Yazar "Dogan, Mahmut" seçeneğine göre listele

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    Exposure to Air Accelerates the Gelation of Gelatin: Steady and Dynamic Shear Rheological Characterization to See the Effect of Air on the Strength of Gelatin Gel
    (Taylor & Francis Inc, 2016) Karaman, Safa; Cengiz, Ebubekir; Kayacıer, Ahmed; Dogan, Mahmut
    In the current study, the effect of air exposure to the gelatin solution on improvement of gel structure was investigated in terms of the steady and dynamic shear rheological properties. Prepared gelation solution (5% w/v) was covered to prevent air incorporation and it was subjected to 5 h gelatin and rheological analyses were carried out for the comparison of non-covered ones. It was observed that the preventing of air into the gelatin solution affected the rheological parameters. Apparent viscosity and complex viscosity values of samples increased during gelation and these values were measured to be tremendously high (1.894 and 8.346 Pa s, respectively) in non-covered gelatin solution while they were 0.474 and 1.611 Pa s in covered samples after 5 h gelation, respectively. Similarly, storage modulus (G) of samples increased with the increase in gelation time and it was recorded to be 52.203 Pa in gelatin solution exposed to air while it was 9.848 Pa in gelatin solution covered to prevent air incorporation. These results showed importance of air in gelatin solution to the food industry using gelatin in food formulation for the structure of processed foods.
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    Investigation of fatty acid composition and trans fatty acid formation in extracted oils from French-fried potatoes and classification of samples using chemometric approaches
    (Tubitak Scientific & Technical Research Council Turkey, 2015) Yildirim, Elif; Toker, Omer Said; Karaman, Safa; Kayacıer, Ahmed; Dogan, Mahmut
    The present study investigates fatty acid composition and trans fatty acid formation in oils extracted from French-fried potatoes, which were produced in the laboratory and collected from different restaurants. Potatoes were fried at 180 degrees C at different frying periods (1, 7, 13, 19, 25, and 31 min) and the fatty acid composition of the extracted oils was determined. Principal component analysis and hierarchical cluster analysis were used to characterize and classify the samples. Four major fatty acids were identified in the samples, namely palmitic acid, stearic acid, oleic acid, and linoleic acid. Linolelaidic acid (C18:2 trans) was detected in the oil samples extracted from potatoes fried in margarine. Three principal components (PCs) and 4 main clusters were obtained from the chemometric analysis, which characterized the samples. Three PCs were found to be explanatory of more than 84.96% of the total variability in the data set.
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    Production of deep-fried corn chips using stale bread powder: Effect of frying time, temperature and concentration
    (Elsevier Science Bv, 2017) Yuksel, Ferhat; Karaman, Safa; Gurbuz, Melek; Hayta, Mehmet; Yalcin, Hasan; Dogan, Mahmut
    In this study, utilization of stale bread powder was evaluated to produce low fat snack food formulation and for this purpose, corn chips were manufactured using stale bread at different concentrations. Response surface modeling technique was used to study the simultaneous effects of stale bread level (0 -50%), frying time (40-60 s) and frying temperature (170-190 degrees C) on some physicochemical, textural and sensory properties of corn chips enriched with stale bread powder. Also, optimization of processing variables was performed for desired products. Results indicated that the addition of stale bread into the formulation decreased the oil content of the final product up to addition of 25% stale bread level. The hardness and yellowness of samples decreased with the increasing of stale bread level; while, the dry matter and ash contents as well as firmness value and sensory scores of samples increased with the increasing stale bread level. Generally, corn chips produced with the addition of stale bread were more preferred by the panel compared to control samples. (C) 2017 Published by Elsevier Ltd.
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    A response surface methodology study on the effects of some phenolics and storage period length on vegetable oil quality: change in oxidation stability parameters
    (Tubitak Scientific & Technical Research Council Turkey, 2014) Karaman, Safa; Toker, Omer Said; Ozturk, Ismet; Yalcin, Hasan; Kayacıer, Ahmed; Dogan, Mahmut
    In the present study, response surface methodology was conducted for the determination of effects of some phenolics (gallic acid, ellagic acid, and quercetin) on some stability parameters of mixed oil prepared with sunflower and hazelnut oils (50:50, v/v). In this respect, peroxide value (PV), free fatty acids (FFAs), p-anisidine value, induction period, and refractive index of mixed oil were investigated. Predictive regression equations were constructed for the estimation of each studied parameter (R-2 > 0.861). The storage period caused a significant increase in the peroxide value, FFAs, p-anisidine, and refractive index values of the mixed oil, while it decreased the induction period value of oil (P < 0.01). The addition of gallic acid significantly retarded oxidation (P < 0.05), and in general gallic acid and quercetin were found to be effective for preserving oil against oxidation.
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    Steady shear rheological characteristics of model system meat emulsions: Power law and exponential type models to describe effect of corn oil concentration
    (Springer India, 2015) Karaman, Safa; Yılmaz, Mustafa Tahsin; Kayacıer, Ahmed; Dogan, Mahmut; Yetim, Hasan
    The effect of oil concentration (57.50, 58.75, 60.00 and 61.25 %) and temperature (5, 10 and 15 degrees C) on steady shear rheological properties of O/W model system meat emulsions were investigated. The effect of temperature and oil concentration was modeled using power law and exponential type functions. The meat emulsions showed non-Newtonian flow behavior because flow behavior index was lower than unity. Consistency coefficient and flow behavior index values of O/W model system meat emulsions were calculated using Oswald de Waele model with higher coefficients of determination. Apparent viscosities of emulsions at a specified shear rate (50 s(-1)) were in the range of 0.652-0.941 Pa s. Increasing oil concentration provided an increase in apparent viscosity and increase in temperature levels resulted a decrease in consistency coefficient values. The exponential function performed better than the power-law function (R-2>0.922) in terms of describing the effect of oil concentration on the steady shear rheological properties of the model system meat emulsions. Higher coefficients of determination (R-2=0.979-0.999) were observed in exponential-type function compared to a power law function (R-2=0.880-0.946).