Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7148
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Article Influence of Innovative Thawing Approaches on the Thermal and Chemical Structure Changes of Frozen Beef Liver(Springer, 2026) Avsar, Nazlican; Uzuner, SibelFreezing effectively preserves meat quality, but the formation of ice crystals during the process can impact tenderness and functionality. Thawing is a critical step, as it can lead to physicochemical changes-such as protein oxidation and further ice crystal growth-that may reduce product quality and consumer appeal. Therefore, the thawing method plays a key role in determining the final quality of frozen meat. This study evaluated the physicochemical and structural characteristics of beef liver frozen at - 18 +/- 2 degrees C for 20 h and thawed using three methods: water immersion thawing (WIT), ultrasonic bath thawing (UBT), and air fryer thawing (AFT). No significant differences in drip loss were observed among the UBT, AFT, and WIT samples (p > 0.05). Color measurements (L*, a*, b*) were significantly higher in raw liver than in AFT and UBT samples (p < 0.05). Compared to raw liver and the WIT method, AF and UB thawing lowered the denaturation temperature, indicating reduced thermal stability. The lowest metmyoglobin (MetMb) content was found in the UBT sample (36.57 +/- 0.87%), followed by the AFT sample (41.71 +/- 1.29%), suggesting better pigment preservation with UB thawing. Highlights circle AF and UB thawing methods resulted in a lower denaturation temperature. circle UBT showed the lowest MetMb content, helping to minimize oxidation. circle UBT caused less damage to protein chains and better preserved structural stability. circle UBT preserved desirable aroma characteristics more effectively.Article 3D-Printed Soy Protein and Microalga Films: A Sustainable Approach with Antioxidant Functionality(Elsevier, 2026) Barekat, Sorour; Dogan, Buse; Uzuner, Sibel; Ubeyitogullari, AliThis study investigated the optimization and fabrication of soy protein isolate (SPI)-green microalga (MA) 3D-printed films. For optimizing 3D printing, the effects of MA concentration, nozzle size (0.52-0.81 mm), and speed (10-20 mm/s) were examined. The printed films were then dried, and color, mechanical properties, water vapor permeability, structure, and antioxidant activity were analyzed. All the formulations showed shear-thinning behavior and rapid recovery. The concentration of 3 % MA, nozzle size of 0.72 mm, and printing speed of 20 mm/s were selected as the optimized conditions for the best 3D printability. Compared with the control, their elongation at break decreased by more than 16 %, while puncture strength increased by over 12 %, and tensile strength rose by more than 40 %. Water vapor permeability decreased by more than 40 % with the addition of MA. The microstructure images and secondary structure confirmed the formation of a less porous and stronger gel network with an increase in MA concentration from 0 to 5 % (w/w). The antioxidant properties of SPI films also increased two-fold with the addition of MA. These findings highlight that the 3D-printed edible films with antioxidant properties could be used as an eco-friendly and nutritious alternative to petroleum-based films in food packaging.Article Valorizing Sugar Industry Byproduct Through Microalga for Pigment Production(Springer, 2025) Engin, Iskin; Uzuner, SibelCurrently, consumers are seeking ways to obtain natural food colorants, and food supplements. Microalgal food colorants and supplements have become established in the food industry due to their ability to generate substantial biomass rich in polysaccharides, pigments, lipids, vitamins, and other bioactive compounds. However, the high costs associated with microalgal cultivation have gained interest in more economical alternatives. This study investigated the potential of using vinasse, a byproduct of the sugar industry, as a nutrient source to produce biomass, chlorophyll, and carotenoids with Parachlorella kessleri SAG211-11 h. The effects of culture conditions (vinasse concentration, light intensity and light/dark cycle) on chlorophyll a (Chl a), chlorophyll b (Chl b), and carotenoid content were investigated using Response