Browsing by Author "Zihin YILDIRIM"

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    Determination of sweetpotato [Ipomoea batatas (l.) lam.] genotypes suitable to the Aegean Region of Turkey
    (2011) Zihin YILDIRIM; ÖZLEM TOKUŞOĞLU; Gülsüm ÖZTÜRK
    A total of ten sweetpotato genotypes were grown in a field trial in 2003 and 2004 and certain agronomical and quality characteristics were determined. Local variety Hatay Kirmizi (Hatay Red) was selected as suitable to the Aegean Region for storage root number (7.7) and storage root yield (8.1 tons /ha ) as well as acceptable quality characteristics: dry matter content: 41.8 %; sugar content: 2229.3 mg /kg; ßeta carotene 7.03 mg/100 g; vitamin A: 11716.3 IU; vitamin C: 38.6 Mg /100 g. Another introduced variety Regal was also selected for yield (6.6 ton /ha) and starch content (31.1 g/100 g), ßeta carotene (7.04 mg /100 g) and vitamin A (11745 IU) for the Aegean Region.
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    Effects of cooking methods on the anthocyanin levels and antioxidant activity of a local Turkish sweetpotato [ipomoea batatas (l.) lam] cultivar Hatay Kırmızı: Boiling, steaming and frying effects
    (2012) ÖZLEM TOKUŞOĞLU; Zihin YILDIRIM
    The study was conducted on the anthocyanin (TA) level and antioxidant activity (AA) of a local genotype of sweetpotato (Hatay Kirmizi) and heating process effects including boiling, steaming, frying on TA and AA levels. The anthocyanin calibration graph of standard cyanidin-3-glucoside gave linear equation (y= 0.0113x+ 0.0045 ; R2 = 0.9986). Anthocyanin level of sweetpotato Hatay Kirmizi (as cyanidin-3-glucoside (C3G) equivalent) was determined as 11992 ± 15.86 mg/100g) (n=8) (p≤0.05). Anthocyanins were detected as 13767 ± 8.94 mg/100g; 24756 ± 6.70 mg/100g; 6755 ± 10.22 mg/100g in boiled, steamed and fried sweetpotatoes, respectively (n=2) (p≤0.05). The total anthocyanins increased as 1.14 fold after boiling process and increased 3.22 fold after steaming process and decreased 1.78 fold after frying process (p≤0.05). It was determined that steaming process, was the most effective among the heat-treated sweetpotatoes (HTSPs). Antioxidant activities of the HTSPs was 78.76%, 89.67%, 97.92% and 57.89% (as radical inhibition percent), respectively. With using steaming process, radical inhibition percent increased 1.24 fold. Tubers of sweetpotato Hatay Kirmizi can be consumed not only steamed > boiled > fried forms but also can be processed into food products, such as muffins, cookies, biscuits, breakfast foods with longer shelf-life, and improved characteristics. It was proposed that sweetpotato Hatay Kirmizi can be processed into flour and used as a thickener, antioxidant enhancer and color source in industrial powder soups, gravy, extruder snacks, and some bakery products.