Sürdürülebilir Kalkınma Amaçları

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• MakaleAçık Erişim2025/r/munzur/6133
  Determination of Suitable Drying Model and Energy Efficiency of Mixed Culture Microalgal Biomass by Infrared Drying

  Yoğurtçu, Hakan; Kalender, Mehmet

  In this study, a modeling approach using infrared (IR) drying data of mixed-culture algae, an energy efficiency analysis of the drying process, and some surface proper-ties of the dried product were presented. New model equations derived from com-monly known drying models were applied to experimental data obtained from drying microalgal biomass at various temperatures ranging from 5 to 105 °C. Among these, the DM13 equation, based on the Newton model, best represented the drying behav-ior. The specific moisture extraction rate (SMER) and moisture extraction rate (MER) increased with higher drying temperatures, while, as expected, the specific energy consumption (SEC) decreased. According to the energy efficiency analysis, the IR drying method can be considered suitable for drying microalgal biomass. FT-IR re-sults indicated characteristic green algae peaks attributed to components such as carbohydrates, proteins, and cellulose–fatty acids. Peaks at 2900 cm⁻¹ and 3386 cm⁻¹ decreased with increasing drying temperature and disappeared at 105 °C. SEM imag-es showed that microalgal cells experienced shrinkage at 60 °C. Furthermore, while dried microalgal biomass exhibited a porous structure at 50 °C and 60 °C, pores were almost absent at 70 °C and 105 °C.

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  İncele
• MakaleYalnız künye2024Scopus SJRQ2/r/munzur/2176
  Evaluation of effect of boric acid on thermoplastic starch: Morphological, mechanical, barrier, and optical properties

  Yoğurtçu, Hakan; Gürler, Nedim

  In this study, starch was modified with different amounts of boric acid, and the degree of substitution of the synthesized compounds at different temperatures and times was determined by Fourier transform infrared (FTIR) and titration methods. The degrees of substitution in both methods showed similar tendency. Optimum conditions were determined, and thermoplastic starch (TPS) and boric acid (B) films were prepared by casting method using glycerol as plasticizer. The morphological properties of the films were studied by scanning electron microscope-energy dispersive spectrometry (SEM-EDS). According to the FTIR results, it was observed that the B-O and B-O-C stretching vibrations increased when the amount of boric acid increased. The tensile strength, water barrier (swelling capacity, solubility, and water vapor permeability), and optical properties of samples were investigated. The swelling capacity, solubility, and water vapor permeability of the films decreased with the addition of 0.5% boric acid to the starch, but the highest tensile strength was achieved. The tensile strength for TPSB0.5% increased compared to control group TPS. In addition, the film showed the highest transparency. Thermoplastic film containing 0.5% boric acid can be used as a packaging material due to its improved mechanical and water barrier. Highlights: The thermoplastic starch and boric acid composite were successfully produced. The presence of boric acid was confirmed by energy dispersive spectrometry (EDS). The degree of substitution was determined by two different methods. Transparency increased with the addition of boric acid. Tensile strength improved with boric acid content.

  AtıfScopus26·WoS25·OpenAlex27

  İncele
• MakaleAçık Erişim2019Scopus SJRQ2/r/munzur/3337
  Optimization of microwave apple drying using response surface method; [Yanit yüzey metodu kullanarak mikrodalga ile elma kurutmanin optimizasyonu]

  Yoǧurtçu, Hakan

  In this study, the effects of microwave output power and slice thickness on microwave drying of apple slices were studied by using response surface method (RSM) in a modified domestic microwave oven. For experimental design, the central composite rotatable design approach was used. The values of response variables, effective diffusion coefficient, drying rate constant, color change, Hue angle, total drying time and energy consumption, were determined from the experiments performed under design conditions. It was seen that the obtained second order polynomial equations successfully represent the response variables. The results of analysis of variance (ANOVA) and response surface curves revealed that microwave output power and slice thickness were significantly effective on response variables. The effects of the independent variables on the responses and the significance level of these effects were evaluated statistically and the optimum drying conditions were determined for the aims of min color change, total drying time, energy consumption and max Hue angle. Verification experiments were performed with a maximum of 9.54% error at the recommended optimum test conditions. It has been shown that the response surface method can be successfully applied in the microwave drying of apples.

