Browsing by Author "Polat, Ahmet"

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    Application of Different Drying Techniques on Peach Puree
    (Ankara Üniversitesi, 2021-06-04) Polat, Ahmet; Taşkın, Onur; İzli, Nazmi; Ziraat Fakültesi
    In 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 (ΔE), 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.
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    Intermittent Microwave Drying of Apple Slices: Drying Kinetics, Modeling, Rehydration Ratio and Effective Moisture Diffusivity
    (Ankara Üniversitesi, 2020-03-05) İzli, Nazmi; Polat, Ahmet; Ziraat Fakültesi
    In this research, thin layer drying characteristics, rehydration ratio and effective moisture diffusivity of apple were investigated using microwave dryer which has intermittent and continuous modes. Drying time varied between 25 and 215 minutes and they declined with the rise in microwave power and reduction in pulsing ratio. In an attempt to pick the optimum thin layer models for the drying applications, 8 mathematical models suited to the experimental results. On the grounds of the statistical tests evaluation, Midilli et al model which represent drying characteristics are optimally suited than other models. The highest rehydration ratio was recorded for the samples dried at 100W continuous mode and the lowest ratio at 300W continuous application. Effective moisture diffusivity values were computed by the 2nd law of Fick and changing between 3.04x10-9 and 2.53x10-8 m2 s-1. Consequently, the intermittent microwave method could be used as a favorable drying method for obtaining high-quality fruit slices or processing valuable material and continuous microwave drying can be taken as another drying approach for apple samples.