Food Engineering / Gıda Mühendisliği

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2’-Methylklavuzon Causes Lipid-Lowering Effects on A549 Non-Small Cell Lung Cancer Cells and Significant Changes on Dna Structure Evidenced by Fourier Transform Infrared Spectroscopy
(Elsevier, 2020) Ceylan, Çağatay; Çağır, Ali; Aksoy, Hatice Nurdan; Ceylan, Çağatay; Çağır, Ali; Çetinkaya, Hakkı; 03.08. Department of Food Engineering; 04.01. Department of Chemistry; 03. Faculty of Engineering; 04. Faculty of Science; 01. Izmir Institute of Technology
Various chemical agents are used in the treatment of Non-Small Cell Lung Cancer (NSCLC). 2?-methylklavuzon was proposed as a potential chemotherapeutic agent in cancer treatment based on its topoisomerase inhibition activity. In this study the cellular effects of 2?-methylklavuzon was evaluated on A549 cancer cells using FTIR spectroscopy. 2?-methylklavuzon induced significant changes on both the whole cell lyophilizates and the lipid extracts of the A549 lung cancer cells. 2?-methylklavuzon caused significant structural changes in A549 cell DNA structure: T, A and G DNA breathing modes are lost after the drug application indicating the loss of topoisomerase activity. The level of transcription and RNA synthesis was enhanced. 2?-methylklavuzon induced single stranded DNA formation evidenced by the increase in the ratio of asymmetric/symmetric phosphate stretching modes. 2?-methylklavuzon induced band shifts only in the asymmetric mode of phosphate bonds not in the symmetrical phosphate bond stretching. 2?-methylklavuzon induced A form of DNA topography. In addition to the changes in the DNA structure and transcription 2?-methylklavuzon also caused lipid-lowering effect in A549 cancer cells. 2?-methylklavuzon suppressed lipid unsaturation, however, it induced formation of lipids with ring structures. 2?-methylklavuzon suppressed phosphate-containing lipids significantly and decreased carbonyl containing lipids and cholesterol slightly. 2?-methylklavuzon caused increases in the hydrocarbon chain length. Overall, 2?-methylklavuzon can be used as a lipid-lowering compound in the treatment of NSCLC and other cancer therapies. © 2020 Elsevier B.V.
Citation - WoS: 48
Citation - Scopus: 64
Active Packaging of Ground Beef Patties by Edible Zein Films Incorporated With Partially Purified Lysozyme and Na 2edta
(John Wiley and Sons Inc., 2011-06) Uysal Ünalan, İlke; Korel, Figen; Korel, Figen; Yemencioğlu, Ahmet; 03.08. Department of Food Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
In this study, antimicrobial activity of zein films incorporated with partially purified lysozyme and disodium ethylenediaminetetraacetic acid (Na 2EDTA) has been tested on selected pathogenic bacteria and refrigerated ground beef patties. The developed films containing 700μgcm -2 lysozyme and 300μgcm -2 Na 2EDTA showed antimicrobial activity on Listeria monocytogenes, Escherichia coli O157:H7, and Salmonella typhimurium. The application of lysozyme and Na 2EDTA incorporated zein films on beef patties significantly decreased total viable counts (TVC) and total coliform counts after 5days of storage compared to those of control patties (P<0.05). Zein films incorporated with lysozyme and Na 2EDTA or Na 2EDTA alone significantly slowed down the oxidative changes in patties during storage (P<0.05). Redness indices of patties coated with zein films were significantly lower than those of uncoated control patties during storage (P<0.05). This study demonstrated the potential usage of zein films containing lysozyme and Na 2EDTA for active packaging of refrigerated meat products. © 2011 The Authors. International Journal of Food Science and Technology.
