Kahraman, Kevser
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Kahraman, K. Kahraman, Kevser Kahraman, Keyser
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Prof. Dr.
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kevser.kahraman@agu.edu.tr
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02.07. Malzeme Bilimi ve Nanoteknoloji Mühendisliği
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Book Part Ionizing Radiation(CRC Press, 2024-09-13) Braşoveanu, Mirela M.; Emlek, Betul Oskaybaş; Sabbaghi, Hassan; Kahraman, Kevser; Muti, Serpil Ozturk; Sher, Farooq; Nemţanu, Monica R.Ionizing radiation processing has demonstrated the potential to bring significant transformations in both the structure and functioning of starch. These modifications cover crucial features, including granular and molecular characteristics, pasting properties, rheological attributes, and gelatinization behavior. This comprehensive chapter aims mainly to provide a consolidated overview of the key findings that have been made recently about major alterations in the fundamental attributes of starch generated by diverse plant sources when exposed to ionizing radiation processing. Beyond articulating these modifications, the chapter explores other relevant topics, including analytical methods employed for characterizing irradiated starch, clarification of the radiation-induced reaction mechanism, and a discussion on safety considerations and regulatory frameworks associated with the utilization of ionizing radiation for treating starch within the context of food-related applications. Furthermore, based on all the highlighted elements, future research directions are proposed, with a focus on characterizing and defining the internal structure of irradiated starch, as well as exploring the functionalities of radiation-modified starches in both innovative and traditional food formulations. © 2024 Elsevier B.V., All rights reserved.Book Part Citation - Scopus: 7Starch(Elsevier, 2023) Köksel, Hamit F.; Muti, Serpil Ozturk; Kahraman, KevserStarch is the major source of carbohydrates in the human diet. It occurs in most plants in granules, which are usually between 1 and 100µm in diameter, depending on the plant source. Starch is the major component in cereals, comprising 60%-75% of the grain weight. Besides its nutritive value, starch is a valuable component because it affects the physical properties of foods. Different starches have characteristic features, varying in molecular structure, morphological properties, crystallinity, gelatinization and pasting, and enzyme digestibility. In recent years, modified starches and enzyme-resistant starches have also gained importance because of their functional benefits in foods. In addition, starch is an important industrial raw material in products like syrups, ethanol, textiles, and paper. This chapter explains the molecular structure of starch, its physical, physicochemical, and functional properties, as well as modified and resistant starches, focusing on the starches in cereal grains. © 2023 Elsevier B.V., All rights reserved.Article Citation - WoS: 10Citation - Scopus: 14Modelling the Effects of Debranching and Microwave Irradiation Treatments on the Properties of High Amylose Corn Starch by Using Response Surface Methodology(Springer, 2018-04-28) Mutlu, Selime; Kahraman, Kevser; Severcan, Sebnem; Ozturk, SerpilResponse surface methodology was applied to determine the effects of pullulanase debranching, microwave irradiation time (2-4 min) and power (20-100%) on resistant starch (RS) formation and in-vitro glycemic index (GI) values in high amylose corn starch, Hylon VII. Starch:water (1:10) suspensions were cooked and autoclaved, debranched with pullulanase (1000 PUN/g; 1500 U/kg starch) at 60 A degrees C and then different microwave-storing cycles and drying (oven or freeze drying) processes were applied. In order to describe the relationship between the dependent and independent variables (microwave power and irradiation time), the response values were fitted by first order polynomial regression models. Significance