scholarly journals Development of Physical Properties of Apple during Dehydration

Author(s):  
Rym Mbarek ◽  
Daoued Mihoubi

The evolution of physical properties (shrinkage, density and porosity) of cylindrical shaped apple samples (Golden Delicious) during convective drying was investigated. For this purpose, the weight and the dimensions (diameter, height) of apple samples were monitoring at regular time intervals of the drying process. A constant drying rate period was not detected although considering the reduction of the exchange surface area. Apple exhibited a clear anisotropy behavior of the shrinkage coefficients. The volume shrinkage of apple samples showed a linear relationship with moisture content (R2 = 0.996). A theoretical relation between the surface ratio and the volume ratio was determined (R2 = 0.956). During drying process, the apparent density of apples decreased with decrease in moisture content following a second-degree polynomial curve (R2 = 0.991), whereas the true density aggrandized with removal of water. The porosity of apple samples was showed to increase as drying progressed. At the starting of the drying process, the porosity changes resulted from the reduction of the total volume. Then, the porosity changes during drying were found to be a consequence of a loss of water and a simultaneous reduction of gaseous volume.

2020 ◽  
Vol 11 (1) ◽  
pp. 39
Author(s):  
Aminullah Aminullah ◽  
Tjahja Muhandri ◽  
Subarna Subarna

The drying process of corn noodles was an effort to increase the shelf life and it was a form of noodles diversification. The objective of this research was to study and analyze the effect of guar gum addition on the physical quality of the extruded dry corn noodle made from a mixture of wet and dry corn flour. Manufacturing dry corn noodles was conducted using wet corn noodles from a mixture of wet and dry corn flour, which was then dried in a tray dryer at a temperature of 60-70 °C for 1 - 1.5 hours. The treatments used were a combination of alum levels of 0.01%; moisture content of 80% (dry base); and guar gum concentration of 0%, 1%, and 2%. Physical properties of dry corn noodles included rehydration time, hardness, adhesiveness, suppleness, elongation, and cooking loss. The results showed that the optimum rehydration time for dry corn noodles was about 9 minutes. The addition of guar gum to the physical qualities of dry corn noodles tended not to be significant statistically, but as a score, an increase in guar gum levels tended to increase the elongation of dry corn noodles. While, increasing levels of guar gum tended to reduce the stickiness and cooking loss levels of them.


This paper represents a numerical study of the massive (60mm) and thin (38mm) wood drying using oscillating drying regimes applied on beech timber (Fagus sylvatica). All thermo-physical properties relative of studied wood are taken from the literature on appropriate experiments. We showed that Luikov’s model can be used to predict temperature and moisture content evolutions using oscillating regimes. First numerically tests on 60mm timber wood consists in increasing and decreasing alternation of the drying parameters (temperature), at the rising 12-15°C and at the descent 10- 12°C, every alternation being higher than the precedent with 2-4°C. Second numerical test consists to oscillate the values of equilibrium moisture content with the oscillation amplitudes of ±10% and ±20% at the frequencies of 6hours. These practical experiments are detailed in the literature. Luikov’s model gives satisfactory results, according to the experiments obtained in the literature. But, convective transfer coefficients are function of each experiment and we observed a short difference between oscillation amplitudes of ±10% and ±20% on moisture content evolution. Thus, Luikov’s model can be a tool to study oscillation drying timber in order to reduce consumption of energy during the drying process.


2020 ◽  
Vol 28 (4) ◽  
Author(s):  
Joko Nugroho Wahyu Karyadi ◽  
Dwi Ayuni ◽  
Tsania Ayu Rohani ◽  
Devi Yuni Susanti

Nowadays, coffee has become one of the most favorable commodities for beverages, flavoring as well as for cosmetic industries. In Indonesia, coffee becomes more popular, especially among youngsters. In this study, the spray drying process was evaluated, giving the potential of how simple spray dryer can help local farmers of Indonesia to produce their coffee powders. One small scale of spray dryer was constructed with the total dimensions of 2.85 x 0.64 for length x width, with a height of 2.32 m. The spray dryer was equipped with a digital thermo regulator, the pneumatic nozzle system, and 4 finned heaters with the power of 2700 watt for each. The spray drying constructed was revealed to be able to produce coffee powders with fine quality. The inlet temperature of the drying chamber, as well as the initial Brix content of feed solution, were proven to affect the physical properties of powder produced such as moisture content, product yield, and solubility. The final moisture content of powders was ranged from 3 - 7% db, with the high product yield of the drying process, which could reach up to 70%.


2021 ◽  
Vol 937 (3) ◽  
pp. 032060
Author(s):  
V Agafonychev ◽  
V Makhonina ◽  
D Roslikov

Abstract Convective drying is a common method of dehydration of meat snacks (chips), which largely forms the competitive properties of the finished product. The kinetic parameters of drying (for example, the change in moisture and mass of the drying object during the process, the intensity and duration of drying) are the basis for the development and selection of equipment for the drying section of the industrial production of dehydrated meat products and process control. These indicators were determined experimentally, since they largely depend on the physical properties of a particular drying object, and it is not yet possible to calculate them with an accuracy sufficient for engineering practice. The kinetic parameters of convective drying of salted samples in the form of plates with a thickness of 2, 3, 4, 6, 8, 10 mm, made of chicken fillet meat blocks, have been determined. In order to ensure the adequacy of the research results to the conditions of industrial production, the main stages of the industrial technological process and the characteristics of the raw material samples were physically modeled: the composition of the curing mixture, the dimensions and physical properties of the raw material samples, and drying modes. The presence of complete volumetric evaporation during a period of constant drying rate of samples of raw materials with a thickness of 2, 3, 4 mm was revealed, as well as partial volumetric evaporation (about 90%) for samples with a thickness of 6, 8, 10 mm. A change in the physical mechanism of the drying process in the period of decreasing speed (cessation of volumetric evaporation and a multiple decrease in the intensity of evaporation) has been established. Dependences of the duration of the complete drying process (the sum of the periods of constant and decreasing speed) on the thickness of the raw material samples have been determined (for example, a 4 mm thick sample dries 25% slower than a 2 mm sample). Based on the research results, the possibility of increasing the productivity of the drying equipment (up to 60%) and optimizing the drying agent supply system to the drying object is shown.