Surface Methodology. The results showed that light intensity and light/dark cycle had a significant effect, especially on Chl a content (p < 0.05). Light intensity also showed a significant effect on Chl b and carotenoid content (p < 0.05). Response optimization was conducted under conditions of 5% vinasse concentration, 110 mu mol photons m(-2)s(-1), and 16:8 light dark cycle, yielding a Chl a content of 10.89 +/- 0.14 mg/L, Chl b content of 7.25 +/- 1.12 and carotenoid content of 2.79 +/- 0.94 mg/L. These results revealed that the chlorophyll content of P. kessleri cells can be enhanced under mixotrophic conditions by changing cultivation conditions with the usage of vinasse-based medium. Meanwhile, this research highlights vinasse as a sustainable carbon source for the cultivation of P. kessleri SAG211-11 h cells for chlorophyll and carotenoid production.Article Citation - WoS: 3Citation - Scopus: 3Shelf-Life Extension of Traditional Licorice Root “sherbet” With a Novel Pulsed Electric Field Processing(Frontiers Media S.A., 2023) Akdemir Evrendilek, Gulsun; Demir, Irem; Uzuner, SibelPulsed electric field (PEF) processing of licorice root "sherbet" (LRS) by various electric field strengths (7.00, 15.50, and 24.10 kV/cm), treatment times (108, 432, and 756 mu sec), and processing temperatures (6, 18, and 30 degrees C) according to the Box-Behnken design were performed. The samples were analyzed for pH, titratable acidity, conductivity, turbidity, total reducing sugar, color (L*, a*, and b*), hue, chroma, total color difference, color intensity, color tone (yellow, red, and blue color tones), total antioxidant capacity, total phenolic substance content, and sensory properties. Results revealed that PEF processing did not adversely affect most of the physical, chemical, and sensory properties of LRS, with a maximum of 2.48, 4.04, 1.78, and 1.20 log reductions on the initial total mesophilic aerobic bacteria, total mold and yeast, Bacillus circulans, and Candida tropicalis. The response variable modeled for the PEF was found to be conductivity, with the optimum processing conditions of 6.90 kV/cm, 756.00 mu s, and 7.48 degrees C. After that, the samples were stored at 4 degrees C and 22 degrees C for shelf-life studies. Control samples at 4 degrees C and 22 degrees C were spoiled on the fifth and second days, whereas PEF-treated samples stored at 4 degrees C began to deteriorate after the 40th day and the samples stored at 22 degrees C after the 30th day, respectively. It was revealed that PEF is a suitable process to extend the shelf-life of licorice "sherbet" with preservation of physicochemical and sensory properties.Article Production of Microalgae-Derived Exo-Polygalacturonase for Fruit Juice Clarification(Frontiers Media S.A., 2022) Uzuner, Sibel; Evrendilek, Gulsun Akdemir; Kurhan, SebnemDue to the growing demand for commercial enzymes derived from renewable and sustainable resources with higher efficacy, algal biomass has gained more attention. Thus, the production of exo-polygalacturonase (PGase) from Bacillus subtilis under submerged fermentation (SmF) using algal feedstocks as a carbon source in fermentation medium and its potential use for the clarification of apple and carrot juices with the optimization of the enzyme loading, pH, and time using Box-Behnken response surface methodology (RSM) were prompted. The maximum PGase activity of 510.61 +/- 7.86 U/L was achieved at pH 5.0 after 48 h at 40 degrees C using 0.5% (w/v) pectin, 0.1% (w/v) yeast extract, 0.02% (w/v) MgSO47H2O, 0.02% (w/v) K2HPO4, 0.3% (w/v) glucose, and 0.583% (w/v) microalgae hydrolysate as a fermentation medium. PGase production without glucose was favored by SmF with a shake flask working volume of 100 ml (248.90 +/- 4.58 U/L) as compared to a bioreactor with a working volume of 1 L (192.99 +/- 0.84) for 48 h. Both carrot and apple juices were treated with the crude PGase (248.9 U/L) at different concentrations (0.1-0.5%), temperature (30-50 degrees C), and time (30-120 min), and the maximal clarification conditions were obtained as 0.3% (w/v) enzyme concentration at 50 degrees C for 30 min exposure time. This study revealed that microalgae-derived PGase in crude form could be effectively used for clarification of the juices.Article