Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7148
Browse
35 results
Search Results
Article Citation - WoS: 21Citation - Scopus: 22Characterization and Encapsulation Efficiency of Zein Nanoparticles Loaded With Chestnut Fruit Shell, Cedar and Sweetgum Bark Extracts(Elsevier, 2023) Konuk Takma, Dilara; Bozkurt, Semra; Koç, Mehmet; Korel, Figen; Şahin Nadeem, HilalZein nanoparticles (ZNPs) loaded with bioactive extracts of chestnut (Castanea sativa Mill.) shell, cedar (Cedrus libani) and sweetgum (Liquidambar orientalis) bark wastes were produced using different methods. Nanoprecipitation, high-speed homogenization and ultrasonic homogenization allowed the fabrication of ZNPs with particle sizes smaller than 202.40 nm, 430.25 nm and 325.50 nm, respectively. The smallest nanoparticle size was achieved at 132.81 nm for sweetgum bark extract-loaded ZNPs obtained by the nanoprecipitation method. Encapsulation efficiency (EE) was between 34.03 and 96.83% for all zein nanoparticles fabricated under different mixtures and process conditions. Zein concentration and extract ratio played an essential role in the EE of nanoparticles. The best conditions were determined to obtain the desired properties of ZNPs based on particle size, polydispersity index and EE by using a central composite rotatable design. The nanoprecipitation method was more appropriate for producing chestnut and cedar shell/bark extract-loaded nanoparticles. In contrast, the high-speed homogenization method was suitable for producing sweetgum bark extract-loaded nanoparticles. As a result of the encapsulation of various shell/bark extracts within zein nanoparticles, value-added products were generated from wastes having bioactive compounds. The developed zein nanoparticles for each extract type would offer eco-friendly, simple and safe food processing and packaging systems. © 2023Article Citation - WoS: 7Citation - Scopus: 9A Screen-Printed Electrode Modified With Gold Nanoparticles/ Cellulose Nanocrystals for Electrochemical Detection of 4,4'-methylene Diphenyl Diamine(Elsevier, 2023) Büyüktaş, Duygu; Ghaani, Masoud; Rovera, Cesare; Carullo, Daniele; Olsson, Richard T.; Korel, Figen; Farris, StefanoDeveloping simple, cost-effective, easy-to-use, and reliable analytical devices if of utmost importance for the food industry for rapid in-line checks of their products that must comply with the provisions set by the current legislation. The purpose of this study was to develop a new electrochemical sensor for the food packaging sector. More specifically, we propose a screen -printed electrode (SPE) modified with cellulose nanocrystals (CNCs) and gold nanoparticles (AuNPs) for the quantification of 4,4'-methylene diphenyl diamine (MDA), which is one of the most important PAAs that can transfer from food packaging materials into food stuffs. The electrochemical performance of the proposed sensor (AuNPs/CNCs/SPE) in the presence of 4,4'- MDA was evaluated using cyclic voltammetry (CV). The modified AuNPs/CNCs/SPE showed the highest sensitivity for 4,4'-MDA detection, with a peak current of 9.81 mu A compared with 7.08 mu A for the bare SPE. The highest sensitivity for 4,4'-MDA oxidation was observed at pH = 7, whereas the detection limit was found at 57 nM and the current response of 4,4'-MDA rose linearly as its concentration increased from 0.12 mu M to 100 mu M. Experiments using real packaging materials revealed that employing nanoparticles dramatically improved both the sensitivity and the selectivity of the sensor, which can be thus considered as a new analytical tool for quick, simple, and accurate measurement of 4,4 '-MDA during converting operations.Article Citation - WoS: 7Citation - Scopus: 6Development of a Nano-Modified Glassy Carbon Electrode for the Determination of 2,6-Diaminotoluene (tda)(Elsevier, 2021) Büyüktaş, Duygu; Ghaani, Masoud; Rovera, Cesare; Olsson, Richard T.; Korel, Figen; Farris, StefanoThe objective of this study was to improve the overall performance of a glassy carbon electrode (GCE) for the detection of 2,6-diaminotoluene (TDA), a possibly carcinogenic primary aromatic amines (PAAs) that poses a serious risk for the consumer' health because they can transfer from multilayer food packages including adhesives based on aromatic polyurethane (PU) systems, to the food. The modification of the electrode surface was made by means of multi-walled carbon nanotubes (MWCNTs) and mesopomus carbon nanoparticles (MCNs). The MWCNTs-MCNs/GCE allowed achieving the best performance in terms of sensitivity, as revealed by cyclic voltammetry - CV, with an oxidation peak of 20.95 mu A over 0.079 mu A of the bare GCE. The pH of the medium influenced the oxidation of 2,6-TDA, with highest sensitivity at pH similar to 7. Amperometry experiments led to an estimated detection limit of 0.129 mu M, and three linear ranges were obtained for 2,6-TDA: 0.53-11.37 mu M, 11.37-229.36 mu M, and 229.36-2326.60 mu M. Chronoamperometry experiments combined with Cottrell's theory allowed estimating a diffusion coefficient of 2,6-TDA of 1.34 x 10(-4) cm(2) s(-1). The number of electrons (n similar to 1) involved in the catalytic oxidation of 2,6-TDA was determined