During the drying process, the diffusion coefficient increased linearly with temperature, ranging from 8.15 × 10−10 to 1.76 × 10−9 m2 s−1 for green pequi slices and 1.01 × 10−9 to 2.04 × 10−9 m2 s−1 for ripe pequi slices. Practical applications: Pequi fruit is characterized as an important native product of the Brazilian Cerrado, being a considerable source of income for the producing regions. Due to seasonality, there is a need to store the fruits. Thus, this study aims to help researchers and the pequi processing industry, proposing an alternative for marketing in the dehydrated fruit form, by infrared drying, to enable and preserve the quality of the product. [ABSTRACT FROM AUTHOR]

Predictive modeling is useful to estimate future events based on collected data and discipline‐specific knowledge to guide decision making. Machine learning is one of the most frequently used methods to develop predictive models. There is limited literature in which machine learning techniques have been applied to soybeans' behavior during storage, and thus, the goal of this study was to test different model frameworks that estimate dry matter loss of soybeans utilizing data acquired from a dynamic grain respiration system with different levels of moisture content (12, 14, 18, and 22%, wet basis—w.b.) and temperature (25, 30, and 35°C). Five different models were trained and tested with a 2,625 point data set, which was partitioned into a training set (90%) and a testing set (10%). In the training step, 10‐fold cross‐validation was used to choose the best hyperparameters for each of the models. All fitted models were evaluated using standard metrics of Root Mean Square Error (RMSE), coefficient of determination (R2), dispersion of residual values, and a coefficient of performance. The Random Forest model performed best in terms of the distance between predicted and observed values, with three predicting variables. The use of predictive modeling in the recent Agriculture 4.0 scenario is a promising development for risk management and decision making in the context of grain and oilseed storage. Practical Applications: Soy is one of the most important crops in the world. The dry matter loss through respiration is a major problem during storage. The results of this study can aid researchers and the soybean industry in managing storage as a risk management and decision‐making tool. [ABSTRACT FROM AUTHOR]

The reduction of moisture content in coffee cherries, during drying, directly influences their physical and aerodynamic properties and quality. The knowledge of these properties is essential for cost reduction, correct conservation, and defining parameters and operation of equipment in the main postharvest operations of the crop. In this study, the main physical properties (unit specific mass, sphericity, circularity, geometric diameter, projected area, volume, and volumetric contraction) and aerodynamic properties (terminal velocity and drag coefficient, actual, and theoretical) were determined during the coffee cherries drying. The reduction of the moisture content during drying provides a reduction of 30% in the specific density of coffee cherries. In addition, it promotes the reduction of sphericity, circularity, projected area, geometric diameter, and volume of the fruits. A volumetric reduction of 40% during the drying process was observed. A new model was proposed to represent the volumetric contraction of coffee cherries during drying. The experimental terminal velocity of coffee cherries decreased during the drying process, while the drag coefficient showed an increasing trend. The theoretical aerodynamic properties found in this study, presented values close to the experimental ones, representing satisfactorily the phenomena in the function of the moisture content. Practical Applications: Coffee is one of the most important commercial cultures in the world. The physical and aerodynamic properties are essential for the correct handling, separation, cleaning, storage, and transport of coffee. This data will provide important information needed to design different aspects of coffee processing (such as cleaning, sorting, and drying) and storage. [ABSTRACT FROM AUTHOR]

The desorption isotherms and thermodynamic properties of sugar beet seeds of cv. ' Chata do Egito' variety was determined at 10, 20, 30, 40 and 50C over a range of water activities ( Aw) from 0.11 to 0.96. Equilibrium moisture content data were correlated by the Guggenheim-Anderson-de Boer model, which presented good fit to the data, according to statistical procedures. Equilibrium moisture content ranged from 1.50 to 20.0% d.b. (dry basis). Desorption isotherms of sugar beet seeds exhibited type II sigmoid shape. Thermodynamic properties were determined related to desorption process. Differential enthalpy values varied between 3,614.51 and 4,093.90 kJ/kg. Differential entropy and Gibbs free energy presented values between 3.67-4.08 kJ/kg.K and 0.75-508.11 kJ/kg, respectively. The enthalpy-entropy compensation theory is valid for the moisture desorption phenomena of sugar beet seeds, being enthalpy controlled. Practical Applications Almost 100% of the Brazilian sugar beet seeds are imported throughout the world and its commerce between different countries. Higher distances lead to physical, chemical and microbiological changes in sugar beet seeds. This trend could cause the deterioration of food products. Information on the sorption characteristics of sugar beet seeds could not be found in the literature, regardless of this culture importance. Sorption isotherms data are key information to predict optimum storage and trading conditions to ensure quality of sugar beet seeds for crop production. Finally, the lack of quality may affect employees, entrepreneurs and other professionals who work with sugar beet. This paper presents the desorption isotherms and thermodynamic properties of ' Chata do Egito' sugar beet seed variety. [ABSTRACT FROM AUTHOR]