  AtıfScopus6·WoS5·OpenAlex3·TR Dizin3

  İncele
• MakaleYalnız künye2018Scopus SJRQ3/r/munzur/4766
  TIME-INDEPENDENT RHEOLOGICAL BEHAVIOUR OF PEANUT BUTTER: MODELLING AND ARTIFICIAL NEURAL NETWORK APPLICATION

  Yogurtcu, Hakan

  In this study, the rheological behaviour of semisolid peanut butter samples with a fat ratio of 42.7 % were examined in a temperature interval of 10-50 degrees C via rotational rheometer at different shear rates. Peanut butter samples display non-Newtonian yield-pseudoplastic behaviour. Seven model equalities were used for representing the time-independent rheological behaviour of peanut butter and the representation ability of the models were determined by way of determination coefficient (r(2)), mean absolute percentage error (MA%E), chi-square (chi(2)) and root mean square error (RMSE) statistical parameters. It was observed that the O'foli model was the most successful among the models applied to experimental data. Temperature dependency of viscosity at shear rates of 0.1, 0.4 and 0.75 s(-1) was determined via Arrhenius equality and activation energies varied between the interval of 46818.63-51952.52 J/mol. Three-layer model suggested for estimating viscosity using artificial neural network method was observed to be quite successful.

  İncele
• MakaleYalnız künye2016/r/munzur/5447
  Experimental Study and Mathematical Modeling on Thin Layer Microwave Drying of Zucchini (C. pepo) Slices

  Yoğurtçu, Hakan

  In this study, drying behavior of zucchini (C. pepo) that is a species of Cucurbitaceae family was investigated in microwave oven. Zucchini slices with 3, 6 and 8 mm thick were dried at different microwave output powers (90, 180, 360, 600 W at 2450 MHz frequency) by using domestic microwave oven and monitored pairs of drying time and zucchini mass. It was observed that drying rate of zucchini slices increased with increasing of the microwave output power. On the other hand the drying time for the final moisture contents of zucchini slices increased with increasing of the thick of them. Ten thin layer drying models, available in the literature, were used to evaluate the experimental data. It was observed that Weibull Distribution and Midilli et al. models among the models used are the best mathematical models represented the microwave drying behavior of zucchini slices.

  AtıfTR Dizin1

  İncele
• MakaleYayıncıda açık erişim2016Scopus SJRQ3/r/munzur/4875
  Determination of Drying Kinetics of Tunceli Garlic with Microwave Drying Technique

  Yogurtçu, Hakan

  In this study, drying kinetics of 4 mm-thick slices of Tunceli garlic (Allium tuncelianum) was investigated by using microwave technique at an interval of 90-600 W microwave output power. Ten mathematical models were used to represent the experimental data in this study. The determination of coefficient (R-2), root mean square error (RMSE), chi-square (chi(2)) and percentage error (E%) values that show compatibility to these models were determined. The determination of coefficient (R-2) values were found to vary at an interval of 0.9440-0.9993. The Midilli et al model was determined to be the best model that represents the experimental data. It was seen that drying rate increases with the increase in microwave output power (P) and decreases with the increase in sample mass (m). Effective diffusion coefficients (D-eff) and drying rate constants (k) were determined for different sample masses at microwave output power of 90 W. Activation energies for both effective diffusion coefficients and drying rate constants were determined by using an Arrhenius type exponential equation. Activation energies from effective diffusion coefficients and drying rate constants were found as 3.85 W g(-1) and 3.99 W g(-1) respectively.

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  AtıfWoS2·OpenAlex3

  İncele
• MakaleYalnız künye2014/r/munzur/5556
  Lemon Drying in Microwave Oven: Kinetics and Modeling

  Yoğurtçu, Hakan

  Thin-layer drying kinetics of lemon was investigated by using microwave oven in this study. Lemon sliceswith 8 mm thick were dried at different microwave output power (90, 180, 360, 600 W at 2450 MHz frequency)and monitored pairs of drying time and lemon mass. It was observed that drying rate of lemon increased withincreasing of the microwave output power. The final moisture contents of lemon for 90, 180, 360 and 600 Wmicrowave output power were obtained at end of 52, 16, 8 and 5.5 min drying time, respectively. Page,Henderson & Pabis and Logarithmic thin layer drying models, available in the literature were used to evaluatethe experimental data. All the models were compared according to statistical parameters; i.e. model efficiency(R2), chi-square (2) and root mean square error (RMSE). It was observed that Page model among the modelsused is best mathematical model represented the microwave drying behavior of lemon.

  AtıfTR Dizin5

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