Citation - WoS: 110
Citation - Scopus: 120
Alkaline Protease Production From Alkalophilic Bacillus Sp. Isolated From Natural Habitats
(Elsevier Ltd., 2006-08) Gençkal, Hande; Tarı, Canan; Tarı, Canan; 03.08. Department of Food Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
Bacillus strains isolated under extreme alkaline conditions (Izmir, Turkey), were screened and identified for high alkaline protease activity. Strains with high protease yields were optimized with respect to inoculum concentration, temperature, agitation speed, initial medium pH and incubation time. Three Bacillus strains coded as I18, L18 and L21 showed high potential, for alkaline protease activity (160-222 U/ml) among 85 isolates. The specific growth rates were estimated from the growth curves as 0.49 h-1 for I18, as 0.6 and 0.7 h-1 for L18 and L21, respectively. The optimum temperatures were determined as 30 °C for strain I18 and 37 °C for the strains L18 and L21. Similarly, the optimum agitation speeds were 100 rpm for I18 and 180 rpm for L18 and L21. For all three strains, the optimum inoculation ratio and incubation time, were determined as 5% (v/v) and 96 h, respectively. The optimum initial media pH was found as pH 10 for strain L18 and L21. Bacillus sp. L21 with the highest specific protease activity (60 U/mg protein) and a broader pH range was chosen for further study. The biomass and product yield for this strain was determined as 0.023 g cell/g glucose and 0.021 U/g glucose, respectively. The crude enzyme of this strain was further characterized and was determined as a bleach stable, serine alkaline protease with an optimum temperature of 60 °C and a pH of 11, with a potential to be a candidate for the applications in the detergent industry.
Citation - WoS: 7
Citation - Scopus: 7
Ankaferd Influences Mrna Expression of Iron-Regulated Genes During Iron-Deficiency Anemia
(SAGE Publications Inc., 2018-09) Güleç, Afife; Güleç, Şükrü; Güleç, Şükrü; 03.08. Department of Food Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
Ankaferd Blood Stopper (ABS) comprises a mixture of plants and stops bleeding via forming a protein network by erythroid aggregation. Bleeding causes reduction of iron levels in body. It has been indicated that ABS contains significant amount of iron. Thus, we investigated the biological activity of ABS-derived iron on iron-regulated genes during iron-deficiency anemia (IDA). IDA We selected Caco-2 and HepG2 cell lines as in vitro models of human intestine and liver, respectively. Iron deficiency anemia was induced by deferoxamine. The cells were treated with ferric ammonium citrate (FAC) and ABS. Messenger RNA levels of iron-regulated genes were analyzed by quantitative reverse transcription polymerase chain reaction to elucidate whether iron in ABS behaved similar to inorganic iron (FAC) during IDA. The results showed that ABS-derived iron influenced transcriptions of iron-regulated marker genes, including divalent metal transporter (Dmt1), transferrin receptor (TfR), ankyrin repeat domain 37 (Ankrd37), and hepcidin (Hamp) in IDA-induced Caco-2 and HepG2 cells. Our results suggest that when ABS is used to stop tissue bleeding, it might have an ability to reduce levels of IDA.
Citation - WoS: 370
Citation - Scopus: 443
Antibacterial and Antioxidant Activity of Essential Oil Terpenes Against Pathogenic and Spoilage-Forming Bacteria and Cell Structure-Activity Relationships Evaluated by Sem Microscopy
(MDPI Multidisciplinary Digital Publishing Institute, 2014-11) Zengin, Hatice; Baysal, Ayşe Handan; Baysal, Ayşe Handan; 03.08. Department of Food Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
The antibacterial activity and antioxidant effect of the compounds α-terpineol, linalool, eucalyptol and α-pinene obtained from essential oils (EOs), against pathogenic and spoilage forming bacteria were determined. The antibacterial activities of these compounds were observed in vitro on four Gram-negative and three Gram-positive strains. S. putrefaciens was the most resistant bacteria to all tested components, with MIC values of 2% or higher, whereas E. coli O157:H7 was the most sensitive strain among the tested bacteria. Eucalyptol extended the lag phase of S. Typhimurium, E. coli O157:H7 and S. aureus at the concentrations of 0.7%, 0.6% and 1%, respectively. In vitro cell growth experiments showed the tested compounds had toxic effects on all bacterial species with different level of potency. Synergistic and additive effects were observed at least one dose pair of combination against S. Typhimurium, E. coli O157:H7 and S. aureus, however antagonistic effects were not found in these combinations. The results of this first study are encouraging for further investigations on mechanisms of antimicrobial activity of these EO components.