BACKGROUND Detailed knowledge of coffee production systems enables optimization of crop management, harvesting and post-harvest techniques. In this study, coffee quality is mapped as a function of coffee variety, altitude and terrain aspect attributes. The work was performed in the Zona da Mata, Minas Gerais, Brazil. RESULTS A large range of coffee quality grades was observed for the Red Catuai variety. For the Yellow Catuai variety, no quality grades lower than 70 were observed. Regarding the terrain aspect, samples from the southeast-facing slope ( SEFS) and the northwest-facing slope ( NWFS) exhibited distinct behaviors. The SEFS samples had a greater range of quality grades than did the NWFS samples. The highest grade was obtained from an NWFS point. The lowest quality values and the largest range of grades were observed at lower altitudes. The extracts from the highest-altitude samples did not produce any low-quality coffee. CONCLUSIONS The production site's position and altitude are the primary variables that influenced the coffee quality. The study area has micro-regions with grades ranging from 80 to 94. These areas have the potential for producing specialty coffees. © 2015 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

The purpose of this work was to evaluate texture alterations due to compression load on tomatoes stored at 15 and 25C, which simulates transport in type ' K' wooden boxes. The following mechanical properties were analyzed during storage: firmness, proportional deformity modulus, energy to deform the product, penetration force of the tomato skin and the energy required for penetration. Structural alterations were noticed solely by a puncture test. The mechanical property values significantly decreased during storage. The weight loss varied significantly among control and treatment tomatoes during storage, and the tomatoes stored at 25C obtained higher weight loss values. These results will aid in generating logistic procedures to prevent mechanical damage to tomatoes when they are transported in wooden boxes, thus increasing producer profitability. Furthermore, if damage to tomatoes does occur, professionals will be able to predict the shelf life of the tomatoes. Practical Applications Results of this manuscript may aid and alert developers of packages to prevent quality loss due to compression loads throughout transport and/or storage. Furthermore, in order to analyze quickly the quality of tomatoes, puncture test can be used, in which its parameters were obtained. The manuscript states clearly that refrigeration is not efficient in order to prevent quality loss if the tomato fruits are submitted to compression loads. Thus, prior to storage temperature, compression of tomatoes stacked on top of one another must be avoided in order to maintain quality and increase shelf life of this product. [ABSTRACT FROM AUTHOR]

Summary The desorption isotherms and thermodynamic properties of cocoa beans were obtained during the drying process of this product. The isotherms were determined by dynamic method for various temperature (25, 35, 45 and 55 °C) and relative humidity (RH) conditions (30, 40, 50, 60, 70 and 80%). Equilibrium moisture content data were correlated by the Guggenheim-Anderson-de Boer (GAB) model, which presented good fit to the data, according to statistical procedures. Equilibrium moisture content ranged from 5.90 to 16.67 d.b.; it increased with an increment in the RH and decreased with increased temperature at a constant RH. Enthalpy values for each model coefficient were encountered, ranging from −90.05 to 545.96 kJ kg−1. The integral isosteric heat of desorption and differential entropy increased with decreased equilibrium moisture content, a tendency also found for Gibbs free energy. [ABSTRACT FROM AUTHOR]

The water sorption isotherms of pearl millet grain and the thermodynamic properties obtaining during the process of drying pearl millet were examined. Equilibrium moisture content ( Xeq) was determined under several temperature ( T) and relative humidity (RH) conditions. The Xeq data were correlated by six mathematical models. The modified Henderson was the model that best fitted the experimental data. The Xeq decreased with an increase in T at constant RH. Hysteresis was also studied; increasing T led to a decrease in this phenomenon. Integral isosteric heat of sorption ( Qst), differential entropy (Δ S) and the enthalpy–entropy compensation theory were studied. Qst values decreased when Xeq increased because the Qst values of adsorption were lower than Qst desorption values. The values of Δ S decreased with increases in Xeq, because Δ S values were higher for desorption than for adsorption. The enthalpy–entropy compensation theory is valid for describing the water sorption processes of pearl millet grain. [ABSTRACT FROM AUTHOR]

The desorption isotherms and thermodynamic properties of two cultivars of sweet corn were obtained during the drying process of these products. The isotherms were determined by a dynamic method for various temperature and humidity conditions. Equilibrium moisture content ( Xeq) data were correlated by the Guggenheim–Anderson–de Boer model and an artificial neural network (ANN) model. These models were fitted to the experimental data. The Xeq for corn grain increased with an increase in the relative humidity at fixed temperature and decreased with an increase in temperature at a constant relative humidity. The experimental data were analysed by a thermodynamic approach to obtain the isosteric heat of desorption (Δ H), differential entropy (Δ S), activation energy ( Ea) and Gibbs free energy (Δ G). The Δ H and Δ S increased with a decrease in moisture content, while Δ G decreased exponentially with an increase in Xeq. The Arrhenius equation was used to obtain Ea values, with Supersweet corn having higher Ea. [ABSTRACT FROM AUTHOR]