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Öğe The change of apparent viscosity of liquid whole egg during ohmic and conventional heating(2012) Bozkurt H.; Icier F.Electrical heating of food products is a novel technique which provides rapid and uniform heating, resulting in less thermal damage to the product. Although the technology offers many advantages, the rheological behavior of liquid whole egg during ohmic heating has not been known yet in the literature. The objective of this research was to examine effects of conventional and electrical heating methods on the rheological behavior of liquid whole egg at a temperature range between 20 and 60C by using concentric rotational viscometer. The ohmic heating was applied at the voltage gradient of 20 V/cm at 50 Hz by matching the same heating curve with the conventional method. The liquid whole egg exhibited characteristics of non-Newtonian shear thinning fluid. The flow behavior index (n) of liquid whole egg was in the range of 0.908-0.992 and 0.909-0.983 for ohmic and conventional heating, respectively. The consistency coefficient decreased as the temperature increased. The apparent viscosity of heated liquid egg was not statistically different for both heating methods (P > 0.05). The activation energy values for temperature dependency of predicted apparent viscosity were not statistically different for rheological models applied (P > 0.05), while they were significantly different according to heating method (P < 0.05). The liquid whole egg was more sensible to temperature changes during conventional heating. It was concluded that this difference could be either the result of the electrical effect on the apparent viscosity of the liquid whole egg or thermal effect during ohmic heating and fast homogeneous heating during ohmic treatment. © 2011 Wiley Periodicals, Inc.Öğe Electrical conductivity changes of minced beef-fat blends during ohmic cooking(2010) Bozkurt H.; Icier F.Minced beef-fat blends having different fat level (2%, 9% and 15%) and full meat-fat samples were ohmically cooked by different voltage gradients (20, 30 and 40 V/cm). Main factors affecting the electrical conductivity were the temperature and the composition of the blends. Although the effect of initial fat content on electrical conductivity was statistically significant, voltage gradient did not affect the electrical conductivity changes during cooking treatment (p > 0.05). The electrical conductivity of the samples increased with increasing temperature up to the critical initial cooking temperature (60-70 °C) depending on the fat level, and then decreased due to structural changes and the increase in the bound water during cooking. The results of the nonlinear mathematical model including the effects of initial fat level and the temperature on the electrical conductivity changes had good agreement (r = 0.952; SEM = 0.009) with the experimental data. The determination of electrical conductivity changes being affected by process variables is crucial to characterize the ohmic cooking of meat products and design of ohmic systems. © 2009 Elsevier Ltd. All rights reserved.Öğe In vitro activity of linezolid against Mycobacterium tuberculosis strains isolated from western Turkey(2009) Ermertcan Ş.; Hoşgör-Limoncu M.; Eraç B.; Taşli H.; Çavuşoglu C.; Bozkurt H.We investigated the linezolid susceptibility of Mycobacterium tuberculosis strains isolated from a tertiary care hospital in Izmir. A total of 67 M. tuberculosis strains (33 multidrug-resistant [MDR] and 34 non-MDR) were isolated and identified by the Tuberculosis Laboratory, Department of Microbiology and Clinical Microbiology, Faculty of Medicine, Ege University. The activity of linezolid was studied by the standard agar proportion method. For all of the strains, the MIC range was 0.06-1 mg/L, and the MIC50 and MIC 90 values were 0.5 mg/L. No differences were observed between the MDR and non-MDR isolates. In general, linezolid was found to be effective for both the non-MDR and MDR M. tuberculosis strains.