Citation - WoS: 43
Citation - Scopus: 47
Antifungal Activity of Biopolymers Containing Natamycin and Rosemary Extract Against Aspergillus Niger and Penicillium Roquefortii
(John Wiley and Sons Inc., 2008-11) Türe, Hasan; Soyer, Ferda; Eroğlu, Erdal; Özen, Fatma Banu; Soyer, Ferda; Özen, Fatma Banu; 04.03. Department of Molecular Biology and Genetics; 03.08. Department of Food Engineering; 03. Faculty of Engineering; 04. Faculty of Science; 01. Izmir Institute of Technology
Antimicrobial agent-releasing films have been proposed as an effective way of inhibiting chiefly surface spoilage of food products. Antifungal activities of natamycin (NA), rosemary extract (RE) and NA + RE were tested against Aspergillus niger and Penicillium roquefortii with agar disc diffusion assay. NA, RE and NA + RE were also included into biopolymers made from gluten and methyl cellulose. Minimum inhibitory concentrations (MIC) of NA in both films were 2 and 1 mg NA per 10 g film solution against A. niger and P. roquefortii, respectively. RE did not show any inhibitory antifungal activity alone. Although NA incorporated into both films at a concentration of 1.5 mg NA per 10 g film solution was not effective against A. niger, combination of NA at the same concentration with RE in the films inhibited the growth of this mould. NA in solution or in biopolymers is very effective in inhibiting the growth of selected organisms, and RE acted synergistically with NA to prevent the growth of A. niger when incorporated into both films. © 2008 Institute of Food Science and Technology
Citation - WoS: 36
Citation - Scopus: 38
Antimicrobial Activity of Lactoperoxidase System Incorporated Into Cross-Linked Alginate Films
(John Wiley and Sons Inc., 2009-03) Yener, Fatih Yalçın Güneş; Yemenicioğlu, Ahmet; Korel, Figen; Korel, Figen; Yemenicioğlu, Ahmet; 03.08. Department of Food Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
In this study, the antimicrobial effect of lactoperoxidase (LPS) incorporated alginate films was investigated on Escherichia coli (NRRL B-3008), Listeria innocua (NRRL B-33314), and Pseudomonas fluorescens (NRRL B-253) in presence of different concentrations of H2O2 (0.2, 0.4, and 0.8 mM) and KSCN (1, 2, and 4 mM). The incorporation of 70 nmol ABTS/min/cm2 LPS into alginate films gave 0.66 to 0.85 nmol ABTS/min/cm2 enzyme activity at 0.2 to 0.8 mM H2O 2 concentration range. The antimicrobial activity of LPS system on target bacteria changed according to the concentrations of KSCN and H 2O2. The growth of all tested bacteria was prevented for a 6-h period by applying LPS system in presence of 0.4 or 0.8 mM H 2O2 and 4 mM KSCN. At 0.8 mM H2O2 and 4 mM KSCN, the LPS system also inhibited growth of L. innocua and P. fluorescens for a 24-h incubation period, whereas E. coli growth could not be inhibited for 24 h under these conditions. At 0.2 mM H2O2 and 1 to 4 mM KSCN, a considerable inhibitory effect was obtained only on P. fluorescens. The decreasing order of the resistance of studied bacteria to LPS system is as follows: E. coli, L. innocua, and P. fluorescens. The developed antimicrobial system has a good potential for use in meat, poultry, and seafood since alginate coatings are already used in these products. Further studies are needed to test the LPS incorporated edible films in real food systems.
Citation - WoS: 113
Citation - Scopus: 133
Antioxidant Activity and Phenolic Content of Fresh and Dry Nuts With or Without the Seed Coat
(Academic Press Inc., 2009-05) Arcan, İskender; Yemenicioğlu, Ahmet; Yemenicioğlu, Ahmet; 03.08. Department of Food Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
Total antioxidant activities based on ABTS free radical scavenging activity and phenolic content of fresh or dry hazelnuts, walnuts and pistachios assayed with their seed coats changed between 3063 and 11,076 μmol trolox equivalents/100 g d.w. and 256 and 755 mg gallic acid equivalents/100 g d.w., respectively. The walnuts used in this study showed the highest antioxidant activity, followed by pistachios and hazelnuts. The removal of seed coat reduced the total antioxidant activity of hazelnuts, walnuts and pistachios almost 36, 90 and 55%, respectively. The total antioxidant activities of investigated fresh and dry nuts are not considerably different. However, phenolic content and antioxidant activity in hydrophilic and ethanolic fractions obtained by successive extraction of nuts showed some variation. The antioxidant activity in 1-serving portion of fresh or dry walnuts is equivalent to that in almost 2-serving portions of black tea, and 1.2-1.7-serving portions of green and Earl Grey tea. One-serving portions of dry hazelnuts and fresh or dry pistachios contained antioxidant activity equivalent to that in 0.7-1-serving portions of black tea. The antioxidant activity measurements correlated with phenolic content (r2 = 0.70). This study showed the potential of using fresh or dry nuts to develop functional foods with high antioxidant activity.
