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A study on the effect of the physical properties and moisture sorption isotherm of palm kernels constitutes the critical criteria in evaluating the drying performance. The drying was evaluated as a function of moisture content (MC) in the range of 0.31–0.02 kg/kg (d.b.). Whereas, the equilibrium moisture content (EMC) of palm kernels (whole kernel...
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... saturated salt solution was used to maintain a fixed RH. Seven saturated salt solutions were prepared, corresponding to a wide range of RH from 10% to 81% and are listed in Table 1 [23]. For each experiment, three glass jars were used, which were all sealed and equipped with sample holders hanged above the saturated salt solution (Figure 1). ...Citations
... The dimensional characteristics of any fruit shape are essential to provide information for cultivation and plant-breeding research purposes [28]. From a production perspective, the fruits' dimensional parameters are necessary for selecting appropriate equipment for processing, such as sorting, cleaning, packaging, and storage. ...
... Benseddik et al. and Ferradji and Matallah [26,34] stipulated that they observed changes in sorption Table 3. Equilibrium moisture content (EMC) of cowpea varieties flour as a function of water activity (a w ). isotherms with an increase in temperature is relative to the composition of the products in starch content and its solubility with an increase in thermal agitation within the samples [35]. Though, at high temperatures, the state of excitation is stronger and favors the reduction of the forces of attraction of molecules among them (Figure 3). ...
In sub-Sahara, preservation of processed cowpea flour remained a challenge, and there are no standard isotherm conditions for drying cowpea flour. This study aims to define the optimum isotherm conditions for cowpea flour and assess their functional properties. Adsorption isotherms of three varieties of cowpea at temperatures 30, 40, and 50°C and in each case with six different applications depending on the constant relative humidity of the medium were executed. Water and oil absorption capacities including swelling index were determined. Results show that water content at equilibrium is inversely proportional to the temperature, and at the same temperature, the water content increases when water activity augments. The adsorption isotherms are of type II according to the fitted BET and GAB models. The absorption capacities ranged from 1.06 ± 0.01, 1.08 ± 0.02, and 1.09 ± 0.01(mL/g), respectively, for CS133, CS032, and control. However, the swelling index was significantly separated (P < 0.05). The adsorption isotherm curve of the sample CS032 at 50°C shows a stronger correlation (R2 = 0.9274) than the other varieties regardless of the mathematical isotherm model used. It can be concluded that depending on some functional properties of cowpea variety flour, these varieties seemed to behave separately vis-a-vis their sorption isotherm.
... Senadeera et al. (2000) ties of green peas dried in a fluidized bed dryer and found that significant changes in physical properties were dependent on drying conditions [15]. Habibiasr et al. (2020) studied the effect of physical properties of palm kernel during drying and results showed that length, width, thickness, bulk density, surface area, and specific surface area was decreased with the decrease of moisture content and true density and porosity increased with the decreased of moisture content [16]. ...
... Senadeera et al. (2000) ties of green peas dried in a fluidized bed dryer and found that significant changes in physical properties were dependent on drying conditions [15]. Habibiasr et al. (2020) studied the effect of physical properties of palm kernel during drying and results showed that length, width, thickness, bulk density, surface area, and specific surface area was decreased with the decrease of moisture content and true density and porosity increased with the decreased of moisture content [16]. ...
... It was observed that shrinkage increased from 33.84% À 43.29% with an increase in temperature from 40 to 60°C. The maximum shrinkage was obtained at higher temperature due to rapid mass transfer causing free space within the seed and thus, the seeds shrink [16]. Similar results were obtained for melon seeds dried in a microwave-assisted fluidized bed dryer [21]. ...
To design some processing equipment, for dried pumpkin seeds the knowledge of some engineering properties is necessary. In the present study, the effect of different drying temperatures in a tray dryer i.e., 40, 50, and 60 °C on the physical properties of pumpkin seeds are investigated. The geometric properties such as linear dimension and its dependent properties (Da, Dg, Φ, SA, Volume, and shrinkage) are found to be significantly affected by different drying temperatures in the 95% level of confidence. The maximum reduction in dimensions are obtained in thickness (29.56%) followed by width (12.82%) and length (7.44%) at 60 °C temperature. Similar trends are found in equivalent diameters, sphericity, surface area, and volume with the increase of temperature. It is found that the bulk density and true density were significantly decreased while porosity of seeds significantly increased after drying when temperature increased from 40 to 60 °C respectively. Thus, it can be concluded that the drying temperatures significantly affects the physical properties of pumpkin seeds.
