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ABSTRACT Tamarind is used in the food and pharmaceutical industry, and its seed is the main means for the reproduction of this species, thus justifying studies that ensure its post-harvest viability. This research aimed to study the thermodynamic properties of tamarind seeds as a function of the equilibrium moisture content. The experimental data of the water activities were obtained by the indirect static method. The Cavalcanti Mata model was used to determine the thermodynamic properties of tamarind seeds, as it was the model that best fitted the experimental data of the desorption isotherms. The results showed that the thermodynamic properties are influenced by the moisture content and temperature, with an increase in the energy required to remove water from the product with a decrease in moisture content. The net isosteric heat of desorption increases with a reduction of moisture content ranging from 2,618.85 to 2,510.25 kJ kg−1 for the moisture content range of 10.52 to 21.10% db. The latent heat of vaporization, the differential enthalpy, and the Gibbs free energy increase with a reduction of the moisture content of tamarind seeds.

ABSTRACT The knowledge of hygroscopicity is essential for the storage of tamarind seeds, but there is a limitation of a judicious statistical parameter to define the best mathematical model to adjust the isotherms of plant products. Therefore, this study aimed to determine the desorption isotherms of tamarind seeds and test the Akaike information criterion (AIC) and Schwarz Bayesian information criterion (BIC) for choosing the best mathematical model. Seeds with an initial moisture content of 21.00 ± 0.10% dry basis (db) were dried at 45 °C until they reached moisture contents of 17.27 ± 0.10, 15.04 ± 0.16, 14.14 ± 0.06, 12.41 ± 0.17, and 10.52 ± 0.12% db. The water activity of the product was determined by the static-indirect method at temperatures of 10, 20, 30, and 40 °C. Mathematical models frequently used to predict the isotherms of plant products were adjusted to the experimental data. The Cavalcanti Mata model is recommended to estimate the desorption isotherms of tamarind seeds because it presents better adjustments. The AIC and BIC criteria contribute to the choice of the model to predict the desorption isotherms of tamarind seeds.

ABSTRACT Drying is the most widely used process to ensure the quality and stability of plant products. Therefore, this study aimed to determine the effective water diffusivity and activation energy in grain sorghum during drying at different temperatures and initial moisture contents. Sorghum grains (cultivar DeKalb 640) were harvested with an initial moisture content of 0.49 kg water kg−1 dry matter. The effective diffusion coefficient was determined from different initial moisture contents of approximately 0.49, 0.40, 0.31, and 0.23 kg water kg−1 dry matter. Grains with different moisture contents were dried under four temperature conditions of 40, 60, 80, and 100 °C on perforated trays. The spherical geometry model was used for liquid diffusion. The experiment was conducted in a completely randomized design in a 4 × 4 factorial scheme (four moisture contents × four temperatures), with three replications. Data were subjected to analysis of variance and regression using the statistical software SISVAR®. Sorghum grain diffusivity increases at the same drying temperature as an increase of the initial moisture content of grains. The activation energy was higher for grains with higher initial moisture content, with values of 27.32, 26.75, 22.55, and 20.94 kJ mol−1, respectively.

ABSTRACT This study aimed to fit different mathematical models to the experimental data on drying of baru fruits (Dipteryx alata Vogel), determine and assess the effective diffusion coefficient, as well as obtain the activation energy and thermodynamic properties for the drying process under different air temperature conditions. Baru fruits with an initial moisture content of 0.429 ± 0.044 (dry basis, db) were dried in a forced air ventilation oven under four temperature conditions (40, 60, 80, and 100 °C) until reaching a moisture content of 0.065 ± 0.018 (decimal db). These data were fitted to mathematical models frequently used to represent the drying of vegetal products. The Logarithmic model presented the best fit to describe the phenomenon. The effective diffusion coefficient increased as temperature increased, being described by the Arrhenius equation, with an activation energy of 37.64 kJ mol-1. Enthalpy and entropy decreased, while Gibbs free energy increased as drying temperature increased.

ABSTRACT: The objective of this study was to determine and evaluate the thermodynamic properties for different equilibrium moisture contents in baru fruits (Dipteryx alata Vogel), using the direct static method to obtain the experimental data. The Modified Halsey model was used to determine the thermodynamic properties of baru fruits. Results concluded that thermodynamic properties are influenced by moisture content. The water vaporization latent heat increases with the decrease in equilibrium moisture content. The baru fruit desorption process is controlled by enthalpy. Gibbs free energy is positive for the temperatures studied with the increase over desorption, which describes a non-spontaneous process.

ABSTRACT Biofortified sweet potato (Ipomoea batatas) is one of the foods with the highest contributions of carotenoids in the diet, especially provitamin A carotenoids. Thus, this study aimed to analyze the drying kinetics of the biofortified sweet potato pulp using the Akaike (AIC) and Schwarz's Bayesian (BIC) information criteria for model selection, as well as determine the effective diffusion coefficient and activation energy under different drying conditions. The biofortified sweet potatoes were sliced into chips and submitted to drying in an air circulation oven at 1.0 m s−1 at temperatures of 45, 55, 65, and 75 °C until constant mass. The mathematical models Wang and Singh, Verma, Thompson, Page, Newton, Midilli et al., logarithmic, Henderson and Pabis, two-term exponential, two-term, diffusion approach, frequently used to predict the drying of vegetal products, were adjusted to the data. The Wang and Singh model was selected to represent the drying of the biofortified sweet potato pulp by exhibiting the best adjustment for most conditions. The AIC and BIC criteria were suitable for selecting the Wang and Singh model. The effective diffusion coefficient increased as drying air temperature increase and the activation energy for liquid diffusion was 29.18 kJ mol−1.

ABSTRACT One of the main phytosanitary problems in major crops are phytonematodes, which are characterised as difficult to control. In view of this, biocontrol, through the use of biological agents, has become a driving force in controlling these pathogens. The aim of this study was to evaluate the compatibility of microorganisms, and detect the possibility of antagonistic effects, influence on growth, or synergistic action when microorganisms are jointly applied to crops. Microbiological analyses were carried out to observe the interaction of the fungus Trichoderma asperellum with the bacteria Bacillus subtilis and Bacillus methylotrophicus. It was found that the interaction between the genera Bacillus and Trichoderma did not promote any increase in the fresh or dry weight of the roots or shoots of the soya plants; however, based on the results of the microbiological analysis of the fungi and bacteria, the interaction was found to be promising, particularly in the evaluation carried out on the seventh day. Considering the number of viable spores, the interaction between B. subtilis + T. asperellum showed better results than B. methylotrophicus + T. asperellum. The Interaction between the genera Bacillus and Trichoderma showed the potential for joint use in the biological control of the soya bean.