Citation - WoS: 2
Citation - Scopus: 2
Assessing Edible Composite Film Polymer From Potato Industry Effluent Under High Hydrostatic Pressure and Its Antimicrobial Properties
(Wiley, 2022-11) Akdemir Evrendilek, Gülsün; Uzuner, Sibel; Bulut, Nurullah; Uzuner, Sibel; 03.08. Department of Food Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
Development of edible film from potato industry effluent having antimicrobial properties against Salmonella enteritidis and Escherichia coli O157:H7 by addition of Citrus sinensis volatile oil (VO), and changes of its textural properties under high hydrostatic pressure (HHP) are investigated. The optimum operational conditions are determined as 500 MPa pressure, 36.97 µL VO, and 15 min processing time with the minimum force value of 372.33 × g. Textural properties are also modeled through empirical modeling, best fit Box-Behnken design, and artificial neuron network. Inhibition zones for Salmonella enteritidis and E. coli O157:H7 at the optimum HHP conditions are 1.50 ± 0.11 and 2.18 ± 0.07 cm, respectively. Textural properties of force and elongation at break of the HHP-processed films range from 2.27 ± 0.52 to 5.23 ± 0.38 N, and from 8.57 ± 1.31 to 13.36 ± 1.36 mm, respectively. Thermal transition of the edible film is observed at 87.42 °C for 7.36 min. Addition of C. sinensis VO improves the antimicrobial properties, whereas HHP improves the textural properties of the film. It is suggested that the developed film has potential to be used as an edible food packaging material.
Citation - WoS: 8
Citation - Scopus: 9
Authentication of Pomegranate Juice in Binary and Ternary Mixtures With Spectroscopic Methods
(Elsevier, 2023-04) Aykaç, Başak; Özen, Fatma Banu; Çavdaroğlu, Çağrı; Çavdaroğlu, Çağrı; Özen, Banu; 03.08. Department of Food Engineering; 01. Izmir Institute of Technology; 03. Faculty of Engineering
Fruit juices are among the most commonly adulterated food products and especially pomegranate juice as a high value product is mixed with different adulterants for unfair economic profit. It was aimed to investigate the performances of UV–visible and Fourier-transform infrared (FTIR) spectroscopies combined with chemometric methods to determine adulteration of pomegranate juice with dark colored sour cherry and black carrot juices. Binary and ternary mixtures of pomegranate juice with 2 adulterants were prepared at 5–25% levels. After various data transformations, both spectroscopic data of authentic and adulterated samples were evaluated with different chemometric classification tools. Classification models with 97% correct classification rate for validation set were obtained both for UV–visible and FTIR spectral data. Accurate predictions of adulterant concentration were also achieved with chemometric models using both spectroscopic data. These spectroscopic techniques provide rapid and accurate prediction of pomegranate juice adulteration in binary and ternary mixtures with dark colored juices.
Citation - WoS: 22
Citation - Scopus: 25
Bacillus Cereus: a Review of “fried Rice Syndrome” Causative Agents
(Academic Press, 2023) Leong, Sui Sien; Korel, Figen; King, Jie Hung; Korel, Figen; 03.08. Department of Food Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
“Fried rice syndrome” originated from the first exposure to a fried rice dish contaminated with Bacillus cereus. This review compiles available data on the prevalence of B. cereus outbreak cases that occurred between 1984 and 2019. The outcome of B. cereus illness varies dramatically depending on the pathogenic strain encounter and the host's immune system. B. cereus causes a self-limiting, diarrheal illness caused by heat-resistant enterotoxin proteins, and an emetic illness caused by the deadly toxin named cereulide. The toxins together with their extrinsic factors are discussed. The possibility of more contamination of B. cereus in protein-rich food has also been shown. Therefore, the aim of this review is to summarize the available data, focusing mainly on B. cereus physiology as the causative agent for “fried rice syndrome.” This review emphasizes the prevalence of B. cereus in starchy food contamination and outbreak cases reported, the virulence of both enterotoxins and emetic toxins produced, and the possibility of contaminated in protein-rich food. The impact of emetic or enterotoxin-producing B. cereus on public health cannot be neglected. Thus, it is essential to constantly monitor for B. cereus contamination during food handling and hygiene practices for food product preparation. © 2023 Elsevier Ltd