Öğe Investigation of anti-htlv-i/ii seroprevalence in healthy blood donors in Izmir region, Turkey [Izmir bölgesinde saglikli kan verícílerínde antí-HTLV-I/II seroprevalansinin araçtirilmasi](2010) Sertöz R.; Turhan A.; Bozkurt H.; Çamlioglu P.; Degrmenci A.; Aydinok Y.; Erensoy S.Almost 10-20 million people in the world are thought to be infected by human deltaretroviruses, namely human T-cell lymphotropic virus (HTLV) type I and II, recently. HTLV-I is endemic in southwestern Japan, the Caribbean and sub-Saharan Africa, whereas HTLV-II is more prevalent in intravenous drug addicts, and in American indián populations, endemically. HTLV-I is mainly responsible for adult T-cell leukemia (ATL) and HTLV-I-associated myelopathy/tropical spastic paraparesis (HAM/TSP), however, HTLVII is not clearly associated with a known clinical disease. Both viruses may be transmitted by sexual contact, parenteral route, whole blood transfusion and breast-feeding. In most of the countries [USA, Canada, South America, Caribbean, Japan, Taiwan and some Europe countries (France, UK, Ireland, Sweden, Denmark, The Netherlands, Portugal, Romania, Greece)] routine screening of anti-HTLV-I/II in blood donors is mandatory, however, there is no such practice in Turkey since seroepidemiologic data on HTLVI/II infections is insufficient. In this study, the seroprevalence of HTLV-I/II in healthy blood donors admitted to the blood bank of Ege University Medical Faculty Hospital, Izmir (located at Aegean region), was investigated to support data on the decision making process on routine screening of anti-HTLV-I/II in blood centers. Serum samples from 10.000 healthy blood donors (mean age: 32.6 years; 87.8% were male), who succeeded the donor history questionnaire, were included to the study, and HTLV-I/II antibodies were screened by a commercial enzyme immunoassay (ELISA) (Murex HTLVI-II, Murex Diagnostics, UK) method. Serum samples which were yielded reactive and borderline results were retested by ELISA, and repeated reactive/borderline results were then confirmed by HTLV-I/II confirmation test (INNO-LIA HTLV-I/II, lnnogenetics, Belgium). Seven samples yielded reactive/borderline reactive results by both ELISA lots, however, all of them were found negative by confirmatory test. According to our data HTLV-I/II infections are not endemic in Izmir region, and anti-HTLV-I/II screening of blood donors is not required in our blood center currently. Nevertheless, screening HIV which is very rare in prevalence among the donor population, is mandatory for blood donors in our country. Thus, even its prevalence is very low, much more comprehensive and multi-centered studies are necessary for making the decision of integrating HTLV-I/II in routine blood bank screening tests in Turkey.Öğe Ohmic blanching(CRC Press, 2014) İçier F.; Bozkurt H.Blanching is an essential prior step in vegetable processing, which destroys the enzymes and microorganisms and helps in prevention of quality deterioration particularly during drying, freezing, frying, or storage. Besides, it also expels the air entrapped intercellularly inside the tissues. Blanching has also proved to aid reconstitution and textural improvement in the product. Hot water blanching is by far the most popular and commercially adopted process, as it is a simple technique whereby the mechanism of heat penetration is by conduction. In such systems the resistance to heat transfer at the surface is negligible compared to the internal resistance to heat transfer. It was shown that in such systems the rate of heat penetration is proportional to the square of the characteristic dimension of the object. The time required for blanching depends upon the time required for inactivation of enzymes and thus on the rate of heat transfer. The longer time required for the temperature rise at the slowest heating point, normally the geometric center of a relatively large object, could damage the quality of the kernels and result in considerable loss of nutrients such as carbohydrates, proteins, water-soluble minerals, vitamins, and sugars. On the contrary, shortening the blanching time could reduce the degree of enzyme inactivation and result in a shorter shelf life. Because of this, the practical blanching time of such product is quite often a compromise. © 2014 by Taylor & Francis Group, LLC.