Browsing by Author "POLAT, AHMET"
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Publication Application of different drying techniques on peach puree(Ankara Üniversitesi, 2021-01-01) Polat, Ahmet; Taşkın, Onur; İzli, Nazmi; POLAT, AHMET; TAŞKIN, ONUR; İZLİ, NAZMİ; Bursa Uludağ Üniversitesi/Ziraat Fakültesi/Biyosistem Mühendisliği Bölümü; 0000-0002-5741-8841; 0000-0002-2084-4660; 0000-0003-1673-7165; R-7996-2016; AAG-8333-2021; AAH-5018-2021In this study, six various applications were performed to dry peach puree using methods of convective drying (CD), microwave drying (MW1, MW2 and MW3) and combined convective-pulsed microwave drying (CD+MW2 and CD+MW3). Effect of drying on time, color, pH, Brix and micrographs were evaluated. The data of total drying time revealed that the maximum value was belonged to "CD" (220 min). The minimum value was obtained by "MW1" (10 min). By comparison of total color change (.E), the highest values were achieved with "CD+MW3", whereas the lowest values were achieved with "MW2". Under all drying applications, the maximum pH and Brix changes were observed with "CD+MW2". From the microstructure, the samples to which the microwave method was applied displayed a collapsed structure as to the sample dried by the convective method.Publication Drying characteristics and quality evaluation of 'Ankara' pear dried by electrohydrodynamic-hot air (EHD) method(Elsevier, 2022-04-01) Polat, Ahmet; İzli, Nazmi; POLAT, AHMET; İZLİ, NAZMİ; Bursa Uludağ Üniversitesi/Ziraat Fakültesi/Biyosistem Mühendisliği Bölümü; 0000-0003-1673-7165; R-7996-2016; AAG-8333-2021The fruits are seasonal and usually available at a particular season of the year. The post-harvest processes are applied to ensure that the products are consumed throughout the year. Drying is one of the most important postharvest processes, and the hot air method is generally used. In this study, 'Ankara' pear samples were dried by combining the electrohydrodynamic method, a promising drying technology, with hot air. This study aims to investigate the effects of different air velocity and voltage values on drying time, color, rehydration capacity, and microstructure. In addition, ten mathematical drying models were applied to the experimental results of the drying processes to obtain the model that best explains the drying curves. Two different air velocities (1.5 and 2.5 m/s) and four different voltage values (15, 20, 25, and 30 kV) were used for the drying processes. The process of drying pear products in the shortest time (80 min) was in the application of 30 kV-2.5 m/s. The models that best explain the drying curves of 'Ankara' pear were found to be the Logarithmic and Midilli et al. models. While the highest L* value was observed in the fresh product, the closest value to this value was observed in 15 kV-1.5 m/s applications. Rehydration capacity values of pear samples dried at high voltage values (25 and 30 kV) increased with increasing air velocity. The EHD-hot air method used in this study can be an alternative to conventional drying and can be a viable method in the drying industry by determining the appropriate air velocity and voltage value in order to provide better quality products in a short time.Publication Influence of ultrasound pre-treatment and convective drying on the quality parameters of carrots ( Daucus carota l.)(Plapiqui(uns-conicet), 2022-01-01) Polat, Ahmet; İzli, Nazmi; Taşkın, Onur; POLAT, AHMET; İZLİ, NAZMİ; TAŞKIN, ONUR; Uludağ Üniversitesi/Ziraat Fakültesi/Biyosistem Mühendisliği Bölümü; 0000-0002-5741-8841; R-7996-2016; AAG-8333-2021; AAH-5018-2021In this study, carrot samples with different slice thicknesses (2 and 4 mm) were dried by applying ultrasound pre-treatment at different time periods (0, 20 and 40 min) and the changes in colour, rehydration, pH and degrees Brix values were evaluated. Besides, microstructures of dried samples under different conditions were observed through scanning electron microscopy images. Drying was carried out in a modified oven at temperatures of 60 and 70 degrees C with an air velocity of 1 m/s. When compared to fresh potatoes, a decrease in yellowing values (b*) was observed for the different drying conditions employed. Carrots samples with a thickness of 2 mm, dried at 60 degrees C and treated with ultrasound for 40 min, presented the highest rehydration ratio (6.930). It was observed that pH and degrees Brix values changed from 6.705 to 6.120 and from 68.70 to 6.80, respectively. It was observed that the longer the duration of pre-treatment with ultra-sound, the greater the change in the structure of the product. The results showed that the pre-treatment by ultrasound can be used as an alternative method for drying carrot sample.Publication Investigation of potato drying kinetics and quality parameters applying ultrasound pre-treatment(Plapiqui(uns-conicet), 2020-01-01) Polat Ahmet; İzli, Nazmi; POLAT, AHMET; İZLİ, NAZMİ; Bursa Uludağ Üniversitesi/Biyosistem Mühendisliği Bölümü; AAG-8333-2021; R-7996-2016In this study, the effect of ultrasound pre-treatment on quality parameters (colour, rehydration, pH and degrees Brix) of potato samples was investigated. In addition, the drying kinetics of the potato samples was evaluated and ten different thin-layer mathematical models were fitted to experimental data to select the best model for the drying processes. Two different slices of potato samples (2 and 4 mm) were ultrasound pre-treated for 0, 20 and 40 min before drying. Drying was carried out in a modified oven at 60 and 70 degrees C at an air velocity of 1 m/s. As the ultrasound pre-treatment time applied to the samples increased, the drying time of the product decreased. Drying rate decreased with increasing product slice thickness. When compared to fresh potatoes, a decrease in yellowing values (b*) was observed for the different drying conditions employed. Rehydration ratio values under all conditions ranged from 2.856 to 2.640. Potato samples with a thickness of 4 mm, dried at 60 degrees C without ultra-sound pre-treatment, presented the highest pH value. The potato samples of 2 mm thick-ness, dried at 70 degrees C and treated with ultrasound for 40 min, showed the content of water-soluble solids (degrees Brix) closest to the fresh product. The results showed that the pre-treatment by ultrasound can be used as an alternative method for drying potato with hot air.