Citation - WoS: 5
Citation - Scopus: 3
Basidiomycota Species in Drosophila Gut Are Associated With Host Fat Metabolism
(Nature Research, 2023) Bozkurt, Berkay; Sezgin, Efe; Terlemez, Gamze; Sezgin, Efe; 03.08. Department of Food Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
The importance of bacterial microbiota on host metabolism and obesity risk is well documented. However, the role of fungal microbiota on host storage metabolite pools is largely unexplored. We aimed to investigate the role of microbiota on D. melanogaster fat metabolism, and examine interrelatedness between fungal and bacterial microbiota, and major metabolic pools. Fungal and bacterial microbiota profiles, fat, glycogen, and trehalose metabolic pools are measured in a context of genetic variation represented by whole genome sequenced inbred Drosophila Genetic Reference Panel (DGRP) samples. Increasing Basidiomycota, Acetobacter persici, Acetobacter pomorum, and Lactobacillus brevis levels correlated with decreasing triglyceride levels. Host genes and biological pathways, identified via genome-wide scans, associated with Basidiomycota and triglyceride levels were different suggesting the effect of Basidiomycota on fat metabolism is independent of host biological pathways that control fungal microbiota or host fat metabolism. Although triglyceride, glycogen and trehalose levels were highly correlated, microorganisms’ effect on triglyceride pool were independent of glycogen and trehalose levels. Multivariate analyses suggested positive interactions between Basidiomycota, A. persici, and L. brevis that collectively correlated negatively with fat and glycogen pools. In conclusion, fungal microbiota can be a major player in host fat metabolism. Interactions between fungal and bacterial microbiota may exert substantial control over host storage metabolite pools and influence obesity risk. © 2023, Springer Nature Limited.
Citation - WoS: 70
Citation - Scopus: 82
Batch Production of L(+) Lactic Acid From Whey by Lactobacillus Casei (nrrl B-441)
(John Wiley and Sons Inc., 2004-09) Büyükkileci, Ali Oğuz; Harsa, Hayriye Şebnem; Harsa, Hayriye Şebnem; Büyükkileci, Ali Oğuz; 03.08. Department of Food Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
The effects of temperature, pH, and medium composition on lactic acid production by Lactobacillus casei were investigated. The highest lactic acid productivity values were obtained at 37 °C and pH 5.5. The productivity was 1.87 g dm-3 h-1 at 37 °C in shake flasks. In the fermenter, a productivity of 3.97 g dm-3 h-1 was obtained at pH 5.5. The most appropriate yeast extract concentration was 5.0 g dm-3. Whey yielded a higher productivity value than the analytical lactose and glucose. Initial whey lactose concentration did not affect lactic acid productivity. MnSO4·H2O was necessary for lactic acid production by L casei from whey. Product yields were approximately 0.93 g lactic acid g lactose-1.
Citation - WoS: 21
Citation - Scopus: 22
Characterization and Classification of Turkish Wines Based on Elemental Composition
(American Society for Enology and Viticulture, 2014-03) Şen, İlknur; Tokatlı, Figen; Tokatlı, Figen; Şen, İlknur; 03.08. Department of Food Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
Commercial wines from 13 native and nonnative varieties in Turkey were analyzed for their elemental composition. Wines from four vintages (2006-2009) were analyzed by inductively coupled plasma with atomic emission spectrometry and mass spectroscopy (ICP-AES and ICP-MS) followed by multivariate statistics to study vintage, varietal, and regional differences. According to the partial least squares-discriminant analysis, wines from western regions could be discriminated with their higher Pb content. The red wines of two native grapes, Boǧazkere and Öküzgözü, were separated from the remaining varieties based on their high Ca and low B and Cu levels. Öküzgözü wines were different from Syrah and Cabernet Sauvignon wines. Similarly, native Emir wines showed differences from Muscat wines. The effective variables for discrimination analysis were natural minerals (Sr, Li, Al, Ba, and B) and minerals originating from agricultural activities, processing, or pollution (Ca, Cu, Mg, Co, Pb, and Ni). Characteristics of Turkish wines from native and nonnative grape varieties such as Cabernet Sauvignon, Merlot, Syrah, and Chardonnay were defined in terms of their mineral content for the first time.
