Browsing by Author "Koksel, Hamit"

Now showing 1 - 7 of 7

Effect of different resistant starch sources and wheat bran on dietary fibre content and in vitro glycaemic index values of cookies
(ACADEMIC PRESS LTD- ELSEVIER SCIENCE LTD, 24-28 OVAL RD, LONDON NW1 7DX, ENGLAND, 2019) Kahraman, Kevser; Aktas-Akyildiz, Eda; Ozturk, Serpil; Koksel, Hamit; 0000-0001-7870-9464; 0000-0002-2786-3944; AGÜ, Mühendislik Fakültesi, Malzeme Bilimi ve Nanoteknoloji Mühendisliği Bölümü
Cross-linked starches produced in lab-scale from corn and wheat starches with TDF contents of 80.4% and 83.6% were used in cookie formulation to obtain high fibre and low glycaemic index (GI) cookies. Different resistant starch (RS) sources including and wheat bran were also used for comparison. RS sources were added into the formulation at the levels of 25, 50 and 75%. Overall cookie quality (spread ratio, hardness, colour) results showed that among the RS sources and wheat bran, lab-scale produced cross-linked wheat starch (XL-W) had an improving effect on cookie quality, whereas the other sources had detrimental effect. Cookie samples supplemented with XL-W had the highest total dietary fibre (TDF) contents regardless of the addition level. High levels of TDF content were also observed with the wheat bran supplemented cookie samples; however, quality of these cookies were low. RS and wheat bran supplementation caused significant decrease in the in vitro GI of the cookies and the lowest GI value was achieved with the cookie supplemented with XL-W. This study proved that XL-W produced in this study can be used as an alternative ingredient to produce high fibre and low GI cookies without any deteriorative effect on the quality.
Effects of resistant starch type 4 supplementation of bread on in vitro glycemic index value, bile acid-binding capacity, and mineral bioavailability
(WILEY, 111 RIVER ST, HOBOKEN 07030-5774, NJ USA, 2020) Aribas, Merve; Kahraman, Kevser; Koksel, Hamit; 0000-0002-2786-3944; 0000-0003-4150-2413; AGÜ, Mühendislik Fakültesi, Malzeme Bilimi ve Nanoteknoloji Mühendisliği Bölümü
Background 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.
A functional barley-based fermented soup (tarhana) with high β-glucan content
(SPRINGER, 2025) Koksel, Hamit; Ozkan, Kubra; Tekin-Cakmak, Zeynep Hazal; Karasu, Salih; Kahraman, Kevser; Oruc, Sena; Sagdic, Osman; Sestili, Francesco; 0000-0002-2786-3944; AGÜ, Mühendislik Fakültesi, Malzeme Bilimi ve Nanoteknoloji Mühendisliği Bölümü; Kahraman, Kevser
This study investigates the impact of using different flours, including high beta-glucan barley, on the nutritional properties of tarhana. Mineral composition, phenolic content, and antioxidant capacity of tarhana powder samples produced using flours of high beta-glucan hull-less barley (cv. Chifaa; ChF), hull-less barley cv. Yalin (YF), bread wheat cv. Tosunbey (white flour: TWF1 and whole wheat flour: TWF2). Furthermore, in vitro glycemic index (GI), pasting properties, and RVA soup index of their soups were investigated. Tarhana made with Chifaa barley flour (Tar-ChF) exhibited significantly higher levels of key minerals (K, Mg, Ca), beta-glucan and total phenolic content compared to those made with other flours (Tar YF, Tar TWF1, and Tar TWF2). Barley tarhana samples also showed greater antioxidant activity of bound phenolic fractions and lower GI values, indicating a healthier profile. The study highlights the potential of high beta-glucan barley flour to enhance tarhana's nutritional benefits without significantly affecting its sensory properties, such as color and viscosity. This research supports the integration of health-promoting ingredients like barley flour into traditional Mediterranean foods to improve their nutritional quality.