Citation - WoS: 1Citation - Scopus: 1Enhancing the Sustainable Protein Extraction Process From Black Cumin Seed Cake Press for Eco-Friendly Protein Supplements(Springer Science and Business Media Deutschland GmbH, 2025) Ammas, B.; Uzuner, Sibel; Uzuner, S.Finding new protein sources is essential to meet the global population’s needs. Nigella sativa (black cumin) seeds and the residual cake left after oil cold pressing contain valuable nutritional compounds, including proteins, phenolics, essential amino acids, and various bioactive compounds. In the literature, the structural characteristics and functional properties of proteins from black cumin seeds have been extensively studied. However, there are limited reports on the use of emerging extraction technologies for extracting soluble proteins from black cumin seed cake press (BCSCP). Therefore, two distinct extraction techniques—microwave (MW) and ultrasonication (US)—were assessed for their effectiveness in extracting soluble proteins from BCSCP. The aim of this study was to investigate the effects of various operational conditions on protein extraction yield and functional properties of proteins extracted from BCSCP. The maximum protein yield (27.04%) was achieved using a 10% solid/liquid ratio (SLR) at 33 °C for a 30-min extraction time with the US extraction technique. After ultrafiltration, the protein yield increased to 33.83%, showcasing the predominance of sarcosine (17.18 g/100 g), glutamine (11.63 g/100 g), and proline (33.46 g/100 g) amino acids. The water-holding capacity (WHC), oil-holding capacity (OHC), foam capacity (FC), and foam stability (FS) of the BCSCP isolate were found to be 5.4 ± 0.3 g/g, 9.4 ± 0.0 g/g, 43.6 ± 6.4%, and 39.0 ± 4.7%, respectively. The study revealed that US is a suitable extraction process for obtaining soluble proteins from BCSCP with favorable functional properties. Further studies are needed to evaluate the bioavailability and health impacts of bioactive peptides in order to develop food applications. © The Author(s) 2024.Article Citation - WoS: 5Citation - Scopus: 6Corn Processing by Pulsed Electric Fields With Respect To Microbial Inactivation and Improvement of Seed Vigour(Elsevier Sci Ltd, 2024) Evrendilek, Gulsun Akdemir; Atmaca, Bahar; Uzuner, SibelPulsed electric field (PEF) treatment of corn grains to improve seed vigour and inactivation of endogenous microflora by energies ranging from 1.20 to 28.8 J were applied to determine effectiveness of applied energies on germination rate (GR), normal seedling rate (NSR), electrical conductivity (EC), ability to germinate under salt (100- and 200 mM salt) and cold (at 10 degrees C for 7 days and at 25 degrees C for 5 days) stresses. Moreover, the effect of PEF treatments was further investigated for the inactivation of total aerobic mesophilic bacteria (TAMB), total mold and yeast (TMY), and inactivation rate (%) of Aspergillus parasiticus. Increased energy provided 11.10 % increase in GR, 21.22 % increase in NSR, 95.50 % increase in germination at 10 degrees C for 7 days. Germination under stress conditions revealed 32.53 %, 68.35 %, and 76 % increase in germination at 25 degrees C for 5 days, under 100 mM- and 200 mM NaCI salt stresses. Inactivation on the mean initial TAMB and TMY were approximately 9.25 and 7.93 log, respectively, with 63.33 +/- 0.22 % reduction in A. parasiticus culture. PEF treated corn seedlings had stronger and taller body formation with stronger roots. The most optimal processing parameters were detected as 300 Hz, 28.80 J, and 19.78 sec. PEF treatment carries a high potential to improve corn vigour with inactivation of surface microflora.Article Citation - WoS: 2Citation - Scopus: 2Enhanced Reducing Sugar Production and Extraction for Chlorella Vulgaris in Mixotrophic Cultivation Using High Hydrostatic Pressure Processing and Ultrasound(Taylor & Francis, 2023) Uzuner, Sibel; Kurhan, Şebnem; Akdemir Evrendilek, GülsünAlthough extraction of polysaccharides to convert reducing sugars (RS) from microalgae by acid or alkali pretreatments and enzymatic hydrolysis has been extensively studied, few reports exploring the use of high hydrostatic pressure processing (HHP) and ultrasonication (US) as emerging technologies for the extraction