Browsing by Author "Tekin, Aziz"

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Effect of Priming Treatment on Germination at Stressful Temperatures, Fatty Acid, Sugar Content and Enzymatic Activity of Pepper Seeds
(Ankara Univ, Fac Agr, 2010) Kaya, Gamze; Demir, Ibrahim; Tekin, Aziz; Yasar, Fikret; Demir, Koeksal
This research was conducted to investigate the effects of priming (controlled hydration at 25 degrees C for 48 h) on germination at stressful temperatures (low 15 degrees C and high 35 degrees C), sugar content, total oil, fatty acid composition and enzymatic activities of pepper (Capsicum annuum L.) seeds in two consecutive runs. The experiments were conducted on pepper cultivars of Corbaci, Sera Demre 8 and Yalova Yaglik. Results revealed that priming enhanced germination of seeds of all cultivars at stressful temperatures. The highest increase in germination was determined in cv. Corbaci at (15 degrees C) with 12% and 35 degrees C with 21%. Priming decreased total oil content dependent upon cultivars. The highest decrease in oil content by priming was determined in Demre with 2.5-3.5%. On the other hand, fatty acid composition was not changed and the highest fatty acid of the seeds was linoleic acid (78.9%) followed by palmitic (9.16-11.79%) and oleic (7.28-11.40%). Priming resulted in decrease in sucrose which declined from 0.599% to 0.390% in Yalova Yaglik. Glucose was detected as trace in both control and primed seeds. The most important effects of priming on enzymatic activities were recorded in catalase which increased remarkably with priming in both runs. Catalase activity was measured in primed seeds with 11.2 mu mol min(-1) g(-1) and in control with 9.3 mu mol min(-1) g(-1) in run 1. They were determined as 16.6 mu mol min(-1) g(-1) and 9.6 mu mol min(-1) g(-1) in run 2, respectively. Even though not the same extent, priming also increased ascorbate peroxidase and superoxide dismutase activities.
Oxidative Changes in Hazelnut, Olive, Soybean, and Sunflower Oils During Microwave Heating
(Taylor & Francis inc, 2017) Javidipour, Issa; Erinc, Hakan; Basturk, Ayhan; Tekin, Aziz
The effects of microwave heating for 3, 6, and 9 min at a frequency of 2450 MHz on fatty acid composition, tocopherols, iodine value, free fatty acids (%), peroxide value, conjugated dienes and trienes, and hexanal contents of refined hazelnut, soybean, sunflower, and virgin olive oils were investigated. A significant (p < 0.05) decrease was observed in linoleic and linolenic acids contents of soybean oil during exposure to microwave heating. Tocopherol contents of oil samples significantly decreased (p < 0.05) during microwave heating. Free fatty acids of the samples slightly increased and iodine value showed reduction throughout the process. Conjugated dienes contents of samples showed an increasing trend up to the 6 min, followed by a reduction at 9 min. Conjugated triene fatty acids of all the samples significantly increased (p < 0.05) throughout the application. While peroxide value showed increasing trend up to the 3 min and sharply decreased at 9 min, hexanal contents of refined hazelnut, virgin olive, soybean, and sunflower oils increased 63, 28, 55, and 389 fold, respectively, after 9 min exposure to microwave heating. Kinetic analysis of data showed that the reaction orders for peroxide and hexanal formation were zero and first order, respectively, and in the tested oils the reaction rate followed the order: soybean oil ? sunflower oil ? hazelnut oil ? virgin olive oil for peroxide, and sunflower oil ? soybean oil ? hazelnut oil ? virgin olive oil for hexanal formation. It was concluded that hexanal could be considered as a parameter for evaluation of the quality of oils exposed to microwave heating.
Priming Uygulamasının Biber Tohumlarının Stres Sıcaklıklarında Çimlenme, Yağ Asitleri, Şeker Kapsamı ve Enzim Aktivitesi Üzerine Etkisi
(2010) Tekin, Aziz; Kaya, Gamze; Yasar, Fikret; Demir, İbrahim; Demır, Koksal
Bu araştırma, biber (Capsicum annuum L.) tohumlarında priming (kontrollü nemlendirme, 48 saat, 25°C) uygulamasının stres sıcaklıklarında (düşük 15°C ve yüksek 35°C) çimlenme, tohumun şeker, toplam yağ, yağ asitleri ve enzim aktivitesindeki değişimlere etkisini incelemek amacıyla iki tekrarlı olarak yürütülmüştür. Araştırmada Çorbacı, Sera Demre 8 ve Yalova Yağlık çeşitleri kullanılmıştır. Priming ile çimlenme oranında kontrole göre en yüksek artış Çorbacı çeşidinde %12 ile 35°C’de, %21 ile de 15°C’de belirlenmiştir. Priming uygulaması biber tohumlarında toplam yağ oranını çeşitlere bağlı olarak farklı seviyelerde azaltmış, uygulama ile yağ oranında gözlenen en fazla düşüş Demre çeşidinde %2.5-3.5 olarak belirlenmiştir. Yağ asitleri kompozisyonu uygulamaya bağlı olarak değişmemiştir. Biber tohumlarının çeşit ve yıllara bağlı olarak %78.9 ile en yüksek düzeyde linoleik asit, %9.1-11.7 ile palmitik ve %7.2-11.4 ile de oleik asit kapsadığı saptanmıştır. Uygulama sakaroz oranını azaltmış ve %0.599’ dan %0.390’a düşerek en önemli değişimi Yalova Yağlık çeşidinde göstermiştir. Glukoz ise uygulama ve kontrolde çok düşük seviyelerde bulunmuştur. Uygulamanın enzimatik değişimler bakımından en önemli etkisi, katalaz’da gözlenmiş, her iki tekrarda da uygulanmış tohumlarda bu enzim kapsamı kontrole göre daha yüksek ve istatiksel olarak farklı (P<0.05) bulunmuştur. Uygulanmış tohumlarda katalaz enzim aktivitesi birinci tekrarda 11.2 iken, kontrolde 9.2 μmol min-1 g-1 olarak belirlenmiştir. Đkinci tekrar için bu değerler, 14.9 μmol min-1 g-1 ve 11.1 μmol min-1 g-1 olarak saptanmıştır. Askorbat peroksidaz ve süperoksit dismutaz enzimlerinde de uygulama ile artış olduğu gözlenmiştir.
Utilization of Zero-Trans Non-Interesterified and Interesterified Shortenings in Cookie Production
(Springer india, 2014) Dinc, Saliha; Javidipour, Issa; Ozbas, Ozen Ozboy; Tekin, Aziz
The effects of zero-trans chemically interesterified (in-es) and non-interesterified (non-in-es) cottonseed (CO), hazelnut (HO) and olive oil (OO) and their blends (25, 50 and 75%) with palm oil (PO) were studied in the production of cookies. All the experimental shortenings had zero-trans fatty acids (TFA) while the shortening contained 14.20% TFA. Incorporation of CO in PO considerably increased the linoleic acid content whereas the raising of HO and OO ratio in the blend increased the oleic acid content. Zero-TFA and lower saturated /unsaturated fatty acid ratio (SFA/UFA) of some of the experimental shortenings indicated an important in nutritional properties of cookies produced from these experimental shortenings. Cookies with in-es shortenings showed significantly higher (p < 0.05) spread ratios and L Hunter color than their non-in-es shortenings added counterparts. It can be concluded that chemical interesterification is a promising method to produce cookie shortenings with zero-TFA.