according to the Lavimn's theory. Real sample tests demonstrated that the modification of the sensor using nanoparticls allowed to obtain a highly sensitive and selective sensor, which can possibly used as an alternative analytical device for the rapid, easy, and reliable determination of 2,6-TDA.Book Part Citation - Scopus: 6Quality Assessment of Aquatic Foods by Machine Vision, Electronic Nose, and Electronic Tongue(Wiley, 2010) Korel, Figen; Balaban, Murat ÖmerThe increase in demand for seafood products has catalyzed the desire for higher standards regarding safety and quality issues. Since seafoods are perishable, freshness is a major quality parameter to be considered [1,2]. There is no unique freshness or spoilage indicator for seafood, therefore combinations of selected indicators need to be used to evaluate freshness [3,4]. An important and widely used method to determine freshness is sensory evaluation [5]. The Quality Index Method (QIM) uses a demerit point scoring system [6] based on the evaluation of the important sensory attributes (odour, texture, and appearance) of fish and other aquatic foods. The sensory quality is expressed by the sum of the demerit points, and a linear correlation between these points and the storage time is used to predict the freshness of the target seafood [5,7,8]. The QIM has been developed for various seafood species and products, such as Atlantic mackerel (Scomber scombrus), horse mackerel (Trachurus trachurus), European sardine (Sardina pilchardus) [9], gilthead seabream (Sparus aurata) [10], farmed Atlantic salmon (Salmo salar) [11,12], and cod (Gadus morhua) [13], etc. Even though QIM is fast and reliable in determining the freshness of seafood, it still requires experts to evaluate the quality attributes. Alternatively, appearance, odour, and taste can be measured by machine vision system (MVS), electronic nose (e-nose), and electronic tongue (e-tongue), respectively.Article Citation - WoS: 71Citation - Scopus: 76Characterization of Bacterial Cellulose Nanocrystals: Effect of Acid Treatments and Neutralization(Elsevier Ltd., 2021) Arserim-Uçar, Dilhun Keriman; Korel, Figen; Liu, LinShu; Yam, Kit LIn this study, bacterial cellulose nanocrystals (BCNCs) were obtained from bacterial cellulose nanofibers (BCNFs) by controlled hydrolysis of sulfuric and hydrochloric acids. The influence of hydrolysis temperature and acid type with the addition of the post-treatment step was studied. The obtained BCNCs were analyzed based on the structural characterization and the properties of the nanocrystals. The BCNCs crystallinity increased, and the size of nanocrystals decreased with increasing 10 °C hydrolysis temperature for both acid hydrolysis conditions. Hydrolysis conditions with neutralization post-treatment did not alter the thermal stability of nanocrystals, and BCNCs had high thermal stability like raw BCNFs. Elemental analysis results indicated that sulfur content (S %) was very low for sulfuric acid hydrolyzed samples, and X-ray results did not show any sulfate salt peaks. Thermal stable BCNCs with high crystallinity were successfully produced to meet the process requirements in various applications, especially in the food industry.Article Citation - WoS: 151Citation - Scopus: 179Active Packaging Films as a Carrier of Black Cumin Essential Oil: Development and Effect on Quality and Shelf-Life of Chicken Breast Meat(Elsevier Ltd., 2019) Konuk Takma, Dilara; Korel, FigenFabrication of active PET films assembled with antimicrobial chitosan and alginate coatings incorporating black cumin oil(BCO) was performed by layer-by-layer(LbL) technique and effect of active packaging film on quality and shelf-life of chicken breast meats stored at 4 degrees C for 5 days was investigated. Multilayer films were characterized in terms of surface morphology, color, thickness, and antimicrobial activity. Incorporation of BCO into film demonstrated antimicrobial activity against Staphylococcus aureus and Escherichia coll., and spherical particles on surface profile. Changes in weight loss, color, pH, total aerobic mesophilic(TAMC), and psychrotrophic bacteria counts(PBC) of chicken meat, packaged in trays containing antimicrobial films, were observed. Increase in pH values was higher in control samples than samples packaged with antimicrobial film during storage. Samples stored in active packaging had slightly lower TAMC and PBC compared to control samples. Results indicated that active film containing BCO has the potential to maintain safety and quality of chicken meat.Article Effect of Storage Temperature and Packaging Material on the Shelf-Life of Newly-Developed No-Added Sugar Almond Paste(Consulting and Training Center - KEY, 2018) Konuk Takma, Dilara; Korel, Figen; Avcı, Başak; Edeer, ÖzgürAlmond paste is a traditional dessert made from sweet almonds which are rich in: omega-6 fatty acids, sugar, and water. Development of no added sugar, low calorie, protein and high fiber source almond paste can be preferred by diabetics and calorie conscious people as a healthy snack. The objectives of this study were to determine the best formulation of no added sugar almond paste by sensory evaluation and