2020 ◽  
Vol 175 ◽  
pp. 05021
Author(s):  
Sergey Antipov ◽  
Andrey Klyuchnikov ◽  
Dmitry Kazartsev

At the present time the maim quantity of free-running food products, including grains, are dried in units with convective method of heat input. To intensify convective drying, general attention is paid to improving the method of moving and mixing the product with drying agent, to guarantee fast and quality drying. The use of high and super-high frequency allows can significantly intensify the drying processes, because the phenomenon of super-high frequencies energy into heat conversion throughout the processed material volume contributes to the most uniform heating of the product, compared to other heat input methods. The optimal solution for drying free-running food products is a combination of convective and high-frequency heat input methods. This combination allows controlling gradients of moisture content and temperature, changing its directions, which significantly affects quality of the resulting dry product. In this regard, combined approach to drying process modeling is of practical interest: on the one hand, there are used analytical solutions, based on physical laws application or phenomenological equations, and, on the other hand, experimentally established a relationship between temperature and moisture content of media, which is considered as a heat and mass transfer characteristic for each material.


Author(s):  
Elton A. S. Martins ◽  
André L. D. Goneli ◽  
Cesar P. Hartmann Filho ◽  
Munir Mauad ◽  
Valdiney C. Siqueira ◽  
...  

ABSTRACT Safflower is an oil crop and its oil can be used for food and industrial purposes. However, there is little information about the physical properties of these grains, which is important for the planning and execution of post-harvest stages. Thus, this study was carried out with the aim of evaluating the effect of drying on the main physical properties of safflower grains. Safflower grains were harvested with an initial moisture content of approximately 0.445 decimal d.b. (dry basis) and subjected to drying in an oven with forced air circulation at 40 °C, until the grains reached a final moisture content of 0.073 ± 0.008 decimal d.b. During the drying, bulk density and true density, porosity, thousand-grain mass, circularity, sphericity, projected and surface area, and surface-volume ratio were measured. Based on these results, it is concluded that all gravimetric and geometrical characteristics of safflower grains were reduced due to the reduction of moisture content, except for the surface-volume ratio.


2016 ◽  
Vol 37 (6) ◽  
pp. 3871
Author(s):  
Udenys Cabral Mendes ◽  
Osvaldo Resende ◽  
Juliana Rodrigues Donadon ◽  
Dieimisson Paulo Almeida ◽  
Anísio Correa da Rocha ◽  
...  

The goal of the present study was to assess the effect of drying on the physical properties of adzuki bean (Vigna angularis Willd.). Adzuki beans with moisture content of 47.9% were dried in a oven with forced air ventilation at temperatures of 40, 60 and 80 °C and relative humidity of 18.5, 8.6, and 3.8%, respectively, until the moisture content reached 12.9%. We used 15 adzuki beans individualised in aluminium capsules. The orthogonal axes of the beans (length, width, and thickness) were measured at intervals of five percentage points during the reduction of moisture content. The parameters determined were: sphericity; circularity; volume of beans; volumetric contraction index; volume contraction percentage; surface area; projected area; and surface-volume ratio. The drying conditions altered the physical properties of adzuki bean. As a result of moisture content reduction, there was increased sphericity and surface-volume ratio, and decreased volume, unitary volumetric contraction, surface area, and projected area. Circularity was not influenced by the drying temperatures within the range of moisture content analysed.


Author(s):  
Divine Nde Bup ◽  
César Kapseu ◽  
Dzudie Tenin ◽  
Alexis Kuitche ◽  
Charles Fon Abi ◽  
...  

The effect of moisture content and drying temperature of Vitellaria paradoxa Gaertn kernels on some of its physical properties was investigated. The kernels which were harvested at a moisture content of about 60% (wet basis) and hence prone to high post harvest losses from two ecological zones of Cameroon (Bangoua in West province and Tchabal in Adamawa province) were dried in a forced convection dryer at 40oC, for 6, 20, 48, 72 and 96 hours to give moisture contents ranging from 10 to 60% wet basis. Ten trees from each of the zones were carefully selected to serve as sources for the ripe kernel bearing shea fruits that were used as samples for this study. For each parameter studied, a sample population of 30 kernels selected at random per tree was used. The results obtained revealed that there was a significant difference in the physical properties of the kernels from different trees irrespective of the locality. The bulk density, true density, sphericity and porosity varied non-linearly with the moisture content. Kernels with larger masses showed a different variation pattern of bulk density and porosity with moisture content compared to the lighter kernels. The variation of the bulk density, sphericity, porosity of sheanut kernels with moisture content and temperature was satisfactorily modelled with empirical equations. The samples underwent considerable shrinkage (up to 35%) during the drying process. Three empirical models were used to describe the shrinkage behaviour of the kernels and it is proposed that these models could be incorporated in drying models.


2020 ◽  
Vol 36 (6) ◽  
Author(s):  
Aline Almeida Da Paixão ◽  
Paulo Cesar Corrêa ◽  
Fernanda Machado Baptestini ◽  
Juliana Soares Zeymer ◽  
Jaime Daniel Bustos-Vanegas

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.


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