Öğe Ohmic cooking of ground beef: Effects on quality(2010) Bozkurt H.; Icier F.Conventional cooking tends to be slow and the surface of the food always receives a much more severe heating treatment than the rest of the food. Ohmic heating has the potential to be much faster and produces even more cooking. In this work cylindrical ground beef samples having different initial fat contents (2%, 9% and 15%) were cooked ohmically (20, 30 and 40 V/cm) and conventionally. Ohmic cooking was faster than the conventional cooking (p < 0.05). Ohmically cooked samples were firmer than those conventionally cooked but yield and fat retention was similar. However, the reduction in volume during cooking was significantly smaller from 5.36% to 6.97% in ohmic cooking than the conventional system which was measured from 26.01 to 31.59. The voltage gradient applied during ohmic cooking was not related to the quality of the cooked meat. These results show that ohmic cooking could be a fast-alternative method for meat products. © 2009 Elsevier Ltd. All rights reserved.Öğe Ohmic thawing of frozen beef cuts(2012) Bozkurt H.; Içier F.In this study, the application of ohmic heating to thaw the frozen beef cut samples was investigated. The center temperature of different sample sizes of beef cuts (2.5 cm × 2.5 cm × 5 cm; 2.5 cm × 5 cm × 5 cm; 3: 5 cm × 5 cm × 5 cm) was aimed to reach +10C from -18C. The ohmic thawing was performed by the application of different voltage gradients (10, 20 and 30 V/cm), whereas the conventional thawing was performed at controlled conditions (25C, 95% RH). The effects of sample size, thawing method and voltage gradient on thawing time, drip loss, color, temperature homogeneity and EUR were investigated. Significant differences were found between thawing methods in terms of the temperature homogeneity, the thawing time and the thawing loss (P < 0.05). The results indicated that as the voltage gradient increased, the thawing time decreased, while the thawing loss remained unchanged. There was a decrease in the EUR (47-70%) with the increase in the sample size and the voltage gradient applied during ohmic thawing. The results of this study will provide valuable data for the design of the industrial ohmic thawing systems and give useful insights to further studies on this subject. © 2009 Wiley Periodicals, Inc.Öğe The prevalence of microalbuminuria and relevant cardiovascular risk factors in Turkish hypertensive patients(2011) Kozan Ö.; Özcan E.E.; Sancaktar O.; Kabakci G.; Sözcüer A.H.; Kerpeten A.; Delice A.; Içli A.; Sökmen A.; Gürlek A.; Abaci A.; Bayram A.; Köşüş A.; Çamsari A.; Sakalli A.; Sert A.; Temizhan A.; Yilmaz A.; Daver A.; Aydinlar A.; Ergin A.; Kiliçoglu A.E.; Birdane A.; Aribaş A.; Lazoglu A.; Özdemir A.; Fiskeci A.; Çelik A.; Bitigen A.; Keskin A.; Yavuz A.; Akyüz A.; Karanfil A.; Ünsal A.; Sinci A.; Gülmez A.U.; Irmak A.; Vural A.; Güven A.; Ilerigelen B.; Erol B.; Polat B.; Tosun B.; Agçal C.; Genç C.; Kirdar C.; Rezzagil C.; Köz C.; Nazli C.; Ceyhan C.; Örem C.; Uyan C.; Türkoglu C.; Gaffari D.; Aytekin D.; Ural D.; Yeşilbursa D.; Aras D.; Semiz E.; Koçak E.; Atalar E.; Varol E.; Onrat E.; Şensoy E.; Acartürk E.; Akarca E.; Aygün E.; Ertaş F.S.; Koca F.; Özmen F.; Ulusoy F.V.; Özerkan F.; Inceer F.K.; Dönmez G.; Topkara G.; Daş G.; Bozkurt H.; Kültürsay H.; Tikiz H.; Akgöz H.; Kaymak H.; Öney H.; Yegin H.; Boga H.; Gök H.; Vural H.; Atasever H.; Arinç H.; Bozdemir H.; Gündüz H.; Tunar H.; Atmaca H.; Dogru I.; Özdogru I.; Susal I.; Kurt I.T.; Dinçer I.; Biyik I.; Tandogan I.; Jordan J.; Kulan K.; Şahna K.; Öztaş K.; Dönmez K.; Övünç K.; Kaya K.; Aytemir K.; Özdemir K.; Tigen K.; Saraç L.; Sirkeci M.T.; Çakmak M.; Şahin M.; Kutlu M.; Bilge M.; Bostan M.; Melek M.; Sunay M.Ö.; Şeker M.; Güçel M.