Drying characteristics of jujube (Zizyphus jujuba) slices in a hot air dryer and physicochemical properties of jujube powder

Elmas, Feyza; Varhan, Emine; Koç, Mehmet

doi:10.1007/s11694-018-9920-3

Cited by 28 publications

(24 citation statements)

References 33 publications

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“…The increments in D eff values may be explained by increasing temperature and vapor pressure inside the samples which lead to the diffusion of moisture rapidly toward the surface (Lee & Zuo, 2013). Similar results were obtained by Elmas, Varhan, and Koç (2019) for jujube slices (1.2–3.55 × 10 −9 m 2 s −1 ), Vega‐Galvez, Miranda, Diaz, Lopez, and Rodriguez (2010) for olive‐waste cake (1.71–2.03 × 10 −9 ), Rafiee et al (2010) for orange slices (0.62–3.50 × 10 −9 m 2 s −1 ) and Dadali, Kılıc‐Apar, and Ozbek (2007) for okra (2.05–11.91 × 10 −9 m 2 s −1 ).…”

Section: Resultssupporting

confidence: 91%

Microwave pre‐treatment for vacuum drying of orange slices: Drying characteristics, rehydration capacity and quality properties

Karabacak

Acoğlu

Ömeroğlu

et al. 2020

J Food Process Engineering

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Microwave pre‐treatment for vacuum drying is a promising method in order to enhance heat and mass transfer rate. In this study, the influences of microwave pre‐treatment (90 W 30 min) on vacuum drying conducted at different combinations of drying temperature and absolute pressure (60, 70, and 80°C with 15 and 30 kPa) were investigated by evaluating the drying characteristics, rehydration capacity, and some quality attributes of orange slices. The vacuum drying treatments were carried out both with (MWVD) and without the microwave‐pretreatment (VD) at the same temperature and absolute pressure combinations. It was revealed that application of MWVD shortened the drying time of orange slices while increasing drying rate, effective moisture diffusivity and rehydration capacity. Six different semi‐theoretical mathematical models were applied, and Page, Modified Page, Logarithmic, and Lewis models were best fitted to experimental data of orange slices. It was observed that, among the different drying conditions applied in the scope of the study, VD at 80°C–15 kPa caused lowest color change (ΔE) that indicates the difference between the dried and fresh orange slices. All drying treatments caused a reduction in ascorbic acid content (AAC) (56.24–59.34%), total phenolic content (TPC) (15.92–55.79%) and total antioxidant capacity (TAC) (6.05–35.18%, 21.03–42.28%, and 54.76–69.07% for DPPH, FRAP, and CUPRAC assays, respectively) of orange slices. When MWVD and VD were compared, it was observed that MWVD caused less decrease in TPC and more in AAC and TAC. In conclusion, MWVD method is suggested as the more effective method providing lower drying time, faster drying rate, and better quality parameters of the product. Practical applications Orange including various nutrients with health beneficial effects is a perishable fruit. Therefore it is processed in to frozen, dried, canned, jam and fruit juice forms in order to increase its shelf life. Especially in seasons with overproduction, orange can be processed into dried form, and it can be turned into an alternative healthy snack with increased commercial value. In this research, drying characteristics of orange slices by microwave pre‐treated for vacuum drying were assessed with mathematical modeling. Drying conditions affected rehydration capacity, total phenolic content (TPC), total antioxidant capacity (TAC), ascorbic acid content (AAC) and color values of orange slices. Based on those outcomes, the optimum process conditions for an industrial drying application can be designed to enhance heat and mass transfer rate and to improve quality attributes of the product.

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Section: Resultssupporting

confidence: 91%

Microwave pre‐treatment for vacuum drying of orange slices: Drying characteristics, rehydration capacity and quality properties

Karabacak

Acoğlu

Ömeroğlu

et al. 2020

J Food Process Engineering

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“…At lower velocities, the total drying time is longer. The decreasing of drying time with increasing of drying air temperature and air velocity has been reported for many agricultural products such as jujube slices (Elmas et al, 2019), potato slice, garlic, cantaloupe , mushroom slices (Ghanbarian, Dastjerdi, & Torki-Harchegani, 2016), beef (Ahmat, Barka, Aregba, & Bruneau, 2015). The effect of temperature on drying time is greater than that of the dryer air velocity in the process of drying the product (Darıcı & Sen, 2015).…”

Section: Drying Kineticmentioning

confidence: 95%

“…The product's drying curve moves downwards at a high gradient at the beginning of the process due to the evaporation of surface moisture, and after this time, due to the onset of water penetration from inside the material to the surface, the curve falls at a lower gradient level (Coskun, Doymaz, Tunçkal, & Erdogan, 2017). The reason for this phenomenon is that by increasing air velocity, the vapor pressure of the environment is reduced and, as a result, the MC of the product will face less resistance to exit and will be released more quickly (Elmas, Varhan, & Koç, 2019;Kaveh, Sharabiani, et al, 2018). As the temperature rises, the time required for the product to dry decreases due to increased moisture evaporation rate.…”

Section: Drying Kineticmentioning

confidence: 99%

Prediction kinetic, energy and exergy of quince under hot air dryer using ANNs and ANFIS