... Furthermore, mechanical properties are closely related to the texture and influence other aspects of post-process quality (Firouz, Alimardani, Mobli, & Mohtasebi, 2021). Due to the importance of the physical, mechanical, and thermal properties of agricultural products in the field of the development of automatic processing equipment (Wang, Ma, Fu, Cui, & Majeed, 2020), much research has been done to determine these properties for seeds (Bajpai, Kumar, Singh, Prabhakar, & Meghwal, 2020;Gade, Meghwal, & Prabhakar, 2020;Rokhbin, Azadbakht, & Asghari, 2021; grains (Carvalho, Polachini, Augusto, Telis-Romero, & Bon, 2021;Pohndorf et al., 2018), nuts (Kilanko et al., 2020;Kumar, Prabhakar, Srivastav, & Bhowmick, 2016), kernels (Habibiasr, Mokhtar, Ibrahim, Md Yunos, & Ibrahim, 2020;Razavi & Edalatian, 2012), and fruits (Tan, Tan, Ghazali, & Tan, 2021;Vahedi Torshizi, Khojastehpour, Tabarsa, Ghorbanzadeh, & Akbarzadeh, 2020). Although determining physical properties is more common than mechanical properties, there are reports that investigate the rupture force (Akar & Aydin, 2005;Sirisomboon, Kitchaiya, Pholpho, & Mahuttanyavanitch, 2007), rupture energy (Kılıçkan & Güner, 2008;Sirisomboon et al., 2007), toughness (Lucas et al., 2012;Sirisomboon et al., 2007), hardness (Nwanjika, Onuegbu, & Amaefule, 2017), modulus of elasticity (Mirzabe, Hajiahmad, & Asadollahzadeh, 2021b;Nwanjika et al., 2017), maximum normal contact stress (Mirzabe et al., 2021b;Nwanjika et al., 2017), and Poisson's ratio (Gładyszewska & Ciupak, 2009;Grotte, Duprat, Piétri, & Loonis, 2002) for agricultural crops. ...
To optimally design post-harvest handling and processing equipment for unripe green grape berries, it is necessary to determine the physical and mechanical properties of the product. In the current study, dimensional (by image processing), gravimetrical, frictional, and aerodynamic (by image processing) properties of unripe green grape berries affected by storage time (31 days in refrigerator) were investigated. Besides, rupture force, rupture energy, elasticity modulus, toughness, hardness, maximum compressive contact stress, Poisson's ratio (by image processing), and shear modulus in horizontal and vertical loading under different moisture content and loading rate levels were measured. Moreover, to model loading and stress-relaxation behavior of bulk berries, berries were poured into cylinder and compressed. Effects of cylinder diameter, loading rate, the height of layers, and number of layers on loading and stress-relaxation behavior were investigated. During storage, as the moisture content decreased from 94.57 to 83.88% (w.b.), dimensions and mass of the berries decreased while bulk density and true density increased. With decreasing the moisture, friction angles on galvanized, iron, and rubber were ranged from 22.43° to 26.73°, from 25.38° to 28.53°, and from 29.7° to 34.2°, respectively. Filling angle of repose ranged from 13.44° to 17.65° and emptying angle of repose ranged from 13.95° to 18.33°. In the mentioned moisture range, terminal velocity increased from 0.202 to 0.275 m s⁻¹, and drag coefficient increased from 0.180 to 0.272. Reducing moisture content and increasing rupture energy of the fruits during storage indicates that berries' juice should be extracted immediately after harvest.
Practical Applications
Unripe grape berries with a sour taste can be processed into several sour sauce and verjuice products. Therefore, determining the physical properties of unripe grape berries is essential for the design of harvesting and post-harvesting equipment. The current work aims to determine unripe grape berries' physical and mechanical properties to recognize their relevance in physico-mechanical processing. Some of the necessary information for designing and manufacturing harvesting and post-harvesting machines is provided in this research. Thus, the results provided in the present study would contribute to improving juice extractors, sorters, separators, cleaners, storage structures, dryers, aeration equipment, conveyors, pneumatic elevators, and so forth, designed for the unripe grape berries.