analysis showed that microwave irradiation time had significant effect on RS content and GI value of the samples treated with one cycle of microwave-storing prior to freeze-drying. Microwave power had significant factor on the GI value of the samples that were oven-dried after one cycle of microwave-storing. Solubility and water binding capacity values of all heat treated samples were higher than those of native starch. On the other hand, RVA viscosity values were lower than native starch for oven-dried samples. Water binding capacity, solubility and final viscosity values of the freeze-dried samples were higher than those of oven-dried ones.Master Thesis Omega-3 Yağ Asitlerinin Nişasta Nanopartiküllerle Stabilize Edilmiş Emülsiyonlar İçine Enkapsüle Edilmesi(Abdullah Gül Üniversitesi, Fen Bilimleri Enstitüsü, 2021) Korkut, Ayşe; Kahraman, KevserBu tez çalışmasının temel amacı emülsiyon stabilizatörü olarak kullanılacak nişasta nanopartiküllerini üretmektir. Tezin ilk bölümünde asit hidrolizi ile nişasta nanopartikülleri üretilmiş ve nişasta nanopartikülleri morfolojik özellikler ve boyut, kristalinite ve yapısal özellikler açısından karakterize edilmiştir. Pickering emülsiyonlar, iki farklı yağ fraksiyonunda (Φ0.6 ve Φ0.8) ve farklı yağlarla (ayçiçeği ve mısır yağı) hazırlanmıştır. En iyi emülsiyon stabilitesini sağlayan nişasta nanopartikülünü belirlemek için emülsiyonlar %2 nişasta nanopartikülü (mg nişasta/g emülsiyon) ilavesiyle hazırlanmıştır. Emülsiyonlar, oda koşullarında 30 gün süreyle depolanmış ve faz ayrımı olup olmadığı gözlenmiştir. En stabil emülsiyon, Φ0.6 yağ fraksiyonunda mısır yağı ile 1:3 nişasta:H2SO4 oranı (1:3 (3)) ile 3 gün hidrolize edilmiş nişasta nanopartikülü (%2) kullanılarak hazırlanmıştır. Tezin ikinci bölümünde, omega-3 yağ asitleri Pickering emülsiyonlar içine enkapsüle edilmiştir. Omega-3 kaynağı olarak keten tohumu yağı seçilmiştir. Emülsiyonlar, %3 oranında nişasta nanopartikülleri (1:3(3)) ilavesiyle Φ0.2 yağ fraksiyonunda hazırlanmıştır. Emülsiyonlar 25±1°C' de 15 gün depolanmış ve depolama sırasında emülsiyonlardaki değişiklikler fiziksel stabilite, peroksit sayısı, pH, partikül boyutu ve zeta potansiyeli açısından incelenmiştir. Omega-3 yağ asitlerinin enkapsüle edilmesi için kullanılan nişasta nanopartikülleri ile stabilize edilen Pickering emülsiyonlar, keten tohumu yağını birincil oksidasyona karşı daha dirençli hale getirmiştir.Article Citation - WoS: 5Citation - Scopus: 5Development of Buckwheat Starch-Capric Acid Complex-Based Film: Process Optimization and Film Characterization(Wiley-VCH Verlag GmbH, 2025-02-26) Koca, Esra; Kahraman, Kevser; Oskaybas-Emlek, Betul; Ozbey, Ayse; Aydemir, Levent YurdaerTo overcome the limitations of starch usage alone, the film formation ability of the buckwheat starch-capric acid complex (BS-CA) was optimized, and the films were characterized. Significant models were obtained for tensile strength (TS) and Young's modulus (YM) of BS-CA film (p < 0.0001). The glycerol/starch ratio, temperature, and their interactions were significant in the YM model (R-2 is 0.9851). The BS-CA film had a better water vapor barrier (0.463 +/- 0.02 g mm/m(2) h kPa), with lower water solubility (WS) (34.18 +/- 1.70%) and moisture content (MC) (16.87 +/- 0.09%) than the buckwheat starch (BS) film (p < 0.05). It had lower thickness (0.073 +/- 0.00 mm) and TS (0.624 +/- 0.04 MPa) but higher elasticity (114.60 +/- 3.12%). The non-covalent interactions were determined between BS and CA, since new peaks were not observed in the film's FTIR spectrum. BS-CA film had a typical V-type crystalline structure and had slightly lower decomposition temperatures than the BS film. Contact angle measurements (55.19 degrees +/- 1.7), and images of AFM topography and SEM showed that the BS-CA film surface was hydrophilic; height and average roughness values were 1014 and 276 nm, respectively, which were quite higher than those of BS film. The results reveal that starch modification with fatty acid is a promising way to develop starch-based films to be used in practical applications.Article Citation - WoS: 21Citation - Scopus: 23Effects of Resistant Starch Type 4 Supplementation of Bread on in Vitro Glycemic Index Value, Bile Acid-Binding Capacity, and Mineral Bioavailability(Wiley, 2019-10-28) Aribas, Merve; Kahraman, Kevser; Koksel, HamitBackground and objectives RS4 is an alternative dietary fiber source with some potential physiological benefits giving better quality end products. Common dietary fiber sources including bran usually have deteriorative effect on color, textural properties, and consumer acceptability of breads. This study was designed to investigate the effect of RS4 supplementation on the bread quality as well as mineral bioavailability, bile acid-binding capacity, in vitro glycemic index. Findings Loaf volumes of the breads supplemented with RS4 were higher than the bread supplemented with wheat bran (WB). Among the bread samples, the one supplemented with WB had the darkest color and highest firmness values. During storage, WB supplementation caused the highest increase in bread firmness. RS4 supplementation caused higher total dietary fiber (TDF) and mineral bioavailability values and lower in vitro glycemic index than bran supplementation. Conclusions RS4 supplementation of bread caused increases in TDF content, bile acid-binding capacity, and mineral bioavailability and has less deteriorative effect on the quality than WB supplementation. Breads supplemented with WB had a faster staling rate than the breads supplemented with RS4. Significance and novelty Besides the better appearance and texture of the RS4 supplemented bread samples, the improvement in nutritional properties proved that RS4 is a better dietary fiber source than WB.Article Citation - WoS: 40Citation - Scopus: 63Optimization of Resistant Starch Formation From High Amylose Corn Starch by Microwave Irradiation Treatments and Characterization of Starch Preparations(Elsevier, 2017-02) Mutlu, Selime; Kahraman, Keyser; Ozturk, SerpilThe effects of microwave irradiation on resistant starch (RS) formation and functional properties in high-amylose corn starch, Hylon VII, by applying microwave-storing cycles and drying processes were investigated. The Response Surface Methodology (RSM) was used to optimize the reaction conditions, microwave time (2-4min) and power (20-400%), for RS formation. The starch:water (1:10) mixtures were cooked and autoclaved and then different microwave-storing cycles and drying (oven or freeze drying) processes were applied. The RS contents of the samples increased with increasing microwave storing cycle. The highest RS (43.4%) was obtained by oven drying after 3 cycles of microwave treatment at 20% power for 2 min. The F, p (<0.05) and R-2 values indicated that the selected models were consistent. Linear equations were obtained for oven-dried samples applied by 1 and 3 cycles of microwave with regression coefficients of 0.65 and 0.62, respectively. Quadratic equation was obtained for freeze-dried samples applied by 3 cycles of microwave with a regression coefficient of 0.83. The solubility, water binding capacity (WBC) and RVA viscosity values of the microwave applied samples were higher than those of native Hylon VII. The WBC and viscosity values of the freeze-dried samples were higher than those of the oven-dried ones. (C) 2016 Elsevier B.V. All rights reserved.Article Citation - WoS: 17Citation - Scopus: 24Clarification of Apple Juice Using New Generation Nanocomposite Membranes Fabricated With TiO2 and Al2O3 Nanoparticles(Springer, 2019-11-26) Severcan, Solmaz Sebnem; Uzal, Nigmet; Kahraman, KevserTo enhance anti-fouling properties of polymeric membranes during apple juice clarification, PSF/PEI (20/2 wt%) ultrafiltration (UF) membranes were modified with TiO2 and Al2O3 nanoparticles using the phase inversion method. Turbid apple juice samples were clarified using cross-flow membrane filtration system. All fabricated nanocomposite UF membranes had higher apple juice flux values than PSF/PEI membrane. Membrane prepared with 0.01% TiO2 (UFT1) had the highest apple juice flux (at steady state, 44.6 L/m(2)h). The FRR (%) value of TiO2 and Al2O3 incorporated