Abbaspour‐Gilandeh

Jahanbakhshi

Kaveh

2019

Food Science & Nutrition

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This study aimed to predict the drying kinetics, energy utilization (E u ), energy utilization ratio (EUR), exergy loss, and exergy efficiency of quince slice in a hot air (HA) dryer using artificial neural networks and ANFIS. The experiments were performed at air temperatures of 50, 60, and 70°C and air velocities of 0.6, 1.2, and 1.8 m/s. The thermal parameters were determined using thermodynamic relations. Increasing air temperature and air velocity increased the effective moisture diffusivity (D eff ), E u , EUR, exergy efficiency, and exergy loss. The value of the D eff was varied from 4.19 × 10 -10 to 1.18 × 10 -9 m 2 /s. The highest value E u , EUR, and exergy loss and exergy efficiency were calculated 0.0694 kJ/s, 0.882, 0.044 kJ/s, and 0.879, respectively. Midilli et al. model, ANNs, and ANFIS model, with a determination coefficient (R 2 ) of .9992, .9993, and .9997, provided the best performance for predicting the moisture ratio of quince fruit. Also, the ANFIS model, in comparison with the artificial neural networks model, was better able to predict E u , EUR, exergy efficiency, and exergy loss, with R 2 of .9989, .9988, .9986, and .9978, respectively. K E Y W O R D S adaptive neuro-fuzzy inference system, artificial neural networks, drying, quince, thermodynamic parameters | 595 ABBASPOUR-GILANDEH Et AL.focusing on energy and exergy analysis is very important (Lingayat, Chandramohan, & Raju, 2018;Yogendrasasidhar & Setty, 2018).Şevik, Aktaş, Dolgun, Arslan, and Tuncer (2019) analyzed the exergy and energy in the process of drying mint and apple slices in a solar and solar-infrared. The results indicated that the loss of exergy and exergy efficiency increases by increasing the air temperature. Exergy efficiency for mint in solar dryer and solar-infrared was 69.35% and 59. 07%, respectively. Akpinar, Midilli, and Bicer (2006) analyzed the energy and exergy in pumpkin. They reported that the pumpkin dried within the time range of 5.66-12 hr with a loss of exergy from 0 to 1.165 kJ/s. The maximum exergy of the system input was 2.198 kJ/s. Also, with increased exergy loss, the energy used in the solar dryer increased. Karthikeyan and Murugavelh (2018) studied the energy and exergy required to dry turmeric in a mixed-mode forced convection solar tunnel dryer and concluded that the loss of exergy and energy utilization ratio and its efficiency was increased with increasing temperature.

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“…The temperature dependence of effective diffusivity coefficient can be described by the Arrhenius equation (Eqn (7)):

D_{normaleff} = D_{0} \exp (- \frac{E_{a}}{R (T + 273.15)})

where D 0 is the pre‐exponential factor of the Arrhenius equation (in m 2 s −1 ); E a is the activation energy (in kJ mol −1 ); T is temperature of drying air (°C) and R is the universal gas constant (8.314 × 10 −3 kJ mol −1 K −1 ). Equation (7) can be changed into the form:

\ln D_{ef f} = \ln D_{0} - \frac{E_{a}}{R (T + 273.15)}

…”

Section: Methodsmentioning

confidence: 99%

Effects of sodium alginate‐based coating pretreatment on drying characteristics and quality of heat pump dried scallop adductors

et al. 2019

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Background Drying efficiency and quality maintenance are the major concerns of both manufactures and consumers. Heat pump drying (HPD) is suitable for heat sensitive foodstuffs due to its ability to independently control the drying operation parameters. However, lower drying rate and energy efficiency in the later period of HPD are the bottlenecks that restrain its application. A novel approach using hydrocolloids as pretreatment coatings prior to drying was designed to solve these problems. The effects of sodium alginate (SA) coating, drying temperatures and air velocities on the drying characteristics and quality attributes of scallop adductors were evaluated. Results Drying took place in the falling rate period. Drying time decreased with increasing temperature, air velocity and SA coating. The Two Term model and the Wang and Singh model gained the best fit for thin‐layer drying of scallop adductors and SA film, respectively. Effective moisture diffusivity increased with temperature, velocity and SA coating and were in the range 7.352–14.620 × 10−11, 9.890–17.100 × 10−11 and 2.348–4.604 × 10−10 m2 s−1 for uncoated scallop adductors, SA coated scallop adductors and SA films, respectively. The activation energies for SA films, coated and uncoated scallop adductors were 17.07, 20.78 and 26.17 kJ mol−1, respectively. Dried scallop adductors with SA coating pretreatment exhibited a significant lower value of shrinkage rate and hardness, and higher value of toughness than uncoated ones at 30 °C and 2.0 m s−1 (P < 0.05). Conclusion Hydrocolloid coating is a promising pretreatment in improving HPD efficiency and enhancing quality attributes of dried scallop adductors. © 2019 Society of Chemical Industry

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Drying characteristics of jujube (Zizyphus jujuba) slices in a hot air dryer and physicochemical properties of jujube powder

Cited by 28 publications

References 33 publications

Microwave pre‐treatment for vacuum drying of orange slices: Drying characteristics, rehydration capacity and quality properties

Microwave pre‐treatment for vacuum drying of orange slices: Drying characteristics, rehydration capacity and quality properties

Prediction kinetic, energy and exergy of quince under hot air dryer using ANNs and ANFIS

Effects of sodium alginate‐based coating pretreatment on drying characteristics and quality of heat pump dried scallop adductors

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