... Lavender leaves desorption isotherms were determined experimentally at 30 • C using the static gravimetric method (Habibiasr et al., 2020). Five saturated salt solutions were placed into separate tightly closed glass jars to maintain a constant water activity, namely KOH, Mg (NO 3 ) 2 , NaBr, NaCl and KCl having water activities ranging between 7.4 and 83.6%. ...
In the present work, an experimental and numerical study is performed for describing the unsteady heat and moisture transport occurring in Lavandula x allardii leaves during non-isothermal drying, for time-varying temperature profiles. Drying experiments were conducted in a laboratory-scale convective dryer for an initial temperature level of 40°C, ramping up to 60°C at different temperature advancing rates under a constant airflow velocity of 2 m/s. A simultaneous heat and mass transfer model under a nonconjugated approach is proposed for leafy products, considering conduction and liquid diffusion among the inner layers of leaves. A computational algorithm was developed to predict the temporal and spatial changes of temperature and moisture during processing. Numerical results were validated with the experimental dehydration curves. The proposed modeling approach was found adequately fast and accurate for simulating the non-isothermal drying process of herbal leaves and can be further utilized for product-specialized dryer design, control or process optimization.
... Estas propiedades pueden ser estudiadas a partir de las isotermas de adsorción y desorción sobre la cual influyen estos dos factores, además de la humedad relativa y la temperatura. (3) En el caso del secado es determinante saber el contenido de humedad de equilibrio del material ya que indica el contenido mínimo de humedad que puede alcanzar éste bajo distintas condiciones del agente secante. (4) La importancia de conocer el proceso de adsorción de moléculas de agua para la ciencia farmacéutica se basa en la capacidad para predecir cambios potenciales en la estabilidad de la droga seca, a la vez que es útil para seleccionar envases y prever la máxima humedad permitida durante el almacenamiento de la planta seca. ...
Introduction: Water molecules in plant materials are held together through attractive
forces or are strongly bound to an adsorbent substance. Because of this, the term
adsorption is used to denote the water-adsorbent interaction. Linden is a plant species
of the Acanthaceae family and for its drying the knowledge of the sorption processes of
this species is not always taken into account. Therefore, describing the equilibrium
isotherm of this plant is of paramount importance in predicting its shelf life.
Objective: To determine the adsorption isotherm of water molecules in the leaves of
Justice pectoralis Jacq. (linden).
Methods: To obtain the isotherm, the analytical technique of hygroscopic equilibrium
was used at a temperature of 27±2 ºC. The experimental values were adjusted using the
equations of GAB (Guggenheim, Anderson and Boer), BET (Brunauer, Emmett and
Teller), Henderson, Smith, DAW (D ́ Arcy-Watt), Halsey, Peleg and Caurie and the
curve obtained was classified.
Conclusions: The model that best adjusts the equilibrium moisture content values is
that of GAB, which describes the sigmoid behavior of the isotherm and classifies it as
Type III. It is shown that dried linden leaves have few adsorption points with relatively
strong bonds, so the process of moisture extraction during drying can be carried out in a
short time. The results indicate that to be stored safely in the climatic conditions of
Cuba, plant material must be dried to humidity between 5 and 8%.
Keywords: Acanthaceae; adsorption; isotherm; theoretical models; linden.
BACKGROUND
Palm kernel is the edible seed of the oil palm fruit obtained during the palm oil milling process. For efficient processing and storage, the moisture content of palm kernel must be reduced to an optimal level by drying. This study aimed to see how drying influenced the physical structure and physicochemical properties of palm kernel and oil. Before and after drying, the free fatty acid (FFA), color, fatty acid composition, Fourier transform infrared, thermal properties and structure of palm kernel were investigated.
RESULTS
Results show that drying significantly (P < 0.05) reduced FFA and color of palm kernel oil. Drying also significantly affected (P < 0.05) composition of some fatty acids in palm kernel oil such as capric acid, lauric acid, myristic acid, palmitic acid and oleic acid. However, drying did not affect palm kernel and palm kernel oil functional groups and thermal properties. After drying, structural damage of palm kernel was observed.
CONCLUSION
Based on these findings, the quality of kernel oil may be maintained after drying, and it can even be improved based on lower FFA content. © 2022 Society of Chemical Industry.