UF membranes was between 90.9-94.0% and 79.6-97.6%, respectively, and these FRR values were higher than that of PSF/PEI membrane (UF2, 60.3%). Porosity and hydrophilicity of the UF membranes significantly increased with the addition of nanoparticles and the highest porosity and hydrophilicity was achieved in the 0.01% TiO2 incorporated UF membrane (UFT1) membrane. Higher flux recovery ratio (FRR) and lower relative flux reduction (RFR) values of Al2O3 and TiO2 incorporated nanocomposite membranes, compared with the unmodified membrane, demonstrated the enhancement in the anti-fouling properties of the PSF/PEI membrane. SEM images of the nanocomposite membranes also proved the nanoparticle incorporation to the PSF/PEI matrix. Color, turbidity, total soluble solid, total phenolic content, and antioxidant capacity of the samples using nanocomposite membranes were better than that of clarified using both commercial and unmodified membranes. TiO2 incorporated nanocomposite membranes had superior performance than Al2O3 incorporated nanocomposite membranes and among these membranes, the ones prepared with the addition of 0.01 wt% TiO2 exhibit the best performance in terms of clarification of apple juice.Article Development of Resistant Starch Type-5 and Its Utilization in Cookie-Preparation(North University Center Baia Mare, 2025-11-30) Oskaybas-Emlek, Betul; Ozbey, Ayse; Kahraman, KevserThe objective of this study was the production of resistant starch type-5 (RS-5), its characterization, and utilization in cookie making. In first part of the study, the effects of starch-fatty acid complex formation (RS-5) between tapioca starch and lauric acid on the structure, digestibility, thermal and morphological properties of tapioca starch were investigated. X-ray diffraction revealed that the RS-5 had a V-type crystalline pattern. FT-IR analysis showed that a distinctive peak at 2846 cm-1 was only observed in RS-5. The resistant starch (RS) content of native starch increased from 22.76% to 28.02% with RS-5 formation. In the second part of the study, the RS-5 was added as a replacement for wheat flour with 10%, 20%, and 30% compared to control sample made with 100% wheat flour in cookie-making. The effects of RS-5 replacement of cookie samples on some physicochemical, estimated glycemic index (eGI) value, physical, and hardness properties were determined. Compared to control cookie, the cookie samples included RS-5 had lower hardness value, higher spread ratio. The eGI value of cookie samples was slightly decreased with the replacement with RS-5. The results demonstrated that the RS-5 has good potential for developing softer cookie with no adverse impact on eGI value.Article Citation - WoS: 3Citation - Scopus: 3Formation of Resistant Starch From Amylotype Corn Starch and Determination of the Functional Properties(Wageningen Academic Publishers, 2013-12) Kahraman, K.; Koksel, H.High amylose corn starch was hydrolysed with HCl at 40 degrees C for 0.5-2.0 h. Then the native and acid-modified starch samples were subjected to 2 different heat treatments (HT). In HT1, heat treated/autoclaved samples were dried after storage and in HT2, heat treated/autoclaved samples were dried without storage. Relative quantities of high- and medium-molecular weight fractions decreased and relative quantities of low-molecular weight fractions increased as a result of acid modification. Resistant starch (RS) contents of the acid-modified starches were between 15.7-16.4% and increased up to 29.4% due to HT1 and up to 17.5% due to HT2. The results indicated that RS contents of the high amylose starch can be increased by HT and storing prior to drying. Rapid ViscoAnalayser viscosity values decreased as the acid modification level increased. Water absorption and solubility values of the samples prepared with both heat treatments were higher than those of the native starch and hydrolysates. Emulsifying capacity/stability values of soy protein solution supplemented with the hydrolysates and heat treated samples were higher than those supplemented with the native and heat treated native starch.