investigate the effect of storage temperature and packaging material on shelf-life of newly-developed almond paste. Three different formulated almond pastes were provided by Egepak Company and sensory analysis was performed by using 5-point hedonic scale and ranking tests. Sensory properties including: appearance, taste, sweetness, texture, overall acceptability and ranking were evaluated statistically by using ANOVA. Almond pastes were stored both in small glass jars (GJ) and polyethylene packaging bags (PPB) at 4°C and 21°C. During 56 days of storage, total aerobic mesophil-ic bacteria (TAMB), yeast-mold and coliform counts were determined using: 3M PetrifilmTM aerobic count plates, potato dextrose agar (PDA) and violet red bile agar (VRBA) incubated at 35°C/48h, 25°C/5days and 35°C/24h, respectively. The most desired formulation was determined based on the highest sensory scores: 4.2, 4.2, 3.8, 4.0 for appearance, taste, sweetness, texture, respectively. Microbial counts on TAMB ranged from 3.30 to 3.66 log cfu/g at the end of storage with the most pronounced effect being achieved by PPB at 4°C. No fungal growth was observed during storage on almond paste stored in GJ at 4°C and 21°C. Significant increase occurred in coliform counts at 4°C and 21°C and no advantage was found in samples stored in GJ compared to that in PPB. The combination of 4°C storage temperature and GJ and PPB packaging materials provided the best shelf-life for newly-developed no-added sugar almond paste. © 2019, Consulting and Training Center - KEY. All rights reserved.Conference Object Citation - WoS: 14Citation - Scopus: 16Drying of Olive Leaves in a Geothermal Dryer and Determination of Quality Parameters of Dried Product(Elsevier, 2019) Helvacı, Hüseyin Utku; Menon, Abhay; Aydemir, Levent Yurdaer; Korel, Figen; Gökçen Akkurt, GüldenIn this study, a cabinet type geothermal dryer was designed, operated and tested for drying olive leaves with minimum losses of phenolic content and antioxidant capacity by optimization of drying conditions. Two factors; face centered central composite design was applied and response surface methodology was used to optimize the drying conditions of olive leaves. The results indicate that phenolic content stability were mainly affected by air temperature, whereas antioxidant capacity is affected by both air temperature and velocity (p<0.05). The optimal drying conditions were found to be at 50°C of air temperature and 1 m/s of air velocity for the minimum losses of determined quality parameters, where 88.8% of phenolic content and 95.3% of antioxidant capacity were recovered.Article Citation - WoS: 12Citation - Scopus: 16Control of Lactic Acid Bacteria in Fermented Beverages Using Lysozyme and Nisin: Test of Traditional Beverage Boza as a Model Food System(Wiley, 2018) Sözbilen, Gözde Seval; Korel, Figen; Yemenicioğlu, AhmetThe objective of this study was to increase quality and limited shelf-life of boza (3–15 days), a traditional Balkan origin fermented beverage using lysozyme (LYS) and/or nisin (NIS). For this purpose, the effectiveness of NIS, LYS and LYS:NIS combinations was first tested in a broth medium at 4 °C for 3 weeks on Lactobacillus plantarum, one of the frequently isolated lactic acid bacteria in boza. Stability of LYS and NIS in boza, their effects on LAB counts, and chemical and sensory properties of boza were then evaluated during cold storage at 4 °C. Results of LAB counts as well as pH, d- and l-lactic acid, and titratable acidity measurements showed that LAB in boza containing NIS (250 μg g−1) or LYS:NIS (500:250 μg g−1) could be controlled without reducing LAB counts below 6 log CFU mL−1 during 2 weeks shelf-life. In contrast, LYS (500 μg g−1) alone could not control LAB in boza to delay its acidic spoilage. Positive effects of NIS and LYS:NIS application on quality of boza were also proved with sensory analysis by panelists and e-nose measurements. This work showed that use of natural GRAS agents in preservation of fermented beverages containing probiotic LAB is possible without affecting their characteristic aroma and flavour.Conference Object Risk Management of Ready-To Meat Products Contaminated With Listeria Monocytogenes(Technical Research Center of Finland, 2009) Korel, FigenNowadays, the modern life style relies heavily on the availability, quality, and safety of ready-to-eat (RTE) food products. The quality of the raw material, handling, processing, transportation and storage are the important factors influencing the microbial quality of the finished product. The mostly consumed RTE meat products are hamburgers, frankfurters, hot dogs, dry/semi-dry fermented sausages, salami, and deli meats. Several pathogens could be found on RTE meat products, including Escherichia coli O157:H7, Salmonella, Listeria monocytogenes, and Staphylococcus aureus. Vegetative pathogens are destroyed during thorough cooking and processing of these products. Contamination during post-processing in the plant, and further contamination and improper handling during storage, at retail or in home cause microbial growth. Pathogens can multiply under inappropriate conditions causing foodborne diseases and outbreaks.