Citation - WoS: 13
Citation - Scopus: 16
Characterization of Antimicrobial Activities of Olive Phenolics on Yeasts Using Conventional Methods and Mid-Infrared Spectroscopy
(Springer, 2019) Canal, Canan; Özen, Fatma Banu; Özen, Banu; Baysal, Ayşe Handan; Baysal, Ayşe Handan; 03.08. Department of Food Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
Olive fruit is very rich in terms of phenolic compounds. Antimicrobial activities of various phenolic compounds against bacteria and fungi are well established; however, their effects on yeasts have not been examined. Aim of this study was to investigate the antimicrobial effects induced by olive phenolic compounds, including tyrosol, hydroxytyrosol, oleuropein, luteolin and apigenin against two yeast species, Aureobasidium pullulans and Saccharomyces cerevisiae. For this purpose, yeasts were treated with various concentrations (12.5-1000ppm) of phenolic compounds and reduction in yeast population was followed with optical density measurements with microplate reader, yeast colony forming units and mid-infrared spectroscopy. All phenolic compounds were effective on both yeasts, especially 200ppm and higher concentrations have significant antimicrobial activity; however, effects of lower levels depend on the type of phenolic compound. According to mid-infrared spectral data, significant changes were observed in 1200-900cm(-1) range corresponding to carbohydrates of yeast structure as a result of exposure to all phenolic compounds except tyrosol. Spectra of tyrosol and luteolin treated yeasts also showed changes in 1750-1500cm(-1) related to amide section and 3600-3000cm(-1) fatty acid region. Since phenolic compounds from olives were effective against yeasts, they could be used in food applications where yeast growth showed problem. In addition, FTIR spectroscopy could be successfully used to monitor and characterize antimicrobial activity of phenolic compounds on yeasts as complementary to conventional microbiological methods.
Citation - WoS: 11
Citation - Scopus: 12
Characterization of the Self-Assembly and Size Dependent Structural Properties of Dietary Mixed Micelles by Molecular Dynamics Simulations
(Elsevier Ltd., 2019-05) Tuncer, Esra; Bayramoğlu, Beste; Bayramoğlu, Beste; 03.08. Department of Food Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
The bile salts and phospholipids are secreted by the gallbladder to form dietary mixed micelles in which the solvation of poorly absorbed lipophilic drugs and nutraceuticals take place. A comprehensive understanding of the micellization and structure of the mixed micelles are crucial to design effective delivery systems for such substances. In this study, the evolution of the dietary mixed micelle formation under physiologically relevant concentrations and the dependence of structural properties on micelle size were investigated through coarse grained molecular dynamics simulations. The MARTINI force field was used to model cholate and POPC as the representative bile salt and phospholipid, respectively. The micellization behavior was similar under both fasted and fed state concentrations. Total lipids concentration and the micelle size did not affect the internal structure of the micelles. All the micelles were slightly ellipsoidal in shape independent of their size. The extent of deviation from spherical geometry was found to depend on the micellar POPC/cholate ratio. We also found that the surface and core packing density of the micelles increased with micelle size. The former resulted in more perpendicular alignments of cholates with respect to the surface, while the latter resulted in an improved alignment of POPC tails with the radial direction and more uniform core density.
Citation - WoS: 50
Citation - Scopus: 59
Characterization of Three-Phase Partitioned Exo-Polygalacturonase From Aspergillus Sojae With Unique Properties
(Elsevier Ltd., 2008-04) Doğan, Nergiz; Tarı, Canan; Tarı, Canan; 03.08. Department of Food Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
Exo-polygalacturonase enzyme produced by Aspergillus sojae ATCC 20235 was purified using three-phase partitioning (TPP), an emerging bio-separation technique where a single step as compared to the classical multi-step purification was used. Using this technique, crude enzyme solution (pH 6.6) saturated to 30% (w/v) with ammonium sulphate and with a crude extract to tert-butanol ratio of 1:1 (v/v) at 25 °C resulted in 25.5% recovery of exo-polygalacturonase with a 6.7-fold purification. The purified enzyme was characterized with respect to its activity and stability at various pH and temperature ranges. Optimum pH and temperature for maximum activity were determined as pH 4 and 55 °C. The enzyme was stable at both acidic and alkaline pH for 2 h at 30 °C. The thermal stability study showed that the purified enzyme had an inactivation energy of 68.41 kcal/mol and a half-life (t1/2) value of 3.6 h at 75 °C presenting a large thermal stability. The kinetic constants Km and Vmax using polygalacturonic acid as substrate were 0.75 g l-1 and 1.14 μmol min-1, respectively. SDS-PAGE profiling revealed that the purified exo-polygalacturonase had two bands with the molecular weights of 36 and 53 kDa. The enzyme was completely inhibited in the presence of Mn2+ and SDS and induced significantly by EDTA, glycerol and β-mercaptoethanol.