of sugars from microalgae biomass exist. Thus, the present study was conducted to determine the effects of mixotrophic growth and stress conditions (NaNO3 and CO2 concentration and light intensity) on RS and protein accumulation in the unicellular green alga Chlorella vulgaris in addition to optimization of the effectiveness of the sequential applications of HHP and US with dilute acid as well as simultaneous enzymatic saccharification on the production of RS from microalga cells. High light intensity, high CO2 concentration and limited nitrogen concentration promoted RS production. The maximum protein content (0.0683 mg g(-1)) was achieved at 0.3 g l(-1) NaNO3 concentration, 7000 mu mol photons m(-2) s(-1) and 6 l min(-1) CO2 concentration. The highest RS content of C. vulgaris after 48 h enzymatic saccharification (583.86 +/- 13.23 mg g(-1)) was obtained at 1% (w/w) acid concentration and 80% amplitude for 30 min with 79.4% RS yield. Combined US-assisted dilute acid pretreatment and enzymatic hydrolysis were also found to be more effective than HHP assisted dilute acid pretreatment and enzymatic saccharification. Therefore, microalgal biomass can be considered a suitable renewable feedstock used in fermentation. Highlights center dot The cultivation period of Chlorella vulgaris was reduced from 25 days to 14 days using mixotrophic growing conditions.center dot Mixotrophic conditions enhanced reducing sugar productivity.center dot Novel extraction techniques enhanced the extraction of reducing sugar from microalgae.Article Citation - WoS: 2Citation - Scopus: 3High-Pressure Processing of Traditional Hardaliye Drink: Effect on Quality and Shelf-Life Extension(MDPI, 2023) Atmaca, Bahar; Demiray, Merve; Akdemir Evrendilek, Gülsün; Bulut, Nurullah; Uzuner, SibelHardaliye, as one of the oldest and lesser known traditional beverages, is produced using red grape pomace from wine production. This drink production is achieved through lactic acid fermentation, with the addition of sour cherry leaves and mustard seeds-either heat-treated, grinded, or whole-in various concentrations. Hardaliye has a very short shelf life; thus, efforts have recently been made to process hardaliye with novel processing technologies in order to achieve shelf-life extension. Therefore, the high-hydrostatic-pressure (HHP) processing of hardaliye was performed to determine its impact on important properties, including in microbial inactivation and shelf-life extension, with respect to a Box-Behnken experimental design. Maximum log reductions of 5.38 & PLUSMN; 0.6, 5.10 & PLUSMN; 0.0, 5.05 & PLUSMN; 0.2, and 4.21 & PLUSMN; 0.0 with HHP were obtained for Brettanomyces bruxellensis, total mesophilic aerobic bacteria, Lactobacillus brevis, and total mold and yeast, respectively. The processing parameters of 490 MPa and 29 & DEG;C for 15 min were found as the optimal conditions, with the response variables of an optical density at 520 nm and the inactivation of L. brevis. The samples processed at the optimal conditions were stored at both 4 and 22 & DEG;C for 228 d. While the non-treated control samples at 4 and 22 & DEG;C were spoiled at 15 and 3 d, the HHP-treated samples were spoiled after 228 and 108 d at 4 and 22 & DEG;C, respectively.Review Citation - WoS: 7Citation - Scopus: 7Ultrasonication Effects on Quality of Tea-Based Beverages(MDPI, 2023) Uzuner, SibelTea is the most popular consumed drink after water. Teas and tea-based beverages have grown in popularity due to bioactive compounds. Tea-based beverages have started to take their place in the market. Extraction is a crucial step for the production of functional tea-based beverages. Compared to conventional methods, ultrasound is attractive due to its lower energy requirements, and shorter extraction time. This review aimed to discuss recent marketing aspects of tea-based beverages as well as the potential and challenges of a novel infusion technique. This review describes the health benefits and technological aspects of tea-based beverages in relation to how to best solve nutritional and microbial concerns. Current and future challenges and opportunities of the novel infusion technique and its scaling-up for the extraction of bioactive compounds are also covered in the present review.