Ş.; Yazici M.; Kayikçioglu M.; Öç M.; Gürsürer M.; Dagalp M.; Bilaloglu M.; Yalçin M.; Şerifi M.; Gökçe M.; Kiliçkap M.; Polat M.; Şan M.; Tahtasiz M.; Yilmaz M.; Etemoglu M.; Coşkun N.; Aran N.S.; Ata N.; Sönmez N.; Çam N.; Koylan N.; Özer N.; Keser N.; Döven O.; Tartanoglu O.; Ergene O.; Elönü O.H.; Onbaşili O.A.; Özbek Ö.; Pinar P.; Akdemir R.; Kargin R.; Topsakal R.; Yoldaş R.; Uçar R.; Ateşal S.; Toktaş S.; Cinsoy S.; Güleç S.; Aytekin S.; Çolak S.; Mecit S.; Sakalli S.; Sevimli S.; Topaloglu S.; Aydogdu S.; Turan S.C.; Kahraman S.; Yorganci S.; Coşkun Ş.; Ünal Ş.; Durmaz T.; Ulusoy T.; Keleş T.; Kirat T.; Gündogdu T.T.; Peker T.; Sümerkan U.; Aytekin V.; Koca V.; Çam V.; Gökçe V.; Gürlertop Y.; Balbay Y.; Çavuşoglu Y.; Erzurum Y.; Selçoki Y.; Yakar Y.; Işilak Z.; Tosun Z.; Kaplan Z.; Tartan Z.Objectives: A growing body of data illustrates the importance of microalbuminuria (MAU) as a strong predictor of cardiovascular risk in the hypertensive population. The present study was designed to define the prevalence of MAU and associated cardiovascular risk factors among Turkish hypertensive outpatients. Study design: Representing the Turkish arm of the multinational i-SEARCH study involving 1,750 sites in 26 countries around the world, a total of 1,926 hypertensive patients from different centers were included in this observational and cross-sectional survey study. Patients with reasons for a false-positive MAU test were excluded. The prevalence of MAU was assessed using a dipstick test, and patients were inquired about comorbidities, comedication, and known cardiovascular risk factors. Results: The overall prevalence of MAU was 64.7% and there was no difference between genders. Most of the patients (82.5%) had uncontrolled hypertension, 35.6% had dyslipidemia, and 35.5% had diabetes, predominantly type 2. Almost one-third of the patients (26.4%) had at least one cardiovascular-related comorbidity, with 20.3% having documented coronary artery disease (CAD). Almost all patients (96.8%) had one or more risk factors for cardiovascular disease in addition to hypertension, including family history of myocardial infarction or CAD, diabetes, dyslipidemia, lack of physical exercise, and smoking. A trend towards higher MAU values in the presence of CAD was determined. Conclusion: Microalbuminuria tests should be routinely used as a screening and monitoring tool for the assessment of subsequent cardiovascular morbidity and mortality among hypertensive patients. © 2011 Turkish Society of Cardiology.Öğe Rheological characteristics of quince nectar during ohmic heating(2009) Bozkurt H.; Icier F.Electrical heating of food products provides rapid and uniform heating, resulting in less thermal damage to the product. In this study, ohmic heating as an electrical heating method was applied to the quince nectar by matching the same heating curve of conventional method by changing voltage gradient (10-40 V/cm) at 50 Hz. The change of rheological constants of quince nectar was determined for different holding times (0, 10, 15, 20, and 30 minutes) in the temperature range of 65-75°C by using concentric type viscosimeter. Shear stress-shear rate data were fitted to the Newtonian, Bingham, Herschel Bulkley, Power law and Casson Models. It was found that Herschel-Bulkley model was the best model to fit the experimental rheogram adequately since higher regression coefficients (R2; 0.9997) and low standard errors (SE; 0.054) were obtained by Herschel-Bulkley equation compared to other model equations. It was concluded that quince nectar showed time independent non-Newtonian pseudoplastic character during heating in the range of 20-75°C, independent on heating method. The activation energy values were 9.88±3.24 kJ/mol and 10.08±2.53 kJ/mol for ohmic heating and conventional heating respectively. Results showed that there was no electrical effect rather than thermal effects of ohmic heating since similar rheological constants were obtained with both methods statistically (p < 0.05). Ohmic heating could be recommended as an alternative fas heating method for fruit nectars.
