Browsing by Author "Karhan, Mustafa"

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    Cevap yüzey metodu kullanılarak keçiboynuzu ekstraktında bulunan D-pinitolün nanofiltrasyon uygulamasıyla zenginleştirilmesinin optimize edilmesi
    (2020) Hacıoğlu, Ahmet; Zoua, Ursula Tania Assoumou; Yıldız, Melis; Kulcan, Aslı Arslan; Yavuz, İbrahim; Karhan, Mustafa
    Bu çalışmada keçiboynuzu ekstraktında bulunan D-pinitolün 1-5 kDa ayırma sınırı aralığında nanofiltreler kullanılarak zenginleştirilmesi amaçlanmıştır. Zenginleştirme aşamaları ekstraksiyon,durultma,adsorbanuygulaması ve nanofiltrasyon uygulamalarından oluşmaktadır. Nanofiltrasyon uygulamasını optimize etmek amacıyla Box-Behnken Cevap Yüzey Metodu (CYM) kullanılmıştır. Son aşamada elde edilen ürünün saflık kontrolü için D-pinitol içeriği, şeker kompozisyonu, toplamfenolik madde (TFM), toplam kuru madde (TKM) ve mineral madde kompozisyonları kullanılmıştır.Ekstraktlarda en yüksek D-pinitol konsantrasyonuna 5 kDa ayırma sınırındaki nanofiltrasyonda, 3 bar besleme basıncı, 25°C besleme sıcaklığı ve %83,3 permeat oranı koşullarında ulaşılmıştır. Bu koşullarda elde edilen permeat akısının D-pinitol içeriği 10,48 g/L olarak belirlenmiştir. Çalışmada ayrıca nanofiltrasyon prosesi için basınç, sıcaklık ve permeat/retentat oranı değişkenlerine bağlı bir optimizasyon modeli oluşturulmuş ve farklı koşullara bağlı olarak ekstraktların D-pinitol konsantrasyonundakideğişim yüksek doğrulukla (R2=0,91)matematikselolarak modellenmiştir. Bu modele bağlı olarak, keçiboynuzu ekstraktlarında en yüksek sakkaroz, TFM ve TKM miktarları D-pinitol konsantrasyonunun %8,7 olduğu koşulda belirlenmiştir.
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    Effect of process parameters on stevioside and rebaudioside a content of stevia extract obtained by decanter centrifuge
    (WILEY, 2021) Arslan Kulcan, Aslı; Karhan, Mustafa
    The aim of this research is to determine the possibility of decanter extraction for the isolation of steviol glycosides from stevia leaves. Extraction parameters such as temperature, time, and leaf/water ratio were optimized by using Response Surface Methodology. The optimal combination determined as a result of optimization studies was 25 degrees C, 1/27.6 leaf/water ratio, and 105 min extraction time. Under these conditions, experiments were carried out at three different speeds of 4,500, 4,900, and 5,280 rpm (2,264, 2,684, 3,117 g, respectively) in a decanter extraction system to investigate the effect of rotational speed. The amount of stevioside in samples obtained at 4,500, 4,900, and 5,280 rpm was 1080.82, 1919.18, and 2507.35 mg/L, respectively. The amount of rebaudioside A was 761.34, 1417.17, and 1801.93 mg/L, respectively. Results showed that the rotational speed of the decanter had a considerable effect on all the parameters examined. Practical applications Stevia is a product that is widely used in food formulations in the scope of combating obesity and diabetes. In this study, the decanter was applied for the first time to extract stevia leaves and optimum process conditions for decanter extraction of steviol glycosides were determined. It has been observed that stevia extraction can be successfully performed at 25 degrees C with high efficiency using decanter. The yield of the extract increased with increasing decanter rotational speed. The decanter extracted 73% of the total stevioside and rebaudioside A present in the leaves. The results of this study may be used by manufacturers who want to process the stevia plant with more economical and environmentalist approaches.
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    Quality stability of clear pomegranate juice treated with cyclodextrin
    (Springer, 2019) Kulcan, Aslı Arslan; Öziyci, Hatice Reyhan; Karhan, Mustafa
    Protective effect of cyclodextrin (CD) on some quality characteristics of clear pomegranate juice (CPJ) was investigated. CPJ with no CD addition (Control) and CPJ samples, subjected to different type (?-CD and Hydroxy propyl (HP-?-CD) and concentration (0.5, 1% and 2%) combinations of CD, were stored at 25 °C for 3 months. The changes in color characteristics (polymeric color and total color difference ? ?E), total phenolic content (TPC) and antioxidant activity (AA) of all PJ samples monitored at 1 month intervals. Although overall color change of the PJ samples was hardly perceived visually, none of the treatments were successful to protect the initial color of clear PJ technically (P > 0.05). Among the CD treatments, HP-?-CD with a concentration of 0.5% was found effective to prevent TPC and AA losses of PJ (P < 0.05). On the other hand, ?-CD addition did not cause any improvement in protecting color, TPC and AA of clear PJ during storage, compared to control juice. © 2019, Association of Food Scientists & Technologists (India).