Citation - WoS: 7
Citation - Scopus: 10
Chemical Composition and Biological Activities of Cypriot Propolis
(Taylor and Francis Ltd., 2021) Nalbantsoy, Ayşe; Sarıkahya, Nazlı Böke; Özverel, Cenk Serhan; Barlas, Ayşe Berçin; Kırcı, Damla; Akgün, İsmail Hakkı; Yalçın, Tansel; Güven, Gamze; Kışla, Duygu; Demirci, Betül; Topçu, Gülaçtı; Gören, Ahmet Ceyhan
Propolis compositions are highly variable, depending on the geographic region and the season of collection. In this study, propolis samples from seven different regions of Cyprus were studied for the first time by means of chemical content and biological activities. Secondary metabolite composition was determined by LC-HRMS. While the major flavonoids found were isosakuranetin, naringenin, rhamnocitrin, diosmetin, chrysin and acacetin, interestingly verbascoside, a phenylethanoid glycoside, and chlorogenic acid were identified as the major compounds in the ethanol-water extracts. alpha-Pinene was detected as the major compound of propolis extracts according to the volatile compositions via GC-MS. Karaoglanoglu and Tirmen extracts, presenting different chemical profiles, exerted enormous cytotoxic activity by MTT assay (IC50: 2.36-11.56 mu g/mL; 1.44-9.33 mu g/mL, respectively). The highest iNOS inhibition potential was detected in the Karpaz extract (IC50:2.6 mu g/mL) in LPS induced RAW 264.7 cells whereas the Guzelyurt sample demonstrated remarkable antioxidant (88.82 +/- 0.10%) and antimicrobial activities (with a MIC value of 31.2 mu g/mL against S. aureus, S. epidermidis, E. faecium, and E. faecalis).
Citation - Scopus: 10
Chemical Composition and Biological Activities of Cypriot Propolis
(Taylor and Francis Ltd., 2022) Nalbantsoy, A.; Düven, Gamze; Sarıkahya, N.B.; Özverel, C.S.; Barlas, A.B.; Kırcı, D.; Akgün, İ.H.; Yalçın, Tansel; Düven, Gamze; 03.08. Department of Food Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
Propolis compositions are highly variable, depending on the geographic region and the season of collection. In this study, propolis samples from seven different regions of Cyprus were studied for the first time by means of chemical content and biological activities. Secondary metabolite composition was determined by LC-HRMS. While the major flavonoids found were isosakuranetin, naringenin, rhamnocitrin, diosmetin, chrysin and acacetin, interestingly verbascoside, a phenylethanoid glycoside, and chlorogenic acid were identified as the major compounds in the ethanol-water extracts. α-Pinene was detected as the major compound of propolis extracts according to the volatile compositions via GC-MS. Karaoglanoglu and Tirmen extracts, presenting different chemical profiles, exerted enormous cytotoxic activity by MTT assay (IC50: 2.36–11.56 µg/mL; 1.44–9.33 µg/mL, respectively). The highest iNOS inhibition potential was detected in the Karpaz extract (IC50:2.6 µg/mL) in LPS induced RAW 264.7 cells whereas the Guzelyurt sample demonstrated remarkable antioxidant (88.82 ± 0.10%) and antimicrobial activities (with a MIC value of 31.2 μg/mL against S. aureus, S. epidermidis, E. faecium, and E. faecalis). © 2021 International Bee Research Association.
Citation - WoS: 7
Citation - Scopus: 6
Chromatographic Separation of Amyloglucosidase From the Mixtures of Enzymes
(Elsevier Ltd., 2001-10) Harsa, Hayriye Şebnem; Harsa, Hayriye Şebnem; Furusaki, Shintaro; 03.08. Department of Food Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
An affinity chromatographic separation of amyloglucosidase (AMG) enzyme using β-cyclodextrin-chitosan matrix was investigated in this study. The adsorbent selectively adsorbed AMG from the mixtures of enzymes (lactase and α-amylase), and this selectively bound AMG was eluted from the column in two steps with a recovery yield of about 72%. A small fraction of AMG and other contaminating proteins did not bind to the column specifically and were eluted easily. Purified AMG was visualised on the sodiumdodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) experiments

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