A Novel high-amylose wheat-based functional cereal soup (tarhana) with low glycemic index and high resistant starch
(Academic Press, 2024) Koksel, Hamit; Tekin-Cakmak, Zeynep Hazal; Ozkan, Kubra; Pekacar, Zeynep; Oruc, Sena; Kahraman, Kevser; Ozer, Cagla; Sagdic, Osman; Sestili, Francesco; 0000-0002-2786-3944; AGÜ, Mühendislik Fakültesi, Malzeme Bilimi ve Nanoteknoloji Mühendisliği Bölümü; Kahraman, Kevser
This study investigated the potential of high-amylose wheat flour (Svevo-HA) to enhance the dietary profile of tarhana, a traditional Mediterranean fermented cereal yogurt mixture. The moisture content of tarhana powders ranged from 7.81% to 11.64%. Color parameters varied depending on the type of flour used, with Svevo-HA samples demonstrating decreased L* values and increased a* and b* values. Mineral compositions differed significantly among tarhana samples, with higher levels of K, Mg, Mn, Fe, Cu, and Zn observed in samples prepared with Svevo-HA. Gallic acid was identified as the major phenolic compound in all the tarhana samples for free fraction, while ferulic acid was determined as the major phenolic compound for its bound form. Supplementation of tarhana soups with heat-treated Svevo-HA flour increased the resistant starch content and decreased in vitro glycemic index value compared to soups prepared with conventional wheat flour. These findings highlight the potential of utilizing Svevo-HA flour to develop healthier versions of traditional foods.
Optimisation of the reaction conditions for the production of cross-linked starch with high resistant starch content
(ELSEVIER SCI LTD, 2015) Kahraman, Kevser; Koksel, Hamit; Ng, Perry K. W.; 0000-0002-2786-3944; AGÜ, Mühendislik Fakültesi, Malzeme Bilimi ve Nanoteknoloji Mühendisliği Bölümü; Kahraman, Kevser
The optimum reaction conditions (temperature and pH) for the preparation of cross-linked (CL) corn and wheat starches with maximum resistant starch (RS) content were investigated by using response surface methodology (RSM). According to the preliminary results, five levels were selected for reaction temperature (38–70 C) and pH (10–12) in the main study. RS contents of the CL corn and wheat starch samples increased with increasing temperature and pH, and pH had a greater influence on RS content than had temperature. The maximum RS content (with a maximum p value of 0.4%) was obtained in wheat starch cross-linked at 38 C and pH 12. In the case of CL corn starch, the optimum condition was 70 C and pH 12. CL corn and wheat starch samples were also produced separately under the optimum conditions and their RS contents were 80.4% and 83.9%, respectively. These results were also in agreement with the values predicted by RSM.
Quality, Nutritional Properties, and Glycemic Index of Colored Whole Wheat Breads
(MDPI, 2023) Koksel, Hamit; Cetiner, Buket; Shamanin, Vladimir P.; Tekin-Cakmak, Z. Hazal; Pototskaya, Inna V.; Kahraman, Kevser; Sagdic, Osman; Morgounov, Alexey I.; 0000-0002-2786-3944; AGÜ, Mühendislik Fakültesi, Malzeme Bilimi ve Nanoteknoloji Mühendisliği Bölümü; Kahraman, Kevser
The main aim of this study was to investigate the quality and nutritional properties (dietary fiber, phenolic, antioxidant contents, and glycemic index) of breads made from whole wheat flours of colored wheats. White (cultivar Agronomicheskaya 5), red (Element 22), purple (EF 22 and Purple 8), and blue (Blue 10) colored wheats were used in the study. The whole wheat flours of Blue 10 and Purple 8 had higher farinograph stability, lower softening degree, and higher quality numbers indicating that they had better rheological properties. Bread produced from whole wheat flour of blue-colored grain had significantly higher loaf volume and better symmetry, crust color, crumb cell structure, and softness values among others (p < 0.05). The whole wheat bread produced using Element 22 had the highest crust and crumb L* color values, while Purple 8 and EF 22 had the lowest crust and crumb L* color values, suggesting that purple-colored grains have a tendency to make whole wheat bread with darker crust and crumb color. Bread produced from cultivar Blue 10 had the lowest firmness values while Element 22 had the highest firmness values. The highest total phenolic content and antioxidant capacity values were obtained from the whole wheat bread sample from purple-colored wheat (Purple 8). The whole wheat flour of Element 22 had the highest total dietary fiber content among all samples (p < 0.05). The differences between whole wheat bread samples in terms of total dietary fiber and glycemic index were not statistically significant. The results of the present study indicated that colored wheats can be used to produce whole wheat breads with higher nutritional properties and acceptable quality characteristics.
Starch
(ELSEVIER: ScienceDirect, 2023) Koksel, Hamit; Muti, Serpil Ozturk; Kahraman, Kevser; 0000-0002-2786-3944; AGÜ, Mühendislik Fakültesi, Malzeme Bilimi ve Nanoteknoloji Mühendisliği Bölümü; Kahraman, Kevser
Starch 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.