Infrared dehydration is more advantageous than the convective system under similar conditions, and studying this process is important to further develop equipment and procedures. Thus, the aim of this work was to study the dehydration process of tomato (Solanum lycopersicum L.) slices obtained by infrared drying at three different maturity stages throughout two different procedures: Firstly, the drying model was determined by applying the mass and energy balances under wet bulb temperature for the constant drying rate period and secondly, the mass effective diffusion coefficient was determined throughout the experimental data and the theory of diffusion of the liquid phase for the decreasing drying rate period. Tomato fruits cv. Santa Cruz were used. Three maturity stages were selected: green (stage 1), orange (stage 2), and red (stage 3). Mathematical models frequently used to represent drying of agricultural products were fitted to the experimental data of tomato drying. The effective diffusion coefficient was obtained by adjusting the liquid diffusion mathematical model to the experimental data of the descending period of dehydration. The two-term model was the best one to represent the tomato dehydration process. The critical moisture content for tomato dehydration was 2.97 kgw kgdm -1. There is an initial dehydration period in which the drying rate reaches its maximum (approximately 1.05 kgw kgdm -1 , about 3 min). Three different methods were used to obtain values of the effective diffusion coefficient, including the finite element method, which had the lowest values for the least square sum of deviation 1.00 × 10 -7 m 2 s -1 . The global coefficient of heat transfer was 12.45 W m -2 K -1 , and the global coefficient of mass transfer was 0.0105 m s -1 .

Beans are the main source of protein of plant origin in the Brazilian diet, they also contain phenolic compounds, antioxidants, iron, fibers and vitamins. The BRSMG Majestoso cultivar belongs to the commercial group of carioca beans, displays high productivity, excellent health and a 90-day cycle, has high yield and is resistant to disease. The study of physical properties enables the prediction of agricultural products behavior relative to responses of physical and chemical treatments, in order to allow the maintenance of quality and safety of processed foods. The aim of the present study was to evaluate the effect of drying on the physical characteristics of beans of the BRSMG Majestoso cultivar. Beans with an initial moisture content of approximately 0.2660 d.b. (dry basis) were used, and dried at 40ºC. The following physical characteristics were determined: bulk density, unit density, intergranular porosity, 1000-grain weight, sphericity, circularity, geometric diameter, unit volume, projected area, surface area and the surface to volume ratio. Based on the results, a reduction in the moisture content of the beans promotes an increase in bulk density, unit density, porosity, sphericity, circularity and the surface to volume ratio. Conversely, the 1000-grain weight, geometric diameter, unit volume, projected area and surface area decreased as the moisture content of the beans was reduced.

The objective of this research was to determine the mechanical properties of beans (BRSMG Majestuoso) coated with carnauba wax solution. Grains with 0.1481 (d.b.) moisture content was used. Treatments 0, 1 and 2 were respectively defined as the control sample, application of the wax diluted 1/1 (carnauba wax solution/water) and application of carnauba wax without dilution. Uniaxial compression tests were performed in the universal test apparatus, TA HD Texture Analyzer with 500 N load cell. Compression tests were carried out during the storage period of in-nature grains, in those that underwent the hydration process at 40 and 50 °C of temperature and in grains during the cooking process. Only the storage time had a significant effect (P<0.05) on the rupture force and the proportional deformity module. Hydration and cooking of the grains provided a reduction in the values of the studied variables.

Edible waxes are widely used to maintain foodstuff until they are consumed. However, some products may be subjected to industrial procedures, such as hydration, prior to their consumption. Hydration of a material is a complex process, which aims to reconstitute the original characteristics of a product when in contact with a liquid phase. An important agricultural product that requires this procedure is beans. Thus, the purpose of this work is to study the hydration process of beans (cultivar BRSMG Majestoso) in different temperatures and concentrations of carnauba wax, which is applied on the product surface. Beans with initial moisture content of 0.2015, 0.1972 and 0.1745 (d.b.) corresponding to treatments 0 (witness), 1 (wax diluted in water in the ratio 1:1), and 2 (carnauba wax, without dilution) were used. Later, these samples were imbibed in distilled water at temperatures of 20, 30 and 40 ºC, for 15 h. The temperature and the carnauba wax influenced the water absorption rate. The Peleg model described satisfactory experimental data and the Mitscherlich model presented biased residual distribution. The constants C 1 and C 2 of the Peleg model exhibited opposite behaviors with increasing temperatures in the hydration process. Key words: Cultivar BRSMG Majestoso. Peleg model. Mitscherlich model. ResumoO uso de ceras comestíveis em produtos agrícolas é vastamente utilizado, de modo a conservar o alimento até o seu consumo. Contudo, alguns produtos podem sofrer algum processo industrial para o seu consumo, como a hidratação. A hidratação de materiais é um processo complexo que tem como objetivo reconstituir as características originais do produto, quando submetido ao contato com uma fase líquida. Um importante produto agrícola no qual requer esse processo é o feijão. Assim, objetivou-se com este trabalho estudar o processo de hidratação de grãos de feijão do cultivar BRSMG Majestoso para diferentes temperaturas e concentração de cera de carnaúba aplicada na superfície do produto. Foram utilizados grãos de feijão com teores de água de 0,2015; 0,1972 e 0,1745 (b.s.)

Edible waxes are widely used to maintain foodstuff until they are consumed. However, some products may be subjected to industrial procedures, such as hydration, prior to their consumption. Hydration of a material is a complex process, which aims to reconstitute the original characteristics of a product when in contact with a liquid phase. An important agricultural product that requires this procedure is beans. Thus, the purpose of this work is to study the hydration process of beans (cultivar BRSMG Majestoso) in different temperatures and concentrations of carnauba wax, which is applied on the product surface. Beans with initial moisture content of 0.2015, 0.1972 and 0.1745 (d.b.) corresponding to treatments 0 (witness), 1 (wax diluted in water in the ratio 1:1), and 2 (carnauba wax, without dilution) were used. Later, these samples were imbibed in distilled water at temperatures of 20, 30 and 40 ºC, for 15 h. The temperature and the carnauba wax influenced the water absorption rate. The Peleg model described satisfactory experimental data and the Mitscherlich model presented biased residual distribution. The constants C 1 and C 2 of the Peleg model exhibited opposite behaviors with increasing temperatures in the hydration process. Key words: Cultivar BRSMG Majestoso. Peleg model. Mitscherlich model. ResumoO uso de ceras comestíveis em produtos agrícolas é vastamente utilizado, de modo a conservar o alimento até o seu consumo. Contudo, alguns produtos podem sofrer algum processo industrial para o seu consumo, como a hidratação. A hidratação de materiais é um processo complexo que tem como objetivo reconstituir as características originais do produto, quando submetido ao contato com uma fase líquida. Um importante produto agrícola no qual requer esse processo é o feijão. Assim, objetivou-se com este trabalho estudar o processo de hidratação de grãos de feijão do cultivar BRSMG Majestoso para diferentes temperaturas e concentração de cera de carnaúba aplicada na superfície do produto. Foram utilizados grãos de feijão com teores de água de 0,2015; 0,1972 e 0,1745 (b.s.)